// Video settings input

import AVFoundation

func createAudioInput(sampleBuffer: CMSampleBuffer) -> AVAssetWriterInput {
let audioSettings = [
AVFormatIDKey: kAudioFormatMPEG4AAC,
AVSampleRateKey: 48000,
AVEncoderBitRatePerChannelKey: 64000,
AVNumberOfChannelsKey: 2
] as [String : Any]

let audioInput = AVAssetWriterInput(mediaType: .audio, outputSettings: audioSettings, sourceFormatHint: sampleBuffer.formatDescription)

audioInput.expectsMediaDataInRealTime = false

return audioInput
}

func createVideoInput(videoBuffers: CVPixelBuffer) -> AVAssetWriterInput {
let videoSettings = [
AVVideoCodecKey: AVVideoCodecType.h264,
AVVideoWidthKey: CVPixelBufferGetWidth(videoBuffers),
AVVideoHeightKey: CVPixelBufferGetHeight(videoBuffers)
] as [String: Any]

let videoInput = AVAssetWriterInput(mediaType: .video, outputSettings: videoSettings)
videoInput.expectsMediaDataInRealTime = false

return videoInput
}

func createPixelBufferAdaptor(videoInput: AVAssetWriterInput) -> AVAssetWriterInputPixelBufferAdaptor {
let attributes = [
kCVPixelBufferPixelFormatTypeKey: kCVPixelFormatType_32ARGB,
kCVPixelBufferWidthKey: videoInput.outputSettings?[AVVideoWidthKey] as Any,
kCVPixelBufferHeightKey: videoInput.outputSettings?[AVVideoHeightKey] as Any
] as [String: Any]

return AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: videoInput, sourcePixelBufferAttributes: attributes)
}