[FFmpeg-devel] [PATCH] Mimic decoder

Mike Melanson mike
Sat Mar 22 02:09:14 CET 2008


Ramiro Polla wrote:
> Hello,
> 
>>> ffmpeg -i mimic1-womenloveffmpeg.cam mimic1-womenloveffmpeg.mpg
>> A few questions:
>>
>> 1) Why is the framerate 1000 frames/second?
> 
> The timestamps are given in ms. The frames come at random times, 
> whenever MSN has finished sending the last one. The timestamps are 
> non-monotonic, like in this example:
> 4191196
> 4191384
> 4191453
> 4191531
> 4191597
> 4193731
> 4193798
> 4193930
> 4193997
> 4194663
> 4194721
> 4195131
> 4195863

I trust that there are not actually several thousand encoded frames in
those files. Is there any way to ask FFmpeg to skip over unchanged frames?

>> 2) Is there any way to enable the bitexact option so that output will be
>> consistent across platforms?
> 
> Is there anything not bitexact in this decoder? I thought bitexact only 
> mattered for encoders with date/time and version info...

Bit exactness is a big problem whenever the letters 'D', 'C', and 'T'
are involved. The results are different on x86_32 and PPC (similar, but
not bit exact). For more:

  http://guru.multimedia.cx/the-mpeg124-and-h26123-idct/

-- 
	-Mike Melanson




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