[?] [2727] [x64] AIMP: WASAPI Exclusive (Event) Play-Pause-Play sound error

[Dimon911]

Hi,

discovered by a chance a bug.

In WASAPI Exclusive (Event) device mode by pressing pause then play again sound "jitter" is present.
Visualization is delayed in the moment of pressing pause.


No such behavior in:

• Direct Sound and
• WASAPI

device modes

WASAPI Push device mode has no sound "jitter", but a visualization and sound delay. Try repeatedly (like 2 times/s) press play/ pause.

    
AIMP v5.40.2727

A4 3.2 skin

[Artem]

I've tried to reproduce an error, but I failed. Playback starts without any jitters in my case. What output settings you uses for the device?

[Dimon911]

What output settings you uses for the device?

Please see attachment.


Also I tested the impact of fading and cross-mixing options; same stuttering/ jitter for 300-400 ms.

There is no such behavior by changing track or navigate on wave. On play pause play only.

Is there something like release-activate procedure on pause/play action? Some player have this option (see second attachment)

[Artem]

Please, try to increase device buffer up to 200 msecs.

[Dimon911]

try to increase device buffer

Absolutely no idea how to do that...  Need a hint here.

It is an USB Audio Device with generic USB Audio driver from microsoft.

And start searching: (https://learn.microsoft.com/en-us/windows-hardware/drivers/audio/low-latency-audio)

WASAPI "If an application doesn't specify a buffer size, then it will use the default buffer size." and!
"Allow an app to specify that it wishes to render/capture in the format it specifies without any resampling by the audio engine"


I guess AIMP have no option to specify a buffer size, and I see SoXR-VHQ (resampler?) sometimes if track sample rate is different from selected., this can be done with wasapi..... if used (with WASAPI IAudioClient3 interface).

[Artem]

But you've attached screenshot of settings dialog. Isn't this the audio card settings?

[Dimon911]

Sorry for the confusion, my mistake.


some_app.png

This screenshot is from Media Player Classic (MPC) audio interface configuration. I wish windows driver configuration would look similar like that.

It is an Audio Renderer from MPC (https://www.free-codecs.com/download/mpc_audio_renderer.htm)

This renderer  has implemented WASAPI with more specific user controls. My guess: AIMP using WASAPI too, but with "default" preset.

I tested playback with MPC, tried play-pause-play with different WASAPI settings, no issues at any setting combination. Maybe because  buffer size of MPC WASAPI is 50-100 ms. To compare AIMP's preset showing 400 ms (0.400s).


I'm sure it is possible to implement GUI for fine tune WASAPI interface settings, but it takes resources. On other side WASAPI is a "windows-thing" not to use on android or Linux.

But the main (from my perspective) feature of WASAPI is not fully implemented in AIMP: auto switch sample rate

without any resampling by the audio engine

This working just fine with MPC.

Maybe is step-by-step approach is a golden alternative? Starting with buffer-size settings option.

I get this behavior (sound error) with all my Audio devices Bluetooth and USB..

[Artem]

In AIMP6, we've introduced the "Allow device to choose preferred buffer size" option. I think it may solve the issue.

[Dimon911]

Yes, I saw this option on some screenshots earlier. I need to try this.

WASAPI  is a closest thing to ASIO on windows.
May I request general improvements on WASAPI interface in general? Like an Audio Renderer from MPC on screenshot (some_app.png ).


Minimal settings - huge impact. "Bit exact output" is primary interesting for me.

Top eature of WASAPI is not fully implemented in AIMP: auto switch sample and bit rate: Is track 44kHz 16bit - device mode auto selected to 44kHz 16bit, If 48kHz 24bit - device mode auto selected to it, no resample needed no impact on audio source.

Buffer size options. From my perspective are really for debugging only; If there no issues no reason to change it

 smaller buffer high responsibility lower latency; bigger buffer can increase latency, but also can induce issues when fast buffer clearance is required.

Release device when idle, can be also interesting.

Thanks!

[Artem]

auto switch sample and bit rate: Is track 44kHz 16bit - device mode auto selected to 44kHz 16bit, If 48kHz 24bit - device mode auto selected to it, no resample needed no impact on audio source.

We have no plans to do that:
https://aimp.ru/forum/index.php?topic=53609.100

[Dimon911]

It is an old topic... Looong time ago. Nobody really remembers decisions made long ago... 

I mean: it would be top-super-mega to have good implemented WASAPI with (a little) user control GUI.

[Artem]

I mean: it would be top-super-mega to have good implemented WASAPI with (a little) user control GUI.

What settings you need for WASAPI?

[Dimon911]

🟧
🟧 ✅ Allow auto switch sample and bit rate (most wanted, Device = Track)
🟧
🟧  If previous Track rates not eq. with next Track rates, need probably some resample, or API can handle this scenario too, i honestly don't know.
🟧

🔵
🔵 ✅ Allow buffer size change manually 10 ms ⫦-------⫰--------⫞ 500 ms     in supported by HW range
🔵
🔵 Wanted for debugging, values are provided by API. Once properly defined will probably not changed. But current auto-values are to high
🔵

🧊
🧊 ✅ Allow Bit exact output (QoL / nice to have,  Windows Audio Processing = actively suppressed/disabled by AIMP)
🧊
🧊 No audio effects by windows audio engine; no other post-processing, AIMP Volume fixed to 100%,  EQ and effects are bypassed.
🧊

https://learn.microsoft.com/en-us/windows-hardware/drivers/audio/low-latency-audio

Theoretically can WASAPI  with Windows Audio Processing Objects take care of "...graphic equalizers, reverb, tremolo, Acoustic Echo Cancellation (AEC) and Automatic Gain Control (AGC)."  but it is info only, not to implement.

https://learn.microsoft.com/en-us/windows-hardware/drivers/audio/windows-audio-processing-objects

🪗🎵🎶 Thank You ! 🖥️🔊🎧

[Artem]

As I say before, we have no plans to make automatic switch for output parameters. Firstly, this mode will only work for ASIO / WASAPI Exclusive, secondly, in this mode, the mix settings and gapless playback will not work at all.

Allow buffer size change manually

In AIMP6, we've introduced option "allow device to choose preffered buffer size". In this case, AIMP will use default buffer size for device. If option is unset, AIMP will calculate optimal buffer size by itself. Too small buffer size may lead to small sound gaps due playback.

[Dimon911]

Too small buffer size may lead to small sound gaps due playback.

Yes I red something on CSGO forum. Player try to reduce audio delay by reducing buffers to << 1ms and have mouse input pulling rates by 8000 per sec. They get sound errors due to those setting/ HW combination.

In AIMP6, we've introduced option "allow device to choose preffered buffer size".

Is there some docu? Or how You can describe the method? Is it some kind of benchmark run or values read out from audio driver by AIMP?

Firstly, this mode will only work for ASIO / WASAPI Exclusive, secondly, in this mode, the mix settings and gapless playback will not work at all.

Yes, You pointed it. WASAPI Exclusive is it what I'm writing about all the time, and Yes there are some cuts the user of auto switch sample/bit- rate have/ready to accept.

Auto switch sample/bit- rate happens not by AIMP internally but by API; AIMP send track data to API buffer and also parameter of this data to API. According to API documentation.