Arshia, Thank you for clearing that up.
On Wed, Jul 11, 2018 at 4:10 PM, Arshia Cont <[email protected]> wrote: > Bartosz, > > Laurent was mentioning the installTapOnBus. Your published code would not > need that. You are just playing MIDI. You would be concerned if you had to > do custom real-time audio processing on the audio output of your MIDI > device (such as FFT analysis). > > Arshia > > On 11 Jul 2018, at 16:04, Bartosz Nowotny <[email protected]> > wrote: > > Laurent, > > What you said about not being able to achieve latency lower than 100ms is > worrisome. I need a realtime MIDI synth, low latency is absolutely crucial. > Does the limitation you mention apply only to signal processing or other > applications of the API as well, in particular MIDI synthesis? > > Regards, > Bartosz > > > On Wed, Jul 11, 2018 at 3:30 PM, Laurent Noudohounsi < > [email protected]> wrote: > >> Thanks Benjamin for the precision. I thought that `installTapOnBus` was >> the successor of `RenderCallback`. >> For me it was not natural to mix old api like `kAudioUnitProperty_ >> SetRenderCallback` in AVAudioEngine. >> >> So as Arshia said, I'm also looking for a way to use real-time processing >> with AVAudioEngine. >> >> Le mer. 11 juil. 2018 à 15:05, Arshia Cont <[email protected]> a >> écrit : >> >>> Interesting thread here! >>> >>> Anyone has achieved low-latency processing on AVAudioEngine? >>> >>> The RenderCallback seems natural to me (which is the good “old” way of >>> doing it with AUGraph). But I’m curious to hear if anyone has done/achieved >>> real stuff here with AVAudioEngine real-time processing and how. >>> >>> >>> Arshia >>> >>> >>> On 11 Jul 2018, at 15:00, Benjamin Federer <[email protected]> wrote: >>> >>> Laurent, >>> >>> `installTapOnBus` is not intended for realtime processing as a tap only >>> provides the current frame buffer but does not pass it back into the signal >>> chain. The documentation reads `Installs an audio tap on the bus to record. >>> monitor, and observe the output of the node`. >>> >>> Although I have not done that myself yet my understanding is that for >>> realtime processing you can still retrieve the underlying audio unit from >>> an AVAudioNode (or at least some nodes?) and attach an input render >>> callback via AudioUnitSetProperty with kAudioUnitProperty_SetRenderCa >>> llback. >>> >>> I assume the other way would be to subclass AUAudioUnit and wrap that >>> into an AVAudioUnit which is a subclass of AVAudioNode. Yes, it confuses >>> me, too. Random Google result with further information: >>> https://forums.developer.apple.com/thread/72674 >>> >>> Benjamin >>> >>> >>> Am 11.07.2018 um 14:34 schrieb Laurent Noudohounsi < >>> [email protected]>: >>> >>> Hi all, >>> >>> I'm interested in this topic since I've not found any information about >>> it yet. >>> >>> Correct me if I'm wrong but AVAudioEngine is not able to lower than >>> 100ms latency. It's what I see in the header file of `AVAudioNode` with its >>> method `installTapOnBus`: >>> >>> @param bufferSize the requested size of the incoming buffers in sample >>> frames. Supported range is [100, 400] ms. >>> >>> Maybe I'm wrong but I don't see any other way to have a lower latency >>> audio processing in an AVAudioNode. >>> >>> Best, >>> Laurent >>> >>> Le mer. 11 juil. 2018 à 13:57, Arshia Cont <[email protected]> a >>> écrit : >>> >>>> Benjamin and list, >>>> >>>> I double Benjamin’s request. It would be great if someone from the >>>> CoreAudio Team could respond to the question. >>>> >>>> Two years ago, after basic tests I realised that AVAudioEngine was not >>>> ready for Low Latency Audio analysis on iOS. So we used AUGraph. I have a >>>> feeling that this is no longer the case on iOS and we can move to >>>> AVAudioEngine for low-latency audio processing. Anyone can share experience >>>> here? We do real-time spectral analysis and resynthesis of sound and go as >>>> low as 64 samples per cycle if the device allows. >>>> >>>> Thanks in advance. >>>> >>>> >>>> Arshia >>>> >>>> >>>> PS: I actually brought the deprecation issue of AUGraph in a local >>>> Apple Dev meeting where the EU director of developer relation was present. >>>> According to him, when Apple announces a deprecation, it WILL happen. My >>>> interpretation of the conversation is that AUGraph is no longer maintained >>>> but provided as is. >>>> >>>> On 11 Jul 2018, at 12:36, Benjamin Federer <[email protected]> wrote: >>>> >>>> Since it was mentioned in another email (thread) I’m giving this topic >>>> a bump. Would be great if someone at Apple, or anyone else in the know, >>>> could take the time to respond. The documentation at the link cited below >>>> still has no indication of deprecation. Will it come with one of the next >>>> Xcode Beta releases? >>>> >>>> On another note I am really interested in how transitioning over to >>>> AVAudioEngine is working out for everyone. I know AVAudioEngine on iOS. >>>> What I am interested in is any macOS specifics or hardships. >>>> >>>> From my experience AVAudioEngine is relatively robust in handling >>>> multiple graphs, i.e. separate chains of audio units. I had some issues >>>> with the AVAudioPlayerNode connecting to multiple destinations in that >>>> scenario. Also connect:toConnectionPoints:fromBus:format: did not work >>>> for me as it only connected to one of the destination points. Anyone else >>>> experienced problems in that regard? >>>> >>>> Thanks >>>> >>>> Benjamin >>>> >>>> >>>> Am 08.06.2018 um 16:59 schrieb Benjamin Federer <[email protected]>: >>>> >>>> Last year at WWDC it was announced that AUGraph would be deprecated in >>>> 2018. I just browsed the documentation (https://developer.apple.com/d >>>> ocumentation/audiotoolbox?changes=latest_major) but found >>>> Audio Unit Processing Graph Services not marked for deprecation. >>>> The AUGraph header files rolled out with Xcode 10 beta also have no mention >>>> of a deprecation in 10.14. I searched for audio-specific sessions at this >>>> year’s WWDC but wasn’t able to find anything relevant. Has anyone come >>>> across new information regarding this? >>>> >>>> Judging by how much changes and features Apple seems to be holding back >>>> until next year I dare ask: Has AUGraph API deprecation been moved to a >>>> later time? >>>> >>>> Benjamin >>>> >>>> >>>> _______________________________________________ >>>> 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/arshia >>>> cont%40antescofo.com >>>> >>>> This email sent to [email protected] >>>> >>>> >>>> _______________________________________________ >>>> 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/lauren >>>> t.noudohounsi%40gmail.com >>>> >>>> This email sent to [email protected] >>>> >>> >>> >>> >> _______________________________________________ >> 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/bartos >> znowotny%40gmail.com >> >> This email sent to [email protected] >> >> > _______________________________________________ > 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/ > arshiacont%40antescofo.com > > This email sent to [email protected] > > >
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