CMSampleBuffer是Core Media框架中用来封装音视频样本数据的对象,而AVAudioPCMBuffer是AVFoundation框架中用来表示音频PCM数据的对象。
要使用CMSampleBuffer创建AVAudioPCMBuffer,需要进行以下步骤:
使用CMSampleBuffer创建AVAudioPCMBuffer的示例代码如下所示:
import AVFoundation
func createAVAudioPCMBuffer(from sampleBuffer: CMSampleBuffer) -> AVAudioPCMBuffer? {
guard let formatDescription = CMSampleBufferGetFormatDescription(sampleBuffer) else {
return nil
}
let format = AVAudioFormat(cmAudioFormatDescription: formatDescription)
guard let audioBufferList = CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(sampleBuffer, bufferListSizeNeededOut: nil, bufferListOut: nil, bufferListSize: MemoryLayout<AudioBufferList>.size, blockBufferAllocator: kCFAllocatorDefault, blockBufferMemoryAllocator: kCFAllocatorDefault, flags: kCMSampleBufferFlag_AudioBufferList_Assure16ByteAlignment, audioBufferListOut: nil) else {
return nil
}
let frameCapacity = AVAudioFrameCount(audioBufferList.pointee.mBuffers.mDataByteSize) / format.streamDescription.pointee.mBytesPerFrame
guard let pcmBuffer = AVAudioPCMBuffer(pcmFormat: format, frameCapacity: frameCapacity) else {
return nil
}
pcmBuffer.frameLength = AVAudioFrameCount(audioBufferList.pointee.mBuffers.mDataByteSize) / format.streamDescription.pointee.mBytesPerFrame
for bufferIndex in 0..<pcmBuffer.format.channelCount {
let audioBuffer = audioBufferList.pointee.mBuffers
let channelData = UnsafeMutableBufferPointer<Float>(start: audioBuffer.mData?.assumingMemoryBound(to: Float.self), count: Int(audioBuffer.mDataByteSize) / MemoryLayout<Float>.size)
let channelDataArray = Array(channelData)
let channelDataArrayPointer = UnsafeMutablePointer(mutating: channelDataArray)
let channelDataBuffer = pcmBuffer.floatChannelData?[Int(bufferIndex)]
channelDataBuffer?.initialize(from: channelDataArrayPointer, count: channelDataArray.count)
}
return pcmBuffer
}
这样,我们就可以使用CMSampleBuffer创建AVAudioPCMBuffer并且获取其中的音频数据。根据具体的应用场景,可以对音频数据进行后续的处理或者分析。
如果在腾讯云的云计算环境中使用,可以考虑使用腾讯云的音视频处理服务,该服务提供了丰富的音视频处理功能,包括音频转码、混音、特效处理等。具体信息可以参考腾讯云音视频处理产品的介绍页面:腾讯云音视频处理。
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