one issue is that the apps that will share their code are generally cross-platform and thus they do not use AUGraph at all (since there is no corresponding abstraction on other platforms). I mean, you could easily read the Ardour code to see how we host AudioUnit plugins, but since our primary goal is to hide the Apple-specifics and avoid platform specific code, that isn't going to help you very much.
On Fri, Mar 20, 2015 at 10:55 PM, Patrick J. Collins < [email protected]> wrote: > Hi everyone, > > So a week or so has gone by, and I feel like I am getting nowhere (or at > least close to nowhere) with my goal of being able to simply to: > > input buffer -> low pass -> new buffer > > Can anyone please please please help me? > > I have read pretty much all of Apple's documentation on this subject and > I just do not understand so many things... > > At first I was trying to just use the default output so that I could at > least hear the low pass happening.. Unfortunately all I hear is > garbage... I figured it's because the asbd is wrong-- so I tried > setting the asbd on the lowpass unit, and I get "-10868" when trying to > set the stream format on the low pass unit's input scope or output > scope... > > Then I tried to set the asbd on the output unit, and then I get error > -50, which says a parameter is wrong-- but.. the parameters are not > wrong! > > AudioStreamBasicDescription asbd; > asbd.mSampleRate = 8000; > asbd.mFormatID = kAudioFormatLinearPCM; > asbd.mFormatFlags = kAudioFormatFlagIsSignedInteger; > asbd.mFramesPerPacket = 1; > asbd.mChannelsPerFrame = 1; > asbd.mBitsPerChannel = 16; > asbd.mBytesPerPacket = 2; > asbd.mBytesPerFrame = 2; > > There should be absolutely nothing wrong with those parameters, so I > don't understand why it's giving a -50 error... > > Regardless, I ultimately don't want to output to the hardward, I want to > do a quick offline render to lowpass filter my buffer... So, I change > my output description from kAudioUnitSubType_DefaultOutput to > kAudioUnitSubType_GenericOytput > > And then suddenly my lowpass input render proc is not getting called-- > which I assume is because I need to call AudioUnitRender... However, I > cannot find any documentation or examples anywhere about how to > correctly do this! > > Where do you call AudioUnitRender? I assume this needs to be in a loop, > but-- clearly I don't want to manually call this in a loop myself... I > tried adding a InputProc callback to my generic output unit, but it > doesn't get called either. > > Here is my code: > > https://gist.github.com/patrick99e99/9221d8d7165d610fd3e1 > > I keep asking myself: Why is this so difficult?? Why is there so > little information out on the internet about how to do this?? All I can > find are a bunch of people asking some-what similar questions on > stackoverflow that aren't similar enough to help answer my questions. > Core audio has been around for a long time, and there are tons of apps > doing this sort of thing, so I am just really surprised by the lack of > information and available help for what seems like should be a simple > thing to do.... > > How about if I try this: > > HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! > > Thank you! > > Patrick J. Collins > http://collinatorstudios.com > > _______________________________________________ > 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/paul%40linuxaudiosystems.com > > This email sent to [email protected]
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