Audio Unit v3 Instrument with inputBusses problem

Nobody? Would be glad for any input!

Here are the changes to the sample code of InstumentDemo.mm by Apple to reproduce:

1. add an inputBusArray to the @interface (and channelCapabilitiesArray)

@interface AUv3InstrumentDemo ()

@property AUAudioUnitBus *outputBus;
@property AUAudioUnitBusArray *outputBusArray;
@property AUAudioUnitBusArray *inputBusArray;
@property NSArray<NSNumber *> *channelCapabilitiesArray;
@property (nonatomic, readwrite) AUParameterTree *parameterTree;

@end

2. add a BufferedInputBus to the @implementation

@implementation AUv3InstrumentDemo {
    // C++ members need to be ivars; they would be copied on access if they were properties.
    InstrumentDSPKernel _kernel;
    BufferedOutputBus _outputBusBuffer;
    BufferedInputBus _inputBusBuffer;
}

3. initialize the BufferedInputBus in the init method, set the inputBusArray and the channelCapabilitiesArray

(instancetype)initWithComponentDescription:(AudioComponentDescription)componentDescription options:
     (AudioComponentInstantiationOptions)options error:(NSError **)outError {
     ...
     // Create the output bus.
    _inputBusBuffer.init(defaultFormat, 2);
    _outputBusBuffer.init(defaultFormat, 2);
    _outputBus = _outputBusBuffer.bus;

     // Create the input and output bus arrays.
    _outputBusArray = [[AUAudioUnitBusArray alloc] initWithAudioUnit:self
                                                             busType:AUAudioUnitBusTypeOutput
                                                              busses: @[_outputBus]];

    _inputBusArray  = [[AUAudioUnitBusArray alloc] initWithAudioUnit:self
                                                             busType:AUAudioUnitBusTypeInput 
                                                              busses: @[_inputBusBuffer.bus]];

     // create the channel capabilities
    NSArray *channelConfig = [NSArray arrayWithObjects:
                              [NSNumber numberWithInt:2],[NSNumber numberWithInt:2],nil];
    _channelCapabilitiesArray = channelConfig;
     ...
}

4. add the inputBusses (and channelCapabilities) getter to the class

...
#pragma mark - AUAudioUnit (Overrides)

- (NSArray<NSNumber *>*)channelCapabilities {return _channelCapabilitiesArray;}

- (AUAudioUnitBusArray *)inputBusses {
    return _inputBusArray;
}
...

5. run in a host and set a breakpoint in the internalRenderBlock callback (you can leave out the channelCapabilities part, makes no difference)

expected result: AudioUnit should go into the internalRenderBlock and hit the breakpoint

actual result: nothing happens, no render callback (everything else works fine)

note: AudioUnit validates correctly with auval and works as standalone app

nobody?

Do you need the inputBus routine of an effect plugin or do you need the inputBus routine for a synth ???

For an Effect (.mm):

#import <AVFoundation/AVFoundation.h>

#pragma mark AudioUnit (Presets)
static const UInt8 kNumberOfPresets = 3;
static const NSInteger kDefaultFactoryPreset = 0;

typedef struct FactoryPresetParameters {
    AUValue cutoffValue;
    AUValue resonanceValue;
} FactoryPresetParameters;
static const FactoryPresetParameters presetParameters[kNumberOfPresets] =
{
    /
    {
        400.0f,/
        -5.0f,/
    },
   
    /
    {
        6000.0f,/
        15.0f,/
    },
   
    /
    {
        1000.0f,/
        5.0f,/
    }
};

static AUAudioUnitPreset* NewAUPreset(NSInteger number, NSString *name)
{
    AUAudioUnitPreset *aPreset = [AUAudioUnitPreset new];
    aPreset.number = number;
    aPreset.name = name;
    return aPreset;
}

@property AUAudioUnitBus *inputBus;
@property AUAudioUnitBus *outputBus;
@property AUAudioUnitBusArray *inputBusArray;
@property AUAudioUnitBusArray *outputBusArray;
@property (nonatomic, readwrite) AUParameterTree *parameterTree;
@end

@implementation AudioUnit
{
    AUAudioUnitPreset   *_currentPreset;
    NSInteger           _currentFactoryPresetIndex;
    NSArray<AUAudioUnitPreset *> *_presets;
}
@synthesize parameterTree = _parameterTree;
@synthesize factoryPresets = _presets;
- (instancetype)initWithComponentDescription:(AudioComponentDescription)componentDescription options:(AudioComponentInstantiationOptions)options error:(NSError **)outError {
    self = [super initWithComponentDescription:componentDescription options:options error:outError];
   
    if (self == nil) {
        return nil;
    }
   
   
    /
    AVAudioFormat *defaultFormat = [[AVAudioFormat alloc] initStandardFormatWithSampleRate:44100. channels:2];
   
   
    /
    AUParameter *param1 = [AUParameterTree
                           createParameterWithIdentifier:@"param1"
                           name:@"Test Parameter 1"
                           address:myParam1
                           min:0
                           max:100
                           unit:kAudioUnitParameterUnit_Percent
                           unitName:nil
                           flags:kAudioUnitParameterFlag_IsReadable | kAudioUnitParameterFlag_IsWritable
                           valueStrings:NULL
                           dependentParameters:nil];
   
   
    /
    param1.value = 1.0;
   
    /
    _parameterTree = [AUParameterTree createTreeWithChildren:@[ param1 ]];
   
    /
    _currentFactoryPresetIndex = kDefaultFactoryPreset;
    _presets = @[NewAUPreset(0, @"First Preset"),
                 NewAUPreset(1, @"Second Preset"),
                 NewAUPreset(2, @"Third Preset")];
   
   
    /
    _inputBus = [[AUAudioUnitBus alloc] initWithFormat:defaultFormat error:nil];
    _outputBus = [[AUAudioUnitBus alloc] initWithFormat:defaultFormat error:nil];
   
    /
    _inputBusArray  = [[AUAudioUnitBusArray alloc] initWithAudioUnit:self busType:AUAudioUnitBusTypeInput  busses: @[_inputBus]];
    _outputBusArray = [[AUAudioUnitBusArray alloc] initWithAudioUnit:self busType:AUAudioUnitBusTypeOutput busses: @[_outputBus]];
   
    /
    /
    __block FilterDSPKernel *filterKernel = &_kernel;
   
    /
    _parameterTree.implementorValueObserver = ^(AUParameter *param, AUValue value) {
        filterKernel->setParameter(param.address, value);
    };
   
    /
    _parameterTree.implementorValueProvider = ^(AUParameter *param) {
        return filterKernel->getParameter(param.address);
    };
    */
   
    /
    _parameterTree.implementorStringFromValueCallback = ^(AUParameter *param, const AUValue *__nullable valuePtr) {
        AUValue value = valuePtr == nil ? param.value : *valuePtr;
       
        switch (param.address) {
            case myParam1:
                return [NSString stringWithFormat:@"%.f", value];
            default:
                return @"?";
        }
    };
   
    self.maximumFramesToRender = 512;
    /
    self.currentPreset = _presets.firstObject;
   
    return self;
}
-(void)dealloc {
    /
}
#pragma mark - AUAudioUnit Overrides
/
- (NSArray <AUAudioUnitPreset *> *)factoryPresets {
    NSArray *parray = @[@"Preset One"];
    return parray;
}
*/
- (NSTimeInterval)latency {
    return 0;
}
- (NSTimeInterval)tailTime{
    return 1.0;
}
- (BOOL)shouldBypassEffect {
    return true;
}
- (NSArray <NSNumber *> *)channelCapabilities{
    NSArray *carray = @[@-1,@-2];
    return carray;
}
- (AUAudioChannelCount)maximumChannelCount{
    return UINT_MAX;
}
- (AUAudioUnitBusArray *)inputBusses {
    return _inputBusArray;
}
- (AUAudioUnitBusArray *)outputBusses {
    return _outputBusArray;
}
- (BOOL)canProcessInPlace {
    return YES;
}
- (BOOL)allocateRenderResourcesAndReturnError:(NSError **)outError {
    if (![super allocateRenderResourcesAndReturnError:outError]) {
        return NO;
    }
   
    /
    /
   
    return YES;
}
- (void)deallocateRenderResources {
    [super deallocateRenderResources];
   
    /
}
#pragma mark - AudioUnit DSP
- (AUInternalRenderBlock)internalRenderBlock {
    /

    return ^AUAudioUnitStatus(AudioUnitRenderActionFlags *actionFlags, const AudioTimeStamp *timestamp, AVAudioFrameCount frameCount, NSInteger outputBusNumber, AudioBufferList *outputData, const AURenderEvent *realtimeEventListHead, AURenderPullInputBlock pullInputBlock) {
        /
       
        return noErr;
       
    };
}
#pragma mark- AUAudioUnit (Optional Properties)
- (AUAudioUnitPreset *)currentPreset
{
    if (_currentPreset.number >= 0) {
        return [_presets objectAtIndex:_currentFactoryPresetIndex];
    } else {
        return _currentPreset;
    }
}
- (void)setCurrentPreset:(AUAudioUnitPreset *)currentPreset
{
    if (nil == currentPreset) { return; }
   
    if (currentPreset.number >= 0) {
        /
        for (AUAudioUnitPreset *factoryPreset in _presets) {
            if (currentPreset.number == factoryPreset.number) {
               
                /
                AUParameter *cutoffParameter = [self.parameterTree valueForKey: @"cutoff"];
                AUParameter *resonanceParameter = [self.parameterTree valueForKey: @"resonance"];
               
                cutoffParameter.value = presetParameters[factoryPreset.number].cutoffValue;
                resonanceParameter.value = presetParameters[factoryPreset.number].resonanceValue;
                */
               
               
                /
                _currentPreset = currentPreset;
                _currentFactoryPresetIndex = factoryPreset.number;
                break;
            }
        }
    } else if (nil != currentPreset.name) {
        /
        _currentPreset = currentPreset;
    } else {
    }
}
@end

please delete the props you dont have ;-)

I'm trying to do the same thing to add an inputBus to an AU v3 instrument in order to get a Sidechain dropdown menu in Logic. I'm also having trouble, did anyone every figure out how to do this?

I was able to reproduce the same behavior as user "jfjs". As far as I can tell this is the same boilerplate as in the AU effects example posted by user "NB System".