[FFmpeg-user] Getting MPEG2 video stream bitrate

Tobias Rapp t.rapp at noa-audio.com
Mon Apr 28 09:10:09 CEST 2014


Carl Eugen Hoyos wrote:
> The stream does not save a (constant or average) bitrate, only the 
> maximum bitrate is stored.

Yes but the stream has a de-facto bitrate defined by the size of each
frame. And if I choose a "probesize" that is too small ffprobe reports:

[mxf @ 0x2f692e0] Stream #0: not enough frames to estimate rate; consider
increasing probesize

So I guess it is estimating the bitrate from frame size but just doen't
report the value. I want to find out if that is caused by an incomplete
arguments list on my side.

> > [mxf  <at>  0x27bd2e0] Field dominance 0 support is not implemented. 
> > Update your FFmpeg version to the newest one from Git. If the problem 
> > still occurs, it means that your file has a feature which has not been 
> > implemented.
> > [mxf  <at>  0x27bd2e0] If you want to help, upload a sample of this file to
> > ftp://upload.ffmpeg.org/MPlayer/incoming/ and contact the ffmpeg-devel 
> > mailing list.
> 
> And it appears that we need such a sample.
> (I don't know much about mxf though.)

I had a look at the MXF input file with the mxfdump tool from mxflib and
that specific file does not contain any "field dominance" descriptor (see
attached log). So ffprobe/ffmpeg reports "0" because this is the
initialized value in ffmpeg.

Best regards,
Tobias
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