Audio is cut off on macOS 27

mpv Information

mpv v0.41.0-dev-gf4d13e1c2 Copyright © 2000-2026 mpv/MPlayer/mplayer2 projects
 built on Aug 10 2026 04:42:17
libplacebo version: v7.360.1
FFmpeg version: 8.1.2
FFmpeg library versions:
   libavcodec      62.28.102
   libavdevice     62.3.102
   libavfilter     11.14.102
   libavformat     62.12.102
   libavutil       60.26.102
   libswresample   6.3.102
   libswscale      9.5.102

Other Information

- macOS version: macOS 27.0 (26A5416b)
- Source of mpv: official CI build (v0.41.0-922-gf4d13e1c2)
- Latest known working version:  v0.40.0
- Issue started after the following happened: started after updating to macOS 27

Reproduction Steps

1. Update to macOS 27 (currently on beta).
2. Try to play any file with the default config: mpv test.ogg --no-config and notice the audio either does not start at all or it does not play to completion.

The issue was probably introduced in #15622.
For context, this is reported by multiple Anki users: https://github.com/ankitects/anki/issues/5157.
Here's an LLM-generated fix that appears to work for me at least, but I'm not confident to submit as a PR yet. Might be useful for reference though: https://github.com/ankitects/anki/pull/5363

Expected Behavior

Audio should work normally.

Actual Behavior

This error is displayed:

[ao/coreaudio] unable to set the input channel layout on the audio unit ([206][255][255][255]/-50)

Log File

output.txt

Sample Files

test.ogg.zip

I carefully read all instruction and confirm that I did the following:

• I tested and confirmed that the issue exists with the latest release version or newer.
• I provided all required information including system and mpv version.
• I produced the log file with the exact same set of files, parameters, and conditions used in "Reproduction Steps", with the addition of --log-file=output.txt.
• I produced the log file while the behaviors described in "Actual Behavior" were actively observed.
• I attached the full, untruncated log file.
• I attached the backtrace in the case of a crash.

Start by reproducing mpv test.ogg --no-config on macOS 27 and reading the attached log around the ao/coreaudio error. Then inspect the CoreAudio changes from #15622 and compare the linked Anki fix for relevant behavior. Done means audio starts and plays to completion without the channel-layout error on macOS 27.