[Openal] Replacing QuickTime with OpenAL

[Chris Robinson]

On Thursday 05 June 2008 05:28:07 am Petr Mikšík wrote:
> Reading OpenAL manual and thinking about the new app's structure, we have
> found difficulty in getting sound samples as our application either plays
> the audio back or exports mixed audio into a file (currently WAV, and AAC).
> We have read about capture device extension but are not sure if this is a
> way to go and what to do if this extension is NOT present (or at least it
> seems that it could be missing).

The capture extension is likely present on any implementation so long as the 
hardware supports capture. That should work fine as long as your card is set 
up to capture output. Open a playback device, open a capture device, then 
capture samples regularly as you use the playback device normally.

Another possibility is to use OpenAL Soft 
<http://kcat.strangesoft.net/openal.html>, which has a Wave File Writer 
device built-in, that writes the mixed output to a standard .wav file (named 
in alsoft.ini in the ApplicationData path;see the packaged alsoftrc.sample 
for more info). If the app is expected to be distributed with that 
capability, the capture method would be more reliable since Windows users 
won't likely have OpenAL Soft.

As for converting to AAC, you can probably use something like FFMPEG, or 
DirectShow, to encode a wave stream into AAC. I've never tried, though, so I 
don't know what would be involved.