public static AudioComponent FindComponent(AudioTypeConverter conveter)
{
var cd = AudioComponentDescription.CreateConverter(conveter);
return(FindComponent(ref cd));
}
void StreamPropertyListenerProc(object sender, PropertyFoundEventArgs args)
{
if (args.Property == AudioFileStreamProperty.DataFormat)
{
dataFormat = audioFileStream.DataFormat;
return;
}
if (args.Property != AudioFileStreamProperty.ReadyToProducePackets)
{
return;
}
if (audioQueue != null)
{
// TODO: Dispose
throw new NotImplementedException();
}
audioQueue = new OutputAudioQueue(dataFormat);
audioQueue.BufferCompleted += HandleBufferCompleted;
AudioQueueStatus status;
aqTap = audioQueue.CreateProcessingTap(TapProc, AudioQueueProcessingTapFlags.PreEffects, out status);
if (status != AudioQueueStatus.Ok)
{
throw new ApplicationException("Could not create AQ tap");
}
// create an augraph to process in the tap. needs to convert from tapFormat to effect format and back
/* note: this is invalidname's recipe to do an in-place effect when a format conversion is needed
* before and after the effect, usually because effects want floats, and everything else in iOS
* core audio works with ints (or, in rare cases, fixed-point).
* the graph looks like this:
* [render-callback] -> [converter] -> [effect] -> [converter] -> [generic-output]
* prior to calling AudioUnitRender() on generic-output the ioData to a pointer that render-callback
* knows about, and NULLs the ioData provided to AudioUnitRender(). the NULL tells generic-output to
* pull from its upstream units (ie, the augraph), and copying off the ioData pointer allows the
* render-callback to provide it to the front of the stream. in some locales, this kind of shell game
* is described as "batshit crazy", but it seems to work pretty well in practice.
*/
auGraph = new AUGraph();
auGraph.Open();
var effectNode = auGraph.AddNode(AudioComponentDescription.CreateConverter(AudioTypeConverter.NewTimePitch));
effectUnit = auGraph.GetNodeInfo(effectNode);
var convertToEffectNode = auGraph.AddNode(AudioComponentDescription.CreateConverter(AudioTypeConverter.AU));
var convertToEffectUnit = auGraph.GetNodeInfo(convertToEffectNode);
var convertFromEffectNode = auGraph.AddNode(AudioComponentDescription.CreateConverter(AudioTypeConverter.AU));
var convertFromEffectUnit = auGraph.GetNodeInfo(convertFromEffectNode);
var genericOutputNode = auGraph.AddNode(AudioComponentDescription.CreateOutput(AudioTypeOutput.Generic));
genericOutputUnit = auGraph.GetNodeInfo(genericOutputNode);
// set the format conversions throughout the graph
var effectFormat = effectUnit.GetAudioFormat(AudioUnitScopeType.Output);
var tapFormat = aqTap.ProcessingFormat;
convertToEffectUnit.SetAudioFormat(tapFormat, AudioUnitScopeType.Input);
convertToEffectUnit.SetAudioFormat(effectFormat, AudioUnitScopeType.Output);
convertFromEffectUnit.SetAudioFormat(effectFormat, AudioUnitScopeType.Input);
convertFromEffectUnit.SetAudioFormat(tapFormat, AudioUnitScopeType.Output);
genericOutputUnit.SetAudioFormat(tapFormat, AudioUnitScopeType.Input);
genericOutputUnit.SetAudioFormat(tapFormat, AudioUnitScopeType.Output);
// set maximum fames per slice higher (4096) so we don't get kAudioUnitErr_TooManyFramesToProcess
const uint maxFramesPerSlice = 4096;
if (convertToEffectUnit.SetMaximumFramesPerSlice(maxFramesPerSlice, AudioUnitScopeType.Global) != AudioUnitStatus.OK)
{
throw new ApplicationException();
}
if (effectUnit.SetMaximumFramesPerSlice(maxFramesPerSlice, AudioUnitScopeType.Global) != AudioUnitStatus.OK)
{
throw new ApplicationException();
}
if (convertFromEffectUnit.SetMaximumFramesPerSlice(maxFramesPerSlice, AudioUnitScopeType.Global) != AudioUnitStatus.OK)
{
throw new ApplicationException();
}
if (genericOutputUnit.SetMaximumFramesPerSlice(maxFramesPerSlice, AudioUnitScopeType.Global) != AudioUnitStatus.OK)
{
throw new ApplicationException();
}
// connect the nodes
auGraph.ConnnectNodeInput(convertToEffectNode, 0, effectNode, 0);
auGraph.ConnnectNodeInput(effectNode, 0, convertFromEffectNode, 0);
auGraph.ConnnectNodeInput(convertFromEffectNode, 0, genericOutputNode, 0);
// set up the callback into the first convert unit
if (convertToEffectUnit.SetRenderCallback(ConvertInputRenderCallback, AudioUnitScopeType.Global) != AudioUnitStatus.NoError)
{
throw new ApplicationException();
}
var res = auGraph.Initialize();
if (res != AUGraphError.OK)
{
throw new ApplicationException();
}
}
