问题
I am trying to capture video/Audio frames from CMSampleBuffer but completely failing to obtain a proper video recording.
Expected Output:
A Video file in .mp4 format that has both audio(from the mic) and video frames.
Current Output: An Empty Directory/A video file without audio.
Crashes on Run : Media type of sample buffer must match receiver's media type ("soun")
I tried almost everything available online to troubleshoot this. I have a deadline coming and I just pulling my hair trying to figure out what exactly is going on. Any help/pointers are highly appreciated.
Below is the source.
CameraController.swift
class CameraController: UIViewController, SFrameCaptureDelegate {
override func viewDidLoad() {
super.viewDidLoad()
setupUI()
assetWriter = AssetManager(filename: UUID().uuidString.appending(".mp4"))
frameBuffer.delegate = self
frameBuffer.startSession()
}
var previewView: PreviewView = {
let instance = PreviewView()
return instance
}()
var frameBuffer = FrameCapture(type: .AudioVideo)
var captureButton: UIButton = {
let instance = UIButton()
instance.setTitle("Capture", for: .normal)
instance.backgroundColor = .white
return instance
}()
// if the user is recording the frames from the phone
var frameCaptureRunning = false
var assetWriter : AssetManager!
var videoDirectoryPath = SFileManager.shared.getDocumentDirectory()
func setupUI() {
view.addSubview(previewView)
previewView.top(to: view)
previewView.left(to: view)
previewView.right(to: view)
previewView.height(view.frame.height)
previewView.session = frameBuffer.session
view.addSubview(captureButton)
captureButton.size(CGSize(width: 100, height: 100))
captureButton.centerX(to: view)
captureButton.bottom(to: view, offset: -20)
captureButton.addTarget(self, action: #selector(startpic), for: .touchDown)
captureButton.addTarget(self, action: #selector(stopic), for: .touchUpInside)
}
@objc func startpic() {
frameCaptureRunning = true
assetWriter.isRecording = true
}
@objc func stopic() {
frameCaptureRunning = false
assetWriter.isRecording = false
assetWriter.finish {
DispatchQueue.main.async {
let activity = UIActivityViewController(activityItems: [self.assetWriter.url!], applicationActivities: nil)
self.present(activity, animated: true, completion: nil)
}
print("This -- ",self.assetWriter.url.path)
do {
let attr = try FileManager.default.attributesOfItem(atPath: self.assetWriter.url.path)
let fileSize = attr[FileAttributeKey.size] as! UInt64
print("H264 file size = \(fileSize)")
DispatchQueue.main.async {
let player = AVPlayer(url: self.assetWriter.url)
let playerLayer = AVPlayerLayer(player: player)
playerLayer.videoGravity = .resizeAspectFill
playerLayer.frame = self.view.bounds
playerLayer.backgroundColor = UIColor.red.cgColor
self.view.layer.addSublayer(playerLayer)
player.play()
}
}catch{
print("issues with finishing")
}
}
}
func capturedFrame(buffers: CMSampleBuffer) {
if !frameCaptureRunning { return }
assetWriter.write(buffer: buffers)
}
}
FrameCapture.swift
protocol SFrameCaptureDelegate: class {
func capturedFrame(buffers: CMSampleBuffer)
}
class FrameCapture: NSObject, AVCaptureVideoDataOutputSampleBufferDelegate, AVCaptureAudioDataOutputSampleBufferDelegate {
init(type: SessionType) {
super.init()
print("SFC - Frame Buffers initialized with Config - ", type.self)
sessionType = type
}
func startSession() {
print("SFC - Frame Buffers Session Starting")
sessionQueue.async {
self.configureSession(type: self.sessionType)
self.session.startRunning()
}
}
weak var delegate: SFrameCaptureDelegate?
enum SessionSetupResult {
case success
case notAuthorized
case configurationFailed
}
enum SessionType {
case Audio
case Video
case AudioVideo
}
let session = AVCaptureSession()
let sessionQueue = DispatchQueue(label: "sessionQueue", qos: .userInitiated)
let videoQueue = DispatchQueue(label: "videoQueue", qos: .userInitiated)
let audioQueue = DispatchQueue(label: "audioQueue", qos: .userInitiated)
var setupResult: SessionSetupResult = .success
var sessionType: SessionType = .Video
@objc dynamic var videoDeviceInput: AVCaptureDeviceInput!
let videoOutput = AVCaptureVideoDataOutput()
let audioOutput = AVCaptureAudioDataOutput()
var photoQualityPrioritizationMode: AVCapturePhotoOutput.QualityPrioritization = .balanced
/// MARK: SessionConfig
func configureSession(type: SessionType) {
if setupResult != .success { return }
session.beginConfiguration()
session.sessionPreset = .high
do {
var defaultVideoDevice: AVCaptureDevice?
if let dualCameraDevice = AVCaptureDevice.default(.builtInDualWideCamera, for: .video, position: .back) {
defaultVideoDevice = dualCameraDevice
} else if let backCameraDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .back){
defaultVideoDevice = backCameraDevice
} else if let frontCameraDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .front){
defaultVideoDevice = frontCameraDevice
}
guard let videoDevice = defaultVideoDevice else {
print("CAM - Camera unavailable")
setupResult = .configurationFailed
session.commitConfiguration()
return
}
let videoInputDevice = try AVCaptureDeviceInput(device: videoDevice)
if session.canAddInput(videoInputDevice) {
session.addInput(videoInputDevice)
videoDeviceInput = videoInputDevice
} else {
print("CAM - Couldn't add input to the session")
setupResult = .configurationFailed
session.commitConfiguration()
return
}
} catch {
print("CAM - Couldn't create device input. Error - ", error.localizedDescription)
setupResult = .configurationFailed
session.commitConfiguration()
return
}
if sessionType == .AudioVideo {
do {
let audioDevice = AVCaptureDevice.default(for: .audio)
let audioDeviceInput = try AVCaptureDeviceInput(device: audioDevice!)
print("SFC - in audio device input")
if session.canAddInput(audioDeviceInput) {
session.addInput(audioDeviceInput)
} else { print("CAM - Couldn't add audio input device to session.") }
} catch { print("couldn't create audio input device. Error - ",error.localizedDescription) }
}
videoOutput.setSampleBufferDelegate(self, queue: videoQueue)
if session.canAddOutput(videoOutput) {
session.addOutput(videoOutput)
photoQualityPrioritizationMode = .balanced
} else {
print("Could not add photo output to the session")
setupResult = .configurationFailed
session.commitConfiguration()
return
}
if sessionType == .AudioVideo {
audioOutput.setSampleBufferDelegate(self, queue: audioQueue)
if session.canAddOutput(audioOutput) {
session.addOutput(audioOutput)
} else {
print("Couldn't add audio output")
setupResult = .configurationFailed
session.commitConfiguration()
}
}
videoOutput.connections.first?.videoOrientation = .portrait
videoOutput.videoSettings = [ kCVPixelBufferPixelFormatTypeKey as String: kCVPixelFormatType_32BGRA ]
videoOutput.alwaysDiscardsLateVideoFrames = true
session.commitConfiguration()
}
/// MARK: CMSampleBufferDelegate
func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
self.delegate?.capturedFrame(buffers: sampleBuffer)
}
}
AssetManager.swift
class AssetManager: NSObject {
private var assetWriter: AVAssetWriter?
private var videoInput: AVAssetWriterInput?
private var audioInput: AVAssetWriterInput?
var url: URL!
let writerQueue = DispatchQueue(label: "writerQueue", qos: .utility)
var isRecording = false
var video_frames_written = false
init(filename: String) {
super.init()
self.videoDirectory.appendPathComponent(filename)
self.url = self.videoDirectory
}
private var videoDirectory = SFileManager.shared.getDocumentDirectory()
private func setupWriter() {
SFileManager.shared.clearPreviousFiles(withPath: videoDirectory.path)
SFileManager.shared.createNewDirectory(withPath: videoDirectory.path)
printLog(item: self.videoDirectory)
self.assetWriter = try? AVAssetWriter(outputURL: self.videoDirectory, fileType: AVFileType.mp4)
let videoOutputSettings = [
AVVideoCodecKey: AVVideoCodecType.h264,
AVVideoHeightKey: 1280,
AVVideoWidthKey:720
] as [String : Any]
self.videoInput = AVAssetWriterInput(mediaType: .video, outputSettings: videoOutputSettings)
self.videoInput?.expectsMediaDataInRealTime = true
if let videoInput = self.videoInput, (self.assetWriter?.canAdd(videoInput))! {
self.assetWriter?.add(videoInput)
}
let audioOutputSettings = [
AVFormatIDKey: kAudioFormatMPEG4AAC,
AVNumberOfChannelsKey: 1,
AVSampleRateKey: 44100,
AVEncoderBitRateKey: 64000
] as [String: Any]
self.audioInput = AVAssetWriterInput(mediaType: .audio, outputSettings: audioOutputSettings)
self.audioInput?.expectsMediaDataInRealTime = true
if let audioInput = self.audioInput, (self.assetWriter?.canAdd(audioInput))! {
self.assetWriter?.add(audioInput)
printDone(item: "Asset writer added, \(String(describing: self.audioInput))")
} else {
printError(item: "No audio Input")
}
}
public func write(buffer: CMSampleBuffer) {
writerQueue.sync {
if assetWriter == nil { self.setupWriter() }
if self.assetWriter?.status == .unknown {
self.assetWriter?.startWriting()
self.assetWriter?.startSession(atSourceTime: CMSampleBufferGetPresentationTimeStamp(buffer))
printDone(item: "Started AssetWriter")
}
if self.assetWriter?.status == .failed {
printError(item: "Asset Writer Failed with Error: \(String(describing: self.assetWriter?.error))")
}
if CMSampleBufferDataIsReady(buffer) {
if let videoInput = self.videoInput, videoInput.isReadyForMoreMediaData {
videoInput.append(buffer)
}
if let audioInput = self.audioInput, audioInput.isReadyForMoreMediaData {
audioInput.append(buffer) // Crashes at this line
}
}
}
}
public func finish(completion: @escaping (() -> Void)) {
writerQueue.async {
self.assetWriter?.finishWriting(completionHandler: { [self] in
printDone(item: "Finished Writing")
completion()
})
}
}
}
回答1:
You are writing a video buffer to your audioInput and depending on how the buffers arrive, you might also write an audio buffer to your videoInput.
In your case, the CMSampleBuffers contain either audio or video, so you append audio buffers to audioInput and video buffers to videoInput.
You can distinguish the two types of buffer by comparing the output in captureOutput:didOutput: to your audioInput and videoOutput or by looking at the buffer's CMSampleBufferGetFormatDescription()'s CMFormatDescriptionGetMediaType(), but that's more complicated.
来源：https://stackoverflow.com/questions/65000687/avassetwriter-unable-to-record-audio-with-video-crashing