[英]Can I get an audio session / apply audio units to playback from MPMusicPlayerController?
我想控制來自MPMusicPlayerController的音頻(即從iPod庫播放)。 例如,我想將EQ應用於它或做DSP,混響,那種事情。
這可能嗎? 有沒有我可以抓住的音頻會話? 或者,是否有某種方法可以使用AVAudioPlayer播放iPod庫中的文件?
MPMusicPLayerController不能與AV框架“很好地”工作我設法得到一些DSP使用MPMusicPlayerController來獲取媒體項然后獲取該項目的URL。 然后使用AVURLAsset和AVAssetReader。 這樣的事情:
MPMediaItem *currentSong = [myMusicController nowPlayingItem];
NSURL *currentSongURL = [currentSong valueForProperty:MPMediaItemPropertyAssetURL];
AVURLAsset *songAsset = [AVURLAsset URLAssetWithURL:currentSongURL options:nil];
NSError *error = nil;
AVAssetReader* reader = [[AVAssetReader alloc] initWithAsset:songAsset error:&error];
AVAssetTrack* track = [[songAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
NSMutableDictionary* audioReadSettings = [NSMutableDictionary dictionary];
[audioReadSettings setValue:[NSNumber numberWithInt:kAudioFormatLinearPCM]
forKey:AVFormatIDKey];
AVAssetReaderTrackOutput* readerOutput = [AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:track outputSettings:audioReadSettings];
[reader addOutput:readerOutput];
[reader startReading];
CMSampleBufferRef sample = [readerOutput copyNextSampleBuffer];
while( sample != NULL )
{
sample = [readerOutput copyNextSampleBuffer];
if( sample == NULL )
continue;
CMBlockBufferRef buffer = CMSampleBufferGetDataBuffer( sample );
CMItemCount numSamplesInBuffer = CMSampleBufferGetNumSamples(sample);
AudioBufferList audioBufferList;
CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(sample,
NULL,
&audioBufferList,
sizeof(audioBufferList),
NULL,
NULL,
kCMSampleBufferFlag_AudioBufferList_Assure16ByteAlignment,
&buffer
);
for (int bufferCount=0; bufferCount < audioBufferList.mNumberBuffers; bufferCount++) {
SInt16* samples = (SInt16 *)audioBufferList.mBuffers[bufferCount].mData;
for (int i=0; i < numSamplesInBuffer; i++) {
NSLog(@"%i", samples[i]);
}
}
//Release the buffer when done with the samples
//(retained by CMSampleBufferGetAudioBufferListWithRetainedblockBuffer)
CFRelease(buffer);
CFRelease( sample );
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.