[Qt-interest] High CPU Usage With QAudioOutput

[Gabriel M. Beddingfield]

On Wed, 6 Apr 2011, Barnes, Clifton A. wrote:

> On Wednesday, April 06, 2011 8:48 AM Jason H wrote:
>
>> I'd go with the Qt Mobility stuff. I'm not sure how QAudioOutput works, but I
>> know Qt Mobility uses your platform's back end which should be hardware
>> accelerated on most platforms.
>
> I looked at the Qt Mobility source:
>
> http://qt.gitorious.org/qt-mobility/qt-mobility/trees/master/src/multimedia/audio
>
> and it appears to be using all of the same QAudioOutput files as the main Qt

That's correct.  In the future, Qt is spinning off 
modules... so the QtMultimedia classes (like QAudioOutput) 
will now be part of the QtMobility module instead of Qt

You said that you were passing a .wav file to the 
QAudioOutput... but I don't think this is correct.  It is 
expecting a RAW PCM stream, and you need to set the format. 
However, a .wav file has metadata etc.

Also, if you don't properly set your audio format... you 
could be getting extra resampling or sample conversions.

-gabriel