在iOS中将录制的音频文件转换为.wav格式

Question

我想录制一个音频文件并以.wav格式上传到服务器,但录制器不允许我将文件录制成wav格式.

用于记录我已经使用过代码: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];

我找到的另一种方法,录音后将文件从caff转换为wav,但这对我来说也不起作用.

我已经使用从caff到wav的转换文件的代码:

  -(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);
}

提前致谢.

任何帮助将非常感激.

Answer 1

您正在将文件上载到服务器,但我建议您不要使用wav格式,因为它的大小比任何其他格式都要大.请改用caf,m4a或任何其他格式.

您可以通过设置AVFormatIDKey为录制wav文件kAudioFormatLinearPCM; 没有其他编码格式可行.

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];