在iOS中录制视频时播放音频文件

我想在用相机录制时播放音频文件。我使用 AVAudioPlayer 来播放音频，使用 AVCamCaptureManager 来录制。

但是当音频开始播放时，预览屏幕冻结。我应该怎么办？

感谢您的帮助。这是代码。 （我正在研究 AVCam 示例。）

这是预览部分。

if ([self captureManager] == nil) {
        AVCamCaptureManager *manager = [[AVCamCaptureManager alloc] init];
        [self setCaptureManager:manager];

        [[self captureManager] setDelegate:self];

        if ([[self captureManager] setupSession]) {             
            AVCaptureVideoPreviewLayer *newCaptureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:[[self captureManager] session]];
            UIView *view = [self videoPreviewView];
            CALayer *viewLayer = [view layer];
            [viewLayer setMasksToBounds:YES];

            CGRect bounds = CGRectMake(0, 0, 480, 320);
            [newCaptureVideoPreviewLayer setFrame:bounds];

            if ([newCaptureVideoPreviewLayer isOrientationSupported]) {
                [newCaptureVideoPreviewLayer setOrientation:[DeviceProperties setPreviewOrientation]];
            }

            [newCaptureVideoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];

            [viewLayer insertSublayer:newCaptureVideoPreviewLayer below:[[viewLayer sublayers] objectAtIndex:0]];

            [self setCaptureVideoPreviewLayer:newCaptureVideoPreviewLayer];
            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
                [[[self captureManager] session] startRunning];
            });

            [self updateButtonStates];          
        }

这是音频播放部分。

NSURL *url = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"%@", sound] ofType:@"wav"]];
    AVAudioPlayer *audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:nil];
    [audioPlayer play];

如果我使用 AudioServicesPlaySystemSound 正常，不会冻结，但这次它只适用于 viewDidLoad。

CFBundleRef mainBundle = CFBundleGetMainBundle();
    CFURLRef soundFileRef;
    soundFileRef = CFBundleCopyResourceURL(mainBundle, (CFStringRef) CFBridgingRetain(@"sound"), CFSTR ("wav"), NULL);
    UInt32 soundID;
    AudioServicesCreateSystemSoundID(soundFileRef, &soundID);
    AudioServicesPlaySystemSound(soundID);

希望设定AVAudioSession类别至AVAudioSessionCategoryPlayAndRecord将解决问题。并将其类别选项设置为AVAudioSessionCategoryOptionDefaultToSpeaker|AVAudioSessionCategoryOptionMixWithOthers。请检查下面的一组代码

@property (strong, nonatomic) AVAudioPlayer *audioPlayer;

NSURL *soundUrl = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"VoicemailSound" ofType:@"mp3"]]; //Download and add a system sound to your project and mention its name and type here
self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:soundUrl error:nil];

[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayAndRecord withOptions:AVAudioSessionCategoryOptionDefaultToSpeaker|AVAudioSessionCategoryOptionMixWithOthers error: nil];

[self.audioPlayer prepareToPlay];
[self.audioPlayer play];