AVPlayer控制音量播放

Question

开发一个自定义播放，用到AVPlayer类，现在想加入UISlider控制音量。

实现代码：

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];

步骤地为什么不好使。请大家帮忙，谢谢。

Answer 1

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];

用这段代码控制音量