我有一个问题AVPlayer
可视化大约两年。就我而言,它涉及 HLS 直播,在这种情况下,据我所知,您将无法运行它。
EDIT这不会让您访问averagePowerForChannel:
方法,但您将可以访问原始数据,并通过 FFT 等获得所需的信息。
不过,我让它可以与本地播放一起使用。您基本上等待玩家的玩家项目启动并运行轨道。那时你需要修补一个MTAudioProcessingTap
进入音频混合。
处理水龙头将运行您指定的回调,您将能够根据需要计算原始音频数据。
这是一个简单的例子(抱歉把它放在 ObjC 中):
#import <AVFoundation/AVFoundation.h>
#import <MediaToolbox/MediaToolbox.h>
void init(MTAudioProcessingTapRef tap, void *clientInfo, void **tapStorageOut) {};
void finalize(MTAudioProcessingTapRef tap) {};
void prepare(MTAudioProcessingTapRef tap, CMItemCount maxFrames, const AudioStreamBasicDescription *processingFormat) {};
void unprepare(MTAudioProcessingTapRef tap) {};
void process(MTAudioProcessingTapRef tap, CMItemCount numberFrames, MTAudioProcessingTapFlags flags, AudioBufferList *bufferListInOut, CMItemCount *numberFramesOut, MTAudioProcessingTapFlags *flagsOut) {};
- (void)play {
// player and item setup ...
[[[self player] currentItem] addObserver:self forKeyPath:@"tracks" options:kNilOptions context:NULL];
}
//////////////////////////////////////////////////////
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)changecontext:(void *)context
if ([keyPath isEqualToString:@"tracks"] && [[object tracks] count] > 0) {
for (AVPlayerItemTrack *itemTrack in [object tracks]) {
AVAssetTrack *track = [itemTrack assetTrack];
if ([[track mediaType] isEqualToString:AVMediaTypeAudio]) {
[self addAudioProcessingTap:track];
break;
}
}
}
- (void)addAudioProcessingTap:(AVAssetTrack *)track {
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 = finalise;
OSStatus err = MTAudioProcessingTapCreate(kCFAllocatorDefault, &callbacks, kMTAudioProcessingTapCreationFlag_PostEffects, &tap);
if (err) {
NSLog(@"error: %@", [NSError errorWithDomain:NSOSStatusErrorDomain code:err userInfo:nil]);
return;
}
AVMutableAudioMix *audioMix = [AVMutableAudioMix audioMix];
AVMutableAudioMixInputParameters *inputParams = [AVMutableAudioMixInputParameters audioMixInputParametersWithTrack:audioTrack];
[inputParams setAudioTapProcessor:tap];
[audioMix setInputParameters:@[inputParams]];
[[[self player] currentItem] setAudioMix:audioMix];
}
有一些讨论正在进行中我的问题 https://stackoverflow.com/questions/19403584/avplayer-hls-live-stream-level-meter-display-fft-data两年多前的作品,所以一定要检查一下。