[FFmpeg-devel] [PATCH 3/5] avcodec/mpeg4videode: Eliminate out of loop VOP startcode reading for studio profile

[Kieran Kunhya]

>
> About the past, it appears to me that there is a deeply rooted aversion by
> some people toward some code. This just doesnt belong here.
>

Correct, mpeg4video decoding is some of the least understandable and
undocumented code in the entirety of libavcodec.
Decoding spans the following files in a completely crazy way:

mpeg4videodec.c
h263dec.c
ituh263dec.c
mpegvideo.c

Lots and lots of undocumented heuristics:
https://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/h263dec.c;h=eae29fa438e3b6b5adadbbe5d94363e2303ef7ee;hb=HEAD#l321
etc.

I appreciate I have the benefit of hindsight but for example with DPCM
there's no way to implement it without doing a block memcpy because of the
weird abstraction.

Kieran