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Created February 27, 2019 00:37
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//
// convertToWav.m
// MixDJ
//
// Created by Jonathan Silverman on 2/26/19.
// Copyright © 2019 Jonathan Silverman. All rights reserved.
//
#import <Foundation/Foundation.h>
#import <AVFoundation/AVFoundation.h>
void convertToWav(NSURL *assetURL, NSString *exportPath) {
// set up an AVAssetReader to read from a URL
AVURLAsset *songAsset =
[AVURLAsset URLAssetWithURL:assetURL options:nil];
NSError *assetError = nil;
AVAssetReader *assetReader = [AVAssetReader assetReaderWithAsset:songAsset
error:&assetError];
if (assetError) {
NSLog (@"error: %@", assetError);
return;
}
AVAssetReaderOutput *assetReaderOutput =
[AVAssetReaderAudioMixOutput
assetReaderAudioMixOutputWithAudioTracks:songAsset.tracks
audioSettings: nil];
if (! [assetReader canAddOutput: assetReaderOutput]) {
NSLog (@"can't add reader output... die!");
return;
}
[assetReader addOutput: assetReaderOutput];
if ([[NSFileManager defaultManager] fileExistsAtPath:exportPath]) {
[[NSFileManager defaultManager] removeItemAtPath:exportPath
error:nil];
}
NSURL *exportURL = [NSURL fileURLWithPath:exportPath];
AVAssetWriter *assetWriter =
[AVAssetWriter assetWriterWithURL:exportURL
fileType:AVFileTypeWAVE
error:&assetError];
if (assetError) {
NSLog (@"error: %@", assetError);
return;
}
AudioChannelLayout channelLayout;
memset(&channelLayout, 0, sizeof(AudioChannelLayout));
channelLayout.mChannelLayoutTag = kAudioChannelLayoutTag_Stereo;
NSDictionary *outputSettings =
[NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:kAudioFormatLinearPCM], AVFormatIDKey,
[NSNumber numberWithFloat:44100.0], AVSampleRateKey,
[NSNumber numberWithInt:2], AVNumberOfChannelsKey,
[NSData dataWithBytes:&channelLayout length:sizeof(AudioChannelLayout)],
AVChannelLayoutKey,
[NSNumber numberWithInt:16], AVLinearPCMBitDepthKey,
[NSNumber numberWithBool:NO], AVLinearPCMIsNonInterleaved,
[NSNumber numberWithBool:NO],AVLinearPCMIsFloatKey,
[NSNumber numberWithBool:NO], AVLinearPCMIsBigEndianKey,
nil];
AVAssetWriterInput *assetWriterInput =
[AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio
outputSettings:outputSettings];
if ([assetWriter canAddInput:assetWriterInput]) {
[assetWriter addInput:assetWriterInput];
} else {
NSLog (@"can't add asset writer input... die!");
return;
}
assetWriterInput.expectsMediaDataInRealTime = NO;
[assetWriter startWriting];
[assetReader startReading];
AVAssetTrack *soundTrack = [songAsset.tracks objectAtIndex:0];
CMTime startTime = CMTimeMake (0, soundTrack.naturalTimeScale);
[assetWriter startSessionAtSourceTime: startTime];
__block UInt64 convertedByteCount = 0;
dispatch_queue_t mediaInputQueue =
dispatch_queue_create("mediaInputQueue", NULL);
[assetWriterInput requestMediaDataWhenReadyOnQueue:mediaInputQueue
usingBlock: ^
{
while (assetWriterInput.readyForMoreMediaData) {
CMSampleBufferRef nextBuffer =
[assetReaderOutput copyNextSampleBuffer];
if (nextBuffer) {
// append buffer
[assetWriterInput appendSampleBuffer: nextBuffer];
// update ui
convertedByteCount +=
CMSampleBufferGetTotalSampleSize (nextBuffer);
NSNumber *convertedByteCountNumber =
[NSNumber numberWithLong:convertedByteCount];
NSLog(convertedByteCountNumber.stringValue);
// [self performSelectorOnMainThread:@selector(updateSizeLabel:)
// withObject:convertedByteCountNumber
// waitUntilDone:NO];
} else {
// done!
[assetWriterInput markAsFinished];
[assetWriter finishWriting];
[assetReader cancelReading];
NSDictionary *outputFileAttributes =
[[NSFileManager defaultManager]
attributesOfItemAtPath:exportPath
error:nil];
NSLog (@"done. file size is %ld",
[outputFileAttributes fileSize]);
NSNumber *doneFileSize = [NSNumber numberWithLong:
[outputFileAttributes fileSize]];
// [self performSelectorOnMainThread:@selector(updateCompletedSizeLabel:)
// withObject:doneFileSize
// waitUntilDone:NO];
// release a lot of stuff
break;
}
}
}];
NSLog (@"bottom of convertTapped:");
}
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