ios - 如何在 Swift 中将 CMSampleBuffer 转换为 Data？

Question

我需要将 CMSampleBuffer 转换为 Data 格式。我正在使用一个第三方框架来执行音频相关任务。该框架为我提供了 CMSampleBuffer 对象中的流媒体(即实时音频)音频。

像这样:

func didAudioStreaming(audioSample: CMSampleBuffer!) {
    //Here I need to conver this to Data format. 
    //Because I am using GRPC framework for Audio Recognization, 
}

请向我提供将 CMSampleBuffer 转换为 Data 的步骤。

仅供引用

    let formatDesc:CMFormatDescription? = CMSampleBufferGetFormatDescription(audioSample)

    <CMAudioFormatDescription 0x17010d890 [0x1b453ebb8]> {
    mediaType:'soun' 
    mediaSubType:'lpcm' 
    mediaSpecific: {
        ASBD: {
            mSampleRate: 16000.000000 
            mFormatID: 'lpcm' 
            mFormatFlags: 0xc 
            mBytesPerPacket: 2 
            mFramesPerPacket: 1 
            mBytesPerFrame: 2 
            mChannelsPerFrame: 1 
            mBitsPerChannel: 16     } 
        cookie: {(null)} 
        ACL: {(null)}
        FormatList Array: {(null)} 
    } 
    extensions: {(null)}
}

Answer 1

尝试下面的代码将 CMSampleBuffer 转换为 NSData。

let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)
CVPixelBufferLockBaseAddress(imageBuffer!, CVPixelBufferLockFlags(rawValue: 0))
let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer!)
let height = CVPixelBufferGetHeight(imageBuffer!)
let src_buff = CVPixelBufferGetBaseAddress(imageBuffer!)
let data = NSData(bytes: src_buff, length: bytesPerRow * height)
CVPixelBufferUnlockBaseAddress(imageBuffer!, CVPixelBufferLockFlags(rawValue: 0))

编辑-

对于 AudioBuffer，请使用以下代码 -

var audioBufferList = AudioBufferList()
var data = Data()
var blockBuffer : CMBlockBuffer?

CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(sampleBuffer, nil, &audioBufferList, MemoryLayout<AudioBufferList>.size, nil, nil, 0, &blockBuffer)

let buffers = UnsafeBufferPointer<AudioBuffer>(start: &audioBufferList.mBuffers, count: Int(audioBufferList.mNumberBuffers))

for audioBuffer in buffers {
    let frame = audioBuffer.mData?.assumingMemoryBound(to: UInt8.self)
    data.append(frame!, count: Int(audioBuffer.mDataByteSize))
}