[Bug]: h.264 encoding on Intel Arc drops bitrate when compiled as generic-x86-v4 (AVX512 support)

[Schlaefer]

Which component impacted?

Encode

Is it regression? Good in old configuration?

None

What happened?

Using constant bitrate encoding the bitrate of the video drops from the desired value to fraction after a while.

Example video (keyframe cut original video/no transcoding):

out.mp4

• Reproducible with cachyos-v4 repo, ALHP-v4 repo and local build native arch (Rocket Lake)
• Drop always happens ca. 750 MB into the recording (the higher the bitrate the faster the issue occurs time-wise)
• Reproducible in gpu-screen-recorder and OBS
• Affects QSV and VA-API encoding
• intel-media-driver 24.4.3 (versions from at least the last few months are affected too)

Example OBS configuration:

What's the usage scenario when you are seeing the problem?

Content Creation, Game Streaming

What impacted?

No response

Debug Information

libva 2.22.0
libva-utils 2.22.0
intel-gmmlib 22.5.2
intel-media-driver 24.4.3

$ ls /dev/dri
total 0
drwxr-xr-x   3 root root        100 26. Nov 21:37 .
drwxr-xr-x  22 root root       5020 27. Nov 15:14 ..
drwxr-xr-x   2 root root         80 26. Nov 21:37 by-path
crw-rw----+  1 root video  226,   0 27. Nov 14:47 card0
crw-rw-rw-   1 root render 226, 128 27. Nov 08:49 renderD128

$ lspci -nn |grep  -Ei 'VGA|DISPLAY'
03:00.0 VGA compatible controller [0300]: Intel Corporation DG2 [Arc A750] [8086:56a1] (rev 08)

libva_trace.log.155.zip

vainfo.log

dmesg.log

Do you want to contribute a patch to fix the issue?

No.