Ich versuche, eine iOS-Anwendung zu schreiben, die den vom Mikrofon empfangenen Ton unverändert an den Lautsprecher weiterleitet. Ich habe Apple Docs und Guides gelesen. Ich habe das erste Muster ausgewähltführen. Aber nichts passiert - Stille. Wie Sie sehen, habe ich versucht, den AUAudioGraph (kommentiert) zu verwenden - das gleiche Ergebnis (brauche ich es überhaupt in diesem einfachen Beispiel?).

Ich habe im Internet nur wenige Beispiele gesehen, in denen Rückrufe verwendet werden, aber ich möchte keine verwenden. Ist es möglich?

Irgendwelche Vorschläge? Danke für die Aufmerksamkeit.

Der eigentliche Code

#import "AudioController.h"
#import <AudioToolbox/AudioToolbox.h>
#import <AVFoundation/AVFoundation.h>
#import <AudioToolbox/AudioServices.h>
#define kInputBus 1
#define kOutputBus 0

@interface AudioController ()
{
    AudioComponentDescription desc;
    AudioComponent component;
    AudioUnit unit;
    AudioStreamBasicDescription audioFormat;
    double rate;
    //AUGraph graph;
}


@end

@implementation AudioController

- (void) setUp {
    AVAudioSession *sess = [AVAudioSession sharedInstance];
    NSError *error = nil;
    rate = 44100.0;
    [sess setPreferredSampleRate:rate error:&error];
    [sess setCategory:AVAudioSessionCategoryPlayAndRecord error:&error];
    [sess setActive:YES error:&error];
    rate = [sess sampleRate];
    if (error) {
        NSLog(@"%@", error);
    }

    NSLog(@"Init...");
    [self createUnitDesc];
    [self getComponent];
    [self getAudioUnit];
    [self enableIORec];
    [self enableIOPb];
    [self createFormat];
    [self applyFormat];
    OSStatus err = AudioUnitInitialize(unit);
    if (noErr != err) {
        [self showStatus:err];
    }
    /*NewAUGraph(&graph);
    AUNode node;
    AUGraphAddNode(graph, &desc, &node);
AUGraphInitialize(graph);
AUGraphOpen(graph);*/
}

- (void) createUnitDesc {
    desc.componentType = kAudioUnitType_Output;
    desc.componentSubType = kAudioUnitSubType_RemoteIO;
    desc.componentFlags = 0;
    desc.componentFlagsMask = 0;
    desc.componentManufacturer = kAudioUnitManufacturer_Apple;

}

- (void) getComponent {
    component = AudioComponentFindNext(NULL, &desc);
}

- (void) getAudioUnit {
    OSStatus res = AudioComponentInstanceNew(component, &unit);
    if (noErr != res) {
        [self showStatus:res];
    }
}

- (void) enableIORec {
    UInt32 flag = 1;
    OSStatus err = AudioUnitSetProperty(unit,
                                  kAudioOutputUnitProperty_EnableIO,
                                  kAudioUnitScope_Input,
                                  kInputBus,
                                  &flag,
                                  sizeof(flag));
    if (noErr != err) {
        [self showStatus:err];
    }
}

- (void) enableIOPb {
    UInt32 flag = 1;
    OSStatus err = AudioUnitSetProperty(unit,
                                  kAudioOutputUnitProperty_EnableIO,
                                  kAudioUnitScope_Output,
                                  kOutputBus,
                                  &flag,
                                  sizeof(flag));
    if (noErr != err) {
        [self showStatus:err];
    }
}

- (void) createFormat {
    // Describe format
    audioFormat.mSampleRate         = rate;//44100.00;
    audioFormat.mFormatID           = kAudioFormatLinearPCM;
    audioFormat.mFormatFlags        = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
    audioFormat.mFramesPerPacket    = 1;
    audioFormat.mChannelsPerFrame   = 1;
    audioFormat.mBitsPerChannel     = 16;
    audioFormat.mBytesPerPacket     = 2;
    audioFormat.mBytesPerFrame      = 2;
}

- (void) applyFormat {
    OSStatus err = AudioUnitSetProperty(unit,
                                  kAudioUnitProperty_StreamFormat,
                                  kAudioUnitScope_Output,
                                  kInputBus,
                                  &audioFormat,
                                  sizeof(audioFormat));
    if (noErr != err) {
        [self showStatus:err];
    }
}

- (void) start {
    NSLog(@"starting");
    OSStatus err = AudioOutputUnitStart(unit);
    //AUGraphStart(graph);
    if (noErr != err) {
        [self showStatus:err];
    }
}

- (void) end {
    NSLog(@"ending");
    OSStatus err = AudioOutputUnitStop(unit);
    //AUGraphStop(graph);
    if (noErr != err) {
        [self showStatus:err];
    }
}

- (void) showStatus:(OSStatus) st{
    NSString *text = nil;
    switch (st) {
        case kAudioUnitErr_CannotDoInCurrentContext: text = @"kAudioUnitErr_CannotDoInCurrentContext"; break;
        case kAudioUnitErr_FailedInitialization: text = @"kAudioUnitErr_FailedInitialization"; break;
        case kAudioUnitErr_FileNotSpecified: text = @"kAudioUnitErr_FileNotSpecified"; break;
        case kAudioUnitErr_FormatNotSupported: text = @"kAudioUnitErr_FormatNotSupported"; break;
        case kAudioUnitErr_IllegalInstrument: text = @"kAudioUnitErr_IllegalInstrument"; break;
        case kAudioUnitErr_Initialized: text = @"kAudioUnitErr_Initialized"; break;
        case kAudioUnitErr_InstrumentTypeNotFound: text = @"kAudioUnitErr_InstrumentTypeNotFound"; break;
        case kAudioUnitErr_InvalidElement: text = @"kAudioUnitErr_InvalidElement"; break;
        case kAudioUnitErr_InvalidFile: text = @"kAudioUnitErr_InvalidFile"; break;
        case kAudioUnitErr_InvalidOfflineRender: text = @"kAudioUnitErr_InvalidOfflineRender"; break;
        case kAudioUnitErr_InvalidParameter: text = @"kAudioUnitErr_InvalidParameter"; break;
        case kAudioUnitErr_InvalidProperty: text = @"kAudioUnitErr_InvalidProperty"; break;
        case kAudioUnitErr_InvalidPropertyValue: text = @"kAudioUnitErr_InvalidPropertyValue"; break;
        case kAudioUnitErr_InvalidScope: text = @"kAudioUnitErr_InvalidScope"; break;
        case kAudioUnitErr_NoConnection: text = @"kAudioUnitErr_NoConnection"; break;
        case kAudioUnitErr_PropertyNotInUse: text = @"kAudioUnitErr_PropertyNotInUse"; break;
        case kAudioUnitErr_PropertyNotWritable: text = @"kAudioUnitErr_PropertyNotWritable"; break;
        case kAudioUnitErr_TooManyFramesToProcess: text = @"kAudioUnitErr_TooManyFramesToProcess"; break;
        case kAudioUnitErr_Unauthorized: text = @"kAudioUnitErr_Unauthorized"; break;
        case kAudioUnitErr_Uninitialized: text = @"kAudioUnitErr_Uninitialized"; break;
        case kAudioUnitErr_UnknownFileType: text = @"kAudioUnitErr_UnknownFileType"; break;
        default: text = @"unknown error";
    }
    NSLog(@"TRANSLATED_ERROR = %li = %@", st, text);
}

- (void) dealloc {
    AudioUnitUninitialize(unit);

    [super dealloc];
}

@end