.wav to any compressed form from AVAssetWritter ios

Question

Well the problem I am facing right now is a size issue problem. I am allowing the user to to choose a song from their library and then chop it up into pieces and then be able to

Answer 1

ANSWER

This is the correct audio options for .m4a and if you want the user to see it as an .mp3 or .wav file just append those onto the end of the file name!

AudioChannelLayout channelLayout;
memset(&channelLayout, 0, sizeof(AudioChannelLayout));
channelLayout.mChannelLayoutTag = kAudioChannelLayoutTag_Stereo;
NSDictionary *outputSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                            [NSNumber numberWithInt: kAudioFormatMPEG4AAC], AVFormatIDKey,
                            [NSNumber numberWithFloat:44100.0], AVSampleRateKey,
                            [NSNumber numberWithInt:2], AVNumberOfChannelsKey,
                            [NSNumber numberWithInt:128000], AVEncoderBitRateKey,
                            [NSData dataWithBytes:&channelLayout    length:sizeof(AudioChannelLayout)], AVChannelLayoutKey,                  

                            nil];    

Answer 2

How about this (sorry for not trying it myself but it should get you closer):

AVAssetWriter *assetWriter = [AVAssetWriter assetWriterWithURL:exportURL
                                                       fileType:AVFileTypeAppleM4A
                                                          error:&assetError];

NSDictionary *outputSettings = [NSDictionary dictionaryWithObjectsAndKeys:
       [NSNumber numberWithInt: kAudioFormatMPEG4AAC], AVFormatIDKey,
       [NSNumber numberWithFloat:44100.0], AVSampleRateKey,
       [NSNumber numberWithInt:2], AVNumberOfChannelsKey,
       [NSNumber numberWithInt:128000], AVEncoderBitRateKey,
       [NSNumber numberWithInt:16], AVLinearPCMBitDepthKey,
       [NSNumber numberWithInt: AVAudioQualityHigh],  AVEncoderAudioQualityKey,
       nil];