[openal] What's that weird sound before we go out?

[Chris Robinson]

On 08/24/2018 09:45 AM, n/a n/a wrote:
> https://youtu.be/LSUd6p2GMFM
> 
> And how to deal with it? (The problem is that before going out, the high tone sounds for a moment. This shouldn't be happening.)
> Experimentally found that the effect is manifested in a delay of up to 1373 MS. In another environment may be different.
> 
> Similar problem, no answer:
> http://openal.org/pipermail/openal/2015-January/000312.html

The problem seems to be the system is playing a bit of old audio before 
output stops. Internally, the system is likely just looping over a 
buffer of audio as OpenAL feeds in more and overwrites it in time to 
play. When stopping there could be a bit of time between OpenAL sending 
the last bit of audio and actually stopping the device, perhaps giving 
the system enough time to loop back and play an old bit of audio.

I'm a bit surprised that there would be so much time before stopping 
that the system has time to loop back like that. I can look into 
stopping the system playback sooner and see if that helps, although if 
you want to try mitigating the issue, it may help to have nothing play 
for a bit before destroying the OpenAL context.