Hey Matt Interesting idea, although I would prefer to keep it all as an app if possible. I know it's possible, because Rogue Amoeba's SoundSource 3 can do it, but they've removed the feature from SS4 (hence why I'm experimenting to see if I can make sure I don't lose the ability in the future!). The Rogue Amoeba folk know a heck of a lot more about this than I do though :)
FWIW, the CAPlayThrough sample does have a varispeed node in the graph, between the input and output nodes, which I think is supposed to compensate for small drifts. Cheers, Chris On Thu, 18 Apr 2019 at 19:33, Matt Ingalls <[email protected]> wrote: > if i remember correctly, that sends audio from one device to another? > and there’s no compensation in that code for clock drift? > > i would instead use an aggregate device (created in Audio MIDI Setup, or > you can do it programmatically with a little pain) > with both devices, enabling drift correction. then copy one to the other > in the single i/o callback. > > -m > > > > On Apr 18, 2019, at 1:40 AM, Chris Jones <[email protected]> wrote: > > > > Hey folks > > > > I'm experimenting with the old CAPlayThrough example code and I'm > hitting a situation I don't understand yet. > > > > Over a period of about an hour on my 4GHz i7 iMac, the audio being > played-through gets more and more delayed. Initial latency looks to be > about 150ms and grows up to about 500ms at which point it decays into > digital noise and then goes silent (the latter I believe being CoreAudio > discarding my late data). > > > > Other than converting some of the C++ objects to ObjC, I don't think > I've diverged significantly from the original code, but it's hard to > compare the running performance because the CAPlayThrough sample doesn't > really build anymore. I've been careful to avoid making ObjC method calls > in the callbacks (there's one, but it's only called before data starts > flowing) and data accessed from the ObjC objects is all done via ivars. > > > > I'm happy to post the code, if someone would like to have a look at it, > or I'd be very grateful for some pointers on what I might be doing wrong. > > > > -- > > Cheers, > > > > Chris > > _______________________________________________ > > 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/matt%408dio.com > > > > This email sent to [email protected] > > -- Cheers, Chris
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