这个问题在过去几年中似乎被问了几次,但没有一个能回答这个问题。我正在尝试处理来自HLS的PCM数据,我必须使用AVPlayer。
这篇文章点击本地文件https://chritto.wordpress.com/2013/01/07/processing-avplayers-audio-with-mtaudioprocessingtap/
此水龙头适用于远程文件,但不适用于 .m3u8 HLS 文件。http://venodesigns.net/2014/01/08/recording-live-audio-streams-on-ios/
我可以播放播放列表中的前两首曲目,但它不会启动获取 pcm 所需的回调,当文件是本地或远程(不是流)时,我仍然可以获取 pcm,但它是 hls 不起作用,我需要 HLS 工作
这是我的代码
//avplayer tap try
- (void)viewDidLoad {
[super viewDidLoad];
NSURL*testUrl= [NSURL URLWithString:@"http://playlists.ihrhls.com/c5/1469/playlist.m3u8"];
AVPlayerItem *item = [AVPlayerItem playerItemWithURL:testUrl];
self.player = [AVPlayer playerWithPlayerItem:item];
// Watch the status property - when this is good to go, we can access the
// underlying AVAssetTrack we need.
[item addObserver:self forKeyPath:@"status" options:0 context:nil];
}
-(void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context
{
if(![keyPath isEqualToString:@"status"])
return;
AVPlayerItem *item = (AVPlayerItem *)object;
if(item.status != AVPlayerItemStatusReadyToPlay)
return;
NSArray *tracks = [self.player.currentItem tracks];
for(AVPlayerItemTrack *track in tracks) {
if([track.assetTrack.mediaType isEqualToString:AVMediaTypeAudio]) {
NSLog(@"GOT DAT FUCKER");
[self beginRecordingAudioFromTrack:track.assetTrack];
[self.player play];
}
}
}
- (void)beginRecordingAudioFromTrack:(AVAssetTrack *)audioTrack
{
// Configure an MTAudioProcessingTap to handle things.
MTAudioProcessingTapRef tap;
MTAudioProcessingTapCallbacks callbacks;
callbacks.version = kMTAudioProcessingTapCallbacksVersion_0;
callbacks.clientInfo = (__bridge void *)(self);
callbacks.init = init;
callbacks.prepare = prepare;
callbacks.process = process;
callbacks.unprepare = unprepare;
callbacks.finalize = finalize;
OSStatus err = MTAudioProcessingTapCreate(
kCFAllocatorDefault,
&callbacks,
kMTAudioProcessingTapCreationFlag_PostEffects,
&tap
);
if(err) {
NSLog(@"Unable to create the Audio Processing Tap %d", (int)err);
return;
}
// Create an AudioMix and assign it to our currently playing "item", which
// is just the stream itself.
AVMutableAudioMix *audioMix = [AVMutableAudioMix audioMix];
AVMutableAudioMixInputParameters *inputParams = [AVMutableAudioMixInputParameters
audioMixInputParametersWithTrack:audioTrack];
inputParams.audioTapProcessor = tap;
audioMix.inputParameters = @[inputParams];
self.player.currentItem.audioMix = audioMix;
}
void process(MTAudioProcessingTapRef tap, CMItemCount numberFrames,
MTAudioProcessingTapFlags flags, AudioBufferList *bufferListInOut,
CMItemCount *numberFramesOut, MTAudioProcessingTapFlags *flagsOut)
{
OSStatus err = MTAudioProcessingTapGetSourceAudio(tap, numberFrames, bufferListInOut,
flagsOut, NULL, numberFramesOut);
if (err) NSLog(@"Error from GetSourceAudio: %d", (int)err);
NSLog(@"Process");
}
void init(MTAudioProcessingTapRef tap, void *clientInfo, void **tapStorageOut)
{
NSLog(@"Initialising the Audio Tap Processor");
*tapStorageOut = clientInfo;
}
void finalize(MTAudioProcessingTapRef tap)
{
NSLog(@"Finalizing the Audio Tap Processor");
}
void prepare(MTAudioProcessingTapRef tap, CMItemCount maxFrames, const AudioStreamBasicDescription *processingFormat)
{
NSLog(@"Preparing the Audio Tap Processor");
}
void unprepare(MTAudioProcessingTapRef tap)
{
NSLog(@"Unpreparing the Audio Tap Processor");
}
void init
被称为void prepare
,process
也必须被称为。
我该怎么做?
我建议你使用FFMPEG库来处理HLS流。这有点困难,但提供了更大的灵活性。几年前我为Android做了HLS Player(使用过这个项目),我相信这同样适用于iOS。
我建议使用新卡因
在iOS和Mac OS X中使用音频单元的真正快速音频很难,并且会让您伤痕累累和流血。过去需要几天才能完成的工作现在只需几行代码即可完成。