mpv takes multiple seconds to open video when no audio devices are available

[oattbread]

mpv Information

mpv v0.40.0-402-gaa2dad035 Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
 built on Oct 23 2025 10:10:53
libplacebo version: v7.357.0 (v7.351.0-87-g9bffcaf-dirty)
FFmpeg version: N-121522-gd01608e02
FFmpeg library versions:
   libavcodec      62.16.100
   libavdevice     62.2.100
   libavfilter     11.9.100
   libavformat     62.6.101
   libavutil       60.14.100
   libswresample   6.2.100
   libswscale      9.3.100

Other Information

- Windows version: Microsoft Windows [Version 10.0.22631.6060]
- GPU model, driver and version: NVIDIA GeForce RTX 4070 Laptop GPU, Game Ready Driver 581.08
- Source of mpv: Windows builds by zhongfly - 2025-10-26 12:11
- Latest known working version: Not sure/ N/A
- Issue started after the following happened: Tried playing video after not having headphones connected.

Reproduction Steps

I have tested with and without an empty %appdata%/mpv folder and the issue still occurs.
2 ways to recreate.

Method 1:

1. Ensure no audio devices are connected. To know that you have done this hover over the volume indicator on the right side of the windows taskbar and see if it says 'No audio device is installed'.
2. Open mpv (this opens instantly like expected).
3. Drag and drop video onto window (error occurs here)

The error occurs in on the third step, with the window freezing for a few (around 8) seconds.

Method 2:

1. Ensure no audio devices are connected. To know that you have done this hover over the volume indicator on the right side of the windows taskbar and see if it says 'No audio device is installed'.
2. Double click video file that has default player as mpv (error occurs here)

The error occurs in the second step, but it is more jarring compared to the first. mpv will not open or show any indication of opening until a few seconds later when the video opens like expected.

Additionally, if a video is started when no audio devices are enabled but one gets enabled during playback, the video will not have sound until closing and reopening mpv

Expected Behavior

Videos should open when no audio devices are available as fast as they do when there is an audio device enabled.

Actual Behavior

Videos take much longer to open when no audio device is available.

Log File

terminal-out.txt

Sample Files

No response

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.

[verygoodlee]

I encountered this issue quite early on, and the --ao=wasapi,null option can avoid it.

It seems that trying to initialize different AO takes too much time.

[verygoodlee]

according to logs on my end, it took 8 seconds ( from 0.135 to 8.140 ) to try to initialize the 'sdl' AO.

[   0.127][v][ao] Trying audio driver 'wasapi'
[   0.127][v][ao/wasapi] requested format: 48000 Hz, stereo channels, floatp
[   0.127][d][ao/wasapi] Init wasapi
[   0.127][d][ao/wasapi] Find device ''
[   0.128][e][ao/wasapi] There are no playback devices available
[   0.128][d][ao/wasapi] Uninit wasapi
[   0.128][d][ao/wasapi] Uninit wasapi done
[   0.128][v][ao] Trying audio driver 'openal'
[   0.128][v][ao/openal] requested format: 48000 Hz, stereo channels, floatp
[   0.135][f][ao/openal] could not open device
[   0.135][v][ao] Trying audio driver 'sdl'
[   0.135][v][ao/sdl] requested format: 48000 Hz, stereo channels, floatp
[   0.136][v][ao/sdl] Channel layouts:
[   0.136][v][ao/sdl]  - mono
[   0.136][v][ao/sdl]  - stereo
[   0.136][v][ao/sdl]  - 2.1
[   0.136][v][ao/sdl]  - 4.0
[   0.136][v][ao/sdl]  - 5.0
[   0.136][v][ao/sdl]  - 5.1
[   0.136][v][ao/sdl]  - 6.1
[   0.136][v][ao/sdl]  - 7.1
[   0.136][v][ao/sdl]  - unknown9
[   0.136][v][ao/sdl]  - unknown10
[   0.136][v][ao/sdl]  - unknown11
[   0.136][v][ao/sdl]  - unknown12
[   0.136][v][ao/sdl]  - unknown13
[   0.136][v][ao/sdl]  - unknown14
[   0.136][v][ao/sdl]  - unknown15
[   0.136][v][ao/sdl]  - unknown16
[   0.136][v][ao/sdl]  - unknown17
[   0.136][v][ao/sdl]  - unknown18
[   0.136][v][ao/sdl]  - unknown19
[   0.136][v][ao/sdl]  - unknown20
[   0.136][v][ao/sdl] result: stereo
[   0.136][v][ao/sdl] requested format: 48000 Hz, 2 channels, 8120, buffer size: 0 samples
[   8.140][e][ao/sdl] could not open audio: WASAPI can't find requested audio endpoint: 找不到元素。
[   8.140][e][ao] Failed to initialize audio driver 'sdl'
[   8.141][e][cplayer] Could not open/initialize audio device -> no sound.

[sfan5]

literally the only thing that happens between the two log lines is a call to SDL_OpenAudio:

mpv/audio/out/ao_sdl.c

Lines 132 to 140 in 1fec44c

	MP_VERBOSE(ao, "requested format: %d Hz, %d channels, %x, "
	"buffer size: %d samples\n",
	(int) desired.freq, (int) desired.channels,
	(int) desired.format, (int) desired.samples);
	SDL_AudioSpec obtained = desired;
	if (SDL_OpenAudio(&desired, &obtained)) {
	if (!ao->probing)
	MP_ERR(ao, "could not open audio: %s\n", SDL_GetError());

I would assume this to be a bug/misbehavior in SDL.

[verygoodlee]

SDL_OpenAudio has been removed in SDL3, as it is an outdated API from SDL1.2 .
libsdl-org/SDL#6999

It is still retained in the SDL2 branch, but it's more recommended to use SDL_OpenAudioDevice, outdated API may no longer be maintained by anyone.
https://github.com/libsdl-org/SDL/blob/SDL2/include/SDL_audio.h#L358-L362

[sfan5]

Ok, it's still a bug in SDL.

[kasper93]

Why do Windows builds bundle SDL?

[Andarwinux]

Is SDL considered deprecated? In that case, we can remove it from the build.

[kasper93]

I don't know, why would you need to use it over WASAPI on Windows. It probably uses it as own backed.

[Andarwinux]

We always try to enable every feature that can be enabled, just in case random users decide to use or test it for some reason.

why would you need to use it over WASAPI on Windows. It probably uses it as own backed.

That makes sense, and considering that mpv only officially supported Windows 10+, WASAPI should be supported unconditionally. Perhaps we could consider making ao auto fallback disabled by default on Windows, just like --ao=wasapi,null

[kasper93]

Perhaps we could consider making ao auto fallback disabled by default on Windows, just like --ao=wasapi,null

Generally probing is problematic if something fails and doesn't run the first thing on the list. But not sure if we should limit every other AO.

[avih]

We could probe SDL last...

[kasper93]

We could probe SDL last...

It is probed last.