Playback start hitches with large audio delays

[emotion3459]

mpv Information

mpv v0.39.0-723-g38ad1ed0 Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
 built on Feb  2 2025 00:04:54
libplacebo version: v7.350.0 (v7.349.0-30-g056b852-dirty)
FFmpeg version: N-118390-g9b5a4c0ae
FFmpeg library versions:
   libavcodec      61.31.101
   libavdevice     61.4.100
   libavfilter     10.9.100
   libavformat     61.9.106
   libavutil       59.56.100
   libswresample   5.4.100
   libswscale      8.13.100

Other Information

- Windows version: Win11 24H2
- GPU model, driver and version: GTX 1080Ti, 572.16
- Source of mpv: scoop
- Latest known working version: N/A
- Issue started after the following happened: N/A

Reproduction Steps

Add a large audio delay to a file (longer than the duration of a single frame).

Expected Behavior

No hitches.

Actual Behavior

Hitches at playback start.

Log File

output.txt

Sample Files

container_delay_3003ms.zip

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

• I tested with the latest mpv version to validate that the issue is not already fixed.
• 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.

[Dudemanguy]

I don't understand the problem? The file plays fine on my end and the audio just starts late.

[emotion3459]

I don't understand the problem? The file plays fine on my end and the audio just starts late.

I had a short discussion with @llyyr elsewhere and apparently the issue is AO related. llyyr stated he could only reproduce with pull AOs.

[Dudemanguy]

I don't see anything unusual with pipewire either.

[Vodes]

I also notice it on my install (windows, no-config)

Fwiw llyyr explicitly mentioned that it also happens on pipewire for them

[raptordaking]

The test file attached was made by me and this issue happens to me on Win 11 24H2 with mpv-git from scoop.
Nvidia driver 572.16

mpv v0.39.0-723-g38ad1ed0 Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
built on Feb 2 2025 00:04:54
libplacebo version: v7.350.0 (v7.349.0-30-g056b852-dirty)
FFmpeg version: N-118390-g9b5a4c0ae
FFmpeg library versions:
libavcodec 61.31.101
libavdevice 61.4.100
libavfilter 10.9.100
libavformat 61.9.106
libavutil 59.56.100
libswresample 5.4.100
libswscale 8.13.100

At 00:03.003 the video pan freezes for what seems like a single frame when the audio starts as it has been delayed using container delay by +3003ms. Tried using --no-config.

[Artoriuz]

@Dudemanguy It's just a microstutter exactly when the audio starts playing.

[Akemi]

i can see the same stutter on macOS. more pronounced with video-sync=display-resample on my end.

[Dudemanguy]

I guess I have to concede that I'm blind but I really don't see anything other than 3:2 pulldown.

Edit: Anyways I presume you guys don't see anything if you do --video-sync=desync or --video-sync=display-desync?

[raptordaking]

Edit: Anyways I presume you guys don't see anything if you do --video-sync=desync or --video-sync=display-desync?

both --no-config --video-sync=desync and --no-config --video-sync=display-desync seem to play normally for me

[kasper93]

I guess I have to concede that I'm blind but I really don't see anything other than 3:2 pulldown.

You can see the stutter in the logs too

[  3.776274]                cplayer: starting audio playback
[  3.817616]                cplayer: Change display sync audio drift: -1
[  3.908361] vo/gpu-next/libplacebo: Estimated source FPS: 23.976, display FPS: 287.712
[  3.963456] vo/gpu-next/libplacebo: Estimated source FPS: 23.976, display FPS: 143.856

[Dudemanguy]

I don't have that in my logs. The only thing other than the "starting audio playback" message is this.

[   0.349][v][vo/gpu-next/libplacebo] Estimated source FPS: 23.923, display FPS: 23.952

This is with pipewire.

[kasper93]

This is with pipewire.

This doesn't matter.

I don't have that in my logs. The only thing other than the "starting audio playback" message is this.

For me it happens after moving back to beginning. Also I have disabled smoothing in libplacebo, because it does more harm than good, so the variations are visible in log probably.

[llyyr]

I couldn't reproduce the frame repeat with null, pulse, or alsa so I thought this was only a pull based AO issue.