audio - 无法播放带有声音的AVMutableComposition

Question

我目前正在使用iPhone应用程序，该应用程序仅播放.mp4的音频轨道。播放器开始播放，但是我听不到任何声音。

这是代码:

    NSURL *videoUrl = [NSURL URLWithString:@"http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4"];

    AVMutableComposition* composition = [AVMutableComposition composition];

    AVMutableCompositionTrack *track = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];

    AVURLAsset* videoAsset = [AVURLAsset URLAssetWithURL:videoUrl options:nil];
    AVAssetTrack *audioTrack = [[videoAsset tracksWithMediaType:AVMediaTypeAudio]objectAtIndex:0];

    NSError *error = nil;
    BOOL success = [track insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) ofTrack:audioTrack atTime:kCMTimeZero error:&error];

    if (!success)
    {
        NSLog(@"error: %@", error);
    }

    AVPlayerItem *playerItem = [AVPlayerItem playerItemWithAsset:composition];

    self.player = [[AVPlayer alloc] initWithPlayerItem:playerItem];

    [self.player play];

Answer 1

我有一个类似的问题，只是发现AVFoundation在格式化构图方面是非常宽容的。我最终回答了我自己的问题-与您在这里的问题相同。

查看我的帖子:
iOS AVFoundation Export Session is missing audio