"-skip_frame nokey" ignored for AV1

[nobody]

I want to process video key frames only. I've been using -skip_frame nokey. This works for other video formats, but not AV1.

To reproduce this, execute:

ffprobe -select_streams v:0 -show_frames -skip_frame nokey -of compact foo.mp4

For AV1, although the output correctly marks frames as key_frame=1 or key_frame=0, it includes every frame.

I am using the ffmpeg builds from ​https://johnvansickle.com/ffmpeg/. Specifically ffmpeg-git-20210724-amd64-static.tar.xz, which says it uses libaom 3.1.2 and libdav1d 0.9.0.

[Balling]

See ​https://trac.ffmpeg.org/ticket/9180#comment:8

[nobody]

Replying to Balling:

See ​https://trac.ffmpeg.org/ticket/9180#comment:8

Is that related? The "pict_type" field already seems to be set correctly.

[Balling]

Does ffplay -vcodec libaom-av1 -i file work? What about ffplay -vcodec libdav1d -i input? Can you try ​https://github.com/BtbN/FFmpeg-Builds/releases builds?

[nobody]

Replying to Balling:

Can you try ​https://github.com/BtbN/FFmpeg-Builds/releases builds?

Yes, the bug is still present in the latest build. For AV1 video files, ffprobe simply ignores -skip_frame nokey and ffmpeg additionally ignores -discard nokey. Curiously, -vf select=key works.

Does ffplay -vcodec libaom-av1 -i file work? What about ffplay -vcodec libdav1d -i input?

I can't try ffplay. I can't seem to get past this error (using Debian 10 Buster):

Could not initialize SDL - No available video device
(Did you set the DISPLAY variable?)

[Carl Eugen Hoyos]

I believe this was fixed by James Almer in 4b053b8db18eb0610b62a2c40d0327ae53f2387c