The Labs.Com Video Lab

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Open-Source Video Resources for UNIX

1. Introduction
2. Resources
3. AVI
4. MPEG & MJPEG
5. Web Video (Streaming)
6. DVD
7. Other Platforms

More and more video approaches for UNIX (Linux, FreeBSD) become available, and also more codecs become available.

In the long run something like AdobePremiere-like GNU based Video-editing system which uses GIMP-plugins to render fadings or effects (see film.gimp.org).

It has to be admitted that SGI provides since years for high-end top-level video-capture and video-editing systems, unfortunatly few can afford to buy.

Note: The movie "Titanic" was rendered on Alpha-based machines running Linux, but models were created on NT and SGI-machines.

Video Lab 2. Resources

Codecs

Video4Linux Primary site Video4Linux 2 (V4L2) Experimental API and specifications ProjectMayo: DivX Opensource video-codec (MPEG4 based) OpenStream by Indrema.Com New open source architecture for full-featured video and multimedia on Linux LinuxTV.Org Linux DVD site NuppelVideo (RTJPEG) Video for slow CPUs (200MHz) with MMX based on RTJPEG The MJPEG/Linux Square MPEG 1/2, MJPEG and editting / basic DVCR functionality

Streamers / Encoders

GStreamer Open-source streaming media framework (mp3, MPEG-1 and -2, AC3, Ogg Vorbis, JPEG, RTJPEG, WAV, AU, V4L etc) FFMpeg - Multi codec streaming MPEG, ASF, AVI, WAV, SWF, Realmedia/Realaudio, PGM, PPM, JPEG, AC3, Raw MJPEG, MPEG video Fame: MPEG Encoder Provides MPEG "software-only" encoder with MMX, and network capability (no sound) The MJPEG/Linux Square MPEG 1/2, MJPEG and editting / basic DVCR functionality MJPEG: Marvel & Rainbow Runner Working QuickTime for Linux Library to read/write QT movies IomageBuz & Linux iomage-buz no longer produced

Misc. Applications

Simple DirectMedia Layer (SDL) The API documentation FXTV (FreeBSD X TV) Bt848 with MPEG streaming (IYUV & PPM) BTTV Linux Video-grabber support for various cards (bt848 chip-based) SunSite: Linux Video Apps Misc video tools (mostly outdated)

Viewers

Xine Video player: mpeg, avi, and other formats XMMS Actually a mp3 player but with a plugin also displaying MPEG and AVI videos (FreeBSD-users: check /usr/ports/graphics/xmms-*) XANIM Good video-view for X11, supports many formats

Right now (March 2002) there are only semi-professional video-recording or video-editing software available for UNIX (Linux, FreeBSD). Especially Brooktree (Bt848/878) based cards are unstable and unreliable (independent of OS and mainboards). Motion JPEG (Zoran) based video-capture cards seem more stable.

Theory

Lurker's Guide To Video Lot of infos on video The Pixel Rosetta Stone: Packings and Colorspaces Very good overview of pixel packaging Video I/O on Linux: Lessons Learned from SGI Background info

How To Video Record

Linux Box as Digital VCR: A success Story Useful hints

Video Lab 3. AVI

AVI support under UNIX is quite rare, but here some references:

Linux AVI FileLibrary AVI Library for Linux, supported formats: IndeoV3.2,4.1, MPEG-4v1,2, DivX, Cinepak Video, ATI VCR-2, I263, MJPEG, MS-ADPCM, PCM, AC3, IMA ADPCM, MPEG Layer-1,2,3, MSN Audio, GSM 6.1 Audio	JPEG to AVI Works with XANIM, but not on WIN95	PPM to AVI No sound support, but works on WIN95
AVI FAQ Very good resource, keep checking it	FourCC (AVI) Overview of all the codecs	OpenDML AVI Format PDF: MJPEG extension defined for AVI

FreeBSD

Install /usr/ports/graphics/avifile which makes also aviplay which plays the famous DiVX;-) files too.

Video Lab 4. MPEG & MJPEG

MPEG (Moving Picture Experts Group) and MJPEG (Motion JPEG) are not the same, even the sound alike.

MPEG is a standard of how to store frames, with predictive frames and vectors from which later frames can be calculated, and the whole things gets quite complicate, you find the detailed infos at MPEG.Org. In general there are following standards:

MPEG-1 1.5Mbit/s MPEG-2 1.5Mbit/s - 200Mbit/s MPEG-4 10Kbit/s - 100Kbit/s

It has to be noted, that the actual frame data compression can be in different format, MPEG just defines the way the data is stored. Often also the YUV data compression is displayed by three numbers

• 4:4:4 (4Y,4U,4V) for each pixels Y,U,V is stored
• 4:2:2 (4Y,2U,2V) for each pixels Y, but U V only for each second pixel
• 4:2:0 (4Y,U,V) for each pixel Y, but U or V (alternate) for each second pixel
• 4:1:1 (4Y,U,V) for each pixel Y, for each 4th pixel U & V

MJPEG compresses each frame using JPEG compression with a certain quality, the advantage is that MJPEG allows frame exact cutting, whereas MPEG cutting require overhead to cut frame exact.

MPEG & MJPEG Resources for UNIX:

FXTV (FreeBSD X TV) Bt848 with MPEG streaming (IYUV & PPM)	Linux Motion Video Experimental MJPEG package	MPEG.Org The best resource center with players
FFMpeg - Multi codec streaming MPEG, ASF, AVI, WAV, SWF, Realmedia/Realaudio, PGM, PPM, JPEG, AC3, Raw MJPEG, MPEG video

One thing has to be noted, if you record MJPEG you lose data as it's not true RGB 24Bit colors, but JPEG compression used for every frame.

Mark Podlipec (XAnim) different MJPEG implementations: Quicktime's MJPEG-A(MJPA) and MJPEG-B(MJPB) formats are different than AVI's "MJPG" format. Although MJPA and MJPG are similiar. Possibly different field orders in some instances. Quicktime and AVI's JPEG codec are interchangable(essentially just JFIF).

Video Lab 5. Web Video (Streaming)

Some people believe MJPEG for the web, it has some advantages, but unless there is more software & tools I doubt its success for the web-use. Always keep an eye on Progressive Networks (Real.Com) has done and still does a good job with highly compressed audio & video for 8kb/s upto 1Mb/s rate.

The final video you may like to share on the web, then several approaches are possible (ordered by our own experience):

1. RealVideo: Real.Com: best compression from 8kb/s upto 1Mb/s, one file several transfer rates supported (5.0 or later). Video conversion-tool support on UNIX (Linux, IRIX) available by February 1999 finally.
2. Shockwave: Flash: Flash Plugin (Linux), authoring tools only for Win/MAC (not Linux yet).
3. MPEG: MPEG.Org: good codec, but not very known, good support of creation tools for UNIX-based systems, also MPEG players available.
4. Animated GIF: GIFMerge: animated GIFs, rather cheap approach, but for blinking light it's sufficient, good for complex script-based animations.
5. Animated GIF: GIMP: supports animated GIFs using layers, best approach for complex but hand-made animations.
6. Java Applet: Java: using a java-applet to animate pictures or show a video, in short: instable, immense memory overhead, slow.

As soon there are hardware & software we at The Labs will provide a video toolbox called Raw Video Studio, like Raw Sound Studio has been for audio.

FFMpeg - Multi codec streaming MPEG, ASF, AVI, WAV, SWF, Realmedia/Realaudio, PGM, PPM, JPEG, AC3, Raw MJPEG, MPEG video	Xiphophorus multimedia open-source effort	StreamingServer.Org Open-source streaming server
Linux QuickTime Player Very promising

Video Lab 6. DVD

DVD are encrypted and so far no sources are available to crack them. It has to be mentioned that on Win95/98 are tools available to read out DVD's and write them back as MPEG-4.

linux-dvd/ Linux DVD

DeCSS.Com Decrypting DVDs

DVD Lab Our own section

Video Lab 7. Other Platforms

AVI FAQ Very good resource, keep checking it

FourCC (AVI) Overview of all the codecs

QuickTime File-Format Apple's quicktime, no UNIX support (no sources available, only API revealed)

                                                                                                                                   

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