SOLVED: AV1 + subtitles doesn't work with hardware acceleration enabled

[manphiz]

Hi,


I've been using the official docker image[1] and enabled hardware acceleration which has been working fine in most cases.  However when trying to enable subtitles for AV1 videos, Jellyfin will get stuck forever, while it plays the same video fine when the subtitle is disabled.  I have also tried changing the subtitle settings with burn-in enabled or disable but it didn't make any difference.

A closer look at the FFmpeg log seems to suggest that libdav1d doesn't support subtitles with hardware acceleration enabled:

[av1 @ 0x55df4e324740] No support for codec av1 profile 0.
[av1 @ 0x55df4e324740] Failed setup for format vaapi: hwaccel initialisation returned error.
[av1 @ 0x55df4e324740] Your platform doesn't suppport hardware accelerated AV1 decoding.
[av1 @ 0x55df4e324740] Failed to get pixel format.
Error while decoding stream #0:0: Function not implemented
[av1 @ 0x55df4e324740] Missing Sequence Header.
Error while decoding stream #0:0: Invalid data found when processing input
[av1 @ 0x55df4e324740] Missing Sequence Header.
Error while decoding stream #0:0: Invalid data found when processing input
Error while decoding stream #0:0: Resource temporarily unavailable
    Last message repeated 33514 times
Too many packets buffered for output stream 0:1.
[libfdk_aac @ 0x55df4e80d1c0] 2 frames left in the queue on closing
Conversion failed!

Note that despite the error log says "Your platform doesn't suppport hardware accelerated AV1 decoding", it did play the same AV1 video fine without subtitles, so I guess that the "profile 0" part should just be the subtitle, but do correct me if I'm wrong.

I wonder whether this is a known issue, and if the developers are familiar with FFmpeg development schedule, is there any plans for supporting this?

[1] https://hub.docker.com/r/jellyfin/jellyfin