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copied!<p>This is how I'm doing it in Objective-C:</p> <pre><code>#import <CoreMedia/CoreMedia.h> #import <AVFoundation/AVFoundation.h> #import <CoreAudio/CoreAudio.h> // or [NSURL URLWithString:@"ipod-library://item/item.mp3?id=2398084975506389321"] NSURL *assetURL = [item valueForProperty:MPMediaItemPropertyAssetURL]; NSMutableData *data = [[NSMutableData alloc] init]; const uint32_t sampleRate = 16000; const uint16_t bitDepth = 16; const uint16_t channels = 2; NSDictionary *opts = [NSDictionary dictionary]; AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:assetURL options:opts]; AVAssetReader *reader = [[AVAssetReader alloc] initWithAsset:asset error:NULL]; NSDictionary *settings = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithInt:kAudioFormatLinearPCM], AVFormatIDKey, [NSNumber numberWithFloat:(float)sampleRate], AVSampleRateKey, [NSNumber numberWithInt:bitDepth], AVLinearPCMBitDepthKey, [NSNumber numberWithBool:NO], AVLinearPCMIsNonInterleaved, [NSNumber numberWithBool:NO], AVLinearPCMIsFloatKey, [NSNumber numberWithBool:NO], AVLinearPCMIsBigEndianKey, nil]; AVAssetReaderTrackOutput *output = [[AVAssetReaderTrackOutput alloc] initWithTrack:[[asset tracks] objectAtIndex:0] outputSettings:settings]; [asset release]; [reader addOutput:output]; [reader startReading]; // read the samples from the asset and append them subsequently while ([reader status] != AVAssetReaderStatusCompleted) { CMSampleBufferRef buffer = [output copyNextSampleBuffer]; if (buffer == NULL) continue; CMBlockBufferRef blockBuffer = CMSampleBufferGetDataBuffer(buffer); size_t size = CMBlockBufferGetDataLength(blockBuffer); uint8_t *outBytes = malloc(size); CMBlockBufferCopyDataBytes(blockBuffer, 0, size, outBytes); CMSampleBufferInvalidate(buffer); CFRelease(buffer); [data appendBytes:outBytes length:size]; free(outBytes); } [output release]; </code></pre> <p>Here <code>data</code> will contain the raw PCM data of the track. Please note that you cannot directly access the file of a song or video, only its data through this method. You can compress it using e. g. FLAC (<a href="https://github.com/H2CO3/PodMail/blob/master/PMViewController.m" rel="nofollow">that's how I'm processing it in my tweak</a>).</p> <p>Since MonoTouch has an 1:1 mapping to Objective-C class and method names, this should be fairly easy to copy over. :)</p>

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