Below is my code about what i have done for this .mov to .wav conversations :
- (void)mp4ForURL:(NSURL *)videoURL{
// Create the asset url with the video file
AVURLAsset *avAsset = [AVURLAsset URLAssetWithURL:videoURL options:nil];
NSArray *compatiblePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:avAsset];
// Check if video is supported for conversion or not
if ([compatiblePresets containsObject:AVAssetExportPresetMediumQuality])////************************************////
{
//Create Export session
AVAssetExportSession *exportSession = [[AVAssetExportSession alloc]initWithAsset:avAsset presetName:AVAssetExportPresetMediumQuality];////************************************////
//Creating temp path to save the converted video
NSString* documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString* myDocumentPath = [documentsDirectory stringByAppendingPathComponent:@"temp.mp4"];
NSURL *url = [[NSURL alloc] initFileURLWithPath:myDocumentPath];
//Check if the file already exists then remove the previous file
if ([[NSFileManager defaultManager]fileExistsAtPath:myDocumentPath])
{
[[NSFileManager defaultManager]removeItemAtPath:myDocumentPath error:nil];
}
exportSession.outputURL = url;
//set the output file format if you want to make it in other file format (ex .3gp)
exportSession.outputFileType = AVFileTypeMPEG4;
exportSession.shouldOptimizeForNetworkUse = YES;
[exportSession exportAsynchronouslyWithCompletionHandler:^{
switch ([exportSession status])
{
case AVAssetExportSessionStatusFailed:
NSLog(@"Export session failed");
break;
case AVAssetExportSessionStatusCancelled:
NSLog(@"Export canceled");
break;
case AVAssetExportSessionStatusCompleted:
{
//Video conversion finished
NSLog(@"Successful!");
[self convertMP4toMP3withFile:myDocumentPath];
}
break;
default:
break;
}
}];
}
else
{
NSLog(@"Video file not supported!");
}
}
-(void)convertMP4toCAFwithFile:(NSString*)dstPath //Converted to Core Audio Format .caf
{
NSURL *dstURL = [NSURL fileURLWithPath:dstPath];
AVMutableComposition* newAudioAsset = [AVMutableComposition composition];
AVMutableCompositionTrack* dstCompositionTrack;
dstCompositionTrack = [newAudioAsset addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
AVAsset* srcAsset = [AVURLAsset URLAssetWithURL:dstURL options:nil];
AVAssetTrack* srcTrack = [[srcAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
CMTimeRange timeRange = srcTrack.timeRange;
NSError* error;
if(NO == [dstCompositionTrack insertTimeRange:timeRange ofTrack:srcTrack atTime:kCMTimeZero error:&error]) {
NSLog(@"track insert failed: %@\n", error);
return;
}
AVAssetExportSession* exportSesh = [[AVAssetExportSession alloc] initWithAsset:newAudioAsset presetName:AVAssetExportPresetPassthrough];
exportSesh.outputFileType = AVFileTypeCoreAudioFormat;
exportSesh.outputURL = dstURL;
[[NSFileManager defaultManager] removeItemAtURL:dstURL error:nil];
[exportSesh exportAsynchronouslyWithCompletionHandler:^{
AVAssetExportSessionStatus status = exportSesh.status;
NSLog(@"exportAsynchronouslyWithCompletionHandler: %li\n", (long)status);
if(AVAssetExportSessionStatusFailed == status) {
NSLog(@"FAILURE: %@\n", exportSesh.error);
} else if(AVAssetExportSessionStatusCompleted == status) {
NSLog(@"SUCCESS!\n");
NSError *error;
//append the name of the file in jpg form
//check if the file exists (completely unnecessary).
NSString *onlyPath = [dstPath stringByDeletingLastPathComponent];
NSInteger randomNumber = arc4random() % 100000;
strDateAndTime = [self getCurrentDateAndTime];
strAudioName = [NSString stringWithFormat:@"%@_%ld_%@.%@", @"Audio", (long)randomNumber, strDateAndTime, @"caf"];
NSString *toPathString = [NSString stringWithFormat:@"%@/%@", onlyPath, strAudioName];
[[NSFileManager defaultManager] moveItemAtPath:dstPath toPath:toPathString error:&error];
//[self uploadAudioOnAWSFromPath:toPathString];
[self convertToWavForFilePath:toPathString];
}
}];
}
- (void)convertToWavForFilePath:(NSString *)cafFilePath
{
// set up an AVAssetReader to read from the iPod Library
// NSString *cafFilePath=[[NSBundle mainBundle]pathForResource:@"test" ofType:@"caf"];
NSURL *assetURL = [NSURL fileURLWithPath:cafFilePath];
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];
NSInteger randomNumber = arc4random() % 100000;
_finalAudioName = [NSString stringWithFormat:@"%@_%ld_%@", @"Audio", (long)randomNumber, strDateAndTime];
// NSString *title = @"MyRec";
NSArray *docDirs = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docDir = [docDirs objectAtIndex: 0];
__block NSString *wavFilePath = [[docDir stringByAppendingPathComponent :_finalAudioName]
stringByAppendingPathExtension:@"wav"];
_finalAudioName = [wavFilePath lastPathComponent];
if ([[NSFileManager defaultManager] fileExistsAtPath:wavFilePath])
{
[[NSFileManager defaultManager] removeItemAtPath:wavFilePath error:nil];
}
NSURL *exportURL = [NSURL fileURLWithPath:wavFilePath];
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_Mono;
NSDictionary *outputSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:kAudioFormatLinearPCM], AVFormatIDKey,
[NSNumber numberWithFloat:44100.0], AVSampleRateKey,
[NSNumber numberWithInt:1], 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];
convertedByteCount += CMSampleBufferGetTotalSampleSize (nextBuffer);
CMTime progressTime = CMSampleBufferGetPresentationTimeStamp(nextBuffer);
CMTime sampleDuration = CMSampleBufferGetDuration(nextBuffer);
if (CMTIME_IS_NUMERIC(sampleDuration))
progressTime= CMTimeAdd(progressTime, sampleDuration);
float dProgress= CMTimeGetSeconds(progressTime) / CMTimeGetSeconds(songAsset.duration);
NSLog(@"%f",dProgress);
}
else
{
[assetWriterInput markAsFinished];
[assetReader cancelReading];
[assetWriter finishWritingWithCompletionHandler:^{
[self uploadAudioOnAWSFromPath:wavFilePath];
}];
}
}
}];
}
In above code, the converted final file which is in .wav format that I have to send on AWS server to get text from it, For text conversation we used Google Speech API, and whenever I send file which is converted from below iOS 11 devices(like iOS 9,10), it shows me this error : Error: WAV header indicates an unsupported format.
Above error is shown by Google Speech API while converting an Audio file(.wav) to Text format.
Above code is working perfectly with latest iOS 11 devices, only below iOS 11(like iOS 9,10) devices are not working properly.