ios - Objective-C : How to control volume of multiple audio players in DiracLE

我正在 objective-c 中创建一个音乐应用程序。我需要同时播放多种声音，并且可以通过使用 DiracLE 音频播放器来实现此目的。

但是此库的音量控制方法-(void)setVolume:(float)volume; 似乎不起作用。

我的初始化DiracAudioPlayer的代码:

DiracAudioPlayer *player1,*player2;
NSURL *url1,*url2;
NSError *error = nil;

url1 = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"song1" ofType:@"mp3"]];
url2 = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"song2" ofType:@"mp3"]];

player1 = [[DiracAudioPlayer alloc] initWithContentsOfURL:mainURL channels:1 error:&error];
[player1 setDelegate:self];
player2 = [[DiracAudioPlayer alloc] initWithContentsOfURL:mainURL channels:1 error:&error];
[player2 setDelegate:self];

设置播放器音量的方法:

-(void)setPlayerVolume
{
   [player1 setVolume:0.5];
   [player2 setVolume:0.2];
}

setVolume:即使对于单人游戏也不起作用，也没有抛出异常。

怎么解决呢？

最佳答案

您也可以通过依次初始化2个AVAudioPlayers并使用[self.player setVolume:volumeFloat];控制音量来实现此目的

...

    NSString *songA = [[NSBundle mainBundle] pathForResource:@"songA" ofType:@"mp3"];
    NSError *soundError = nil;
    self.player = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:songA] error:&soundError];
    if(self.player == nil)
        NSLog(@"%@",soundError);
    else
    {
        [self.player setDelegate:self];
        [self.player setVolume:0.75];
        [self.player play];
    }

    NSString *songB = [[NSBundle mainBundle] pathForResource:@"songB" ofType:@"mp3"];
    soundError = nil;
    self.player = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:songB] error:&soundError];
    if(self.player == nil)
        NSLog(@"%@",soundError);
    else
    {
        [self.player setDelegate:self];
        [self.player setVolume:0.25];
        [self.player play];
    }

...

如果确定要使用DiracAudioPlayer，则可以使用自己的方法在DiracAudioPlayerBase.mm中使用正确的volume参数重新初始化AudioUnit:

-(void)setupInstanceWithUrl:(NSURL*)inUrl numChannels:(int)channels volume:(float)volume
{
    mDelegate = nil;
    mInUrl = [inUrl copy];
    mIsPrepared = NO;
    mIsProcessing = NO;
    mWorkerThread = nil;
    mTotalFramesInFile = 0;
    mIsRunning = NO;
    mVolume = volume;
    mLoopCount = mNumberOfLoops = 0;
    mHasFinishedPlaying = YES;

    if (channels < 1) channels = 1;
    else if (channels > 2) channels = 2;
    mNumChannels = channels;

    mPeak = new SInt16[mNumChannels];
    mPeakOut = new SInt16[mNumChannels];

    for (long v = 0; v < mNumChannels; v++) {
        mPeakOut[v] = 0;
        mPeak[v] = -1;
    }

    OSStatus status = noErr;
    mTimeFactor = 1./kOversample;
    mPitchFactor = kOversample;
    // This is boilerplate code to set up CoreAudio on iOS in order to play audio via its default output

    // Desired audio component
    AudioComponentDescription desc;
    desc.componentType = kAudioUnitType_Output;
#if TARGET_OS_IPHONE
    desc.componentSubType = kAudioUnitSubType_RemoteIO;
#else
    desc.componentSubType = kAudioUnitSubType_HALOutput;
#endif
    desc.componentManufacturer = kAudioUnitManufacturer_Apple;
    desc.componentFlags = 0;
    desc.componentFlagsMask = 0;

    // Get ref to component
    AudioComponent defaultOutput = AudioComponentFindNext(NULL, &desc);

    // Get matching audio unit
    status = AudioComponentInstanceNew(defaultOutput, &mAudioUnit);
    checkStatus(status);

    // this is the format we want
    AudioStreamBasicDescription audioFormat;
    mSampleRate=audioFormat.mSampleRate         = 44100.00;
    audioFormat.mFormatID           = kAudioFormatLinearPCM;
    audioFormat.mFormatFlags        = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
    audioFormat.mFramesPerPacket    = 1;
    audioFormat.mChannelsPerFrame   = mNumChannels;
    audioFormat.mBitsPerChannel     = 16;
    audioFormat.mBytesPerPacket     = sizeof(short)*mNumChannels;
    audioFormat.mBytesPerFrame      = sizeof(short)*mNumChannels;

    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioUnitProperty_StreamFormat,
                                  kAudioUnitScope_Input,
                                  kOutputBus,
                                  &audioFormat,
                                  sizeof(audioFormat));
    checkStatus(status);

    // here we set up CoreAudio in order to call our PlaybackCallback
    AURenderCallbackStruct callbackStruct;
    callbackStruct.inputProc = PlaybackCallback;
    callbackStruct.inputProcRefCon = (__bridge void*) self;
    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioUnitProperty_SetRenderCallback,
                                  kAudioUnitScope_Input,
                                  kOutputBus,
                                  &callbackStruct,
                                  sizeof(callbackStruct));
    checkStatus(status);


    // Initialize unit
    status = AudioUnitInitialize(mAudioUnit);
    checkStatus(status);

    // here we allocate our audio cache
    mAudioBuffer = AllocateAudioBufferSInt16(mNumChannels, kAudioBufferNumFrames);

    // Avoid delay when hitting play by making sure the graph is pre-initialized
    AudioOutputUnitStart(mAudioUnit);
    AudioOutputUnitStop(mAudioUnit);

    [self prepareToPlay];

}

通过登录仔细检查您的音量是否已设置:

NSLog(@"Volume P1: %f", [player1 volume]);
NSLog(@"Volume P2: %f", [player2 volume]);

在Addition中，您还可以通过硬件音量按钮所使用的相同方法来控制混音的输出音量:(这将启动iOS音量更改的UI)

-(void)addVolumeObserver {

    MPVolumeView *volumeView = [MPVolumeView new];
    volumeView.showsRouteButton = NO;
    volumeView.showsVolumeSlider = NO;
    AppDelegate *appDelegate = (AppDelegate *) [[UIApplication sharedApplication] delegate];
    [appDelegate.window.rootViewController.view addSubview:volumeView];


    __weak __typeof(self)weakSelf = self;
    [[volumeView subviews] enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        if ([obj isKindOfClass:[UISlider class]]) {
            __strong __typeof(weakSelf)strongSelf = weakSelf;
            strongSelf->volumeSlider = obj;
            [obj addTarget:strongSelf action:@selector(handleVolumeChanged:) forControlEvents:UIControlEventValueChanged];
            *stop = YES;
        }
    }];
}

- (void)handleVolumeChanged:(id)sender
{
    NSLog(@"Volume: %f", volumeSlider.value);
}

- (void)setVolumeHandlerTo:(float)volume
{
    volumeSlider.value = volume;
}

关于ios - Objective-C : How to control volume of multiple audio players in DiracLE，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/36907412/