ios - insertTimeRange:ofTrack:atTime:error:(类AVMutableCompositionTrack)在iPhone上失败

Question

类AVMutableCompositionTrack的insertTimeRange:ofTrack:atTime:error:在iPhone(但不是模拟器)上返回NO且错误“无法完成操作”。错误消息没有帮助，我很想找出错误的原因，更不用说解决方法了。任何帮助，将不胜感激。

在下面的示例代码中，我要做的就是尝试将音频剪辑添加到AVMutableCompositionTrack。这是代码中发生的事情:

AVMutableComposition和AVMutableCompositionTrack对象是在init中创建的。

调用类方法addPhrase:atTime:将音频剪辑添加到合成音轨。

实际插入的函数是addAudioClip:atTime:。

帮助程序函数audioClipWithName:ofType将请求的音频文件加载到AVAssetTrack中。

-> NSLOG输出:

insertTimeRange atTime = 0.0范围=(0.0，2.1)compositionTrack =
- - - - - 错误!错误域= AVFoundationErrorDomain代码= -11800“操作无法完成” UserInfo = {NSLocalizedDescription =操作无法完成，NSUnderlyingError = 0x16fc1c90 {Error Domain = NSOSStatusErrorDomain代码= -12780“(null)”}，NSLocalizedFailureReason = An发生未知错误(-12780)}

->样本代码:

@interface MyAudioPlayer()

@property (strong, nonatomic) AVMutableComposition *composition;
@property (strong, nonatomic) AVMutableCompositionTrack *compositionTrack;

@end


@implementation MyAudioPlayer

- (id) init
{
    self = [super init];
    if (self != nil) {
        self.composition = [AVMutableComposition composition];
        self.compositionTrack = [self.composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
    }
    return self;
}

// Add the phrase into compositionAudioTrack at the given time.
- (void) addPhrase:(NSString *)phrase atTime:(CMTime)atTime
{
    // Add the phrase to the audio.
    AVAssetTrack *audioClip = [self audioClipWithName:phrase ofType:@"mp3"];
    // Add the phrase to the audio track.
    [self addAudioClip:audioClip atTime];
}

// Add the given audio clip to the composed audio at the given time.
- (void) addAudioClip:(AVAssetTrack *)audioClip atTime:(CMTime)atTime
{
    NSError *error = [[NSError alloc] init];
    CMTimeRange audioClipRange = CMTimeRangeMake(kCMTimeZero, audioClip.timeRange.duration);
    BOOL success = [self.compositionTrack insertTimeRange:audioClipRange ofTrack:audioClip atTime:atTime error:&error];
    NSLog(@"insertTimeRange atTime=%.1f range=(%.1f, %.1f) compositionTrack=%@\n", CMTimeGetSeconds(atTime), CMTimeGetSeconds(audioClipRange.start), CMTimeGetSeconds(audioClipRange.duration), self.compositionTrack);
    if (!success) {
        NSLog(@"----------ERROR! %@", error);
    }
}

// Return an audio clip with the given name and type.
- (AVAssetTrack *) audioClipWithName:(NSString *)name ofType:(NSString *)type
{
    NSString *soundFilePath = [[NSBundle mainBundle] pathForResource:name ofType:type];
    NSURL *fileURL = [[NSURL alloc] initFileURLWithPath:soundFilePath];
    AVAsset *avAsset = [AVURLAsset URLAssetWithURL:fileURL options:nil];
    AVAssetTrack *audioClip = [[avAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
    return audioClip;
}

@end

Answer 1

你的问题在于

- (AVAssetTrack *) audioClipWithName:(NSString *)name ofType:(NSString *)type;

它使轨道拥有的 AVAsset超出范围并被释放，从而使轨道处于不良状态。

确保(至少)一直引用 AVAsset，直到调用 insertTimeRange为止。实际上，这意味着您应该一起传递 AVAsset及其 AVAssetTrack。