Skip to content

Instantly share code, notes, and snippets.

@afrael

afrael/gist:2777859

Created May 23, 2012 21:13
Download ZIP

Revisions

  1. afrael created this gist May 23, 2012.
    110 changes: 110 additions & 0 deletions gistfile1.m
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,110 @@
    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);
    }