[Libav-user] Decoder detects wrong framerate

Carl Eugen Hoyos ceffmpeg at gmail.com
Tue Aug 21 12:25:20 EEST 2018

2018-08-21 11:21 GMT+02:00, Vasiliy Volkov <volk.vasiliy at gmail.com>:
> вт, 21 авг. 2018 г. в 11:44, Carl Eugen Hoyos <ceffmpeg at gmail.com>:
>> Do you have a sample of a file with wrong values in container that
>> gets misdetected by (current) FFmpeg?
> Carl, the problem is fundamental. With container we can't be assured that
> there is no misconfig there, so in robust solutions we can't rely on it. We
> saw such streams, but I have dump for example right now.

If you see such a stream, please provide a sample.

> You also can observe this bug in FFmpeg. We try to use framerate from
> AVCodecContext::framerate, and this value depends on number of threads
> specified for AVCodecContext. FFmpeg uses AVStream from libavformat and
> there exists two framerates: AVStream::r_frame_rate and
> AVStream::avg_frame_rate - and their values are correct, that's why FFmpeg
> shows framerate correctly.

> But decoder ( AVCodecContext ) in FFmpeg has incorrect framerate

I already told you that libavcodec has known, long-time issues with
H.264 timestamps, this is no secret.
I would be surprised if these issues - that are in no way limited to
frame-rates -
wouldn't also manifest themselves in wrong information about stream properties.

Carl Eugen

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