Re: No sound after upgrade to OpenAL soft 1.11.753

On Wednesday 24 February 2010 8:52:46 am Mikko Rytkönen wrote:
> Hi,
> 
> After upgrading OpenAL soft to 1.11.753 (from 1.10.622) on Ubuntu Karmic my
> application no longer outputs any sound. It is using pulse audio backend.
> No errors are returned by any functions, just no audio output.
> 
> What's interesting is that I'm using mixing frequency of 22KHz (an
> attribute in alcCreateContext() call). If I change it to 44KHz the problem
> goes away and sounds play as expected. My samples are stored in 16bit
> 44KHz format, which I load using alBufferData(). 22KHz mixing frequency
> has been working fine before.

Sounds like the same issue talked about here:
http://opensource.creative.com/pipermail/openal/2010-February/012001.html

What's likely happening is that the app requests a 22khz frequency, Pulse 
"fixes" it to 44khz or 48khz to match the output of the sink, then OpenAL Soft 
increases the buffer size to maintain the same latency timing that the 
original buffer size would've had with 22khz playback, pushing it above the 
64KB limit.

There's a problem that OpenAL Soft will take the app-requested frequency and 
tie it with the previously-specified buffer size for timing, instead of the 
original frequency it was set with, which can cause the latency to change 
drastically. I should be able to fix this, though. I should probably also fix 
it so Pulse doesn't try to "fix" an app-requested playback frequency, but that 
would have to be in the hope that apps would allow for using the "default" 
frequency by default (by not specifying the ALC_FREQUENCY attribute at all).

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