conversion from msmpeg4v3 to iso mpeg4 attempt

[ReinerSchweinlin]

The patched ffmpeg works just fine. AFAIK nobody took the effort to fix the muxing-problem since it´s easy solvable via vdub(mod).

[sneaker_ger]

I mainly meant this problems:


- it converts about 80% of the msmpeg4v3 videos he tried perfectly, but he can't figure out what's wrong with the rest
- there are still bugs (some files fail to convert, it's no faster than a regular re-encode, mmx must be disabled, etc.)
- on some problem samples, it looks like certain inter frames aren't having their intra blocks copied properly
- it's almost as if certain blocks are being decoded differently for no apparent reason
- the problems only happen with files he doesnt know how they have been created
- it doesnt seem to be related to old nandub versions, as he, in order to do the conversion, stepped through every line of code that was involved, and there weren't any different workarounds being invoked between files that worked and didn't work
- if you tried "ffmpeg input.avi output.avi" it was fine (albeit re-encoded lossily), but if you tried "ffmpeg -mstomp4 input.avi output.avi" the decoded mb types, vectors and coeffs are the same as before, but it is displayed differently (-mstomp4 tells ffmpeg that the conversion will be lossless. without it ffmpeg does a regular decode->encode)
- he suspects that there's something ffmpeg is doing that he hasn't noticed till now