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Drawing waveform with AVAssetReader



I reading song from iPod library using assetUrl (in code it named audioUrl) I can play it many ways, I can cut it, I can make some precessing with this but... I really don't understand what I gonna do with this CMSampleBufferRef to get data for drawing waveform! I need info about peak values, how I can get it this (maybe another) way?







AVAssetTrack * songTrack = [audioUrl.tracks objectAtIndex:0];

AVAssetReaderTrackOutput * output = [[AVAssetReaderTrackOutput alloc] initWithTrack:songTrack outputSettings:nil];

[reader addOutput:output];

[output release];



NSMutableData * fullSongData = [[NSMutableData alloc] init];

[reader startReading];



while (reader.status == AVAssetReaderStatusReading){



AVAssetReaderTrackOutput * trackOutput =

(AVAssetReaderTrackOutput *)[reader.outputs objectAtIndex:0];



CMSampleBufferRef sampleBufferRef = [trackOutput copyNextSampleBuffer];



if (sampleBufferRef){/* what I gonna do with this? */}







Please help me!



Source: Tips4all

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