Describe LinuxBilderDvd here.

http://linuxjournal.com/article/6631 http://66.123.212.164/~scott/computer/linux/scripts/dvd/dvd-slideshow.html

• Recording videos:

Recording with lavrec look's 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 Crtl-C (nowadays: Strg-C). Sometimes useing -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

Introduction General Warnings Recording videos Creating videos from images Checking if recording was successful Edit the video Creating movie transitions Converting the stream to MPEG or DIVx videos: Creating sound: Converting video: Putting the streams together: Creating MPEG1 Videos Creating MPEG2 Videos Creating VideoCD's Creating SVCD's Creating DIVX Videos Optimizing the stream: Transcoding Trading Quality/Speed SMP and distributed Encoding: Interoperability:

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

Achtung es gibt auch eine deutsche Version bei: http://sourceforge.net/projects/mjpeg

There is also a manpage of this text, you can read it with "man mjpegtools" if installed.

The text version of this text is aviabel via cvs, you should get it with a tarball or the precompiled package (RPM and deb). General Warnings:

You have to compile and install the mjpeg_play package, for this read the README & REQUIRED_SOFTWARE & INSTALL. If you do not want to compile it, you can download the mjpeg .RPM or .DEB Package at sourceforge. There is a script in the scripts/ directory. This script is something that show's you a way how it can be done. It also creates (under certain circumstances) videos that look quite good. Better videos you only get by tuning the parameters yourself.

You will usually have to load the drivers for the Buz or DC10 or LML33 cards. So 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 aviable from: http://www.cicese.mx/~mirsev/Linux/DC10plus/ The driver for the Matrox Marvel card also works, more information about it: http://marvel.sourceforge.net

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.

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 compile the tools on a other platform, not all tools might work. The v4l (video4linux) stuff will very likely fail to work.

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".

One last thing about the data you get before we start: Audio: ( Samlperate * 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 : (768 * 576 * 25 * 80) / (200 * 1024) = 4320 kB/sec NTSC HALF size: (320 * 200 * 30 * 80) / (200 * 1024) = 750 kB/sec NTSC FULL size: (640 * 480 * 30 * 80) / (200 * 1024) = 3600 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 so big that one frame fits into it. The size of one frame is: (width * height * quality ) / (200 * 1024) = kB If the buffer is to small the rate calculation doesn't match any more and buffer overflows can happen.

How video works, and the difference between the video type is explained here:http://www.mir.com/DMG/

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

Recording with lavrec look's 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 Crtl-C (nowadays: Strg-C). Sometimes useing -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.

The cards record at a different size in PAL when recording at -d 1 : BUZ and LML33: 720x576 and the DC10: 768x576

Other example: > lavrec -w -f a -i S -d 2 -l -1 record%02d.avi Should start recoding: -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.

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: http://marvel.sourceforge.net.

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.

All lavtools accept a file description like file*.avi, so you do not have to name each file, but that would also be a posibillity to do.

Note: More options are described in the man-page.

There are more options, but with this you should be able to start.

How about some hints as to 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 encounter problems. If you use much higher settings you will encounter framedropps. 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.

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

It should look like this. The fist 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 at a with a greater declimation, and 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, your machine can't handle it. Take less demanding options, try to use an other sound card.
• (ae) audio errors are never good. Should be 0
• (td1, td2) time difference is 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 whole mjpegtools image processing chain is frame-orientated. Since it is video material that is captured each frame comprised a top field (the 0th, 2nd, 4th and so lines) and a bottom field (the 1st, 3rd, 5th and son on lines).

There are three bad things that can happen with fields:

1. 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 its 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 in time 1/25sec apparent.

2. 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.

3. 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?

1. 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 drastically you know what the problem was and what the solution is!

2. Easy to spot: find a Channel logo or a picture or two areas with a sharp horizontal boundary. If the top or bottom line of an area appear to be "detached" you've got this problem!

3. Use "glav" to find some scene changes. If at the change odd lines are from one scene and even from another you've captured with the wrong field order.

If you use glav or lavplay be soure that you also use the -F/--flicker option. This disables some things that make the picture to look better, and problems are not that hard to be recognized.

If you want to look at the video you can also use yuvplay: > lav2yuv | ... | yuvplay You should see here also some problems.

How can you fix it?

1. To fix this one the fields need to be "shifted" through the frames. Use yuvscaler's -M 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.

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

3. 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 mjpegtools 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 a confusing playback. Use your favourite grafic 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 slow advancing.

If you have a film you should always see 2 pictures that are nearly the same after each other. Nearly because the film frame is split into two field for broadcasting. You can notice this rather easy if you have comb efects when you pause the film because both field should fit together well. 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 yuvscaler's -M 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 yuvscaler 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, reordering them using yuvscaler: > lav2yuv -f 40 video.avi | yuvscaler -M OPTION | y4mtoppm | pnmsplit - pnm/image%d.pnm

Where "OPTION" is what you think it will corrects 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 and shown after each other. Spotting the problem here is harder. You need to find something moving hoziontally 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 my change between the channels, between the films and it may even change in 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 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 -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.)

If you want to encode a mpeg video directly from jpeg images without saving a separate video file type: > jpeg2yuv -f 25 -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 mpeg-video, type: > jpeg2yuv -f 25 -j image%05d.jpg | yuvscaler -O SVCD | mpeg2enc -f 4 -o video.m2v

It's also usefull to put yuvmedianfilter before mpeg2enc. The resulting video will be softer but a bit less sharp: > jpeg2yuv -f 25 -j image%05d*.jpg | yuvmedianfilter | mpeg2enc -o video.m1v

It also depends on the quality (compression) of your jpeg images whether yuvmedianfilter should be used or not.

You can use the -b option to set the number of the image to start with. For example, if your first image is image01.jpg rather than image00.jpg, type: > jpeg2yuv -b 1 -f 25 -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

The number of images to be processed can be specified with the -n number.

For ppm input there is the ppmtoy4m util, there is also a manpage for ppmtoy4m.

So to create a mpeg video try this: > cat *.ppm | ppmtoy4m -o 75 -n 60 -F 25:1 | mpeg2enc -o output.m1v

Cat's 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 *.jpg ppm:- | ppmtoy4m | yuvplay

That means take all '.jpg' images in directory, convert to PPM format, and pipe to stdout, then ppmtoy4m processes them .... Checking if recording was successful:

You can use lavplay or glav. IMPORTANT: NEVER try to run xawtv and lavplay or glav with hardware playback, wont work. If you want 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. Your system has quite a heavy load. You don't need xawtv or anything, though.

The better way: >lavplay -p H record.avi

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

You might also try: >lavplay -p C record.avi

Which will play it back using the hardware, but to the videooutput 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 HW 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 encconding 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: You reduce your quality by using low quality cables. 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, that makes recoding videos very simple named Linux Studio. You can download it at: http://ronald.bitfreak.net Edit the video:

Most tasks can be easily done by glav. Like deleting parts of the video, cut paste and copy parts of the videos. For my part I was not in the need of doing anything that glav couldn't do.

The modifications should be saved because glav does not edit (not destructive) the video. This means that the video is left untouched, and the modifications are kept in an extra "Edit List" file. Readable with a text editor. This files can be used as an input file for the lavtools, like 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, you do not need to recalculate something.

If you want to get an "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.movtar -f m record_1.avi record_2.avi ... record_n.avi -o : specifies the output name -f m: specifies the output format, movtar in this case

This is usually not necessary. Keep in your mind that there is the 2GB file-size-limit on 32Bit systems with an older glibc. Separate pics and sound:

> lavtrans -o sound.wav -f w stream.avi Creates a wav file with the sound of the stream.avi Maybe need if you want to remove noise or something else, or you want to convert it to an an other sound format for other use.

An other version of splitting the sound is: > lav2wav editlist.eli >sound.wav

Creating 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 ....

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 scenery: We have two input videos, intro.avi and epilogue.mov and want make intro.avi transist 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 regarding frame rate and image resolution, at the moment. 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 225, the offset, tells lav2yuv to begin with frame # 225 and -f 25 makes it output 25 frames from there on

Another possibility is: >lav2yuv -o -25 intro.avi

Since negative offsets are counted from the end.

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 equal 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, so that if you pass 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 be automated later, anyway.

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

(This is one line.) 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:

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 -o mpeg1 -O output.mpg file.eli

- will create a mpeg1 with videobitrate=2110 and audio=160 - and resolution 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 res as input .

However, better results can be accomplished by trying out various options and find out which one works best for you. These are discussed below.

The creation of MPEG1 movies is explained with more examples, and with more details because most things that can be used for MPEG1 also fit for the other output formats

For the creation of of VCD/SVCD Stills sequences (-f 6, -f 7 in mpeg2enc) you have to look at: http://www.mir.com/DMG/ 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 MPEG1-layer2 sound files. For MPEG-2 videos you can use MPEG1-Layer2 and MPEG1-Layer3 (MP3). But you should stick to MPEG1-Layer2 because most of the MPEG2 players (DVD Player for example usually the different Winxx Versions have great problems with this too) are not able to play MPEG2-Video and MPEG1-Layer3 sound.

mp2enc is a MPEG layer 2 Audio encoder. The toolame encoder is also able to produce an layer 2 file. You can use that one as well. For mp3 creation I'm 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.

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 sec of audio already encoded.

You can test the output with: > plaympeg sound.mp2

NOTE: plaympeg is a MPEG1 Player for Linux, you can use other players as well, for MPEG audio testing you can also use mpg123. Converting video:

You can create MPEG1 and MPEG2 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 README in the mpeg2enc directory.

Example: > lav2yuv stream.avi stream1.avi | mpeg2enc -o video.m1v

This creates an video file with the default bitrate of 1152kBit/sec. This is the bitrate you need if you want to create VCDs. You can specifie more files, and also use the placeholder %nd. Where n describes the numbers.

Example: > lav2yuv stream*.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 when trying to find similar 16*16 macroblocks of pixels in 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 silly. Lower values (0, 8), improve the encoding speed but you get lower quality (more visible artifacts), higher values (24, 32) improve the quality at the cost of the speed. With the file description of stream*.avi all files are proceed that match this pattern beginning 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 starting: > yuvscaler -h

Using yuvscaler, one can now also downscale the video before encoding it. This can be useful for, for example, users with a DC10+ card, which captures at 384x288 (PAL/SECAM) or 640x480 (NTSC) when using full resolution with decimation two during recording.

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

This will rescale the 384x288 or 768x576 (PAL/SECAM) or 352x240 or 640x480 (NTSC) stream to the VCD-size 352x288 (PAL/SECAM) or 352x240 (NTSC) and encode the resulting output YUV data to an mpeg stream.

It can also do SVCD-scaling to 480x480 (NTSC) or 480x576 (PAL/SECAM): > lav2yuv stream.avi | yuvscaler -O SVCD -M BICUBIC | mpeg2enc -o video.m2v

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 by the bicubic algorithms.

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 have special output format.

Note: yuvscaler can also set a active area, and set everything else to real black using: -I ACTIVE_WidthxHeight+WidthOffset+HeightOffset

Testing is done by: > plaympeg video.mpg

Note: This 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 common you can say the more options used the longer it takes. Note3: MPEG1 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 MPEG1 you have to set -b very high (2500)else VBR does not make much sense. It is not likely that VBR MPEG1 works on HW-players. Note4: Maybe you should give better names than video.mpg. A good idea would be if you see the filename you know the options you've used. (Ex: video_b1500_r16_41_21.m1v) Another possibility is to call all the layer 2 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 based on the SMPG library work well. Other Players are: xmovie, xine, gtv, MPlayer for example.

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!

Note: xine might have a problem with seeking through videos.

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 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.

Example: >plaympeg my_video.mpg or >gtv my_video.mpg Creating MPEG1 Videos: For MPEG1 you can use mpeg layer 2 Audio and mpeg1 video. A subset of MPEG1 Movies are VCD's. You can use VBR (Variable BitRate) for the Video, but the Audio has to be CBR (Constant BitRate).

MPEG1 is recommended for picture sizes up to 352x288 for PAL and 352x240 for NTSC for larger sizes MPEG2 is the better choice. There is no exact line till where MPEG1 is better than MPEG2. Audio creation Example > lav2wav editlist.eli | mp2enc -o sound.mp2

This will fit the MPEG1 quite well. You can save some Bit when telling to use a lower bitrate (-b option) like 160 or 192 kBit/s

> 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. So you do NOT have to create an edited stream with lavtrans to get it converted properly. Video creation Example > lav2yuv editlist.eli | mpeg2enc -b 2000 -r 24 -q 6 -o video.m1v

Then mpeg2enc creates an video with an bitrate of 2000kBit/s (or 2000000Bit/s) but the -q flag activates the variable bitrate and an quality factor of 6. It uses a search radius of 24. An editlistfile used.

Explanation: when mpeg2enc is invoked without the 'q' flag it creates "constant bit-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+21 | 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 to VCD's for this example. To determine the active window extract one frame to the jpeg format: > lavtrans -f i -i 100 -o frame.jpg test.avi The -4 1 and -2 1 options improve 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.

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 artefacts. If you want to reduce bit-rate without annoying artifacts when compressing broadcast material you should try the noise filters. This are for lav2yuv: -n [0..2] and -d [0..3]. There are other filter which are described later. mple: > 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 ensure 2 B frames appear between adjacent I/P frames. Several common MPEG-1 decoders can't handle streams where less than 2 B-frames appear between I/P frames. -g 6 -G 20 : the encoder can dynamically size the output streams group-of-pictures 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 6 and 18 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 uses 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. 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 (not used the -q option).

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 MPEG2 Videos: MPEG2 is recommended for sources with a greater picture than 352x240 for NTSC and 352x288 for PAL. MPEG2 can also handle interlaced sources like recording from TV at full resolution.

MPEG2 allows the usage of mpeg layer 3 (mp3) sound. So you can use your favorite mp3encoder for the creation of the sound. The audio can also be a VBR Stream.

MPEG2 is usually a VBR Stream. MPEG2 creation with optimizing need a lot of CPU power. But a film with the double resolution does NOT is not 4 times larger than an MPEG1 Stream. Depending on your quality settings it will be about 1.5 up to 3 times larger than the MPEG1 Stream at the half resolution. Audio creation Example > lav2wav editlist.eli | mp2enc -o sound.mp2

This will fit the MPEG2 quite well. You can save some Bit when telling to use a lower bitrate (-b option) like 160 or 192 kBit/s

I hope I don't need to explain the usage of an MP3 Encoder ? But you should not use all the fancy options you can use. Video creation Example > lav2yuv editlist.eli | mpeg2enc -f 3 -b 3000 -q 9 -o video.m2v

A very simple example for MPEG2 Video. The most important option is the -f 3. That tells mpeg2enc that it should create a MPEG2 stream. Because it is a generic MPEG2 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 tell mpeg2enc the maximum bitrate that can be used. The -q option tell mpeg2enc which quality the streams should have, but is bound to the maximal bitrate -b we allow.

> 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 is more like a high quality MPEG2 Stream. The -4 1 -2 1 option make a bit better quality. 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 that the default. Dynamic GOP set with -g -G, A larger GOP size can help reduce the bit-rate required for a given quality. 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 interlace-adapted motion compensation an block encoding done. mpeg2enc will switch to this mode if the size of the frames you encode is larger than the VCD size for you TV Norm.

If you denoise the images with yuvdenoise and use the deinterlacing (-F) built in there you should tell mpeg2enc that it does not need to do motion estimation for interlaced material. You have to set the mpeg2enc -I 0 option to tell that the frames are already deinterlaced. This will save a lot of time when encoding. If you don't do it it will cause no other drawbacks.

You can also use scaling an options that optimize (denoise) the images, to get smaller streams. But this options are explained in deep in the according sections. Which values should be used for VBR Encoding (-q) The -q option controls the minimum quantization of the output stream. Quantization controls the precision with which image information is encoded. The higher the value the better the image quality.

Usually you have to set up a maximum bitrate with the -b option. So the tricky task is to set a value for the -q option and the -b option that produces a nice movie without using to much bandwidth and not much artefacts.

A Quality factor should be chosen that way that the mplex output of Peak bit-rate and Average bit-rate differ for about 20-25%.

If the the difference is very small < 10%, it is very likely that you have done something wrong. It is very likely the you have chosen the wrong values for the maximal bitrate or a to high quality factor.

A combination that will produce more artefacts you can count, is a SVCD with a maximal video bitrate of 2500kBit and a qualitfactor set to 1 or 2. For SVCD with a video limit of 2500kBit a quality factor of 7-11 fits quite good.If you use filter programs or have a very good source like digital TV, DVD like material or rendered pictures. If your SVCD/DVD player supports higher bitrates than the official 2788kBit/sec for the video and audio. Use the higher bitrate and a higher quality factor, action scenes for example will look much better.

The same (7-11) quality factor for a full size picture and a top bitrate of 3500 to 4000 kBit won't produce to much artefacts too.

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) MPEG2 supports interlaced movies to be encoded. So a MPEG2 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 yuvdenose -F, or if you have a high quality source, and don't need to use the denoiser, with yuvscaler -O NOT_INTERLACED. Also set the mpeg2enc interlace-mode (-I) option to 0. This means that there is no interlacing. We do here not really need deinterlacing because there is no motion between the fields of the frame. We only need to union them to a single progressive frame.

This movie should be played 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 yuvdenoise -F, you will lose details. But if you plan to play the recorded stream on your DVD player and you TV. It would not be wise to do that. But if you only want to play it back on the Monitor (progressive display) the picture lookes 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 yuvdenose -F, and set the mpeg2enc -I 0. If you do not want do deinterlace th stream, yo do not need to set any special option.(Do not use yuvscaler -F, 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 documentation, where some parts are from an speaker are recorded interlaced and other parts are filmed. You have to decide if you want optimal film sequences and good still images you should deinterlace (yuvdenoise -F, mpeg2enc -I 0). Else you do not need to deinterlace it, and have a better quality of the interlaced sequences. Multiplexing Example > mplex -f 3 -b 300 -r 4750 -V audio.mp3 video.mp3 -o final.mpg

Now both streams are multiplexed, a mp3 audio and a mpeg2 video. You have to use the -f 3 option to tell mplex the output format. You also have to add the -b decoder buffers size with the same value used when encoding the video. -r is that rate of video + audio +1-2% of mplex information. The -V option 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. An this streams usually get BIG. Creating Video CD's: VCD is a cut down version of MEPG1 streams. There are some limitations on VCD's. Like bitrate for video 1152kBit and for audio layer 2 audio with 224kBit stereo. You are not allowed to use the -q option, dynamic GOP 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 player, and you plan to play it back on your DVD player for example. You DVD player might be that flexible to allow larger bitrates, dynamic GOP, larger video buffer and so on. Audio encoding Example > lav2wav stream.avi | mp2enc -V -o sound.mpg

-V force VCD compatible output (same as: -b 224 -r 44100 -s) For hardware players, you should stick to 44.1 224kBps Stereo layer 2 Audio. Video encoding Example > lav2yuv stream.avi | yuvscaler -O VCD | mpeg2enc -f 1 -r 16 -o video.mpg

For a 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. So the multiplexed streams should easily fit on a CD with 650MB.

The default value (-B) is 700MB for the video. mpeg2enc marks automatically every stream at that size if the -B does not set anything else. If you have a CD where you can write more MB like 800, you have to set the -S option else mpeg2enc will mark the stream at 700 MB, and mplex will split the stream there. Which might not be what you want. Multiplexing Example

> mplex -f 1 sound.mpg 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 http://www.hvrlab.org/~hvr/vcdimager/

Example: > 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: http://cdrdao.sourceforge.net/

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 MPEG1 (-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 notices that it helps when you have an MPEG1 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 an other firmware and play it back correct, but there is no guarantee for that.

Storing MPEG's. 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 only 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 but there is currently no means to make a properly structured disk image.

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 AudioVox 1680 for example can handle 2500kBit/s VCD rates (it also handles VCDs with VBR MPEG-1 but other players might not be so forgiving). 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. The -h flag seems to help also if there is a low quality stream, the video does not look that sharp using the flag, but there are not that much glitches as without it.

However, if your player supports it and you have the patience for the much 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 rather less than twice as big. Creating SVCD's: Record at full TV resolution (means: -d 1 for PAL this is 720x576) Audio creation Example > lav2wav stream.avi | mp2enc -V -o sound.mp2

NOTE: 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). 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 -F 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 overheads 2550 may already be marginally too tight. Since the SVCD format permits any audio rate between 32 and 224 kBit/sec you can save a few bits/sec by using 192k audio.

SVCD supports variable bitrate (VBR), because MPEG2 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 mpeg2enc uses this options.

An other 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.

For SVCD encoding, you can of course also use yuvscaler for the downscaling rather than letting lav2yuv doing that.

Don't forget the -S and -B options mentioned above. You want that the stream fits on the CD don't you ? Multiplexing Example

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

-f 4 : tells mplex to encode a SVCD, -r 2750 : is the calculated Audio + Video Bitrate + 1-2% multiplex information -b 300 : is the Buffer aviable on the playback device, the same used for the video encoding (there the -V option).

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 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 DIVX Videos:

The yuv2divx in the mjpeg tools uses the codecs of the avifile library to generate videos. The output formats you can create are dependent on the avifile version you use. It is recommended that you use at least version 0.6 of avifile. (Some distributions come with avifile-0.53, which is no longer supported by the avifile maintainers.)

The prossesing is a little bit different because the audio and video files do not need to be multiplexed afterwards. The output is created in a single pass. You can use the normal video encoding process. The audio file, or the sound that is already in the recorded avi, has to be given yuv2divx as an option. You can specify a WAV file, an edit list, or, as in this case, the same file we're getting the video from.

The prossesing is a little bit different because the audio and video files are not multiplex afterwards. The output is created in a single step. You can use the normal video encoding procces. The audio file, or the sound that is already in the recorded avi, has to be given yuv2divx as option.

Enough talk here is an example: > lav2yuv stream.avi | yuv2divx -A stream.avi -o lowrate.avi

Looks a bit strange because yuv2divx reads the YUV video stream from stdin but has the audio passed in by an option. The -A specifies the audio stream. In this case, it is also in our stream.avi. The output is also a .avi file because Divx is also named avi. The .divx extension is also sometimes used.

Example: > lav2yuv stream.avi | yuvdenoise | yuvscaler -O SIZE_640x480 | yuv2divx -b 2500 -a 196 -E DIV5 -A stream.avi -o output.avi

You see that using other tools to get the stream in the proper form is no problem. Here we set the maximum bitrate to 2500kBit/s, and the audio bitrate to 192kBit/s. The video coded this time used is the DIV5.

A bitrate of 2500 is considered rather high for Divx encoding. Divx encoding offers its greatest utility (giving decent images at high compression) at bitrates that MPEG2 encoding would generate poor quality. Experimentation is encouraged, of course, but the general rule of thumb appears to be that Divx offers similar quality at two-thirds of the bitrate of MPEG2 -- note that this is video bitrate only, audio bitrate remains the same as the same type of encoding is used for both.

lav2divx

If you do not need to perform any audio or video alteration of the audio or video streams, you can perform a conversion to divx in one step using the lav2divx utility.

lav2divx -b 1000 -E DIV5 -o output.avi input.editlist

This takes the edit list and uses that as the source for both the video and the audio. Since it's all done in one step, there's no opportunity to use any of the YUV filters, scalers, and denoisers.

A word on avifile codecs

The lav2divx and yuv2divx utilities are primarily intended for creating Divx avi files. However, since they use avifile, it's possible to generate output in any video format avifile is aware of. You specify the codec by its four letter code ("DIV5" in the examples above; this is sometimes called the codec's "fourcc"). The ones that are available vary greatly depending on the specific libraries available to avifile. Optimizing the stream:

Using filters helps to increase the image quality using fixes bitrate 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 sharpens the image a little. It takes a center pointer avg the pixels around it that fall with the threshold. It then replaces the center pixel with this new value. You can also use the -r (radius) option for an other search radius. Use -t to control the threshold of the pixel count in the avg. The defaults -r 2 and -t 2 look good.

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. If you want yuvdenoise also to deinterlace the stream use the -F option.

Example: > lav2yuv stream.avi | yuvkineco -F 1 | mpeg2enc -o video.m1v yuvkineco is used for NTSC sources. It does the conversation from 29.97 fps to 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.

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 know now the optimal settings for the denoiser, scaler and so on.Replace the mpeg2enc or yuv2divx with yuvplay. yuvplay playes back the yuv frames. So you can see if the options you have choosen are making the thing better or worse.

A command would look like this: > lav2yuv stream.eli | yuvdenoise -options | yuvscaler -options | yuvplay Transcoding of existing MPEG-2

For transcoding existing MPEG-2 streams from digital TV cards or DVD a still lower data-rate than for broadcast will give good results. Standard VCD 1152 Kbps typically works just fine for MPEG1. 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 mjpeg homepage ( http://sourceforge.net/projects/mjpeg ). You also need sox and toolame.

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

So transcoding looks like this: > transcode -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_ac3 tool labeled "SYNC" when run with the "-s" flag.

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 VCD -O 234 : Video timestamp offset in mSec, generated by the lavtrans script, there negative values are allowed vcd_stream.mp2 & vcd_stream.m1v : generated files lowrate.mpg : the VCD compatible output stream

> transcode -S -o svcd_stream mpeg2src.mpg

Here the output format is SVCD (MPEG-2 video).

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: > cat mpeg2src.mpg | mpeg2dec -s -o YUVs | mpeg2enc -I 0 -f 4 -q 9 -V 200 -b 2500 -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 has to look like this:

Extracting Audio: > cat test2.mpg | extract_ac3 - -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 afterwards for the 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_ac3 - -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 output contains the label "SYNC". You have to use this time (referred to as "SYNC_value" below) when doing the multiplexing.

You can generate VCD and SVCD videos, and own mpeg1/2 videos.

For VCD creation use:

> cat test2.mpg | mpeg2dec -s -o YUVh | mpeg2enc -s -o video_vcd.m1v

mpeg2dec: -s : tells mpeg2dec to use program stream demultiplexer -o YUVh: the output size of the extracted frames.

There are other output modes, try "mpeg2dec --help" but the most important here are: YUV : is the full image size YUVs : is SVCD size YUVh : is VCD size

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

-f 1 : generates an VCD stream

For SVCD creation use: > cat test2.mpg | mpeg2dec -s -o YUVs | mpeg2enc -f 4 -q 9 -V 200 -o video_svcd.mpg -q 9 : Quality factor for the stream (VBR stream) (default q: 12) -V 200 : Target video buffer size in KB -o : Output file

Mplex with: > mplex -f 4 -b 200 -r 2755 audio.mp2 video_svcd -o svcd_stream.mpg

-f 4 : generate an SVCD stream

-b 200 : Specify the video buffer also used while video encoding

-r 2755 : Specify data rate of output stream in kBit/sec

For other video output formats this might work:

> cat test2.mpg | mpeg2dec -s -o YUV | yuvscaler -O SIZE_320x200 -O NOT_INTERLACED | mpeg2enc -o strange_video.m1v

If you want to reedit 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. Look for the linux port at the bottom. Available at: http://members.home.net/beyeler/bbmpeg.html

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: > cat video.m1v | mpeg2dec -o YUV | 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_ac3 - -s | ac3dec -o wav 2>/dev/null >sound.wav

Extract video: > cat test2.mpg | mpeg2dec -s -o YUVh | yuv2lav -f a -q 85 -o test.avi

Adding the sound: > lavaddwav test.avi sound.wav fullvideo.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 !

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

dvd-formate

http://sourceforge.net/docman/display_doc.php?docid=11305&group_id=5776

Video: (width * height * framerate * quality ) / (200 * 1024) PAL HALF Size : (352 * 288 * 25 * 80) / (200 * 1024) = 990 kB/sec PAL FULL size : (768 * 576 * 25 * 80) / (200 * 1024) = 4320 kB/sec NTSC HALF size: (320 * 200 * 30 * 80) / (200 * 1024) = 750 kB/sec NTSC FULL size: (640 * 480 * 30 * 80) / (200 * 1024) = 3600 kB/sec

Transcode to SVCD

The advantage of this format is you can play SVCD disks on most existing standalone DVD players. The disadvantage is poor image quality. But, overall, SVCD is the recommended format if you plan to watch your movies on TV and not on a computer. See Listing 2 for the script conv-svcd, which performs the conversion for you.

Listing 2. conv-svcd converts the capture files to SVCD.

#!/bin/sh if [ ! $1 ]; then

• echo "Usage: $0 dirname" exit

fi name=$1 maxfs=793

bitrate=""; format="4"

# bitrate="-w 1580"; format="5" pushd ${name} mkdir -v svcd || exit pushd svcd transcode -i ../dv \

• -V -B 0,15,16 ${bitrate} \ -F ${format},"-a 2 -I 1 -S ${maxfs}" \ -b 128 -E 44100 -J resample \ -y mpeg2enc,mp2enc -o ${name} \ --print_status 10

mplex -f ${format} -o ${name}.mpg ${name}.m2v \

• ${name}.mpa

vcdimager -t svcd --add-dir=SEGMENT \

• ${name}.mpg

popd popd

Linux/Bilder/Dvd (last modified 2008-11-04 07:00:04)