使用Objective C在iPhone中合并两个.wav文件

Question

I want to combine two .wav recording files together. Can any one help me figure out how to achieve this.I tried combining the data but the headers are creating problem. Can we do the combining as we do to combine the wave files.

This is how i am doing the combine,

NSMutableData *datas = [NSMutableData alloc];

NSData *data1 = [NSData dataWithContentsOfFile: [recordedTmpFile1 path]];

NSData *data2 = [NSData dataWithContentsOfFile: [recordedTmpFile2 path]];

 NSLog(@"file1 size : %d", [data1 length]);

 NSLog(@"file2 size : %d", [data2 length]);

[datas appendData:data1];

  [datas appendData:data2];

 NSLog(@"file3 size : %d", [datas length]);

            NSURL *combinedPath = [NSURL alloc];

combinedPath = [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent: 

[NSString stringWithFormat: @"1_20111215.%@",@"wav"]]];

            [[NSFileManager defaultManager] createFileAtPath:[combinedPath path] contents:datas attributes:nil];       

            NSFileManager * fm = [NSFileManager defaultManager];

[fm removeItemAtPath:[recordedTmpFile2 path] error:nil];  

Answer 1

I can achieve the combining of two files by recording the audio in .wav extension and the code is as follows,

NSURL *originalFileName = [NSURL alloc];    

NSURL *RecordingPath =[NSURL fileURLWithPath:[appDelegate.RecordingPath stringByAppendingPathComponent: 
                                              [NSString stringWithFormat:@"RecordingFile.wav"]]];  
NSLog(@"LocalRecoding Path :%@",RecordingPath);


originalFileName=RecordingPath;

NSURL *temporaryFileName = [NSURL alloc];
temporaryFileName = [NSURL fileURLWithPath:[appDelegate.RecordingPath  stringByAppendingPathComponent: 
                                            [NSString stringWithFormat: @"tempRecordingFile.%@", @"wav"]]];

long totalAudioLen = 0;
long totalDataLen = 0;
long longSampleRate = 11025.0;
int channels = 2;
long byteRate = 16 * 11025.0 * channels/8;    

NSData * wav1Data = [NSData dataWithContentsOfFile:[originalFileName path]];
NSData * wav2Data = [NSData dataWithContentsOfFile:[temporaryFileName path]];

if([wav1Data length]>0 && [wav2Data length] >0)
{
int wav1DataSize = [wav1Data length] - 44;  
NSLog(@"WAV I:%d",wav1DataSize);
int wav2DataSize = [wav2Data length] - 44;
NSLog(@"WAV II:%d",wav2DataSize);
NSData *Wave1= [NSMutableData dataWithData:[wav1Data subdataWithRange:NSMakeRange(44, wav1DataSize)]];
NSData *Wave2 =[NSMutableData dataWithData:[wav2Data subdataWithRange:NSMakeRange(44, wav2DataSize)]];

NSLog(@"WAV 1:%d",[Wave1 length]);

NSLog(@"WAV 2:%d",[Wave2 length]);


totalAudioLen=[Wave1 length]+[Wave2 length];

totalDataLen = totalAudioLen + 44;  

Byte *header = (Byte*)malloc(44);
header[0] = 'R';  // RIFF/WAVE header
header[1] = 'I';
header[2] = 'F';
header[3] = 'F';
header[4] = (Byte) (totalDataLen & 0xff);
header[5] = (Byte) ((totalDataLen >> 8) & 0xff);
header[6] = (Byte) ((totalDataLen >> 16) & 0xff);
header[7] = (Byte) ((totalDataLen >> 24) & 0xff);
header[8] = 'W';
header[9] = 'A';
header[10] = 'V';
header[11] = 'E';
header[12] = 'f';  // 'fmt ' chunk
header[13] = 'm';
header[14] = 't';
header[15] = ' ';
header[16] = 16;  // 4 bytes: size of 'fmt ' chunk
header[17] = 0;
header[18] = 0;
header[19] = 0;
header[20] = 1;  // format = 1
header[21] = 0;
header[22] = (Byte) channels;
header[23] = 0;
header[24] = (Byte) (longSampleRate & 0xff);
header[25] = (Byte) ((longSampleRate >> 8) & 0xff);
header[26] = (Byte) ((longSampleRate >> 16) & 0xff);
header[27] = (Byte) ((longSampleRate >> 24) & 0xff);
header[28] = (Byte) (byteRate & 0xff);
header[29] = (Byte) ((byteRate >> 8) & 0xff);
header[30] = (Byte) ((byteRate >> 16) & 0xff);
header[31] = (Byte) ((byteRate >> 24) & 0xff);
header[32] = (Byte) (2 * 8 / 8);  // block align
header[33] = 0;
header[34] = 16;  // bits per sample
header[35] = 0;
header[36] = 'd';
header[37] = 'a';
header[38] = 't';
header[39] = 'a';
header[40] = (Byte) (totalAudioLen & 0xff);
header[41] = (Byte) ((totalAudioLen >> 8) & 0xff);
header[42] = (Byte) ((totalAudioLen >> 16) & 0xff);
header[43] = (Byte) ((totalAudioLen >> 24) & 0xff);


NSData *headerData = [NSData dataWithBytes:header length:44];

//Merge the sound data of the original file with the temp file and create a new sound file with the 
//update header.
NSMutableData * soundFileData = [NSMutableData alloc];
[soundFileData appendData:[headerData subdataWithRange:NSMakeRange(0, 44)]];
[soundFileData appendData:Wave1];
[soundFileData appendData:Wave2];

//delete the original file
NSFileManager * fm = [NSFileManager defaultManager];
[fm removeItemAtPath:[originalFileName path] error:nil]; 

//create a new file with merged audio with the original file name.
NSURL *mergedFilePath = [NSURL alloc];

mergedFilePath = [NSURL fileURLWithPath:[appDelegate.RecordingPath  stringByAppendingPathComponent: 
                                         [NSString stringWithFormat:[originalFileName lastPathComponent]]]];   

[[NSFileManager defaultManager] createFileAtPath:[mergedFilePath path] contents:soundFileData attributes:nil];  

NSLog(@"COMBINED FILE PATH :%@",mergedFilePath);
}

Answer 2

This code will strip the header and return the NSData of just the PCM data.

- (NSData *)stripCAFHeader: (NSString *) path

    NSFileManager* fileMgr = [NSFileManager defaultManager];

    //Load the file in
    NSData* dataBuffer = [fileMgr contentsAtPath: path];
    //This is the data header
    NSData* searchString = [NSData dataWithBytes:"data" length:4];

    //Find where the header starts
    NSUInteger dataWordStart = [dataBuffer rangeOfData:searchString options:0 range:NSMakeRange(0,[dataBuffer length])].location;

    //Create the new range without the header
    //4 bytes for the DATA word, 8 bytes for the data length, and 4 bytes for the edit count
    NSRange dataRange = NSMakeRange(dataWordStart + 4 + 4 + 8, [dataBuffer length] - dataWordStart - 4 - 4 - 8);

    //Copy the new data
    NSData *data = [dataBuffer subdataWithRange:dataRange];
    return data;
}

Answer 3

I've just made that in my project. I'm using the AVMutableComposition method which needs the #import <AVFoundation/AVFoundation.h> . I have two .wav files in my documents directory of the app and combine them to one new .wav file.

AVAsset *audio1 = [AVURLAsset URLAssetWithURL:audioFilePath options:nil];
AVAsset *audio2 = [AVURLAsset URLAssetWithURL:audioFilePath options:nil];

AVMutableComposition* composition = [[AVMutableComposition alloc] init];

AVMutableCompositionTrack *audioCombinedTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
[audioCombinedTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, [audio1 duration]) ofTrack:[audio1.tracks objectAtIndex:0] atTime:kCMTimeZero error:&error];
[audioCombinedTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, [audio2 duration]) ofTrack:[audio2.tracks objectAtIndex:0] atTime:[audio1 duration] error:&error];

AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:composition presetName:AVAssetExportPresetPassthrough];

NSString *exportPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:@"Combined.wav"];
NSURL *exportURL = [NSURL fileURLWithPath:exportPath];

exportSession.outputURL = exportURL;
exportSession.outputFileType = AVFileTypeWAVE;

[exportSession exportAsynchronouslyWithCompletionHandler:^{
    NSLog (@"Exporting. status is %ld", (long)exportSession.status);
    switch (exportSession.status) {
        case AVAssetExportSessionStatusFailed:
        case AVAssetExportSessionStatusCompleted: {
            NSLog(@"export done");
            break;
        }
    };
}];