insertTimeRange:ofTrack:atTime:error: (class AVMutableCompositionTrack) fails on iPhone

Question

insertTimeRange:ofTrack:atTime:error: of class AVMutableCompositionTrack 返回 NO 并且在 iPhone（但不是模拟器）上返回错误 "The operation could not be completed"。错误消息没有帮助，我很难想出错误的原因，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，我所做的只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 对象在 init 中创建。
class方法addPhrase:atTime:调用添加音频剪辑到合成轨道
实际插入的函数是addAudioClip:atTime:.
辅助函数audioClipWithName:ofType将请求的音频文件加载到 AVAssetTrack 中。

--> NSLOG 输出：

insertTimeRange atTime=0.0 range=(0.0, 2.1) compositionTrack= - - - - - 错误！ Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed" UserInfo={NSLocalizedDescription=操作无法完成，NSUnderlyingError=0x16fc1c90 {Error Domain=NSOSStatusErrorDomain Code=-12780 "(null)"}, NSLocalizedFailureReason=发生未知错误(-12780)}

--> 示例代码：

@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

你的问题出在

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

它让轨道的所有者 AVAsset 超出范围并被释放，使轨道处于不良状态。

确保 AVAsset 被引用（至少）直到您调用 insertTimeRange。实际上，这意味着您应该将 AVAsset 及其 AVAssetTrack 一起传递。

insertTimeRange:ofTrack:atTime:error: (class AVMutableCompositionTrack) fails on iPhone

insertTimeRange:ofTrack:atTime:error: (class AVMutableCompositionTrack) fails on iPhone

iphone

objective-c

ios

avmutablecomposition

avasset