[openal] Listing/accessing specific input channels

[Chris Robinson]

On 04/26/2018 10:28 AM, violini wrote:
> Thanks for replying. Yes, I mean channel 1 and 2 comprises one stereo input. 3 and 4 another stereo input, 5 and 6 yet another. etc.
> 
> I just tried specifying AL_FORMAT_QUAD16, the program compiles and the first stereo input works, but the samples from the second stereo input are empty. I presume the samples collected are interleaved? As in 1,2,3,4,1,2,3,4,1,2…. Many thanks.

Correct, they're interleaved just like when used for buffer data. If the 
second two channels are empty, that would mean OpenAL Soft isn't getting 
any samples for them from the system.

Since you mentioned the device has 6 inputs total, I'd first check that 
you connected the inputs properly, and that the system isn't providing 
the second set as the 5th and 6th channels instead of 3rd and 4th.

Otherwise, it would be useful to see a trace log from OpenAL Soft. If 
you set the ALSOFT_LOGLEVEL environment variable to "3" when you run the 
app, it'll print a bunch of information to stderr (you can also set the 
ALSOFT_LOGFILE environment variable to a full path+filename to make it 
write the log there instead; just make sure the path exists and you have 
write permissions for it).