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@@ -0,0 +1,188 @@ + + +ABOUT LIBMPEG2 + +libmpeg2 is a free library for decoding mpeg-2 and mpeg-1 video +streams. It is released under the terms of the GPL license. + +The main goals in libmpeg2 development are: + + * Conformance - libmpeg2 is able to decode all mpeg streams that + conform to certain restrictions: "constrained parameters" for + mpeg-1, and "main profile" for mpeg-2. In practice, this is + what most people are using. For streams that follow these + restrictions, we believe libmpeg2 is 100% conformant to the + mpeg standards - and we have a pretty extensive test suite to + check this. + + * Speed - there has been huge efforts there, and we believe + libmpeg2 is the fastest library around for what it + does. Please tell us if you find a faster one ! With typical + video streams as found on DVD's, and doing only decoding with + no display, you should be able to get about 110 fps on a + PIII/666, or 150 fps on an Athlon/950. This is less than 20 + cycles per output pixel. In a real player program, the display + routines will probably take as much time as the actual + decoding ! + + * Portability - most of the code is written in C, and when we + use platform-specific optimizations (typically assembly + routines, currently used for the motion compensation and the + inverse cosine transform stages) we always have a generic C + routine to fall back on. This should be portable to all + architectures - at least we have heard reports from people + running this code on x86, ppc, sparc, arm and + sh4. Assembly-optimized implementations are available on x86 + (MMX) and ppc (altivec) architectures. Ultrasparc (VIS) is + probably the next on the list - we'll see. + + * Reuseability - we do not want libmpeg2 to include any + project-specific code, but it should still include enough + features to be used by very diverse projects. We are only + starting to get there - the best way to help here is to give + us some feedback ! + +The project homepage is at http://libmpeg2.sourceforge.net/ + + +MPEG2DEC + +mpeg2dec is a test program for libmpeg2. It decodes mpeg-1 and mpeg-2 +video streams, and also includes a demultiplexer for mpeg-1 and mpeg-2 +program streams. It is purposely kept simple : it does not include +features like reading files from a DVD, CSS, fullscreen output, +navigation, etc... The main purpose of mpeg2dec is to have a simple +test bed for libmpeg2. + +The libmpeg2 source code is always distributed in the mpeg2dec +package, to make it easier for people to test it. + +The basic usage is to just type "mpeg2dec file" where file is a +demultiplexed mpeg video file. + +The "-s" option must be used for multiplexed (audio and video) mpeg +files using the "program stream" format. These files are usualy found +on the internet or on unencrypted DVDs. + +The "-t" option must be used for multiplexed (audio and video) mpeg +files using the "transport stream" format. These files are usualy +found in digital TV applications. + +The "-o" option is used to select a given output module - for example +to redirect the output to a file. This is also used for performance +testing and conformance testing. + +The "-c" option is used to disable all optimizations. + + +OTHER PROJECTS USING LIBMPEG2 + +libmpeg2 is being used by various other projects, including: + + * xine (http://xine.sourceforge.net/) - started as a simple + mpeg-2 audio and video decoder, but it since became a + full-featured DVD and video media player. + + * VideoLAN (http://www.videolan.org/) - video streaming over an + ethernet network, can also be used as a standalone player. + + * MPlayer (http://www.MPlayerHQ.hu) - another good player, it is + also very robust against damaged streams. + + * movietime (http://movietime.sourceforge.net/) - still quite + young, but it looks very promising ! + + * mpeg2decX (http://homepage1.nifty.com/~toku/software_en.html) - + a graphical interface for mpeg2dec for macintosh osX. + + * TCVP (http://tcvp.sf.net) - video and music player for unix. + + * drip (http://drip.sourceforge.net/) - a DVD to DIVX transcoder. + + * PoMP + (http://www.dmclab.hanyang.ac.kr/research/project/PoDS/PoDS_sw.htm) - + a research player optimized to minimize disk power consumption. + + * OMS (http://www.linuxvideo.org/oms/) + + * XMPS (http://xmps.sourceforge.net/) + + * GStreamer (http://www.gstreamer.net/) - a framework for + streaming media; it has an mpeg2 decoding plugin based on + libmpeg2. + + * mpeglib (http://mpeglib.sourceforge.net/) - a video decoding + library that usess libmpeg2 when decoding mpeg streams. + + * daphne (http://daphne.rulecity.com/) - a laserdisc arcade game + simulator. + + * GOPchop (http://outflux.net/unix/software/GOPchop/) - a + GOP-accurate editor for MPEG2 streams. + +If you use libmpeg2 in another project, let us know ! + + +TASKS + +There are several places where we could easily use some help: + + * Documentation: libmpeg2 still has no documentation. Every + project using it has had to figure things out by looking at + the header files, at the mpeg2dec sample application, and by + asking questions. Writing down a nice documentation would make + the code more easily reuseable. + + * Testing: If you find any stream that does not decode right + with libmpeg2, let us know ! The best thing would be to mail + to the libmpeg2-devel mailing list. Also, it would be nice to + build a stress test so we can make sure libmpeg2 never crashes + on bad streams. + + * Coding: There is a small TODO list in the mpeg2dec package, + you can have a look there ! Most items are pretty terse + though. + + * Porting: If you're porting to a new architecture, you might + want to experiment with the compile flags defined in + configure.in . When you figure out whats fastest on your + platform, send us a patch ! + + * Assembly optimizations: We only have x86 and altivec + optimizations yet, it would be worthwhile writing routines for + other architectures, especially those that have SIMD + instruction set extensions ! Also the yuv2rgb x86 routines + could probably be optimized a lot. + + +SUBVERSION REPOSITORY + +The latest libmpeg2 and mpeg2dec source code can always be found by +anonymous Subversion: + +$ svn checkout svn://svn.videolan.org/libmpeg2/trunk libmpeg2 + +You can also browse the latest changes online at +https://trac.videolan.org/libmpeg2/browser + + +MAILING LISTS + +See the subscription information at http://libmpeg2.sourceforge.net/lists.html + +libmpeg2-devel + +This is the main mailing list for technical discussion about +libmpeg2. Anyone wanting to work on libmpeg2, or maybe just stay +informed about the development process, should probably subscribe to +this list. + +libmpeg2-checkins + +All libmpeg2 checkins are announced there. This is a good way to keep +track of what goes into CVS. + +libmpeg2-announce + +This is a very low traffic mailing list, only for announcements of new +versions of libmpeg2. Only project administrators can post there. |