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libmpeg2 is a free library for decoding mpeg-2 and mpeg-1 video streams.
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!
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