iOS的AudioUnits通过(iOS AudioUnits pass through)

2019-08-03 10:36发布

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我试图写一个iOS应用，将通过从麦克风接收到扬声器没有任何变化的声音。 我读过苹果文档和指南。 我选用从这个第一模式引导 。 但没有发生的事情 - 沉默。 正如你可以看到我已经尝试使用AUAudioGraph（评论） - 同样的结果（我需要它在这个简单的例子呢？）。

我看到在回调中使用互联网几个例子，但我不希望使用任何。 可能吗？

有什么建议？ 感谢您的关注。

实际的代码

#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

Answer 1:

正如warrenm说，设立帮助远程IO单元之间的连接。 所以，放置所有初始化后的代码来完成： 

AudioUnitConnection conn;
conn.destInputNumber = kOutputBus;
conn.sourceAudioUnit = unit;
conn.sourceOutputNumber = kInputBus;
err = AudioUnitSetProperty(unit, kAudioUnitProperty_MakeConnection, kAudioUnitScope_Input, kOutputBus, &conn, sizeof(conn));
if (noErr != err) { [self showStatus:err]; }

UPDATE为了方便他人使用的解决方案，我将在这里发布完整的代码：

.h文件

#import <Foundation/Foundation.h>

@interface AudioController : NSObject

- (void)setUp;
- (void)start;
- (void)end;
@end

.m文件

#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;
}
@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(@"Initing");
    [self createUnitDesc];
    [self getComponent];
    [self getAudioUnit];
    [self enableIORec];
    [self enableIOPb];
    [self createFormat];
    [self applyFormat];
    OSStatus err = AudioUnitInitialize(unit);
    if (noErr != err) {
        [self showStatus:err];
    }

    AudioUnitConnection conn;
    conn.destInputNumber = 0;
    conn.sourceAudioUnit = unit;
    conn.sourceOutputNumber = 1;
    err = AudioUnitSetProperty(unit, kAudioUnitProperty_MakeConnection, kAudioUnitScope_Input, 0, &conn, sizeof(conn));
    if (noErr != err) {
        [self showStatus:err];
    }
}

- (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;
    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);
    if (noErr != err) {
        [self showStatus:err];
    }
}

- (void)end
{
    NSLog(@"ending");
    OSStatus err = AudioOutputUnitStop(unit);
    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


文章来源: iOS AudioUnits pass through
标签： ios core-audio audiounit avaudiosession
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