我正在使用 Aperture 从屏幕录制音频和视频。我们需要降低视频的比特率，所以我尝试重写它并使用 AVAssetWriter 录制视频。我的实现基于 CustomCamera 项目，并且几乎可以工作。问题出在视频中，几秒钟后它就冻结了，尽管音频正常。请问你能帮帮我吗？我不知道问题出在哪里，也许是缓冲区或垃圾收集器收集一些变量的问题。谢谢。
这是代码：
//
// ViewController.swift
// CustomCamera
//
// Created by Taras Chernyshenko on 6/27/17.
// Copyright © 2017 Taras Chernyshenko. All rights reserved.
//
import AVFoundation
import Photos
class NewRecorder: NSObject,
AVCaptureAudioDataOutputSampleBufferDelegate,
AVCaptureVideoDataOutputSampleBufferDelegate {
private var session: AVCaptureSession = AVCaptureSession()
private var deviceInput: AVCaptureScreenInput?
private var previewLayer: AVCaptureVideoPreviewLayer?
private var videoOutput: AVCaptureVideoDataOutput = AVCaptureVideoDataOutput()
private var audioOutput: AVCaptureAudioDataOutput = AVCaptureAudioDataOutput()
//private var videoDevice: AVCaptureDevice = AVCaptureScreenInput(displayID: 69731840) //AVCaptureDevice.default(for: AVMediaType.video)!
private var audioConnection: AVCaptureConnection?
private var videoConnection: AVCaptureConnection?
private var assetWriter: AVAssetWriter?
private var audioInput: AVAssetWriterInput?
private var videoInput: AVAssetWriterInput?
private var fileManager: FileManager = FileManager()
private var recordingURL: URL?
private var isCameraRecording: Bool = false
private var isRecordingSessionStarted: Bool = false
private var recordingQueue = DispatchQueue(label: "recording.queue")
func setup() {
self.session.sessionPreset = AVCaptureSession.Preset.high
self.recordingURL = URL(fileURLWithPath: "\(NSTemporaryDirectory() as String)/file.mp4")
if self.fileManager.isDeletableFile(atPath: self.recordingURL!.path) {
_ = try? self.fileManager.removeItem(atPath: self.recordingURL!.path)
}
self.assetWriter = try? AVAssetWriter(outputURL: self.recordingURL!,
fileType: AVFileType.mp4)
self.assetWriter!.movieFragmentInterval = kCMTimeInvalid
self.assetWriter!.shouldOptimizeForNetworkUse = true
let audioSettings = [
AVFormatIDKey : kAudioFormatMPEG4AAC,
AVNumberOfChannelsKey : 2,
AVSampleRateKey : 44100.0,
AVEncoderBitRateKey: 192000
] as [String : Any]
let videoSettings = [
AVVideoCodecKey : AVVideoCodecType.h264,
AVVideoWidthKey : 1920,
AVVideoHeightKey : 1080
/*AVVideoCompressionPropertiesKey: [
AVVideoAverageBitRateKey: NSNumber(value: 5000000)
]*/
] as [String : Any]
self.videoInput = AVAssetWriterInput(mediaType: AVMediaType.video,
outputSettings: videoSettings)
self.audioInput = AVAssetWriterInput(mediaType: AVMediaType.audio,
outputSettings: audioSettings)
self.videoInput?.expectsMediaDataInRealTime = true
self.audioInput?.expectsMediaDataInRealTime = true
if self.assetWriter!.canAdd(self.videoInput!) {
self.assetWriter?.add(self.videoInput!)
}
if self.assetWriter!.canAdd(self.audioInput!) {
self.assetWriter?.add(self.audioInput!)
}
//self.deviceInput = try? AVCaptureDeviceInput(device: self.videoDevice)
self.deviceInput = AVCaptureScreenInput(displayID: 724042646)
self.deviceInput!.minFrameDuration = CMTimeMake(1, Int32(30))
self.deviceInput!.capturesCursor = true
self.deviceInput!.capturesMouseClicks = true
if self.session.canAddInput(self.deviceInput!) {
self.session.addInput(self.deviceInput!)
}
self.previewLayer = AVCaptureVideoPreviewLayer(session: self.session)
//importent line of code what will did a trick
//self.previewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
//let rootLayer = self.view.layer
//rootLayer.masksToBounds = true
//self.previewLayer?.frame = CGRect(x: 0, y: 0, width: 1920, height: 1080)
//rootLayer.insertSublayer(self.previewLayer!, at: 0)
self.session.startRunning()
DispatchQueue.main.async {
self.session.beginConfiguration()
if self.session.canAddOutput(self.videoOutput) {
self.session.addOutput(self.videoOutput)
}
self.videoConnection = self.videoOutput.connection(with: AVMediaType.video)
/*if self.videoConnection?.isVideoStabilizationSupported == true {
self.videoConnection?.preferredVideoStabilizationMode = .auto
}*/
self.session.commitConfiguration()
let audioDevice = AVCaptureDevice.default(for: AVMediaType.audio)
let audioIn = try? AVCaptureDeviceInput(device: audioDevice!)
if self.session.canAddInput(audioIn!) {
self.session.addInput(audioIn!)
}
if self.session.canAddOutput(self.audioOutput) {
self.session.addOutput(self.audioOutput)
}
self.audioConnection = self.audioOutput.connection(with: AVMediaType.audio)
}
}
func startRecording() {
if self.assetWriter?.startWriting() != true {
print("error: \(self.assetWriter?.error.debugDescription ?? "")")
}
self.videoOutput.setSampleBufferDelegate(self, queue: self.recordingQueue)
self.audioOutput.setSampleBufferDelegate(self, queue: self.recordingQueue)
}
func stopRecording() {
self.videoOutput.setSampleBufferDelegate(nil, queue: nil)
self.audioOutput.setSampleBufferDelegate(nil, queue: nil)
self.assetWriter?.finishWriting {
print("Saved in folder \(self.recordingURL!)")
exit(0)
}
}
func captureOutput(_ captureOutput: AVCaptureOutput, didOutput
sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
if !self.isRecordingSessionStarted {
let presentationTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer)
self.assetWriter?.startSession(atSourceTime: presentationTime)
self.isRecordingSessionStarted = true
}
let description = CMSampleBufferGetFormatDescription(sampleBuffer)!
if CMFormatDescriptionGetMediaType(description) == kCMMediaType_Audio {
if self.audioInput!.isReadyForMoreMediaData {
//print("appendSampleBuffer audio");
self.audioInput?.append(sampleBuffer)
}
} else {
if self.videoInput!.isReadyForMoreMediaData {
//print("appendSampleBuffer video");
if !self.videoInput!.append(sampleBuffer) {
print("Error writing video buffer");
}
}
}
}
}
