I'm trying to use AVCaptureSession and AVAssetWriter to convert video and audio from an iPhone's camera and microphone into a fragmented video file in AppleHLS format.
Below is part of the code.
It seems that the capture is successful, and I have confirmed that the data received with captureOutput() can be appended to videoWriterIput and audioWriterInput using append().
When executing audioWriterInput!.append(sampleBuffer), sampleBuffer has the following value, and it looks like the audio data has been passed to AssetWriter.
sampleBuffer.duration : CMTime(value: 941, timescale: 44100, flags: __C.CMTimeFlags(rawValue: 1), epoch: 0)
sampleBuffer.totalSampleSize : 1882
However, the final output init.mp4 and *.m4s do not contain Audio. (The video can be played without any problems.)
Could you please tell me any problems or hints as to why Audio is not included?
/// Capture Session
let captureSession = AVCaptureSession()
/// Capture Input
var videoDevice: AVCaptureDevice?
var audioDevice: AVCaptureDevice?
/// Configure and Start Capture Session
func startCapture() {
// Start Configuration
captureSession.beginConfiguration()
// Setup Input Video
videoDevice = self.defaultCamera(cameraSide: cameraSide)
videoDevice!.activeVideoMinFrameDuration = CMTimeMake(value: 1, timescale: 30)
let videoInput = try AVCaptureDeviceInput(device: videoDevice!) as AVCaptureDeviceInput
captureSession.addInput(videoInput)
// Setup Input Audio
audioDevice = AVCaptureDevice.default(for: AVMediaType.audio)
let audioInput = try AVCaptureDeviceInput(device: audioDevice!) as AVCaptureDeviceInput
captureSession.addInput(audioInput)
// Setup Output Video
let videoDataOutput = AVCaptureVideoDataOutput()
videoDataOutput.setSampleBufferDelegate(self, queue: recordingQueue)
videoDataOutput.alwaysDiscardsLateVideoFrames = true
videoDataOutput.videoSettings = [
kCVPixelBufferPixelFormatTypeKey: Int(kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange)] as [String : Any]
captureSession.addOutput(videoDataOutput)
// Setup Output Audio
let audioDataOutput = AVCaptureAudioDataOutput()
audioDataOutput.setSampleBufferDelegate(self, queue: recordingQueue)
captureSession.addOutput(audioDataOutput)
//End Configuration
captureSession.commitConfiguration()
// Start Capture
captureSession.startRunning()
}
private let assetWriter: AVAssetWriter?
private let startTimeOffset: CMTime
private var audioWriterInput: AVAssetWriterInput?
private let videoWriterInput: AVAssetWriterInput?
func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
if assetWriter == nil {
// AssetWriter
assetWriter = AVAssetWriter(contentType: UTType(AVFileType.mp4.rawValue)!)
self.startTimeOffset = CMTime(value: 1, timescale: 1)
// Setup Input of Audio.
let audioCompressionSettings: [String: Any] = [
AVFormatIDKey: kAudioFormatMPEG4AAC,
AVSampleRateKey: 44_100,
AVNumberOfChannelsKey: 1,
AVEncoderBitRateKey: 128_000
]
audioWriterInput = AVAssetWriterInput(mediaType: .audio, outputSettings: audioCompressionSettings)
audioWriterInput!.expectsMediaDataInRealTime = true
assetWriter.add(audioWriterInput!)
// Setup Input of Video.
let videoCompressionSettings: [String: Any] = [
AVVideoCodecKey: AVVideoCodecType.h264
]
let videoCompressionSettings: [String: Any] = [
AVVideoCodecKey: AVVideoCodecType.h264,
AVVideoWidthKey: 1280,
AVVideoHeightKey: 720,
AVVideoCompressionPropertiesKey: [
kVTCompressionPropertyKey_AverageBitRate: 1_024_000,
kVTCompressionPropertyKey_ProfileLevel: kVTProfileLevel_H264_Baseline_AutoLevel
]
]
videoWriterInput = AVAssetWriterInput(mediaType: .video, outputSettings: videoCompressionSettings)
videoWriterInput!.expectsMediaDataInRealTime = true
pixelBuffer = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: videoWriterInput!, sourcePixelBufferAttributes: [kCVPixelBufferPixelFormatTypeKey as String: Int(kCVPixelFormatType_32BGRA)])
assetWriter.add(videoWriterInput!)
// Configure the asset writer for writing data in fragmented MPEG-4 format.
assetWriter.outputFileTypeProfile = AVFileTypeProfile.mpeg4AppleHLS
assetWriter.preferredOutputSegmentInterval = CMTime(seconds: 1.0, preferredTimescale: 1)
assetWriter.initialSegmentStartTime = startTimeOffset
assetWriter.delegate = self
// start AssetWriiter
startTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer)
assetWriter.startWriting()
assetWriter.startSession(atSourceTime: startTime)
}
let isVideo = output is AVCaptureVideoDataOutput
if isVideo {
if videoWriterInput.isReadyForMoreMediaData {
videoWriterInput!.append(sampleBuffer)
}
}else{
if audioWriterInput!.isReadyForMoreMediaData {
audioWriterInput!.append(sampleBuffer)
}
}
}
func assetWriter(_ writer: AVAssetWriter, didOutputSegmentData segmentData: Data, segmentType: AVAssetSegmentType, segmentReport: AVAssetSegmentReport?) {
:
:
}
