在iOS中將錄制的音頻文件轉換為.wav格式

Question

我想錄制一個音頻文件並以.wav格式上傳到服務器，但錄制器不允許我將文件錄制成wav格式。

用於記錄我已經使用過代碼：NSMutableDictionary * recordSetting = [[NSMutableDictionary alloc] init];

[recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];

// Initiate and prepare the recorder
recorder = [[AVAudioRecorder alloc] initWithURL:outputFileURL settings:recordSetting error:nil];
recorder.delegate = self;
recorder.meteringEnabled = YES;
[recorder prepareToRecord];

我找到的另一種方法，錄音后將文件從caff轉換為wav，但這對我來說也不起作用。

我已經使用從caff到wav的轉換文件的代碼：

  -(BOOL)exportAssetAsWaveFormat:(NSURL*)filePath
    {
  NSError *error = nil ;

  NSDictionary *audioSetting = [NSDictionary dictionaryWithObjectsAndKeys:
                              [ NSNumber numberWithFloat:44100.0], AVSampleRateKey,
                              [ NSNumber numberWithInt:2], AVNumberOfChannelsKey,
                              [ NSNumber numberWithInt:16], AVLinearPCMBitDepthKey,
                              [ NSNumber numberWithInt:kAudioFormatLinearPCM], AVFormatIDKey,
                              [ NSNumber numberWithBool:NO], AVLinearPCMIsFloatKey,
                              [ NSNumber numberWithBool:0], AVLinearPCMIsBigEndianKey,
                              [ NSNumber numberWithBool:NO], AVLinearPCMIsNonInterleaved,
                              [ NSData data], AVChannelLayoutKey, nil ];

//  NSString *audioFilePath = filePath;
AVURLAsset * URLAsset = [[AVURLAsset alloc]  initWithURL:recorder.url options:nil];

if (!URLAsset) return NO ;

AVAssetReader *assetReader = [AVAssetReader assetReaderWithAsset:URLAsset error:&error];
if (error) return NO;

NSArray *tracks = [URLAsset tracksWithMediaType:AVMediaTypeAudio];
if (![tracks count]) return NO;

AVAssetReaderAudioMixOutput *audioMixOutput = [AVAssetReaderAudioMixOutput
                                               assetReaderAudioMixOutputWithAudioTracks:tracks
                                               audioSettings :audioSetting];

if (![assetReader canAddOutput:audioMixOutput]) return NO ;

[assetReader addOutput :audioMixOutput];

if (![assetReader startReading]) return NO;



NSString *title = @"WavConverted";
NSArray *docDirs = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docDir = [docDirs objectAtIndex: 0];
NSString *outPath = [[docDir stringByAppendingPathComponent :title]
                     stringByAppendingPathExtension:@"wav" ];

NSURL *outURL = [NSURL fileURLWithPath:outPath];
AVAssetWriter *assetWriter = [AVAssetWriter assetWriterWithURL:outURL
                                                      fileType:AVFileTypeWAVE
                                                         error:&error];
if (error) return NO;

AVAssetWriterInput *assetWriterInput = [ AVAssetWriterInput assetWriterInputWithMediaType :AVMediaTypeAudio
                                                                            outputSettings:audioSetting];
assetWriterInput. expectsMediaDataInRealTime = NO;

if (![assetWriter canAddInput:assetWriterInput]) return NO ;

[assetWriter addInput :assetWriterInput];

if (![assetWriter startWriting]) return NO;




[assetWriter startSessionAtSourceTime:kCMTimeZero ];

dispatch_queue_t queue = dispatch_queue_create( "assetWriterQueue", NULL );

[assetWriterInput requestMediaDataWhenReadyOnQueue:queue usingBlock:^{

    NSLog(@"start");

    while (1)
    {
        if ([assetWriterInput isReadyForMoreMediaData]) {

            CMSampleBufferRef sampleBuffer = [audioMixOutput copyNextSampleBuffer];

            if (sampleBuffer) {
                [assetWriterInput appendSampleBuffer :sampleBuffer];
                CFRelease(sampleBuffer);
            } else {
                [assetWriterInput markAsFinished];
                break;
            }
        }
    }

    [assetWriter finishWriting];


    NSLog(@"finish %@",assetWriter);
}];
return YES;
//  dispatch_release(queue);
}

提前致謝。

任何幫助將非常感激。

Answer 1

您正在將文件上載到服務器，但我建議您不要使用wav格式，因為它的大小比任何其他格式都要大。 請改用caf，m4a或任何其他格式。

您可以通過設置錄制WAV文件AVFormatIDKey到kAudioFormatLinearPCM ; 沒有其他編碼格式可行。

NSURL *url = [NSURL fileURLWithPath: outPath];
NSError *err = nil;
audioRecorder = [[ AVAudioRecorder alloc] initWithURL:url 
                                             settings: audioSetting 
                                                error:&err];

//prepare to record
[audioRecorder setDelegate:self];
[audioRecorder prepareToRecord];
audioRecorder.meteringEnabled = YES;
[audioRecorder recordForDuration:(NSTimeInterval)10000000000];
[audioRecorder record];

Answer 2

試試這個

 NSString *wavFilePath = [[NSBundle mainBundle] pathForResource:@"sampleaudio" ofType:@"wav"];

NSURL *assetURL = [NSURL fileURLWithPath:wavFilePath];
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];

NSString *strcafFileName = [NSString stringWithFormat:@"%@.caf",[wavFilePath stringByDeletingPathExtension]];
NSString *cafFilePath = [delegate.strCassettePathSide stringByAppendingPathComponent:strcafFileName];

NSURL *exportURL = [NSURL fileURLWithPath:cafFilePath];
AVAssetWriter *assetWriter = [AVAssetWriter assetWriterWithURL:exportURL
                                                      fileType:AVFileTypeCoreAudioFormat
                                                         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:11025], 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];
             convertedByteCount += CMSampleBufferGetTotalSampleSize (nextBuffer);

             CMSampleBufferInvalidate(nextBuffer);
             CFRelease(nextBuffer);
             nextBuffer = NULL;
         }
         else
         {
             [assetWriterInput markAsFinished];
             //              [assetWriter finishWriting];
             [assetReader cancelReading];

             break;
         }
     }
 }];