[alsa-devel] OSX Core Audio ASYNC OUT with rate feedback format ?
lee188 at singnet.com.sg
Fri Oct 1 03:30:13 CEST 2010
Alex <lee188 <at> singnet.com.sg> writes:
> Hi Daniel et al,
> I have successfully interfaced the sdr-widget with Linux alsa-driver
> for ASYNC
> OUT with rate feedback. Found out after much trial
> and error and reading of the
> usbaudio alsa-driver source code that you are
> using 12.13 as the format for the
> feedback rate !!! I was trying with 10.14 (UAC1 v1.2 specs
> , I think) in 3 bytes,
> and 16.16 (USB 2.0) in 4 bytes for quite a number of days
> with no success !!!
> However, 12.13 in 4 bytes, whilst working like a charm
> with Linux, does NOT work
> with OSX.
> Would you know the format used by OSX?
Hi Daniel et al,
This is an excerpt from:
associatedEndpoint.type = kUSBIsoc;
associatedEndpoint.direction = kUSBIn;
// The associated endpoint always goes "in"
// The sample rate should be either
a 3-byte 10.14 or a 4-byte 16.16
associatedEndpoint.maxPacketSize = mFeedbackPacketSize;
associatedEndpoint.interval = 0xFF;
mAssociatedPipe = mStreamInterface->FindNextPipe (NULL,
FailWithAction (NULL == mAssociatedPipe, result =
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