如何添加可玩（如WAV，WMV）头与iOS的PCM数据/缓冲？ [英] How to add playable(such as wav,wmv) header with PCM data/buffer in iOS?

问题描述

我想加一个wav头的原始PCM数据之上，使之通过AVAudioPlayer播放。但我无法找到任何解决方案或源$ C ​​$ C要做到这一点使用的Objective-C /斯威夫特的iOS。虽然我发现<一个href=\"http://stackoverflow.com/questions/24772844/convert-a-pcm-float-buffer-to-a-wav-nsdata\">this但它不具有正确的答案。

I am trying to add a wav header on top of raw PCM data to make it playable via AVAudioPlayer. But i couldn't find any solution or source code to do that on iOS using Objective-C/Swift. Though i found this but it doesn't have correct answer.

但我发现了一张code 这里这是在C和还含有一些问题。 WAV文件无法正常播放的是从code产生的。

But i found a piece of code here which is in C and also contains some issue. The wav file doesn't play properly which is generated from that code.

我已经给我的codeS下面，我有codeD为止。

I have given my codes below which i have coded so far.

int NumChannels = AUDIO_CHANNELS_PER_FRAME;
short BitsPerSample = AUDIO_BITS_PER_CHANNEL;
int SamplingRate = AUDIO_SAMPLE_RATE;
int numOfSamples = [[NSData dataWithContentsOfFile:filePath] length];

int ByteRate = NumChannels*BitsPerSample*SamplingRate/8;
short BlockAlign = NumChannels*BitsPerSample/8;
int DataSize = NumChannels*numOfSamples*BitsPerSample/8;
int chunkSize = 16;
int totalSize = 36 + DataSize;
short audioFormat = 1;

if((fout = fopen([wavFilePath cStringUsingEncoding:1], "w")) == NULL)
{
    printf("Error opening out file ");
}

fwrite("RIFF", sizeof(char), 4,fout);
fwrite(&totalSize, sizeof(int), 1, fout);
fwrite("WAVE", sizeof(char), 4, fout);
fwrite("fmt ", sizeof(char), 3, fout);
fwrite(&chunkSize, sizeof(int),1,fout);
fwrite(&audioFormat, sizeof(short), 1, fout);
fwrite(&NumChannels, sizeof(short),1,fout);
fwrite(&SamplingRate, sizeof(int), 1, fout);
fwrite(&ByteRate, sizeof(int), 1, fout);
fwrite(&BlockAlign, sizeof(short), 1, fout);
fwrite(&BitsPerSample, sizeof(short), 1, fout);
fwrite("data", sizeof(char), 3, fout);
fwrite(&DataSize, sizeof(int), 1, fout);

该文件被播放太快，声音失真，只有前10个至20个（左右）秒播放。我想，WAV头不正确生成（因为我能够播放使用AudioUnit / AudioQueue相同的PCM数据/缓冲）。那么，我错过在我的code？任何帮助将是非常美联社preciated。

The file is playing too fast, the sound is distorted and only first 10 to 20(around) seconds are playing. I think, the wav header isn't generating correctly(Because i am able to play same PCM data/buffer using AudioUnit/AudioQueue). So what i am missing in my code ? Any help would be highly appreciated.

先谢谢了。

推荐答案

OK，我回答我的问题，如果它可以帮助别人。经过不懈的努力几天，最后我有它的工作。下面是Objective-C的写了一个完整的功能和C.它需要一个文件路径，其中包含从麦克风直接拍摄的RAW PCM数据，并返回一个包含PCM数据并采取适当的wav头信息的文件路径的参数。然后你就可以玩AVAudioPlayer或AVPlayer该文件。这里是code ...

OK, I am answering my own question if it helps someone else. After few days of tireless trying, at last i have got it working. Below is a complete Function written with Objective-C and C. It takes a file path as a parameter which contains RAW PCM data directly captured from microphone and returns a file path which contains PCM data followed by appropriate wav header info. Then you can play that file with AVAudioPlayer or AVPlayer. Here is the code...

- (NSURL *) getAndCreatePlayableFileFromPcmData:(NSString *)filePath
{
    NSString *wavFileName = [[filePath lastPathComponent] stringByDeletingPathExtension];
    NSString *wavFileFullName = [NSString stringWithFormat:@"%@.wav",wavFileName];

    [self createFileWithName:wavFileFullName];
    NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *docsDir = [dirPaths objectAtIndex:0];
    NSString *wavFilePath = [docsDir stringByAppendingPathComponent:wavFileFullName];

    NSLog(@"PCM file path : %@",filePath);

    FILE *fout;

    short NumChannels = AUDIO_CHANNELS_PER_FRAME;
    short BitsPerSample = AUDIO_BITS_PER_CHANNEL;
    int SamplingRate = AUDIO_SAMPLE_RATE;
    int numOfSamples = [[NSData dataWithContentsOfFile:filePath] length];

    int ByteRate = NumChannels*BitsPerSample*SamplingRate/8;
    short BlockAlign = NumChannels*BitsPerSample/8;
    int DataSize = NumChannels*numOfSamples*BitsPerSample/8;
    int chunkSize = 16;
    int totalSize = 46 + DataSize;
    short audioFormat = 1;

    if((fout = fopen([wavFilePath cStringUsingEncoding:1], "w")) == NULL)
    {
        printf("Error opening out file ");
    }

    fwrite("RIFF", sizeof(char), 4,fout);
    fwrite(&totalSize, sizeof(int), 1, fout);
    fwrite("WAVE", sizeof(char), 4, fout);
    fwrite("fmt ", sizeof(char), 4, fout);
    fwrite(&chunkSize, sizeof(int),1,fout);
    fwrite(&audioFormat, sizeof(short), 1, fout);
    fwrite(&NumChannels, sizeof(short),1,fout);
    fwrite(&SamplingRate, sizeof(int), 1, fout);
    fwrite(&ByteRate, sizeof(int), 1, fout);
    fwrite(&BlockAlign, sizeof(short), 1, fout);
    fwrite(&BitsPerSample, sizeof(short), 1, fout);
    fwrite("data", sizeof(char), 4, fout);
    fwrite(&DataSize, sizeof(int), 1, fout);

    fclose(fout);

    NSMutableData *pamdata = [NSMutableData dataWithContentsOfFile:filePath];
    NSFileHandle *handle;
    handle = [NSFileHandle fileHandleForUpdatingAtPath:wavFilePath];
    [handle seekToEndOfFile];
    [handle writeData:pamdata];
    [handle closeFile];

    return [NSURL URLWithString:wavFilePath];
}

但是，这功能只下面的音频设置工作。

But that function only works with the following audio settings.

// Audio settings.
#define AUDIO_SAMPLE_RATE 8000
#define AUDIO_FRAMES_PER_PACKET 1
#define AUDIO_CHANNELS_PER_FRAME 1
#define AUDIO_BITS_PER_CHANNEL 16
#define AUDIO_BYTES_PER_PACKET 2
#define AUDIO_BYTES_PER_FRAME 2

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