iphone - AVPlayer 播放视频时的音量控制

Question

我现在正在使用AVPlayer类来处理自定义视频播放器，因为我想使用控制来实现音量UISlider控制。

我已经这样做了：

NSMutableArray *allAudioParams = [NSMutableArray array];
AVMutableAudioMixInputParameters *audioInputParams =[AVMutableAudioMixInputParameters audioMixInputParameters];
[audioInputParams setVolume:volumeSlider.value atTime:kCMTimeZero];
[allAudioParams addObject:audioInputParams];
AVMutableAudioMix *audioZeroMix = [AVMutableAudioMix audioMix];
[audioZeroMix setInputParameters:allAudioParams];
[self.playerItem setAudioMix:audioZeroMix];

但这对我不起作用，所以任何人都可以向我建议任何其他解决方案，我已经做了很多研发但无法找到合适的解决方案。

谢谢。

Answer 1

您可以使用以下代码更改音量：

NSArray *audioTracks = [asset tracksWithMediaType:AVMediaTypeAudio];

NSMutableArray *allAudioParams = [NSMutableArray array];
for (AVAssetTrack *track in audioTracks) {
  AVMutableAudioMixInputParameters *audioInputParams = 
    [AVMutableAudioMixInputParameters audioMixInputParameters];
  [audioInputParams setVolume:volume atTime:kCMTimeZero];
  [audioInputParams setTrackID:[track trackID]];
  [allAudioParams addObject:audioInputParams];
}

AVMutableAudioMix *audioMix = [AVMutableAudioMix audioMix];
[audioMix setInputParameters:allAudioParams];

[playerItem setAudioMix:audioMix];

Answer 2

-(void)doVolumeFade
{  
    if (self.player.volume > 0.1) {
        self.player.volume = self.player.volume - 0.1;
        [self performSelector:@selector(doVolumeFade) withObject:nil afterDelay:0.1];       
     } else {
        // Stop and get the sound ready for playing again
        [self.player stop];
        self.player.currentTime = 0;
        [self.player prepareToPlay];
        self.player.volume = 1.0;
    }
}