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POAVAudioPlayer refuses to play modified wav file
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  1. POAVAudioPlayer refuses to play modified wav file
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    copied!<p>The first time i call this method <code>file1</code> will be nil and <code>file2</code> will be returned. When this hapens the file will play normally (so the calling of this method should be fine). But when i call it for the second time it will return an <code>NSURL</code> which the AVAudioPlayer does not play. My guess is I have missed something in the header. In the debugging mode i have seen that the <code>totalLength</code> is exactly as long as the data's length. </p> <pre><code>+(NSURL *)mergeFile1:(NSURL *)file1 withFile2:(NSURL *)file2 { if(file1 == nil) { return [file2 copy]; } NSData * wav1Data = [NSData dataWithContentsOfURL:file1]; NSData * wav2Data = [NSData dataWithContentsOfURL:file2]; int wav1DataSize = [wav1Data length] - 46; int wav2DataSize = [wav2Data length] - 46; if (wav1DataSize &lt;= 0 || wav2DataSize &lt;= 0) { return nil; } NSMutableData * soundFileData = [NSMutableData dataWithData:[wav1Data subdataWithRange:NSMakeRange(0, 46)]]; [soundFileData appendData:[wav1Data subdataWithRange:NSMakeRange(46, wav1DataSize)]]; [soundFileData appendData:[wav2Data subdataWithRange:NSMakeRange(46, wav2DataSize)]]; unsigned int totalLength = [soundFileData length]; NSLog(@"Calculated: %d - Real: %d", totalLength, [soundFileData length]); [soundFileData replaceBytesInRange:NSMakeRange(4, 4) withBytes:&amp;(UInt32){NSSwapHostIntToLittle(totalLength-8)}]; [soundFileData replaceBytesInRange:NSMakeRange(42, 4) withBytes:&amp;(UInt32){NSSwapHostIntToLittle(totalLength)}]; [soundFileData writeToURL:file1 atomically:YES]; return [file1 copy]; } </code></pre> <p>If anyone sees something that can be of help it would be much appreciated! Any questions will be answered asap.</p> <p><strong>EDIT</strong></p> <p>I know there are 2 sorts of wav headers: 44 bytes or 46 bytes. I have tried both.</p> <p><strong>EDIT</strong></p> <p>I have looked at the <a href="http://developer.apple.com/library/ios/#documentation/MusicAudio/Reference/AudioFileConvertRef/Reference/reference.html" rel="nofollow">Audio File Services Reference</a> which contains a lot of nice stuff i might want to use, but i can't figure out how to use all this. I'm not really known with c. Hope anyone could help me out with this.</p> <p><strong>EDIT</strong></p> <p>An example of a merged wav file is found here: <a href="http://www.2shared.com/audio/rtfbVJO7/7--443522512.html" rel="nofollow">7--443522512</a></p>
 

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