OpenAL Streams go to AL_STOPPED state

Hi,

I have the following problem that my OpenAL streams go into AL_stopped state.

My audio code is ran by a thread that is created by std::thread (so a native posix thread).
My audio system is generating buffers with 0 data when no actual audio is played by the game.
I'm filling audio buffers with 20ms of audio data.
Not detecting any buffer underruns.
My audio thread polls the source objects every few ms and does a call to alGetSourcei(, AL_BUFFERS_PROCESSED) and then alSourceUnqueueBuffers to get the buffer handles of buffers that were consumed and then fills them again and calls alSourceQueueBuffers again for those.

Is one of these maybe causing the issue? Or is it related to ALC_SOFT_pause_device maybe?

Any help would be appreciated. Thanks!

FYI My OpenAL code works perfectly against openal on desktop linux (Archlinux, not sure about the OpenAL impl)

Here's an attached test case without any threading. You should be able to run this on your Linux desktop as well as in the browser after building into WASM with Emscripten. The build flags and commands are in the source file.

emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 3.0.0 (3fd52e107187b8a169bb04a02b9f982c8a075205)

I've tested with the following browsers:

Chromium: Version 96.0.4664.45 (Official Build) Arch Linux (64-bit)

Audible audio playback starts only after user interaction (click with mouse or press keyboard) (seems to be according to the web spec)
Audio stops intermittently randomly by itself. Often the stream goes to AL_STOPPED state but sometimes not. This happens even when staying on the same page and without doing any user interaction.
Audio stops (stream goes to AL_STOPPED) when switching to another application
Audio stops (stream goes to AL_STOPPED) when switching to another tab, does not resume when switching back to the WASM tab.

Firefox: 94.0.2 (64-bit)

Audio starts immediately without user interaction. This is in contrast to what happens in Chromium.
Audio sometimes stops if focusing another window other than the FF browser window but sometimes it continues to play
Audio stops when focusing another browser tab, doesn't not resume when tabbing back into the tab that is running the WASM

Summary. A bunch of inconsistent behavior and a random stop in playback on Chromium.

sine.cpp.txt

emscripten-core / emscripten

OpenAL Streams go to AL_STOPPED state #15639