Create a silent audio file with Objective-C

SilentAudioFile.m

- (void)createSilentAudioFileAtURL:(NSURL *)fileURL durationInMilliseconds:(NSInteger)durationInMilliseconds {
    AudioFileID mRecordFile;
    
    AudioStreamBasicDescription audioFormat;
    audioFormat.mSampleRate         = 44100.00;
    audioFormat.mFormatID           = kAudioFormatLinearPCM;
    audioFormat.mFormatFlags        = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
    audioFormat.mFramesPerPacket    = 1;
    audioFormat.mChannelsPerFrame   = 2;
    audioFormat.mBitsPerChannel     = sizeof(short) * 8;
    audioFormat.mBytesPerPacket     = sizeof(short) * 2;
    audioFormat.mBytesPerFrame      = sizeof(short) * 2;
    audioFormat.mReserved           = 0;
    
    OSStatus status = AudioFileCreateWithURL((__bridge CFURLRef)fileURL, kAudioFileCAFType, &audioFormat, kAudioFileFlags_EraseFile, &mRecordFile);
    NSAssert(status != kAudioFileUnsupportedDataFormatError, @"Unsupported data format error.");
    NSAssert(status == noErr, @"Failed to create audio file.");

    double intervalInSamples = 0.5;
    intervalInSamples *= audioFormat.mSampleRate * audioFormat.mChannelsPerFrame;
    
    double durationInSeconds = (double)durationInMilliseconds / 1000.0;
    int inNumberFrames = (intervalInSamples * durationInSeconds);
    
    UInt32 frameBuffer[inNumberFrames];
    
    for (int i = 0; i < inNumberFrames; i++) { frameBuffer[i] = 0; }
    
    UInt32 bytesToWrite = inNumberFrames * sizeof(uint32_t);
    status = AudioFileWriteBytes(mRecordFile, false, 0, &bytesToWrite, &frameBuffer);
    NSAssert(status == noErr, @"Failed to write bytes to audio file.");
    status = AudioFileClose(mRecordFile);
    NSAssert(status == noErr, @"Failed to close audio file.");
}

Awesome, thank you so much:)