DragonFly On-Line Manual Pages

Search: Section:  


MJPEG tools(MJPEG Linux Square)                MJPEG tools(MJPEG Linux Square)

       MJPEG HOWTO - An introduction to the MJPEG-toolsPraschinger
       Bernhardv2.00MJPEG capture/editting/replay and MPEG encoding toolset
       description

       Introduction

       I wrote this things down, because I had many sheets with notes on them.
       This should be some kind of summary of collected knowledge over a long
       period of time.  Andrew Stevens helped with encoding and VCD knowledge
       and hints.

       Mjpegtools is a set of programs that can do recording, playback,
       editing and eventual MPEG compression of audio and video under Linux.

       Although primarily intended for use with capture / playback boards
       based on the Zoran ZR36067 MJPEG codec chip mjpegtools can easily be
       used to process and compress MJPEG video streams captured using xawtv
       using simple frame-buffer devices.

       The HOWTO for the tools intended to give an an introduction to the
       MJPEG-tools and the creation of MPEG 1/2 videos. VCD, SVCD and DVD and
       the transcoding of existing mpeg streams.

       For more information about the programs read the corresponding man-
       page.

       Achtung es gibt auch eine deutsche Version bei:

       There is also a manpage of this text. You can read it with "man
       mjpegtools" if installed.  We also have a info version you should be
       able to read it with info

       The text version of this text is available via cvs. You should get it
       with the tarball or the precompiled package (RPM and deb).

       In the following picture you see the typical workflow when you record a
       video, cut it afterwards and encode it. In the picture you also see the
       connections to other programs. These parts are in grey. The parts in
       blue can be done with the mjpegtools.

       Video encoding workflow

       Unsorted list of useful Hints

       You have to compile and install the mjpeg_play package, for this read
       the README & INSTALL.real an follow the hints from the configure
       script.  If you do not want to compile it, you can download the mjpeg
       .RPM or .DEB package at Sourceforge, or if available use the one that
       comes with your distribution.

       There is a script in the scripts/ directory. This script is something
       that shows you a way it can be done. It also creates (under certain
       circumstances) videos that look quite good. Better videos you will only
       get by tuning the parameters.

       If you use a Linux kernel from the 2.4 series you will usually have to
       load the drivers for the Buz or DC10 or LML33 cards. You have to run
       the update script providing as option the name of your card you have.
       The script is usually in /usr/src/driver-zoran/.  The zoran kernel
       driver below the kernel 2.4.4 do not work.  You have to use the driver
       available from:

       In the 2.6. Linux kernel is the driver for the zoran cards included,
       you just need to make sure that it is loaded correct. If you have a x64
       machine and an kernel that is newer than 2.6.30 we'd be happy to hear
       that you are able to record from the zoran based card. I'm not soure if
       that combination works.

       The driver for the Matrox Marvel card also works, more information
       about it:

       If you compile the tools on a P6 based computer (PPro, P-II, P-III,
       P-4, Athlon,Duron) then never try to let them run on a P5 based
       computer (Pentium, Pentium-MMX, K6, K6-x, Cyrix, Via, Winchip). You'll
       get a "illegal instruction" and the program won't work. That is the
       same for the newer CPU as well. If you use specific optimizations be
       aware of them.

       If lav2yuv dumps core then one possible cause is no dv support was
       included. To enable it make sure that libdv is installed on the system.
       This will be necessary if you are using a digital camera (or analog to
       DV converter such as the Canopus ADVC100 and converting the dv avi
       format into the MPEG format.

       Start xawtv to see if you get an picture. If you want to use HW-
       playback of the recorded streams you have to start xawtv (any TV
       application works) once to get the streams played back. You should also
       check the settings of your mixer in the sound card. If you use v4l2 you
       should give mplayer a try to watch the picture

       If you compile the tools on a platform other than Linux not all tools
       will work.   Mjpegtools on a OS/X system for example will not have V4L
       (video4linux) capability.

       Never try to stop or start the TV application when lavrec runs. If you
       start or stop the TV application lavrec will stop recording, or your
       computer could get "frozen". This is a problem of v4l (video4linux).

       This problem is solved with v4l2. If you use v4l2 you can record the
       video and stop and start the tv application whenever you want.  But
       v4l2 is currently (7. Jan. 2003) only supported for the zoran based
       cards (BUZ, DC10, DC10+, LML33) if you use the CVS driver from
       mjpeg.sf.net tagged with ZORAN_VIDEODEV_2.  And this driver only works
       with the 2.4.20 kernel and the 2.5.* development kernel.

       One last thing about the data you get before we start:

       Audio: ( Samplerate * Channels * Bitsize ) / (8 * 1024)
       CD Quality:(44100 Samples/sec * 2 Chanels * 16 Bit) / (8 * 1024)=172,2 kB/sec

       The 8 * 1024 convert the value from bit/sec to kByte/sec

       Video: (width * height * framerate * quality ) / (200 * 1024)
       PAL HALF Size : (352 * 288 * 25 * 80) / (200 * 1024) = 990 kB/sec
       PAL FULL size : (720 * 576 * 25 * 80) / (200 * 1024) = 4050 kB/sec
       NTSC HALF size: (352 * 240 * 30 * 80) / (200 * 1024) = 990 kB/sec
       NTSC FULL size: (720 * 480 * 30 * 80) / (200 * 1024) = 4050 kB/sec

       The 1024 converts the Bytes to kBytes. Not every card can record the
       size mentioned. The Buz and Marvel G400 for example can only record a
       size of 720x576 when using -d 1, the DC10 records a size of 384x288
       when using -d 2.

       When you add audio and video datarate this is what your hard disk has
       to be able to write constantly streaming, else you will have lost
       frames.

       If you want to play with the --mjpeg-buffer-size. Remember the value
       should be at least big enough that one frame fits in it. The size of
       one frame is: (width * height * quality ) / (200 * 1024) = kB If the
       buffer is too small the rate calculation doesn't match any more and
       buffer overflows can happen. The maximum value is 512kB.

       How video works and the difference between the video types is explained
       here:

       There you also find how to create MPEG Still Images for VCD/SVCD.

       A good description of DV (Digital Video) can be found here:

Some books we found usefull
       written in English:

       Digital Video and HDTV by Charles Poyton (ISBN 1-55860-792-7)

       Digital Video Compression by Peter Symes (ISBN 0-07-142487-3)

       Video Demystified by Keith Jack (ISBN 1-878707-56-6)

       written in German:

       Fernsehtechnik von Rudolf Maeusl (ISBN 3-7785-2374-0)

       Professionelle Videotechnik - analoge und digitale Grundlagen von U.
       Schmidt (ISBN 3-540-43974-9)

       Digitale Film- und Videotechnik von U. Schmidt (ISBN 3-446-21827-0)

       If you know some other really good book about that, write us!

       Recording videos

lavrec examples
       Recording with lavrec looks like this:

       > lavrec -f a -i P -d 2 record.avi

       Should start recording now,

       -f a

       use AVI as output format,

       -i P

       use as input source the SVHS-In with PAL format,

       -d 2

       the size of the pictures are half size (352x288)

       record.avi

       name of the created file.

       Recording is finished by pressing Ctrl-C (on German Keyboards: Strg-C).
       Sometimes using -f A instead of -f a might be necessary

       Other example:

       > lavrec -f q -i n -d 1 -q 80 -s -l 80 -R l -U record.avi

       Should start recording now,

       -f q

       use Quicktime as output format,

       -i n

       use Composite-In with NTSC format,

       -d 1

       record pictures with full size (640x480)

       -q 80

       set the quality to 80% of the captured image

       -s

       use stereo mode (default mono)

       -l 80

       set the recording level to 80% of the max during recording

       -R l

       set the recording source to Line-In

       -U

       With this lavrec uses the read instead of mmap for recording this is
       needed if your sound card does not support the mmap for recording.

       Setting the mixer does not work with every sound card.  If you record
       with 2 different settings and both recordings are equally loud you
       should setup the mixer with a mixer program.  After that you should use
       the -l -1 option when you record using lavrec

       The size of the image depends on the card you use.  At full size (-d 1)
       you get these image sizes: BUZ and LML33: 720x576, the DC10 and DC30:
       768x576

       Other example:

       > lavrec -w -f a -i S -d 2 -l -1 record%02d.avi

       Should start recording,

       -w

       Waits for user confirmation to start (press enter)

       -f a

       use AVI as output format,

       -i S

       use SECAM SVHS-Input (SECAM Composite recording is also possible: -i s)

       -d 2

       the size of the pictures are half size

       -l -1

       do not touch the mixer settings

       record%02d.avi

       Here lavrec creates the first file named record00.avi after the file
       has reached a size of 1.6GB (after about 20 Minutes recording) it
       starts a new sequence named record01.avi and so on till the recording
       is stopped or the disk is full.  With the release of the 1.9.0 Version
       mjpegtools is able to handle AVI files larger than 2GB. So that option
       is present for compatibility.

       Other example:

       > lavrec -f a -i t -q 80 -d 2 -C europe-west:SE20 test.avi

       Should start recording now,

       -f a

       use AVI as output format,

       -i t

       use tuner input,

       -q 80

       set the quality to 80% of the captured image

       -d 2

       the size of the pictures are half size (352x288)

       -C

       choose TV channels, and the corresponding -it and -iT (video source: TV
       tuner) can currently be used on the Marvel G200/G400 and the Matrox
       Millenium G200/G400 with Rainbow Runner extension (BTTV-Support is
       under construction). For more information on how to make the TV tuner
       parts of these cards work, see the Marvel/Linux project on:

       Last example:

       > lavrec -f a -i p -g 352x288 -q 80 -s -l 70 -R l --software-encoding
       test03.avi

       The two new options are -g 352x288, which sets the size of the video to
       be recorded when using --software-encoding, this enables the software
       encoding of the recorded images. With this option you can also record
       from a bttv based card. The processor load is high. This option only
       works for generic video4linux cards (such as the brooktree-848/878
       based cards), it doesn't work for zoran-based cards.

Other recording hints
       All lavtools accept a file description like file*.avi so you do not
       have to name each file but that is a posibility.

       Note: More options are described in the man-page, but with this you
       should be able to get started.

       Here are some hints for sensible settings. Turn the quality to 80% or
       more for -d 2 capture. At full resolution as low as 40% seems to be
       visually "perfect". -d 2 is already better than VHS video (a *lot*!).
       For a Marvel you should not set the quality higher than 50 when you
       record at full size (-d 1). If you use higher settings (-q 60) it is
       more likely that you will encounter problems. Higher settings will
       result in framedrops.  If you're aiming to create VCD's then there is
       little to be gained recording at full resolution as you need to reduce
       to -d 2 resolution later anyway.

       you can record at other sizes than the obvious -d 1/2/4. You can use
       combinations where you use halve horizontal size and full vertical
       size: -d 21.  This would record for NTSC at a size of 352x480. This
       helps if you want to create SVCDs, scaling the 352 Pixles put to 480 is
       not that visible for the eye as if you would use the other combination
       -d 12.  Where you have the full horzontal resolution and half vertical
       this Version will have a size of 720x288 for NTSC

Some information about the typical lavrec output while recording
       0.06.14:22 int: 00040 lst:0 ins:0 del:0 ae:0 td1=0.014 td2=0.029

       The first part shows the time lavrec is recording.  int: the interval
       between two frames. lst: the number of lost frames. ins and del: are
       the number of frames inserted and deleted for sync correction. ae:
       number of audio errors.  td1 and td2 are the audio/video time-
       difference.

       (int) frame interval should be around 33 (NTSC) or 40 (PAL/SECAM). If
       it is very different, you'll likely get a bad recording and/or many
       lost frames

       (lst) lost frames are bad and mean that something is not working very
       well during recording (too slow HD, too high CPU usage, ...) Try
       recording with a greater decimation and possibly a lower quality.

       (ins, del) inserted OR deleted frames of them are normal -> sync. If
       you have many lost AND inserted frames, you're asking too much of your
       machine.  Use less demanding options or try a different sound card.

       (ae) audio errors are never good. Should be 0

       (td1, td2) time differenceis always floating around 0, unless sync
       correction is disabled (--synchronization!=2, 2 is default).

Notes about "interlace field order - what can go wrong and how to fix it"
       Firstly, what does it mean for interlace field order to be wrong?

       The mjpegtools image processing chain is frame-oriented. Since it is
       video material that is captured each frame comprised of a top field
       (the 0th, 2nd, 4th and so lines) and a bottom field (the 1st, 3rd, 5th
       and so on lines).

       There are three bad things that can happen with fields

       This is really only an issue for movies in PAL video where each film
       frame is sent as a pair of fields. These can be sent top or bottom
       field first and sadly it's not always the same, though bottom-first
       appears to be usual. If you capture with the wrong field order (you
       start capturing each frame with a bottom rather than a top or vice
       versa) the frames of the movie get split *between* frames in the
       stream. Played back on a TV where each field is displayed on its own
       this is harmless. The sequence of fields played back is exactly the
       same as the sequence of fields broadcast. Unfortunately, playing back
       on a Computer monitor where both fields of a frame appear at once it
       looks *terrible* because each frame is effectively mixing two moments
       1/25sec apart in time.

       The two fields can simply be swapped somehow so that top gets treat as
       bottom and bottom treat as top. Juddering and "slicing" is the result.
       This occasionally seems to happen due to hardware glitches in the
       capture card.

       Somewhere in capturing/processing the *order* in time of the two fields
       in each frame can get mislabeled somehow. This is not good as it means
       that when playback eventually takes place a field containing an image
       sampled earlier in time comes after an image sampled later.  Weird
       "juddering" effects are the results.

       How can I recognize if I have one of these Problems ?

       This can be hard to spot. If you have mysteriously flickery pictures
       during playback try encoding a snippet with the reverse field-order
       forced (see below). If things improve you know what the problem was and
       what the solution is!

       The two fields can simply be swapped somehow so that top gets treat as
       bottom and bottom treat as top. Juddering and "slicing" is the result.
       This occasionally seems to happen due to hardware glitches in the
       capture card. That problem looks like that:

       Interlacing problem

       Somewhere in capturing/processing the *order* in time of the two fields
       in each frame can get mislabeled somehow. This is not good as it means
       that when playback eventually takes place a field containing an image
       sampled earlier in time comes after an image sampled later. Weird
       "juddering" effects are the result.

       If you use glav or lavplay be sure that you also use the -F/--flicker
       option. This disables some things that improve the picture.

       If you want to look at the video you can also use yuvplay:

       > lav2yuv | ... | yuvplay

       If there is a field order problem you should see it with yuvplay.

       How can you fix it?

       To fix this one the fields need to be "shifted" through the frames. Use
       yuvcorrect's -T BOTT_FORWARD/TOP_FORWARD to shift the way fields are
       allocated to frames. You can find out the current field order for an
       MJPEG file by looking at the first few lines of debug output from: >
       lav2yuv -v 2 the_mjpeg_file > /dev/null Or re-record exchanging -f a
       for -F A or vice-versa.

       This isn't too bad either. Use a tool that simply swaps the top and
       bottom fields a second time. yuvcorrect can do this use the -T
       LINE_SWITCH.

       Is easy to fix. Either tell a tool someplace to relabel the fields or
       simply tell the player to play back in swapped order (the latter can be
       done "indirectly" by telling mpeg2enc when encoding to reverse the flag
       (-z b|t) that tells the decoder which field order to use.

       In order to determine exactly what type of interlacing problem you
       have, you need to extract some frames from the recorded stream and take
       a look at them:

       > mkdir pnm
       > lav2yuv -f 40 video.avi | y4mtoppm | pnmsplit - pnm/image%d.pnm
       > rm pnm/image?.pnm
       > cd pnm
       > xv

       First we create a directory where we store the images. The lav2yuv -f
       40 writes only the first 40 frames to stdout. The program y4mtoppm
       converts the frames to pnm images and the pnmsplit splits the picture
       into two frames in the picture to two single pictures. Then we remove
       the first 10 images because pnmsplit does not support the %0xd
       numbering. Without a leading zero in the number, the files will be
       sorted in the wrong order, leading to confusing playback.

       Use your favorite graphic program (xv for example) to view the
       pictures. As each picture only contain one field out of two they will
       appear scaled vertically. If you look at the pictures you should see
       the movie slowly advancing.

       If you have a film you should always see 2 pictures that are nearly the
       same (because the film frame is split into two field for broadcasting)
       after each other.  You can observe this easily if you have comb effects
       when you pause the film because both fields will be displayed at the
       same time. The two pictures that belong together should have an even
       number and the following odd number. So if you take a look on pictures:
       4 and 5 are nearly identical, 5 and 6 differ (have movement), 6 and 7
       identical, 7 and 8 differ , ....

       To fix this problem you have to use yuvcorrect's -T BOTT_FORWARD or
       TOP_FORWARD. You can also have the problem that the field order
       (top/bottom) is still wrong. You may have to use yuvcorrect a second
       time with -M LINE_SWITCH, or use the mpeg2enc -z (b|t) option.

       To see if you guessed correctly extract the frames again and reorder
       them using yuvcorrect:

       > lav2yuv -f 40 video.avi | yuvcorrect -T OPTION | y4mtoppm | pnmsplit
       - pnm/image%d.pnm

       Where "OPTION" is what you think will correct the problem.  This is for
       material converted from film. Material produced directly for TV is
       addressed below.

       Hey, what about NTSC movies ?

       Movies are broadcast in NTSC using "3:2" pulldown which means that half
       the capture frames contain fields from 1 movie frame and half fields
       from 2 frames. To undo this effect for efficient MPEG encoding you need
       to use yuvkineco.

       If you have an interlaced source like a TV camera you have a frame
       consists of two fields that are recorded at different points in time.
       Spotting the problem here is harder. You need to find something moving
       horizontally from the left to the right. When you extract the fields,
       the thing should move in small steps from the left to the right, not
       one large step forward, small step back, large forward, small
       back......  You have to use the same options mentioned aboth to correct
       the problem.

       Do not expect that the field order is always the same (top- or bottom-
       first) It may change between the channels, between the films, and it
       may even change within a film. If it changes constant you may have to
       encode with the mpeg2enc -I 1 or even -I 2.

       You can only have this problems if you record at full size !!!

       Creating videos from other sources

       Here are some hints and descriptions of how to create the videos from
       other sources like images and other video types.

       You might also be interested in taking a look at the Transcoding of
       existing MPEG-2 section.

Creating videos from images
       You can use jpeg2yuv to create a yuv stream from separate JPEG images.
       This stream is sent to stdout, so that it can either be saved into a
       file, encoded directly to a mpeg video using mpeg2enc or used for
       anything else.

       Saving an yuv stream can be done like this:

       > jpeg2yuv -f 25 -I p -j image%05d.jpg > result.yuv

       Creates the file result.yuv containing the yuv video data with 25 FPS.
       The -f option is used to set the frame rate. Note that image%05d.jpg
       means that the jpeg files are named image00000.jpg, image00001.jpg and
       so on. (05 means five digits, 04 means four digits, etc.) The -I p is
       needed for specifing the interlacing. You have to check which type you
       have.  If you don't have interlacing just choose p for progressive

       If you want to encode a mpeg video directly from jpeg images without
       saving a separate video file type:

       > jpeg2yuv -f 25 -I p -j image%05d.jpg | mpeg2enc -o mpegfile.m1v

       Does the same as above but saves a mpeg video rather than a yuv video.
       See mpeg2enc section for details on how to use mpeg2enc.

       You can also use yuvscaler between jpeg2yuv and mpeg2enc. If you want
       to create a SVCD from your source images:

       > jpeg2yuv -f 25 -I p -j image%05d.jpg | yuvscaler -O SVCD |  mpeg2enc
       -f 4 -o video.m2v

       You can use the -b option to set the number of the image to start with.
       The number of images to be processed can be specified with the -n
       number. For example, if your first image is image01.jpg rather than
       image00.jpg and you only want 60 images to be processed type:

       >jpeg2yuv -b 1 -f 25 -I p -n 60 -j image*.jpg | yuv2lav -o
       stream_without_sound.avi

       Adding the sound to the stream then:

       > lavaddwav stream_without_sound.avi sound.wav stream_with_sound.avi

       For ppm input there is the ppmtoy4m util. There is a manpage for
       ppmtoy4m that should be consulted for additional information.

       To create a mpeg video try this:

       >cat *.ppm | ppmtoy4m -o 75 -n 60 -F 25:1 | mpeg2enc -o output.m1v

       cat each *.ppm file to ppmtoy4m. There the first 75 frames (pictures)
       are ignored and next 60 are encoded by mpeg2enc to output.m1v. You can
       run it without the -o and -n option. The -F  options sets the frame
       rate, default is NTSC (30000:1001), for PAL you have to use -F 25:1.

       Other picture formats can also be used if there is a converter to ppm.

       >ls *.tga | xargs -n1 tgatoppm | ppmtoy4m | yuvplay

       A list of filenames (ls *.tga) is given to xargs that executes the
       tgatoppm with one (-n 1) argument per call, and feeds the output into
       ppmtoy4m.  This time the video is only shown on the screen. The xargs
       is only needed if the converter (tgatoppm) can only operate on a single
       image at a time.

       If you want to use the ImageMagick 'convert' tool (a Swiss Army Knife)
       try:

       >convert *.gif ppm:- | ppmtoy4m | yuvplay

       That means take all '.jpg' images in directory, convert to PPM format,
       pipe to stdout, then to ppmtoy4m for conversion to y4m ....

Decoding streams with mplayer
       Decoding the streams with mplayer is a nice way of bringing every video
       that mplayer can play back to something you can edit or encode to mpeg
       with mjpegtools. This method has been tested with mplayer 1.0rc2 and
       should work with newer versions

       >mkfifo stream.yuv

       >cat stream.yuv | yuv2lav -o mjpeg_wo.avi &

       >mplayer -nosound -noframedrop -vo yuv4mpeg anyfile.mpg

       >mplayer -vo null -ao pcm:file=anyfile.wav anyfile.mpg

       Now you have an example of a mjpeg encoded AVI without sound. The sound
       will be in anyfile.wav. You can choose if you want to add the sound to
       the AVI with lavaddwav and edit the file before encoding.

       You can also use instead of yuv2lav, mpeg2enc or any other tool from
       the mjpeg tools so your command might also look like that:

       > cat stream.yuv | yuvdenoise | yuvscaler -O SVCD | mpeg2enc -f 4 -o
       video_svcd.m2v

       cat the wav file into mp2enc to encode it to MP2 audio. The -vo
       yuv4mpeg option works well with other input types mentioned in the
       mplayer documentation.

Decoding MPEG-2 streams with mpeg2dec
       You can decode mpeg2 streams with the patched mpeg2dec version which
       creates yuv streams. You can pipe that into any other mjpegtools
       program.  Or you use a mpeg2dec version directly from the libmpeg2
       project and use the output mode pgmpipe. With the pgmtoy4m program you
       can convert that pgm output back to yuv.

       If you ask yourself why there is a patched version and pgmtoy4m.  The
       answer is that the patch for yuv output was sent several times to the
       libmpeg2 developers but was never included.  Now we have two ways
       around that problem. Decoding looks like this:

       > mpeg2dec -s -o pgmpipe ANYTS.VOB | pgmtoy4m -i t -a 10:11 -r
       30000:1001 | mpeg2enc -f 8 newvideo.m2v

       You can decode the audio as described in the Transcoding of existing
       MPEG-2 Section.

Other things to know
       If you have Transport streams from your DVB card, or Satelite Receiver
       you might want to demultiplex or cut them. A nice tool for that is
       Project X available from:

       You can process the streams afterwards as you would do with any mpeg
       movie or demultiplexed audio video. So the Transcoding of existing
       MPEG-2 section of this document will be of interest.Checking if
       recording was successful

       You can use lavplay or glav. IMPORTANT: NEVER try to run xawtv and
       lavplay or glav with hardware playback, it will not work. For software
       playback it works fine.

       >lavplay -p S record.avi

       You should see the recorded video and hear the sound. But the decoding
       of the video is done by the CPU which will place a heavy load on the
       system.  The advantage of this method is you don't need xawtv.

       The better way:

       >lavplay -p H record.avi

       The video is decoded and played by the hardware. The system load is
       very low.  This will play it back on-screen using the hardware rather
       than software decoding.

       You might also try:

       > lavply -p C record.avi

       Which will play it back using the hardware but to the video output of
       the card.

       > glav record.avi

       Does the same as lavplay but you have an nice GUI. The options for glav
       and lavplay are nearly the same. Using no option SW playback is used.

       Using hardware playback a signal for the Composite and SVHS OUT is
       generated so you can view the movie on your TV.

       > lav2yuv test.eli | yuvplay

       Is a other way to get the video without sound. You can use yuvplay once
       in the encoding command. When you use yuvplay in the encoding command
       you see the changes made by filters and scaling. You can also use it
       for slow-motion debugging.

       NOTE: After loading the driver's you have to start xawtv to set up some
       things lavplay and glav do not, but they are needed for HW-Playback.
       Don't forget to close xawtv !!

       NOTE2: Do not try to send glav an lavplay into background, wont work
       correct !!!

       NOTE3: SECAM playback is now (12.3.2001) only in monochrome but the
       recording and encoding is done right.

       NOTE4:Bad cables may reduce the quality of the image. Normally you
       can't see this but when there is text you might notice a small shadow.
       When you see this you should change the cable.

       Coming soon: There is a tool which makes recoding videos very simple:
       Linux Studio. You can download it at:

       Edit the video

Edit with glav
       Most tasks can be easily done by glav. Like deleting parts of the
       video, cut paste and copy parts of the videos.

       glav button description

       The modifications should be saved because glav does not destructively
       edit the video. This means that the original video is left untouched
       and the modifications are kept in an extra "Edit List" file readable
       with a text editor. These files can be used as an input to the other
       lavtools programs such as lav2wav, lav2yuv, lavtrans.

       If you want to cut off the beginning and the end of the stream mark the
       beginning and the and, and use the "save select" button. The edit list
       file is than used as input for the lavtools. If you want to split a
       recorded video to some smaller parts simply select the parts and then
       save each part to a different listfile.

       You can see all changes to the video and sound NOW and you do not need
       to recalculate anything.

       If you want to get a "destructive" version of your edited video use:

       > lavtrans -o short_version.avi -f a editlist.eli

       -o

       specifies the output name

       -f a

       specifies the output format (AVI for example)

       editlist.eli

       is the list file where the modifications are described.  You generate
       the list file with the "save all" or "save select" buttons in glav.

Unify videos
       > lavtrans -o stream.qt -f q record_1.avi record_2.avi ... record_n.avi

       -o

       specifies the outputfile name

       -f q

       specifies the output format, quicktime in this case

       This is usually not needed. Keep in your mind that there is a 2GB file-
       size-limit on 32Bit systems with an older glibc. Usually not a problem
       these days

Separate sound
       > lavtrans -o sound.wav -f w stream.avi

       Creates a wav file with the sound of the stream.avi Maybe needed if you
       want to remove noise or if you want to convert it to another sound
       format.

       Another way to split the sound is:

       > lav2wav editlist.eli >sound.wav

Separate images
       >mkdir jpg; lavtrans -o jpg/image%05d.jpg -f i stream.avi

       First create the directory "jpg". Then lavtrans will create single JPG
       images in the jpg directory from the stream.avi file. The files will be
       named: image00000.jpg, image00001.jpg ....

       The jpg images created contain the whole picture. But if you have
       recorded at full size the images are stored interlaced. Usually the
       picture viewers show only the first field in the jpg file.

       If you want to have the image in a single file you can use that version

       > lav2yuv -f 1 stream.avi | y4mtoppm -L >file.pnm

       If you want to split the fields into single files use that:

       >  lav2yuv -f 5 ../stream.avi | y4mtoppm | pnmsplit - image%d.pnm

       Maybe interesting if you need sample images and do not want to play
       around with grabbing a single image.

Creating movie transitions
       Thanks to Philipp Zabel's lavpipe we can now make simple transitions
       between movies or combine multiple layers of movies.

       Philipp wrote this HOWTO on how to make transitions:

       Let's assume simple this scene: We have two input videos intro.avi and
       epilogue.mov and want to make intro.avi transition into epilogue.mov
       with a duration of one second (that is 25 frames for PAL or 30 frames
       for NTSC).

       Intro.avi and epiloque.mov have to be of the same format (the same
       frame rate and resolution). In this example they are both 352x288 PAL
       files. intro.avi contains 250 frames and epilogue.mov is 1000 frames
       long.

       Therefore our output file will contain:

       the first 225 frames of intro.avi

       a 25 frame transition containing the last 25 frames of intro.avi and
       the first 25 frames of epilogue.mov

       the last 975 frames of epilogue.mov

       We could get the last 25 frames of intro.avi by calling:

       >lav2yuv -o 225 -f 25 intro.avi

       -o 255, the offset, tells lav2yuv to begin with frame # 225 and  -f 25
       makes it output 25 frames from there on.

       Another possibility (because negative offsets are counted from the
       end)is:

       > lav2yuv -o -25 intro.avi

       And the first 25 frames of epilogue.mov:

       > lav2yuv -f 25 epilogue.mov

       -o defaults to an offset of zero

       But we need to combine the two streams with lavpipe. So the call would
       be:

       > lavpipe "lav2yuv -o 255 -f 25 intro.avi" "lav2yuv -f 25 epilogue.mov"

       The output of this is a raw yuv stream that can be fed into
       transist.flt.

       transist.flt needs to be informed about the duration of the transition
       and the opacity of the second stream at the beginning and at the end of
       the transition:

       -o num

       opacity of second input at the beginning [0-255]

       -O num

       opacity of second input at the end [0-255]

       -d num

       duration of transition in frames

       An opacity of 0 means that the second stream is fully transparent (only
       stream one visible), at 255 stream two is fully opaque.

       In our case the correct call (transition from stream 1 to stream 2)
       would be:

       > transist.flt -o 0 -O 255 -d 25

       The -s and -n parameters equate to the -o and -f parameters of lav2yuv
       and are only needed if anybody wants to render only a portion of the
       transition for whatever reason. Please note that this only affects the
       weighting calculations - none of the input is really skipped.  If you
       use the skip parameter (-s 30, for example) you also need to skip the
       first 30 frames in lav2yuv (-o 30) in order to get the expected result.
       If you didn't understand this send an email to the authors or simply
       ignore -s and -n. The whole procedure will eventually be automated.

       Now we want to compress the yuv stream with yuv2lav:

       > yuv2lav -f a -q 80 -o transition.avi

       Reads the yuv stream from stdin and outputs an avi file (-f a) with
       compressed jpeg frames of quality 80.

       Now we have the whole command for creating a transition:

       > ypipe "lav2yuv -o 255 -f 25 intro.avi" "lav2yuv -f 25 epilogue.mov" |
       transist.flt -o 0 -O 255 -d 25 | yuv2lav -f a -q 80 -o transition.avi

       The resulting video can be written as a LAV Edit List (a plain text
       file) containing the following lines:

       LAV Edit List
       PAL
       3
       intro.avi
       transition.avi
       epilogue.mov
       0 0 224
       1 0 24
       2 25 999

       This file can be fed into glav or lavplay, or you can pipe it into
       mpeg2enc with lav2yuv or combine the whole stuff into one single mjpeg
       file with lavtrans or lav2yuv|yuv2lav.

       Converting the stream to MPEG or DIVx videos

       First there is some general description in the encoding process and
       afterwards there is a detailed description of some commonly used output
       formats.

       If you want a one command conversation to mpeg videos try lav2mpeg in
       the scripts directory

       The encoding with the lav2mpeg script looks like this for mpeg1 output:

       >lav2mpeg -a 160 -b 2110 -d 320x240 -m mpeg1 -o output.mpg file.eli

       Will create a mpeg1 with videobitrate of 2110kBit/sec and audiobitrate
       of 160 kBit/sec

       at a resolution of 320x240

       Or for the generation of mpeg2 output:

       lav2mpeg -o mpeg2 -O output.mpg file.eli

       Will create a mpeg2 with default bitrate in same resolution as the
       input resolution

       Better results can be accomplished, however, by trying various options
       and find out which ones work best for you. These are discussed below.

       The creation of MPEG-1 movies is explained with more examples and in
       greater detail because most of the things that can be used for MPEG-1
       also work for the other output formats

       For the creation of of VCD/SVCD Stills sequences (-f 6 / -f 7 in
       mpeg2enc) you should see:

       Still sequences are needed for the creation of menus in VCD/SVCD. The
       creation of menus is described in the doku of vcdimager.

Creating sound
       MPEG-1 videos need MPEG-1-Layer2 (MP2) sound files. For MPEG-2 videos
       you can use MPEG-1-Layer2 and MPEG1-Layer3 (MP3). MP3 audio is not an
       offically valid audio format but many VCD players will recognize it.
       MP3 audio is not valid for DVDs.  You should stick to MP2 because many
       of the MPEG-2 players (DVD Player for example, usually the Windows
       Versions have great problems with this too) are not able to play
       MPEG2-Video and MP3 sound.

       mp2enc is a MP2 Audio encoder. The toolame encoder is also able to
       produce an MP2 file. Toolame is much faster than mp2enc but toolame
       does not peform resampling (48000 to 44100 samples/second).  Many
       hardware players will play SVCDs using 48000 rate audio.  For MP3
       creation I'm be sure you have an encoder.

       Example:

       > lav2wav stream.avi | mp2enc -o sound.mp2

       This creates a mpeg sound file out of the stream.avi with 224kBit/sec
       bitrate and a sample rate of 48kHz. If you audio file has 44.1kHz
       mp2enc resamples the audio to create a 48kHz output. If you want a
       44.1kHz output sample rate you have to add -r 44100 to the mp2enc
       command

       Example

       > cat sound.wav | mp2enc -v 2 -V -o sound.mp2

       This creates a VCD (-V bitrate=224, stereo, sampling rate:44100)
       compatible output from the wav file.

       With -v 2 mp2enc is more verbose, while encoding you see the number of
       sec of audio already encoded.

       You can test the output with:

       > plaympeg sound.mp2

       NOTE: plaympeg is a MPEG-1 Player for Linux, you can use other players
       as wellr. For audio testing you can also use mpg123. For both audio and
       video playing there are the universal player like VLC mplayer and
       others.

Converting video
       Creating MPEG-1 and MPEG-2 videos.

       Normally the first video you create is not the best. For optimal
       quality/size you need to play with the bitrate, search radius, noise
       filter .... The options of mpeg2enc are described in the manpage of
       mpeg2enc.

       Example:

       lav2yuv stream.avi stream1.avi | mpeg2enc -o video.m1v

       This creates an video file with the default constant bitrate of
       1152kBit/sec.  This is the bitrate you need if you want to create VCDs.
       You can specify more files and also use the placeholder %nd. Where n
       describes the number. By default mpeg2enc assumes that you want to
       encode a not interlaced video to Mpeg-1. If you want to encode a full
       size video with interlacing that command above will fail.

       Example:

       > lav2yuv streami%02d.avi | mpeg2enc -b 1500 -r 16 -o video.m1v

       mpeg2enc creates a video with a bitrate of 1500kBit/s uses an search
       radius of 16. That means when trying to find similar 16*16 macroblocks
       of pixels between frames the encoder looks up to 16 pixels away from
       the current position of each block. It looks twice as far when
       comparing frames 1 frame apart and so on. Reasonable values are 16 or
       24. The default is 16 so adding the option here is useless.  Lower
       values (0, 8), improve the encoding speed but you get lower quality
       (more visible artifacts) while higher values (24, 32) improve the
       quality at the cost of the speed. With the file description of
       stream%02d.avi all files are processed that match this pattern with 00,
       01....

       Scaling

       Using yuvscaler one can now also scale the video before encoding it.
       This can be useful for users with a DC10 or DC10+ cards which captures
       at -d 1 768x576 or -d 2 384x288 (PAL/SECAM) or -d 1 640x480 (NTSC).

       You get a full description of all commands by reading the manpage or
       running:

       >yuvscaler -h

       Example:

       > lav2yuv stream.avi | yuvscaler -O VCD | mpeg2enc -o video.m1v

       This will scale the stream to VCD size which for PAL/SECAM is 352x288
       and for NTSC is 352x240. The scaled yuvstream is encoded to MPEG-1.

       It can also do SVCD scaling to 480x480 (NTSC) or 480x576 (PAL/SECAM):

       > lav2yuv stream.avi | yuvscaler -O SVCD -M BICUBIC | mpeg2enc -o
       video.m1v

       The mode keyword (-M) forces yuvscaler to use the higher quality
       bicubic algorithms for downscaling and not the default resample
       algorithms. Upscaling is always done using the bicubic algorithm.

       Example:

       > lav2yuv stream.avi | yuvscaler -I USE_450x340+20+30 -O SIZE_320x200 |
       mpeg2enc -o video.m1v

       Here we only use a part of the input and specify a nonstandard output
       resolution.

       NOTE: yuvscaler can set a active area, and set everything else to black
       using: -I ACTIVE_WidthxHeight+WidthOffset+HeightOffset High quality
       scaling: y4mscaler

       y4mscaler has been arround for quite some time. But it was for a quite
       long time a extra tool you needed to compile. There is a comprehensive
       manpage explaining all the details, there also a lot fo helpful
       information on the website:

       One unique feature is that is it able to change the subsampling, and
       Choma Modes. And you can choose the scaler kernels, depending on the
       source that can help a lot.

       Example:

       > cat raw.yuv | y4mscaler -O infer=CLIP -O preset=DVD -O sar=PAL_Wide |
       mpeg2enc video.m1v

       In this example y4mscaler will take the input stream and scale it to
       the coresponding PAL size. The sar option tell to scale is to a wide
       format (16:9).  The infer=clip option will tells y4mscaler that it can
       clip the top and bottom bars away to scale it to the resulting size.

       Example:

       > mpeg2dec -o pgmpipe deluxe.m2v |  pgmtoy4m -x 420jpeg -r 25:1 -i t |
       y4mscaler -I sar=64:36 -I active=344x476+100+48 -O preset=DVD |
       mpeg2enc -f 8 video.m1v

       This is a more the job for y4mscaler.  We have a weird PAL MPEG source
       format with 544x576 pixels in a wide screen 16:9 format, that makes
       black bars all around the original 4:3 image.  This command scales the
       image up to a original 4:3 size, and takes just the interesting center.
       The SAR is the sample aspect ratio get lost somewhere so we specify it
       in the beginning.  So it is specified again, than you tell y4mscaller
       the active size of the picture it shall use to scale up. The active
       keyword is treated different in y4mscaler and yuvscaler.  The DVD is a
       preset for the output format you want. From the stream parameters
       y4mscaler knows that it is a PAL stream and the output parameters. If
       you wanted a 16:9 output you would have to use the keyword: DVD_WIDE.

       Testing is done by:

       > mplayer video.m1v

       NOTE:These are only examples. There are more options you can use. You
       can use most of them together to create high quality videos with the
       lowest possible bitrate.

       NOTE2:The higher you set the search radius the longer the conversion
       will take. In general the more options used the longer encoding takes.

       NOTE3:MPEG-1 was not designed to be a VBR (variable bitrate stream) !!
       So if you encode with -q 15 mpeg2enc sets the maximal bitrate -b to
       1152. If you want a VBR MPEG-1 you have to set -b very high (2500).

       NOTE4:Maybe you should give better names than video.mpg. A good idea is
       to use the options as part of the filename (for example:
       video_b1500_r16_41_21.m1v).  Another possibility is to call all the
       layer 2 audio files ".mp2" all the MPEG-1 video files ".m1v" and all
       MPEG-2 video files ".m2v" Easy to see what's happening then. Reserve
       .mpg for multiplexed MPEG-1/2 streams.

Putting the streams together
       Example:

       > mplex sound.mp2 video.m1v -o my_video.m1v

       Puts the sound.mp2 and the video.m1v stream together to my_video.mpg

       Now you can use your preferred MPEG player and watch it. All players
       (gtv for example) based on the SMPEG library work well for MPEG-1.
       Other players (which can play MPEG-2 as well as MPEG-1 movies) are:
       xmovie, xine, and MPlayer VLC, to name some.

       NOTE: If you have specified the -S option for mpeg2enc mplex will
       automatically split the files if there is in the output filename a %d
       (looks like: -o test%d.mpg) The files generated this way are separate
       stand-alone MPEG steams!

       NOTE2: xine might have a problem with seeking through videos.  mplayer
       has a problem with the "seek backward/forward" with variable bitrate
       streams because it goes forward in the file the amount of data for a
       constant bitrate stream. That amount might be significantly more than
       10 seconds or one minute (those are the amount mplayer seeks for each
       press of the arrow keys). So don't wonder if it seeks much more time
       forward or backward than you expect.

       Variable bit-rate multiplexing: Remember to tell mplex you're encoding
       VBR (-V option) as well as mpeg2enc (see the example scripts). It
       *could* auto-detect but it is not working yet. You should tell mplex a
       video buffer size at least as large as the one you specified to
       "mpeg2enc" Sensible numbers for MPEG-1 might be a ceiling bit-rate of
       2800Kbps, a quality ceiling (quantization floor) of 6 and a buffer size
       of 400K.

       Example:

       > mplex -V -r 1740 audio.mp2 video_vbr.m1v -o vbr_stream.mpg

       Here we multiplex a variable bitrate stream. mplex is a single pass
       multiplexer so it can't detect the maximal bitrate and we have to
       specify it. The data rate for the output stream is: audio bitrate +
       peak videobitrate + 1-2% for mplex information. If audio (-b 224) is
       224kBit and the video is 1500kBit (encoded with -b 1500 -q 9) then we
       have 1724 * 1.01 or about 1740kBit.

       Example:

       > plaympeg my_video.mpg

       or

       > mplayer my_video.mpg

Creating MPEG-1 Videos
       For MPEG-1 videos you can use MP2 audio and MPEG-1 video. A subset of
       MPEG-1 movies are VCD's. You can use VBR (Variable BitRate) for the
       Video (although VCDs are almost always use CBR video) but the Audio has
       to be CBR (Constant BitRate).

       MPEG-1 is recommended for picture sizes up to 352x288 for PAL and
       352x240 for NTSC for larger sizes MPEG-2 is the better choice.  There
       is no exact resolution where MPEG-1 is better than MPEG-2.  Just to
       make soure, MPEG-1 can't handle interlaced sources. If you video is
       interlaced you need MPEG-2 to get it proper encoded.

       MPEG-1 Audio creation Example

       > lav2wav editlist.eli | mp2enc -r 44100 -o sound.mp2

       You can save some bits by telling mp2enc to use a lower bitrate (-b
       option) like 160 or 192 kBit/s.  The -r 44100 option forces mp2enc to
       generate a 44.1kHz audio file.

       > lav2wav editlist.eli | mp2enc -b 128 -m -o sound.mp2

       This creates a mono output with an bitrate of 128kBit/sec bitrate.  The
       input this time is the editlistfile (can have any name) created with
       glav so all changes you made in glav are direct processed and handed
       over to mp2enc.  You do NOT have to create an edited stream with
       lavtrans to get it converted properly.

       MPEG-1 Video creation example

       > lav2yuv editlist.eli | mpeg2enc -b 2000 -r 24 -q 6 -o video.m1v

       mpeg2enc creates an video with an bitrate of 2000kBit/s (or
       2048000Bit/s) but the -q flag activates the variable bitrate and a
       quality factor of 6. It uses a search radius of 24.

       Explanation:when mpeg2enc is invoked without the 'q' flag it creates
       "constantbit-rate" MPEG streams. Where (loosely speaking) the strength
       of compression (and hence picture quality) is adjusted to ensure that
       on average each frame of video has exactly the specified number of
       bits. Such constant bit-rate streams are needed for broadcasting and
       for low-cost hardware like DVD and VCD players which use slow fixed-
       speed player hardware.

       Obviously this is fairly inefficient as it means inactive scenes use up
       bits that could better be "spent" on rapidly changing scenes.  Setting
       the 'q' flag tells mpeg2enc to generate variable bit-rate streams. For
       such streams the bit-rate specified is simply the maximum permissible.
       The 'q' parameter specifies the minimum degree of compression to be
       applied by specifying how exactly picture information is recorded.
       Typically 'q' would be set so that quiet scenes would use less than the
       specified maximum (around 6 or 8) but fast moving scenes would still be
       bit-rate limited. For archival purposes setting a maximum bit-rate high
       enough never to be reached (e.g. 10Mbps) and a q of 2 or 3 are
       reasonable choices.

       Example:

       > lav2yuv stream.avi | yuvscaler -I ACTIVE_352x240+0+24 | mpeg2enc -b
       1152 -r 16 -4 1 -2 1 -o video.m1v

       Usually there is at the top and at the bottom a nearly black border and
       a lot of bandwidth is used for something you do not like. The yuvscaler
       -I ACTIVE option sets everything that is not in the described area to
       black but the imagesize (352x288) is not changed.  So you have a real
       black border the encoder only uses a few bits for encoding them. You
       are still compatible with the VCD's format in this example.  To
       determine the active window extract one frame to the jpeg format:

       > lavtrans -f i -i 100 -o frame.jpg test.avi

       Than use your favorite graphic display program to determine the active
       size.  The -4 1 and -2 1 options improves the quality about 10% but
       conversion is slower.

       At the size of 352x288 (1/2 PAL size created when using the -d 2 option
       when recording) the needed bitrate is/should be between 1000 -
       1500kBit/s. For NTSC it should be about the same, because the image is
       smaller but there are more frames per second than in PAL.

       Anyways, the major factor is quality of the original and the degree of
       filtering. Poor quality unfiltered material typically needs a higher
       rate to avoid visible artifacts.  If you want to reduce bit-rate
       without annoying artifacts when compressing broadcast material you
       should try one (or more) of the noise filters.

       Example:

       > lav2yuv stream.avi | mpeg2enc -b 1500 -n s -g 6 -G 20 -P -o video.m1v

       Here the stream.avi will be encoded with:

       -b 1500

       a Bitrate of 1500kBit/sec

       -n s

       the input Video norm is forced to SECAM

       -P

       This ensures that 2 B frames appear between adjacent I/P frames.
       Several common MPEG-1 decoders can't handle streams that do not have 2
       B-frames between I/P frames

       -g 6 -G 20

       the encoder can dynamically change the group-of-pictures size to
       reflect scene changes. This is done by setting a maximum GOP (-G flag)
       size larger than the minimum (-g flag).  For VCDs sensible values might
       be a minimum of 9 and a maximum of 15.  For SVCD 9 and 15 would be good
       values. If you only want to play it back on SW player you can use other
       min-max values.

       Example:

       > lav2yuv stream*.avi | mpeg2enc -b 1500 -r 16 -4 1 -2 1 -S 630 -B 260
       -o video_n1_1500_r16_41_21_S630_B240.m1v

       lav2yuv processes all the stream files. Then mpeg2enc is given some
       options that make the encoded stream look nicer. Using -S 630 means
       that mpeg2enc marks the stream so that mplex generates a new stream
       every 630MB. One important thing is the use of the -B option which
       specifies the non-video (audio and mplex information) bitrate. The -B
       value of 260 should be fine for audio with 224kBit and mplex
       information. For further information take a look at the encoding
       scripts in the scripts directory.

       MPEG-1 Multiplexing Example

       Example:

        >mplex sound.mp2 video.m1v -o my_video.mpg

       Puts the sound.mp2 and the video.m1v stream together to my_video.mpg.
       It only works that easy if you have CBR (the -q option was not used
       with mpeg2enc).

       Example:

       mplex -V -r 1740 audio.mp2 video_vbr.m1v -o vbr_stream.mpg

       Here we multiplex a variable bitrate stream. mplex is now a single pass
       multiplexer so it can't detect the maximal bitrate and we have to
       specify it. The data rate for the output stream is: audio bitrate *
       peak videobitrate * 1-2% for mplex information. If audio (-b 224) has
       224kBit, video has 1500kBit (was encoded with -b 1500 -q 9) then we
       have 1724 * 1.01 or about 1740kBit.

Creating MPEG-2 Videos
       MPEG-2 is recommended for sources with a greater picture than 352x240
       for NTSC and 352x288 for PAL. MPEG-2 can also handle interlaced sources
       like recording from TV at full resolution.

       MPEG-2 allows the usage of mpeg layer 3 (mp3) sound. So you can use
       your favorite mp3encoder for the creation of the sound.  However, MP3
       audio is not valid for DVDs.  It is best to use MP2 (Layer 2) audio.
       The audio can also be a VBR stream.

       MPEG-2 is usually a VBR stream. MPEG-2 creation with optimization
       requires a lot of CPU power.  A film with the double resolution is NOT
       4 times larger than an MPEG-1 stream. Depending on your quality
       settings it will be about 1.5 up to 3 times larger than the MPEG-1
       stream at its lower resolution.MPEG-2 audio creation example

       > lav2wav editlist.eli | mp2enc -o sound.mp2

       You can save some bits by telling mp2enc to use a lower bitrate (-b
       option) like 160 or 192 kBit/s. You might want to add -r 44100 so that
       mpeg2enc generates 44.1kHz sampling rate audio.  I hope I don't need to
       explain the usage of an MP3 Encoder.  But you should not use all the
       fancy options that are available.MPEG-2 Video creation example

       > lav2yuv editlist.eli | mpeg2enc -f 3 -b 3000 -q 9 -o video.m2v

       A very simple example for MPEG-2 Video.  The most important option is
       the -f 3. That tells mpeg2enc that it should create a MPEG-2 stream.
       Because it is a generic MPEG-2 you have to use the -b bitrate options.
       And should use the -q option because you usually want a space saving
       VBR stream. When using VBR streams the -b option tells mpeg2enc the
       maximum bitrate that can be used. The -q option tell mpeg2enc what
       quality the streams should have.  The bitrate has an upper bound of the
       value specified by -b.

       > lav2yuv editlist.eli | mpeg2enc -f 3 -4 1 -2 1 -q7 -b 4500 -V 300 -P
       -g 6 -G 18 -I 1 -o video.m2v

       This will generate a higher quality MPEG-2 stream because the -4 1 and
       -2 1 options were used.  With -b 4500 -q 7 you tell mpeg2enc the
       maximal bitrate and the quality factor.  -V is the video buffer size
       used for decoding the stream. For SW playback it can be much higher
       than the default. Dynamic GOP is set with -g and -G.  A larger GOP size
       can help reduce the bit-rate required for a given quality but very
       large sizes can introduce artifacts due to DCT/iDCT accumulated
       rounding errors.  The -P option also ensures that 2 B frames appear
       between adjacent I/P frames. The -I 1 option tells mpeg2enc that the
       source is a interlaced material like videos. There is (time consuming)
       interlaced motion compensation logic present in mpeg2enc.  Mpeg2enc
       will use that logic if the size of the frames you encode is larger than
       the VCD size for your TV Norm.

       If you deinterlacing the movie with yuvdeinterlace you should tell
       mpeg2enc that it does not need to do motion estimation for interlaced
       material. You have to use the -I 0 option of mpeg2enc to say that the
       frames are already deinterlaced.  This will save a lot of time when
       encoding. If you don't use -I 0 it will not cause problems, the
       encoding will just take longer.

       You can also use scaling an options that optimize (denoise) the images
       to get smaller streams.  These options are explained in detail in the
       following sections.Which values should be used for VBR Encoding?

       The -q option controls the minimum quantization of the output stream.
       Quantization controls the precision with which image information is
       encoded. The lower the value the better the image quality.  Values
       below 4 are extremes and should only be used if you know what you are
       doing

       Usually you have to set up a maximum bitrate with the -b option.  The
       tricky task is to set a value for the -q option and the -b option that
       produces a nice movie without using too much bandwidth and does not
       introduce too many artifacts.

       A quality factor should be chosen that way that the mplex output of
       Peak bit-rate and average bit-rate differ by about 20-25%.  If the
       difference is very small (less than < 10%) it is likely that you will
       begin to see artifacts in high motion scenes.  The most common cause of
       the average rate being too close (or equal) to the maximum rate is
       wrong value for the maximal bitrate or a quality factor that is too
       high.

       A combination that will produce more artifacts than you can count is a
       SVCD with a maximal video bitrate of 2500kBit and a quality factor of 1
       or 2.  For SVCD with a video limit of 2500kBit a quality factor of 7-11
       fits quite good (8 is the default). If you use filter programs or have
       a very good source like digital TV, DVD like material or rendered
       pictures you can use a quality factor of 6 when creating SVCDs.  If
       your SVCD/DVD player supports non-standard bitrates  you can increase
       the bitrate above the standard maximum of 2788 kBit/sec (video plus
       audio).  When using a higher bitrate and quality factor action scenes
       will look much better but of course the playing time of the disc will
       be less.

       The same (7-11) quality factor for a full size picture and a top
       bitrate of 3500 to 4000 kBit will produce few artifacts.

       For SVCD/DVD you can expect a result like the one described if the
       maximal bitrate is not set too low:

          q <= 6 real sharp pictures, and good quality
          q <= 8 good quality
          q >= 10 average quality
          q >= 11 not that good
          q >= 13 here even still sequences might look blocky

       Encoding destination TV (interlaced) or Monitor (progressive)

       MPEG-2 supports interlaced data in addition to the progressive format.
       A MPEG-2 movie can be interlaced or progressive. It depends on the
       source (film or broadcast) and on the viewing device.

       If you encode a film both fields should be the same. Deinterlace the
       stream with yuvdeinterlace, or if you have a high quality source, and
       don't need to use the denoiser with yuvcorrect -T NOT_INTERLACED. Also
       set the mpeg2enc interlace-mode (-I) option to 0. This means that there
       is no interlacing.  We do not really need deinterlacing here because
       there is no motion between the fields of the frame. We only need to
       unite the two fields into a single progressive frame.

       This movie should play back an any device (TV or Monitor) without
       problems.

       If you have an interlaced source (broadcast) you can encode it as
       interlaced stream. Or deinterlace the stream and encode it as
       progressive stream. If you deinterlace it with yuvdeinterlace you will
       lose details.  But if you plan to play the recorded stream on your DVD
       player and your TV it would not be wise to perform deinterlacing.  If
       you only want to play it back on the Monitor (progressive display) the
       picture looks better when playing it back if it is deinterlaced. If the
       player you use can do deinterlacing it does not matter if your encoded
       video has interlaced frames or progressive frames.

       If you plan to deinterlace the stream you can only do this with
       yuvdeinterlace and set the mpeg2enc -I 0. If you do not want to
       deinterlace the stream you do not need to set any special option (do
       not use yuvdeinterlace and mpeg2enc -I 0)

       If you like to pause the stream and look on the still you should
       deinterlace. Because then the image is flicker free when pausing.

       If you have a film (progressive) with parts from a broadcast
       (interlaced) mixed together (like in a documentary where some parts
       from a speaker are recorded interlaced and other parts are filmed) you
       have to choose between good film sequences with average still images or
       average looking film sequences with good still images.

       For good film with average stills do not deinterlace.  For average film
       sequences with good stills then deinterlace (using yuvdeinterlace and
       mpeg2enc -I 0).MPEG-2 Multiplexing example

       > mplex -f 3 -b 300 -r 4750 -V audio.mp3 video.m2v -o final.mpg

       Now both streams (a mp3 audio and a mpeg2 video) are multiplex into a
       single stream (final.mpg). You have to use the -f 3 option to tell
       mplex the output format. You also have to add the -b decoder buffers
       size option with the same value used when encoding the video. -r is
       that rate of video + audio +1-2% of mplex information.

       The -Voption tells that your source for mplexing is a VBR stream. If
       you don't use this option mplex creates something like a CBR stream
       with the bitrate you have told it with the -r option.  These streams
       are usually get BIG.

Creating Video CDs (VCDs)
       VCD is a constrained version of MPEG-1 video.  VCD format was defined
       by Philips. The goal was to use a single speed CD-drive and other cheap
       hardware (not flexible) to have a cheap HW-Player. Because of that
       there are limitations for video and audio used to make a VCD. The
       bitrate for video is 1152kBit and 224kBit/sec MP2 audio.  You are not
       allowed to use the -q option, dynamic GOP sizes and the video buffer is
       limited to 46kB.  The image size is limited to 352x240 for NTSC, an to
       352x288 for PAL.

       If you have no VCD (only) player and you plan to use your DVD player
       then it is quite possible that the DVD player will be flexible enough
       to allow higher bitrates, dynamic GOP sizes, larger video buffer and so
       onVCD Audio creation Example

       > lav2wav stream.avi | mp2enc -V -o sound.mp2

       -V force VCD 2.0 compatible output.  There the audio samplerate is
       fixed to 44.1kHz. And  you can choose the audio bitrate for mono audio
       to be 64, 96 or 192kBit/sec. If you have stereo audio you can choose
       128, 192, 224 or 384kBit/sec.  For hardware players, you should stick
       to 44.1 224kBps Stereo layer 2 Audio.VCD Video creation Example

       > lav2yuv stream.avi | yuvscaler -O VCD | mpeg2enc -f 1 -r 16 -o
       video.mpg

       For VCD compatible output the -f 1 sets all options in mpeg2enc as
       needed. It seems that many VCD players (Avex for example) are not able
       to play MPEG streams that are encoded with a search radius greater than
       16 so do not use the -r option to override the default of 16.

       > lav2yuv streams.eli | mpeg2enc -f 1 -4 1 -2 1 -S 630 -B 260 -P -o
       video.m1v

       Using '-S 630' means that mpeg2enc marks the stream so that mplex
       generates a new stream every 630MB. One important thing is the use of
       the -B option which specifies the non-video (audio and mplex
       information) bitrate. The -B value of 260 should be fine for audio with
       224kBit and mplex information. For further information take a look at
       the encoding scripts in the scripts directory. The multiplexed streams
       should easily fit on a 650MB CD.

       The default value (-B) is 700MB for the video. mpeg2enc marks
       automatically every stream at that size if the -B option is not used to
       set a different value.  If you have a CD where you can write more data
       (perhaps as much as 800MB) you have to set the -S option or otherwise
       mpeg2enc will mark the stream at 700 MB, and mplex will split the
       stream there.  Which is almost certainly not what you want.

       VCD Multiplexing Example

       > mplex -f 1 sound.mp2 video.mpg -o vcd_out.mpg

       The -f 1 option turns on a lot of weird stuff that otherwise has no
       place in a respectable multiplexer!Creating the CD

       The multiplexed streams have to be converted to an VCD compatible.
       This is done by vcdimager

       > vcdimager testvideo.mpg

       Creates a videocd.bin, the data file, and a videocd.cue which is used
       as control file for cdrdao.

       You use cdrdao to burn the image. Cdrdao is yet another fine
       Sourceforge project which is found at: Notes

       For MPEG-1 encoding a typical (45 minute running time) show or 90 odd
       minute movie from an analog broadcast a constant bit-rate of around
       1800 kBit/sec should be ideal. The resulting files are around 700M for
       45 minutes which fits nicely as a raw XA MODE2 data track on a CD-R.
       For pure digital sources (DTV or DVD streams and similar) VCD 1152
       works fine.

       Note: If you encode VBR MPEG-1 (-q) remember the Hardware was probably
       not designed to do the playback because it is not in the
       specifications. If it works be very happy. I've noticed that it helps
       when you have an MPEG-1 stream to tell vcdimager that it is an SVCD.
       vcdimager complains (but only with a warning and not a fatal error) but
       you should be able to burn it. This could convince the player to use
       different routines in its firmware and play it back correct but there
       is no guarantee of that.Storing MPEGs

       If you record the data as XA mode 2 tracks you can fit appreciably more
       on a CD (at the expense of error correction/detection). You can use
       vcdimager to do this and vcdxrip (part of the vcdimager package) to
       extract ("rip") the resulting files. For better Quality there are SVCD
       and XVCD and DVD.

       Currently SVCD is fully supported with a pre-set format in mplex and
       tools to create disks. MPEG streams that can be played by DVD player
       hardware and software can readily produced using mpeg2enc/mplex

       If your player doesn't support SVCD you may well find it can handle VCD
       streams that have much higher than standard bit-rates. Often as much as
       2500kBit/sec is possible. The several brands of DVD players can also
       play wildly out of spec SVCD and VCD discs.  With higher bit-rates and
       good quality source material it is worth trying mpeg2enc's -h flag
       which produce a stream that is as sharp as the limits of the VCD
       standard permits.

       However, if your player supports it and you have the patience for the
       longer encoding times SVCD is a much better alternative. Using a more
       efficient MPEG format SVCD more than doubles VCD's resolution while
       typically producing files that are less than twice as big.

Creating SVCD
       Super Video CD (SVCD) is an enhancement to Video CD that was developed
       by a Chinese government-backed committee of manufacturers and
       researchers.  The final SVCD spec was announced in September 1998.  A
       good explanation of the SVCD format from Philips can be found here: .

       Record at full TV resolution (means: -d 1 for PAL this is 720x576) The
       resolution is for NTSC is 480x480 of PAL 480x576, so you know why you
       should record at full size.SVCD Audio creation Example

       > lav2wav stream.avi | mp2enc -V -e -o sound.mp2

       The SVCD specifications permit a much wider choice of audio rates, it
       is not necessary to use 224 kBit/sec. Any audio rate between 32 and 384
       kBit/sec is permitted. The audio may be VBR (Variable Bit Rate). The -e
       enables the CRC error protection for the audio. The CRC has to be
       enabled to be SVCD standard compliant but it seems that most players
       don't pay attention to the CRC information. The CRC information need 2
       bytes per Audio frame

       The approximate frame length formula for MPEG-1 layer-II is:

       (frame length in bytes) = 144 * (byte rate) / (sample rate)

       If you have the typical VCD settings the CRC data needs about 0,27% of
       the whole data. In the worst case where you have a MONO 32k Bitrate
       stream the CRC data needs 1,92%.SVCD Video creation example

       > lav2yuv stream.avi | yuvscaler -O SVCD | mpeg2enc -f 4 -q 7 -I 1 -V
       200 -o video.m2v

       -f 4

       sets the options for mpeg2enc to SVCD

       -q 7

       tell mpeg2enc to generate a variable bitrate stream

       -I 1

       tell mpeg2enc to assume that the original signal is field interlaced
       video where the odd rows of pixels are sampled a half frame interval
       after the even ones in each frame. The -I 0 (progressive output (no
       field pictures)) option will also work for PAL

       You can use lower bitrates but the SVCD standard limits total bit-rate
       (audio and video) to 2788800 Bit/sec. So with 224Kbps audio and
       overhead 2550 may already be marginally too tight. Since the SVCD
       format permits any audio rate between 32 and 384 kBit/sec you can save
       a few bits/sec by using 192k audio (or for non-musical material 160k).

       SVCD supports variable bitrate (VBR), because MPEG-2 is usually VBR,
       but with the top video bitrate limit of 2500kBit/sec. With the -f 4
       flag the encoder also sets dynamic GOP with a low limit of -g 6 and a
       high limit of -G 18. This saves a few bits/sec and improves the picture
       quality during scene changes.  When encoding with -f 4 mpeg2enc ignores
       the video bitrate (-b) and search radius (-r) options. If you use -f 5
       you have to specify the bitrate and other options to mpeg2enc.

       Another possibility for movies in PAL (European style 25 frames/50
       fields per sec) video is:

       > lav2yuv stream.avi | yuvscaler -O SVCD | mpeg2enc -f 4 -I 0 -V 300 -o
       video.m2v

       Movies are shot on film at 24 frames/sec. For PAL broadcast the film is
       simply shown slightly "too fast" at 25 frame/sec (much to the pain of
       people with an absolute pitch sense of pitch). The -I 0 flag turns off
       the tedious calculations needed to compensate for field interlacing
       giving much faster encoding.

       Unfortunately, movies broadcast in NTSC (US style 30 frames/60 fields
       sec) video this will produce very poor compression. The "pulldown"
       sampling used to produce 60 fields a second from a 24 frame a second
       movie means half the frames in an NTSC *are* field interlaced.

       Don't forget the -S and -B options mentioned above. You want the stream
       to fit on a CD don't you ?SVCD multiplexing example

       > mplex -f 4 -b 300 -r 2750 sound.mp2 video.m2v -o svcd_out.mpg

       -f 4

       tells mplex to mplex a SVCD

       -r 2750

       is the calculated Audio + Video Bitrate + 1-2% multiplex information

       -b 300

       is the buffer available on the playback device (the same value as used
       for the video encoding (mpeg2enc's -V option).  SVCD creating the CD

       Example:

       > vcdimager -t svcd testvideo.mpg

       Creates a videocd.bin, the data file, and a videocd.cue which is used
       as control file for cdrdao.

       Use cdrdao to burn the image as mentioned earlier.

       NOTE:If you want to build "custom" VCD/SVCD you will need to use the
       mplex -f 2 and -f 5 switches.

       NOTE:The VCD and SVCD stuff may work on your HW player or not. There
       are many reports that it works quite well. Don't be worried if it does
       not work. Nor am I responsible for unusable CDs. ("coasters")

Creating DVD's
       This statement was correct a few years ago: Everything in this section
       is new.  The limitations I mention here might not exist in the current
       version.  Currently (Dec. 2007) DVD creating is working.

       You need obviously a DVD writer. I did own a Ricoh DVD+RW that works,
       and I know of a DVD-RAM writer that is able to to burn DVD-R. That
       disks also work with a DVD-Player. Now most DVD writers ar able to burn
       both media + and -, so that should not be a problem any more.  Which
       programs you use for burning depends on the DVD writer drive.

       For the creation and writing of the VOB, IFO and BUP files we use
       dvdauthor. Aviable from Sourceforge (you might have guessed it) .DVD
       Audio creation example

       > lav2wav stream.eli | mp2enc -o sound.mp2

       The sample rate has to be 48kHz. The mp2enc does create by default a
       sample rate of 48kHz. If it is not a 48kHz mp2enc will resample the
       audio to get the sample rate.  If the audio is recorded at 48kHz then
       no resampling is needed and toolame can be used for the encoding (it is
       faster than mp2enc).  DVD Video creation example

       > lav2yuv stream.eli | mpeg2enc -f 8 -o video.m2v

       -f 8

       This sets the options correctly for a MPEG-2 video that is compliant
       with the DVD standard.  The maximum bitrate is set to 7500kBps and the
       video buffer size is set to 230KB. The default quality factor is set to
       8.  mpeg2enc sets currenty no automatic sequence length as it does for
       VCD/SVCD.

       The other options to get a low bitrate and high quality stream can also
       be used to override the default settings mentioned above.  You can also
       use yuvdenoise to increase the picture quality if the input data is
       noisy (from a VHS tape for example).  A typical command will look like
       this:

       lav2yuv moby.eli | yuvdenoise | mpeg2enc -f 8 -q 7 -4 1 -2 1 -P -I 0 -N
       -o video_DVD.m2vDVD multiplexing example

       > mplex -f 8 sound.mp2 video.m2v -o my_dvdlikestream.mpg

       -f 8

       Here again we specify that we want to have DVD like MPEG stream.  mplex
       cannot do all the fancy things allowed for a DVD, but it is close
       enough that the HW-DVD players accept it.

       -o

       there we specify the output filename.  DVD creation example

       This topic will be covered by the documentation of the dvdauthor
       program.  For questions please see In general it will work like this:

       > dvdauthor -o output/ stream1.mpg stream2.mpg ...
       my_dvdlikestream.mpg; dvdauthor -T -o output/

       You will get a directory with AUDIO_TS and VIDEO_TS directories.
       Burning the data from the disk to a DVD+-R/+-RW writer would be done
       like this:

       growisofs -Z /dev/scd2 -dvd-video mydvd/

       If you own a DVD+RW/+R drive a good place for more information is:

       page. You also need a version of the cdrtools with dvd-video support.
       The cdrtools 1.11a27 is known to work but newer versions already exist.

       For other writers the commands to write a DVD will be different. You
       can get some more information in the dvdauthor package. There is no
       guarantee that it will work at all !!!

Creating DIVX Videos
       lav2avi.sh

       Another way of creating DIVX is the program mencoder which is from the
       mplayer project.  .  For more information about mencoder please read
       mencoder/mplayer help and documents. A first and a second pass give at
       the end of pass hints for bitrate which can be used for encoding to
       specific size (650 MB, 700 MB and 800 MB). The script lav2avi.sh uses
       this information if provided (for short streams it is omitted by
       mencoder).  Look for parameter preferedSize in the script. You can also
       specify other parameters used for encoding with encoderParam option in
       the script. For a description of the usable parameters take a look in
       the mplayer/mencoder manual.

       The outputfilename is that name of your input file (first option) but
       with the extension avi. If the size of file is less then specified by
       preferedSize it's because the source was of very high quality (no
       noise) and the specified bitrate was higher than required.  You usually
       get 700MB for 1.5 hour film at half image size with bitrate around 900
       that means for divx good quality (assuming good quality source material
       of course).

       The script does a 3 step encoding:

       1st step - audio encoding

       2nd step - first video pass

       3rd step - second video pass

       The mplayer/mencoder documentation deprecates the use of the 3 pass
       encoding method (it can cause A/V sync problems) and recommends the use
       of the 2 pass method.   The mencoder/mplayer documentation is extensive
       and has many helpful hints (and a bitrate calculator in the TOOLS/
       directory).

       For encoding use the fast ffmpeg (lavc) codec. It gives nice results
       together with high good performance. For audio encoding mp3 is used.
       For encoding of all parts it uses unix pipes. This mean that you DO NOT
       need additional space on your hard drive where all glav manipulations
       will be done. For audio encoding the script uses a FIFO queue.

       If you want to tweak the script for your own needs use these hints:

       Output of 1st step is file called frameno.avi with encoded audio

       2nd step is using frameno.avi and output is text file called
       lavc_stats.txt with timing informations

       3rd step is using frameno.avi and lavc_stats.txt for encoding the
       stream to the output file movie2.avi

       If you want change only video bitrate keep the file frameno.avi comment
       out the 1st step encoding and repeate 2nd and 3rd step. Dont forget to
       remove the line where the frameno.avi is removed.

       Optimizing the stream

       Using filters helps to increase the image quality of constant bitrate
       (CBR) video streams. With VBR (variable bit rate) video the filesize is
       reduced.

       Example:

       > lav2yuv stream.avi | yuvmedianfilter | mpeg2enc -o video.m1v

       Here the yuvmedianfilter program is used to improve the image. This
       removes some of low frequence noise in the images. It also softens the
       image a little. It takes a center pointer and averages the pixels
       around it that fall within the specified threshold. It then replaces
       the center pixel with this new value.  You can also use the -r (radius)
       option for an other search radius.

       NOTE:a radius greater than the default value of 2 is horrendously slow!

       yuvmedianfilter has separate settings for luma and chroma. You can
       control the search radius and the trigger threshold independently.  If
       you use a threshold of 0 then filtering is disabled (-t 0 disables luma
       filtering, -T 0 disables chroma filtering).

       > lav2yuv stream.avi | yuvmedianfilter -r 3 -t 4 -T 0 | mpeg2enc -o
       video.m1v

       This example uses a search radius of 3 pixels for the luma, a threshold
       of 4 (the default is 2), and disables filtering for the chroma
       components.   Sometimes, depending on the source material, median
       filtering of the chroma can cause a slight color shift towards green.
       Filtering on the luma component (disabling the chroma filtering) is the
       solution to that problem.

       Example:

       > lav2yuv stream.avi | yuvdenoise | mpeg2enc -o video.m1v

       Now we are using yuvdenoise to improve the image. The filter mainly
       reduces color and luminance-noise and flickering due to phase errors
       but is also effective at removing speckles.

       yuvdenoise denoises interlaced if the input is interlaced.  You can of
       course change the denoiser threshold (-g/t).  Creating a black border
       can lower the bitrate of the encoded stream because pure black areas
       compress much better than noise (captures from analog sources such as
       VHS and 8mm usually have several lines at the time and bottom that are
       very noisy). For this you can use the scaler.

       yuvdenoise uses a different approach to filter the noise.  More
       information about how yuvdenoise works as well as descriptions of its
       options are found in the manpage.

       If you have a high quality source you should lower the filter to levels
       like that: -g 0,255,255 -t 2,2,2.  You might also use the mpeg2enc
       -h/--keep-hf option. That option tells mpeg2enc to keep as much high
       frequency information as possible.   Using -h will greatly increase the
       bitrate (filesize).  If the bitrate is too close to the maximum (set
       with -b) the encoder will have to decrease the quality to avoid
       exceeding the maximum bitrate.

       A builtin filter in mpeg2enc is the -N/--reduce-HF option.  This option
       is not really filter in the usual sense.  Rather it changes how exactly
       the high frequency information is encoded.  Often the high frequency is
       noise.  You also have high frequencies on sharp borders or transitions.
       The -N option can have values between 0.0 and 2.0 where 0.0 does
       nothing (disables the high frequency quantizer boost) and 2.0 gives the
       maximum quantization boost.  The value to use depends on the desired
       output quality and filesize.  Values of -N less than 0.5 are very
       subtle while a value of 1.0 will achieve a good balance between bitrate
       reduction and output quality.   Using -N values above 1.5 will
       noticeably reduce the sharpness of the output picture and are normally
       used only for poor quality sources (VHS tapes for example).

       Using yuvmedianfilter's capability to only filter the chroma (-T) is
       moderately effective at reducing noise in dark scenes without softening
       the image during normal (brighter) scenes.   Median filtering of the
       luma (-t) will produce a lower bitrate but can cause loss of detail
       (softening).  Chroma only medianfiltering is less agressive and is a
       good choice to use in combination with yuvdenoise.

       Combining the filters yuvdenoise, yuvmedianfilter and the mpeg2enc -N
       option gives a very fine degree of control over the bitrate (filesize).
       The reduction (or increase) in the bitrate depends on the source
       material and the exact encoding/filter options used.  So we can give no
       exact numbers how much each option and combination will reduce the
       filesize, only guidelines.

       Usually you should use the -N option in a range from 0.5 to 1.5.  Below
       0.5 it does not reduce the bitrate very much (but does preserve
       sharpness).  At 1.5 and higher you will notice a softening in the video
       and possibly artifacts (halo/ringing) around edges of objects
       (text/subtitles especially).  If you combine the filters you should use
       yuvdenoise and maybe afterwards yuvmedianfilter.  Maybe yuvmedianfilter
       even after scaling.  Having yuvmedianfilter in the chain does not
       reduce the bitrate that much.  Often the use of yuvdenoise is enough.
       The yuvmedianfilter helps much if you have low quality sources, and not
       that much if you already have a rather good quality.  When you combine
       the filter and option you will very likely reduce the filesize to about
       the half of the filesize without using the options and programs.

       In general aggressive filtering will produce smaller files (lower
       bitrate) but reduce the quality (details) of the picture.  Less
       aggressive filtering/processing will preserve more detail but result in
       larger files.

       Example:

       > lav2yuv stream.avi | yuvkineco -F 1 | mpeg2enc -o video.m1v

       yuvkineco is used for NTSC sources. It does the conversation from
       30000.0/1001.0 (about 29.97) fps to 24000.0/1001.0 (about 23.976) fps,
       you can call it "reverse 2-3 pulldown" more info about this in the
       README.2-3pulldown. yuvkineco does only remove NTSC specific problems.

       If you want to improve the image you should also use yuvdenoise:

       > lav2yuv stream.avi | yuvkineco | yuvdenoise | mpeg2enc -o video.m1v

       Example

       > lav2yuv stream.avi | yuvycsnoise | mpeg2enc -o video.m1v

       yuvycsnoise is also used for NTSC and is specialized for NTSC Y/C
       separation noise. If video capture hardware has only a poor Y/C
       separator then at vertical stripes (especially red/blue) noises appear
       which seem checker flag and bright/dark invert per 1 frame.
       yuvycsnoise reduces noises of this type. You can also use different
       thresholds for luma/chroma and the optimizing method.  This filter is
       not needed with working with DV (Digital Video) data.

       yuvycsnoise works only correct when we have NTSC with:

       full height (480 lines)

       full motion captured (29.97 fps)

       captured with poor Y/C separator hardware

       For more information about the yuvkineco and yuvycsnoise read the
       README in the yuvfilters directory.

       If you want to experiment to determine the optimal settings for the
       denoiser, scaler and so on replace the mpeg2enc with yuvplay.  yuvplay
       plays back the yuv frames so you can see if the options you have chosen
       are making the thing better or worse.

       A command would look like this:

       > lav2yuv stream.eli | yuvdenoise -options | yuvscaler -options |
       yuvplay

       If you want to know how much each tool lowers the average bitrate.  You
       can use this table to see what you can expect if you have a full size
       video and want to create a DVD with a qality factor of 5 and the
       allowed maximal bitrate of 8500kb/sec.

       no denoising : 8300 kb/s (mostly hitting the upper bound)

       yuvenoise : 7700 kb/s

       mpeg2enc --reduce-hf : 7400 kb/s

       yuvdenoise + yuvmedianfilter : 6000 kb/s

       yuvdenoise + mpeg2enc --reduce-hf : 4900 kb/s

       all of the above : 3600 kb/s

       While -N|--reduce-hf or yuvdenoise alone is only a modest improvement,
       together they reduce the bitrate substantially.  There is not really
       much visible difference between using yuvdenoise alone and yuvdenoise
       with mpeg2enc --reduce-hf. The usefull values are between 0.0 and 1.5.
       Where you can say that the higher the quality factor you want, the less
       this option improves. At a quality factor 4 you save using -N 1.0 about
       1%. If you want a quality factor of 9 and use the -N 1.0 you might save
       up to 40%. But you might save less, that depends on the video you
       encode!!!

       If you ask yourself why not alyways use all of the above filters?  The
       answers are that the image softens (loss of detail) and the encoding
       time increases.  Most of the filters each require about the same amount
       of time as mpeg2enc needs for encoding the video.

       If you have very high quality material and want to keep every detail
       you should try to use the mpeg2enc --keep-hf|-h on the other hand.

       Note: The bitrate reduction you have depends on the material and on the
       noise of the images.

       A other interresting mpeg2enc option is the -E|--unit-coeff-elim
       option. This option is disabled by default. If you enable it, a special
       "unit coefficient elimination" algorithm, is applied to the encoded
       picture blocks.   Basically this proceedure forces blocks of a type
       that do not carry much information (but use many bits to encode) to be
       skipped. A negative value examines the base (DC) as well as the AC
       coefficients. A positive value means that only texture (AC)
       coefficients are examined and possibly zeroed.  The recommended values
       lies between -20 and +20. You usually can expect that you have a 5%
       decreased filesize. The amount the bitrate is reduced can vary
       considerably, the range spans from not really noticable up to 20%.

       If you think a other quantization matrice will help use the
       -K|--custom-quant-matrices option. You can try out your own
       quanitsation matrice or use another builtin than the default.  You can
       choose between kvcd, tmpgenc, hi-res, and your own. Using -K usually
       makes the file smaller except the hi-res option (that makes files
       considerably larger). Exact guidelines are hard to give, sometime a
       other quanitsation matrix saves almost nothing, and the next time up to
       20%. More than 20% is very unlikely, 10-15% at a moderate qualityfactor
       (-q 8-10) are likely.  The higher the qualiy the less it saves, at a
       quality factor of 4-6 the reduction in bitrate may only be 5%

       One thing to keep in mind is that the unit coefficient elimination and
       the quantization matrix option are decreasing the bitrate while
       maintaining the same visual quality.   At this point you can chose to
       use the smaller file to increase the amount of video that will fit on
       the disc media or you could chose to increase the quality even more by
       lowering the -q value by 1 and make a larger (but higher quality) file.

Scaling and offset correction
       The basic scaling is described in the Converting video section

       The scaling takes a part of the picture and scales it to a larger or
       smaller size. The scaling is done by yuvscaler:

       lav2yuv test.eli | yuvscaler -I USE_400x400+50+100 | yuvplay

       Here we only take part of the picture and scale it up to the size of
       the original frame.  But yuvscaler also changes the pixel aspect ratio.
       That means when you look at the stream using yuvplay it looks like a
       square in our example.  After scaling, if the sample (pixel) aspect
       ratio were not changed, the video would not display with the proper
       aspect ratio.  Yuvscaler compensates by adjusting the sample aspect
       ratio.  If you have a interlaced video, the height and HeightOffset
       have to be a multiple by 4 if the video is interlaced. Else the values
       (width, height, widthoffset, heightoffset) have to be a multiple of 2.

       A problem that cannot be solved easily with scaling is when the picture
       is not centered horizontal. On one side you have no black pixels and on
       the other you have 30 for example. Scaling is here is the wrong
       solution.  y4mshift is the perfect solution because it can shift the
       image to the left or right.

       lav2yuv test.eli | y4mshift -n 20 | mpeg2enc -f 3 -b 4000 -q 10 -o
       video.m2v

       That will shift the image 20 pixels to the right. If you use a negative
       the image is shift to the left. You have to use a even number. The
       inserted pixels are set to black.

       Some might wonder why the image is not centered and there is a black
       border around the image when you view what you have recorded. The
       reason for the black border is in history of the CRT (Cathode Ray Tube)
       TV technology.  The history of the TV standard s a very interesting
       story but that topic is described in other (large) books.

       The TV does not show the full picture. A part of the picture is not
       shown because the TV sets overscan (sometimes as much as 10% but more
       common today is 5%).  But when you capture the video with a card you
       see the whole image including the border that TVs lose due to
       overscanning.  A horizontal offset is usually not a problem of the
       capture card. It is a problem when the film is broadcast and not well
       synchronized with the image.  This means that the scan of the source
       not exactly synchronized with the carrier signal, you wont see that on
       TV.

Frame rate conversion
       Ever needed to convert the framerate from PAL to NTSC or the other
       direction around ? Or something much simpler like converting the
       framerate from 24FPS to 24000:1001 for conversation from a film frame
       rate to a valid NTSC frame rate.

       Than yuvfps is your program. It can lower the framerate by dropping
       frames or create a higher framerate by replicating frames. If you have
       a wrong framerate in the header you can only change the header of the
       YUV stream and not modify the stream.

       Because the frames are only replicated (copied) you should denoise
       first and then change the framerate and scale at als last step. If you
       have a interlaced source you should also deinterlace before changeing
       the framerate. If you create a higher frame rate it is very likely that
       you will have weird flickers when you play it back. If you convert PAL
       to NTSC (30000:1001 FPS about 29,97 FPS) the frame rate will lower by
       about the factor 480/576 (NTSC lines / PAL lines).  If you lower the
       frame rate from PAL to NTSC (at 24000:1001) or NTSC FILM (24FPS) the
       bitrate will be about (480 Lines * 24 FPS) / (576 Lines * 25FPS).  If
       you change the frame rate before denoising the yuvdenoise will have
       problems finding the noise across the frames and the needed bandwith
       will slightly increase.

       Example

       > lav2yuv video.eli | yuvfps -r 30000:1001 | yuvscaler -O SVCD |
       mpeg2enc -f 4 -o video_ntsc_svcd.m2v

       This is a example to convert the source video to a NTSC video running
       at 30000:1001 FPS (or about 29,97FPS) at SVCD size.

       Example

       > lav2yuv video.eli | yuvdenoise | yuvfps -r 24000:1001 | yuvscaler -O
       SIZE_720x480 | mpeg2enc -f 3 -b 4000 -q 7 -o video_ntsc.m2v

       This example shows how you should use the tools. Denoise first and than
       change the framerate and in the last step change the image size.

       It can happen that yuvscaler or mpeg2enc do not detect the TV norm
       correct. If that happens you have to add the norm option -n n/p/s to
       the program that chooses the wrong norm.

       If you know that the header tells the wrong framerate, you can simply
       change the framerate of the yuv header this way:

       > lav2yuv video.eli | yuvfps -r 25:1 -c | mpeg2enc -f 3 -b 4000 -q 7 -o
       video_pal.m2v

       You need the -c option. To tell yuvfps that it only should change the
       header of the stream. With the -r 25:1 you tell yuvfps the frame rate
       it should write into the header. In your example the PAL frame rate of
       25 FPS. You always have to use the fractional form.

       If you know that the header is wrong, and you need a different output
       bitrate you can do this in a single step:

       > lav2yuv video.eli | yuvfps -s 24:1 -r 25:1 | mpeg2enc -o
       video.m1vTranscoding of existing MPEG-2

       For transcoding existing MPEG-2 streams from digital TV cards or DVD a
       lower data-rate than for broadcast will give good results.  Standard
       VCD 1152 kbps typically works just fine for MPEG-1. The difference is
       in the Signal/Noise ratio of the original. The noise in the analog
       stuff makes it much harder to compress.

       You will also need to manually adjust the audio delay offset relative
       to video when multiplexing. Very often around 150ms delay seems to do
       the trick.

       You have to download the ac3dec and mpeg2dec packages. You can find
       them at their homepage: mpeg2dec ( ) and ac3dec.  For decoding the
       audio streams mpg123 and mplayer can be very helpfull.  You also need
       sox and toolame.

       In the scripts directory there is a mpegtranscode script that does most
       of the work.

       So transcoding looks like this:

       > mjpegtranscode -V -o vcd_stream mpeg2src.mpg

       -V

       set's the options so that a VCD compatible stream is generated

       -o vcd_stream

       a vcd_stream.m1v (video) and vcd_stream.mp2 (audio) is created

       mpeg2src.mpg

       specifies the source stream

       The script prints also something like this:

       > SYNC 234 mSec

       You will need to adjust the audio/video startup delays when
       multiplexing to ensure audio and video are synchronized.  The exact
       delay (in milliseconds) that you need to pass to mplex to synchronize
       audio and video using the "-v"" is printed by the extract_a52 tool
       labeled "SYNC" when run with the "s" flag. This is the value th
       mjpegtranscode script prints out after the SYNC word.

       Then you need to multiplex them like this:

       > mplex -f 1 -O 234 vcd_stream.mp2 vcd_stream.m1v -o lowrate.mpg

       -f 1

       Mux format is set to VCD

       -O 234

       Video timestamp offset in mSec, generated by the mjpegtranscoding
       script, there negative values are allowed

       vcd_stream.mp2 & vcd_stream.m1v

       generated files by the script

       lowrate.mpg

       the VCD compatible output stream

       Here we have a SVCD (MPEG-2 video) example:

       > mjpegtranscode -S -o svcd_stream mpeg2src.mpg

       You have to multiplex it with:

       > mplex -f 4 -O 234 svcd_stream.mp2 svcd_stream.m2v -o lowrate.mpg

       Problem: There is sometimes a problem with NTSC and VCD playback
       because movies may be recoded with 3:2 pulldown NTSC with 60
       fields/sec. mpeg2dec is designed for playback on computers and
       generates the original 24frames/sec bitrate. If you encode the video
       now 30frames/sec video is created. This video is now much too short for
       the encoded audio.

       The transcoding can be made to work but it must be done manually:

       > mpeg2dec -s -o pgmpipe mpeg2src.mpg | pgmtoy4m -a 59:54 -r 25:1 -i t
       | mpeg2enc -I 0 -f 4 -q 9 -V 230 -p -P -o svcd_stream.m2v

       The -p tells mpeg2enc to generate header flags for 3:2 pull down of
       24fps movie. It may also work if you do not add the -p flag.  You do
       not need the -p flag when transcoding to VCD format because it is not
       supported in mpeg1.

If you want to do every step on your own it will look something like this
       Extracting Audio:

       > cat test2.mpg | extract_a52 - -s | ac3dec -o wav -p sound.wav
       2>/dev/null

       One of the first lines showed contains the label "SYNC" you have to use
       this time later when multiplexing. The 2>/dev/null redirects the output
       of ac3dec to /dev/null.  In the next step you generate the mpeg audio
       file:

       > cat sound.wav | mp2enc -V -v 2 -o audio.mp2

       -V

       forces VCD format, the sampling rate is converted to 44.1kHz from 48kHz

       -v 2

       unnecessary but if you use it mp2enc tells you how many seconds of the
       audio file are already encoded.

       -o

       Specifies the output file.

       cat test2.mpg | extract_a52 - -s | ac3dec -o wav | sox -t wav
       /dev/stdin -t wav -r 44100 /dev/stdout | toolame -p 2 -b 224 /dev/stdin
       audio.mp2

       One of the first lines again output contains the label "SYNC".  You
       have to use this time (referred to as "SYNC_value" below) when doing
       the multiplexing.

       For VCD creation use:

       > mpeg2dec -s -o pgmpipe test2.mpg | pgmtoy4m -a 59:54 -r 25:1 -i t |
       mpeg2enc -s -o video_vcd.m1v

       mpeg2dec:

       -s

       tells mpeg2dec to use program stream demultiplexer

       -o pgmpipe

       the output format of the pictures, suitable for pgmtoy4m

       Mplex with:

       > mplex -f 1 -O SYNC_value audio.mp2 video_vcd.m1v -o vcd_stream.mpg

       -f 1

       generates an VCD stream

       -O SYNC_value

       the value mentioned above

       For SVCD creation use:

       > mpeg2dec -s -o mpeg2src.mpg | pgmtoy4m -a 59:54 -r 25:1 -i t  |
       mpeg2enc -f 4 -q 9 -V 230 -o video_svcd.mpg

       -q 9

       Quality factor for the stream (VBR stream) (default q: 12)

       -V 230

       Target video buffer size in KB

       -o

       Output file

       Mplex with:

       > mplex -f 4 -b 230 audio.mp2 video_svcd -o svcd_stream.mpg

       -f 4

       generate an SVCD stream

       -b 200

       Specify the video buffer size by the playback device.

       For other video output formats this might work:

       > mpeg2dec -s -o pgmpipe test2.mpg | pgmtoy4m -a 59:54 -r 25:1 -i t |
       yuvscaler -O SIZE_320x200 -O NOT_INTERLACED | mpeg2enc -o
       strange_video.m1v

       If you want to edit mpeg streams this also works but in a slightly
       different way. For demultiplexing you can use bbdmux from the bbtools
       package. Splits out either video or audio very cleanly.  You can't get
       it any more from the homepage from Brent Beyler, it can still be found
       when you search for it using that keywords " bbtools linux -suse
       -blackbox". Currenty it can be found at:

       First run:

       > bbdmux myvideo.mpg

       You should get something like this:

       Found stream id 0xE0 = Video Stream 0
       Found stream id 0xC0 = MPEG Audio Stream 0
       Found stream id 0xBE = Padding Stream

       Extract audio with:

       > bbdmux myvideo.mpg 0xC0 audio.mp1

       Convert it to wav:

       > mpg123 -w audio.wav audio.m1v

       Extract video with:

       > bbdmux myvideo.mpg 0xE0 video.m1v

       Converting video to an mjpeg avi stream:

       > mpeg2dec -o pgmpipe video.m1v | pgmtoy4m -a 59:54 -r 25:1 -i t |
       yuv2lav -f a -o test.avi

       Then adding the sound to the avi:

       > lavaddwav test.avi audio.wav final.avi

       If the source video has already the size of the target video use -o
       YUV. Using YUVh makes the video the half size!  The rest can be done
       just like editing and encoding other streams.  If you have videos with
       ac3 sound you only have to adapt the commands above.

       Extracting Audio:

       > cat test2.mpg | extract_a52 - -s | ac3dec -o wav 2>dev/null
       >sound.wav

       Extract video and adding the audio in a single step :

       > mpeg2dec -s -o pgmpipe | pgmtoy4m -a 59:54 -r 25:1 -i t | yuvscaler
       -O VCD | yuv2lav -f a -q 85 -w sound.wav -o test.avi

       NOTE:You need much disk space. 1GB of video has a size of about 2GB at
       SVCD format and of course disk space is needed for some temp files.
       Converting the video to mjpeg also takes some time.  On my Athlon 500 I
       never get more than 6-7 Frames a second.  You loose quality each time
       you convert a stream into an other format! Trading Quality/Speed

       If absolute quality is your objective a modest improvement can be
       achieved using the -4 and -2 flags.  These control how ruthlessly
       mpeg2enc discards bad looking matches between sections of adjacent
       frames during the early stages of the search when it is working with
       4*4 and 2*2 clusters of pixels rather than individual pixels. Setting
       -4 1 -2 1 maximizes quality. -4 4 -2 4 maximizes speed. Note that
       because the statistical criteria mpeg2enc uses for discarding bad
       looking matches are usually fairly reliable the increase/decrease in
       quality is modest (but noticeable).

       Reducing the radius of the search for matching sections of images also
       increases speed. However due to the way the search algorithm works the
       search radius is in effect rounded to the nearest multiple of 8.
       Furthermore on modern CPU's the speed gained by reducing the radius
       below 16 is not large enough to make the marked quality reduction
       worthwhile for most applications.

Creating streams to be played from disk using Software players
       Usually MPEG player software is much more flexible than the hardware
       built into DVD and VCD players. This flexibility allows for
       significantly better compression to be achieved for the same quality.
       The trick is to generate video streams that use big video buffers
       (500KB or more) and variable bitrate encoding (the -f / -q flag to
       mpeg2enc). Software players will often also correctly play back the
       more efficient MPEG layer 3 (yes, "MP3" audio format.  A good MP3
       encoder like lame will produce results comparable to layer 2 at 224Kbps
       at 128Kbps or 160Kbps.SMP and distributed Encoding

       Distributed encoding is a quite dark theory for the typical Machine in
       2013.  So most users can safely skip that point. SMP Encoding is more
       interresting for the average computer

       The degree to which mpeg2enc tries to split work between concurrently
       executing threads is controlled by the -M or --multi-thread [0..32]
       option. This optimizes mpeg2enc for the specified number of CPUs. By
       default (-M 1) mpeg2enc runs with just a little multi-threading:
       reading of frames happens concurrently with compression. This is done
       to allow encoding pipelines that are split across several machines (see
       below) to work efficiently without the need for special buffering
       programs.  If you are encoding on a single-CPU machine where RAM is
       tight you may find turning off multithreading altogether by setting -M
       0 works slightly more efficiently.

       For SMP machines with two ore more processors you can speed up mpeg2enc
       by setting the number of concurrently executing encoding threads's you
       wish to utilize (e.g. -M 2). Setting -M 2 or -M 3 on a 2-way machine
       should allow you to speed up encoding by around 80%.  Values above 3
       are accepted but have very little effect even on 4 cpu systems.

       If you have a real fast SMP machine (currently 1.Aug.03) like a dual
       Athlon MP 2600 or something similar the -M 2 and the filtering might
       not keep both (or more)  CPU's busy. The use of the buffer or bfr
       program with a 10-20MB buffer helps to keep both CPUs busy.

       Obviously if your encoding pipeline contains several filtering stages
       it is likely that you can keep two or more CPU's busy simultaneously
       even without using -M. Denoising using yuvdenoise or yuvmedianfilter is
       particular demanding and uses almost as much processing power as MPEG
       encoding.

       It you more than one computer you can also split the encoding pipeline
       between computers using the standard 'rsh' or 'rcmd' remote shell
       execution commands. For example, if you have two computers:

       > rsh machine1 lav2yuv "mycapture.eli | yuvscaler -O SVCD | yuvdenoise"
       | mpeg2enc -f 4 -o mycapture.m2vi

       Here the computer where you execute the command is doing the MPEG
       encoding and "machine1" is the machine that is decoding scaling and
       denoising the captured video.

       Obviously, for this to work "machine1" has to be able to access the
       video and the computer where the command is executed has to have space
       for the encoded video. In practice, it is usually well worth setting up
       network file-storage using "NFS" or other packages if you are going to
       do stuff like this.  If you have three computers you can take this a
       stage further, one computer could do the decoding and scaling, the next
       could do denoising and the third could do MPEG encoding:

       > rsh machine1 "lav2yuv mycapture.eli | yuvscaler -O SVCD" | yuvdenoise
       | rsh machine3 mpeg2enc -f 4 -o mycapture.m2v

       NOTE:How the remote command executions are set up so that the data is
       sent direct from the machine that produces it to the machine that
       consumes it.

       In practice for this to be worthwhile the network you are using must be
       fast enough to avoid becoming a bottleneck. For Pentium-III class
       machines or above you will need a 100Mbps Ethernet.

       For really fast machines a switched 100MBps Ethernet (or better!) may
       be needed.Setting up the rshd ("Remote Shell Daemon" needed for rsh to
       do its work and configuring "rsh" is beyond the scope of this document,
       but its a standard package and should be easily installed and activated
       on any Linux or BSD distribution.

       Be aware that this is potentially a security issue so use with care on
       machines that are visible to outside networks!Interoperability

       Quicktime files capturing using lavrec can be edited using
       Broadcast2000.  But Broadcast2000 is not available any more on
       heroinewarrior.  mjpeg AVI files captured using the streamer tool from
       the xawtv package can be edited and compressed and played back using
       software.  Hardware playback is not possible for such files due to
       limitations in the Zoran hardware currently supported. Videos recorded
       with NuppelVideo can also be processed with the mjpeg tools.

       If you have a Macintosh (MAC) and want to use the mjpeg tools look
       there:

       MPEG files produced using the tools are know to play back correctly on:

       dxr2 (hardware decoder card)

       xine

       xmovie

       mplayer

       vlc

       MPEG-1 only: gtv

       MS Media player version 6 and 7 and later version

       severals Software based DVD Player

       To find out what you HW-player (most of the time DVD player) can do
       take a look at:

       It seems that the MS Media player likes MPEG-1 streams more if you have
       used -f 1 when multiplexing.

       If you have any problems or suggestions feel free to mail me (Bernhard
       Praschinger): There is a lot of stuff added from the HINTS which Andrew
       Stevens created. Wolfgang Goeller and Steven M. Schultz checked the
       document for bugs and spelling mistakes.

       And to the people who have helped me with program descriptions and
       hints, thanks

SEE ALSO

The mjpeg homepage is at: http://mjpeg.sourceforge.net/ http://sourceforge.net/projects/mjpeg vcdimager is aviable at: http://www.vcdimager.org/ cdrdao is aviable at: http://cdrdao.sourceforge.net/index.html Linux Video Studio is aviable at: http://ronald.bitfreak.net The lavtools: jpeg2yuv(1), lav2wav(1), lav2yuv(1), lavpipe(1), lavplay(1), lavrec(1), lavtrans(1), lavinfo(1), mp2enc(1), mpeg2enc(1), mplex(1), ppmtoy4m(1), pnmtoy4m(1), yuv2lav(1), yuvdenoise(1), yuvkineco(1), yuvmedianfilter(1), yuvplay(1), yuvfps(1), yuvscaler(1), yuvycsnoise(1), y4mblack(1), y4mcolorbars(1), y4mdenoise(1), y4mhist(1), y4minterlace(1), y4mshift(1), y4mstabilizer(1), y4mtopnm(1). y4mtoppm(1). Tools without a man page: lavaddwaw, glav MJPEG tools manual MJPEG tools(MJPEG Linux Square)

Search: Section: