Brian, as I wrote in my email, I am not talking about asynchronous DAC which are, of course, the best solution for audio. I am talking about ADC. Cheap or not, asynchronous mode in record is not clock master. Adaptive is. I would love to get a high-quality chip that works but this is not the point. Xmos does not work either. Thanks,
JC > Le 19 août 2016 à 22:32, Brian Willoughby <[email protected]> a écrit : > > Note that Windows still does not support High Speed USB Audio 2 Class > Devices, while Mac OS X supports all of them with a class compliant driver. > On Windows, each vendor must write a custom driver and users must install > this driver before the device will work. > > Given the choice between a system that supports cheap, low-quality audio out > of the box, versus a system that supports high-quality audio with many > channels without installing drivers, I'd prefer the latter. > > I'm not sure why Adaptive IN is not supported. The USB Specification does > require that Adaptive IN be paired with isochronous synch OUT data. Do these > CMedia and TI chips implement reception of the rate feedback? > > Perhaps there is an incompatibility between CoreAudio's pull model and > adaptive input. I haven't studied the challenges involved at all. > > Brian > > > On Aug 19, 2016, at 12:29 PM, Jean-Charles Rousset <[email protected] > <mailto:[email protected]>> wrote: >> The technical note TN2274 about USB Audio on the Mac stipulates that >> Adaptive mode is not supported for input stream (recording), only >> Synchronous and Asynchronous. >> >> It is actually quite surprising as tons of consumer products integrate >> CMedia or TI chips (usb audio converter) which use Adaptive mode for record. >> >> I tested a lot of them (cheap or not), also developed PCBs and hardware with >> different chips and, indeed, audio buffers are quickly corrupted probably >> due to a clock drift. >> >> This thread shows the problem encountered for more than 5 years by users : >> https://discussions.apple.com/thread/2166616?tstart=0 >> <https://discussions.apple.com/thread/2166616?tstart=0> >> >> What is exactly the limitation to support it on Apple products ? >> >> Note : I never had any problem with DAC (playback). Only ADC (record). >> Note2 : it works on Windows & Android. >
_______________________________________________ Do not post admin requests to the list. They will be ignored. Coreaudio-api mailing list ([email protected]) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/coreaudio-api/archive%40mail-archive.com This email sent to [email protected]
