mpv cannot display the video bitrate in the OSC if there is only one keyframe in the file.

[ghost]

Important Information

• mpv version: shinchiro 20230701 0bfafd2
• Platform and Version: Windows 11 22621.1928
• Source of the mpv binary: shinchiro

  Reproduction steps

  Play the first provided sample file and bring up the info page. Compare to the second video.

  Expected behavior

  The video bitrate should be displayed.

  Actual behavior

  The audio bitrate is displayed, but the video bitrate is never displayed until the second keyframe in the video appears. In the second sample video that's about 5 seconds in. In cases where there is only one keyframe in the entire file (as with the first video) this leads to the bitrate never being displayed, ever. The video bitrate can be inferred from the size of the 1 sec readahead cache, so that might be an entry vector for a fix. Or it may be changed to work how the audio bitrate works where it doesn't care about keyframes, although I'm sure that would have performance implications.

  Log file

  Broken: https://pomf2.lain.la/f/ktmk3ih7.txt Working: https://pomf2.lain.la/f/mampr60a.txt

  Sample files

  Broken: https://pomf2.lain.la/f/jfk7pinl.webm Working: https://pomf2.lain.la/f/k1fahjqe.webm

[N-R-K]

The current behavior seems to be intentional:

https://github.com/mpv-player/mpv/blob/f76c441ba2ec60d34f91341fb2643bcbccecf433/demux/demux.c#L2745-L2746

And also in the docs:

https://github.com/mpv-player/mpv/blob/f76c441ba2ec60d34f91341fb2643bcbccecf433/DOCS/man/input.rst?plain=1#L3164-L3171

[ghost]

I was sure it was intentional at the time. You don't end up relying on keyframes for bitrate calculations by accident. It's still bad.