// Convert AVAudioPCMBuffer to CMSampleBuffer

import AVFoundation

extension AVAudioPCMBuffer {
func toCMSampleBuffer(presentationTime: CMTime) -> CMSampleBuffer? {
var buffer: CMSampleBuffer?

let duration = CMTimeMake(value: 1, timescale: Int32(format.sampleRate))
var timing = CMSampleTimingInfo(duration: duration, presentationTimeStamp: presentationTime, decodeTimeStamp: .invalid)

guard CMSampleBufferCreate(allocator: kCFAllocatorDefault,
              dataBuffer: nil,
              dataReady: false,
              makeDataReadyCallback: nil,
              refcon: nil,
              formatDescription: format.formatDescription,
              sampleCount: CMItemCount(frameLength),
              sampleTimingEntryCount: 1,
              sampleTimingArray: &timing,
              sampleSizeEntryCount: 0,
              sampleSizeArray: nil,
              sampleBufferOut: &buffer) == noErr,
let buffer = buffer,
CMSampleBufferSetDataBufferFromAudioBufferList(buffer,
                                        blockBufferAllocator: kCFAllocatorDefault,
                                        blockBufferMemoryAllocator: kCFAllocatorDefault,
                                        flags: 0,
                                        bufferList: mutableAudioBufferList) == noErr else { return nil }

return buffer
}
}