Seeking broken for some Blu-rays in v0.30.0

mpv version and platform

Commit a9d83eac40c94f44d19fab7b6955331f10efe301 (or current git master) on Linux

Reproduction steps

mpv --start=10:00 --bluray-device /path/to/bluray/disc bluray://

Expected behavior

Seeks to 10:00.

Actual behavior

The timestamp increases but the audio and video are still that of the beginning of the disc.

Log file

With a9d83eac40c94f44d19fab7b6955331f10efe301, chapters were broken but seeking still worked:

[   0.119][v][lavf] queuing seek to 600.000000
[   0.119][v][lavf] execute seek (to 611.650667 flags 32)
[   0.119][v][lavf] seek done
[   0.119][v][cplayer] hr-seek, skipping to 600.000000

Since it has been partially reverted by 1c63869d0ae01fd8e720353719e4c8b8da12e0b5, seeking doesn't work with some discs:

[   0.082][v][demux] Stream is not seekable.
[   0.165][v][disc] queuing seek to 600.000000
[   0.165][v][cplayer] hr-seek, skipping to 600.000000
[   0.165][v][disc] execute seek (to 600.000000 flags 32)
[   0.165][v][disc] seek to: 600.000000
[   0.165][v][lavf] queuing seek to 0.000000
[   0.165][v][lavf] execute seek (to 0.000000 flags 2)
[   0.165][v][lavf] seek done
[   0.165][v][disc] seek done

Sample files

A lot of Blu-Rays are affected (not all) but I'm afraid I can't share one here. It's probably very easy to reproduce.

Start by comparing commits a9d83eac40c94f44d19fab7b6955331f10efe301 and 1c63869d0ae01fd8e720353719e4c8b8da12e0b5, then trace the disc and lavf seek paths shown in the logs. Reproduce with the provided mpv command on an affected Blu-ray and verify that seeking to 10:00 changes both audio and video, not just the timestamp.