[FFmpeg-devel] [PATCH] Mimic decoder
Sat Mar 22 03:01:07 CET 2008
Mike Melanson wrote:
> Ramiro Polla wrote:
>>>> 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:
> 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?
The timestamps for MSN Messenger are obtained with GetTickCount(). What
I meant is that the delay between two images may vary immensely. I had
this same problem with the VFW grabber.
Can FFmpeg pass the input frames to the output without caring for a
framerate? (for formats that accept non-monotonic timestamps). As in 1
frame in, 1 frame out...
>>> 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:
How do other codecs (like jpeg) deal with this issue when bitexact is
asked for? When I grep for CODEC_FLAG_BITEXACT I don't get much results
that seem to work around this.
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