USB Audio Stream Format Control Linux+OSX

[kenmac]

Hi All,

I am wondering if anybody knows what the best way to select stream format on the UAC2 reference design when using Linux and/or OSX. Are there any tools that can do this, or any reference code around that does this programmatically?

Regards,

Kenny

[kenmac]

I have just found that on OSX 10.8.5 this setting can be changed in "Applications/Utilities/Audio MIDI Setup", just like in the Thesycon drivers for the XMOS UAC2 ref design. Didn't look here before because I thought it was only for MIDI.

I still need to be able to choose stream format on Linux however. Does anybody know if this is possible using ALSA or otherwise?

Cheers,

Kenny

[larry]

What do you mean by stream format? Sample rate and resolution?

[kenmac]

The XMOS USB Audio reference design has a control (which I assume is part of the UAC2 standard) which allows selection of bit depth (resolution) and channel count. Specific combinations of bit depth and channel count can be selected in the Thesycon driver control panel and in OSX as described. I haven't found if this control is exposed in Linux through ALSA or otherwise. This control actually selects the hardware mode and is not the same as selecting say 16/24bits in software which would simply truncate/pad with zeros in a 32bit frame.