Ios AVAssetWriterInput追加失败，错误代码为-11800 AVErrorUnknown-12780
我正在尝试使用AVCaptureSession在内存中捕获摄像头视频，以便以后可以将视频数据写入电影文件。虽然我已经能够成功地启动捕获会话，但我无法使用AVAssetWriter成功地将捕获的CMSampleBuffers写入压缩的电影文件 使用AVAssetWriterInput的append方法追加示例缓冲区失败，当我检查AVAssetWriter的error属性时，得到以下结果： Error Domain=AVFoundationErrorDomain Code=-11800“操作无法完成”UserInfo={NSUnderlyingError=0x17005d070{Error Domain=nsossstatuserrordomain Code=-12780”（null）}，NSLocalizedFailureReason=发生未知错误（-12780），NSLocalizedDescription=操作无法完成} 据我所知-11800表示一个未知的错误，但是我还没有找到关于-12780错误代码的信息，据我所知，这是没有记录的。下面我粘贴了我设置的示例项目中的主要文件，以演示该问题 任何指导都将不胜感激。谢谢 ViewController.swiftIos AVAssetWriterInput追加失败，错误代码为-11800 AVErrorUnknown-12780,ios,avfoundation,avassetwriter,cvpixelbuffer,avassetwriterinput,Ios,Avfoundation,Avassetwriter,Cvpixelbuffer,Avassetwriterinput,我正在尝试使用AVCaptureSession在内存中捕获摄像头视频，以便以后可以将视频数据写入电影文件。虽然我已经能够成功地启动捕获会话，但我无法使用AVAssetWriter成功地将捕获的CMSampleBuffers写入压缩的电影文件 使用AVAssetWriterInput的append方法追加示例缓冲区失败，当我检查AVAssetWriter的error属性时，得到以下结果： Error Domain=AVFoundationErrorDomain Code=-11800“操作无法完成
import UIKit
import AVFoundation
class ViewController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate {
private let recordingClipQueue = DispatchQueue(label: "com.example.recordingClipQueue")
private let videoDataOutputQueue = DispatchQueue(label: "com.example.videoDataOutputQueue")
private let session = AVCaptureSession()
private var backfillSampleBufferList = [CMSampleBuffer]()
override func viewDidLoad() {
super.viewDidLoad()
session.sessionPreset = AVCaptureSessionPreset640x480
let videoDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo);
let videoDeviceInput: AVCaptureDeviceInput;
do {
videoDeviceInput = try AVCaptureDeviceInput(device: videoDevice)
} catch {
print("Error creating device input from video device: \(error).")
return
}
guard session.canAddInput(videoDeviceInput) else {
print("Could not add video device input to capture session.")
return
}
session.addInput(videoDeviceInput)
let videoDataOutput = AVCaptureVideoDataOutput()
videoDataOutput.videoSettings = [ kCVPixelBufferPixelFormatTypeKey as NSString : Int(kCMPixelFormat_32BGRA) ]
videoDataOutput.alwaysDiscardsLateVideoFrames = true
videoDataOutput.setSampleBufferDelegate(self, queue: videoDataOutputQueue)
guard session.canAddOutput(videoDataOutput) else {
print("Could not add video data output to capture session.")
return
}
session.addOutput(videoDataOutput)
videoDataOutput.connection(withMediaType: AVMediaTypeVideo).isEnabled = true
session.startRunning()
}
private func backfillSizeInSeconds() -> Double {
if backfillSampleBufferList.count < 1 {
return 0.0
}
let earliestSampleBuffer = backfillSampleBufferList.first!
let latestSampleBuffer = backfillSampleBufferList.last!
let earliestSampleBufferPTS = CMSampleBufferGetOutputPresentationTimeStamp(earliestSampleBuffer).value
let latestSampleBufferPTS = CMSampleBufferGetOutputPresentationTimeStamp(latestSampleBuffer).value
let timescale = CMSampleBufferGetOutputPresentationTimeStamp(latestSampleBuffer).timescale
return Double(latestSampleBufferPTS - earliestSampleBufferPTS) / Double(timescale)
}
private func createClipFromBackfill() {
guard backfillSampleBufferList.count > 0 else {
print("createClipFromBackfill() called before any samples were recorded.")
return
}
let clipURL = URL(fileURLWithPath:
NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] +
"/recorded_clip.mp4")
if FileManager.default.fileExists(atPath: clipURL.path) {
do {
try FileManager.default.removeItem(atPath: clipURL.path)
} catch {
print("Could not delete existing clip file: \(error).")
}
}
var _videoFileWriter: AVAssetWriter?
do {
_videoFileWriter = try AVAssetWriter(url: clipURL, fileType: AVFileTypeQuickTimeMovie)
} catch {
print("Could not create video file writer: \(error).")
return
}
guard let videoFileWriter = _videoFileWriter else {
print("Video writer was nil.")
return
}
let settingsAssistant = AVOutputSettingsAssistant(preset: AVOutputSettingsPreset640x480)!
guard videoFileWriter.canApply(outputSettings: settingsAssistant.videoSettings, forMediaType: AVMediaTypeVideo) else {
print("Video file writer could not apply video output settings.")
return
}
let earliestRecordedSampleBuffer = backfillSampleBufferList.first!
let _formatDescription = CMSampleBufferGetFormatDescription(earliestRecordedSampleBuffer)
guard let formatDescription = _formatDescription else {
print("Earliest recording pixel buffer format description was nil.")
return
}
let videoWriterInput = AVAssetWriterInput(mediaType: AVMediaTypeVideo,
outputSettings: settingsAssistant.videoSettings,
sourceFormatHint: formatDescription)
guard videoFileWriter.canAdd(videoWriterInput) else {
print("Could not add video writer input to video file writer.")
return
}
videoFileWriter.add(videoWriterInput)
guard videoFileWriter.startWriting() else {
print("Video file writer not ready to write file.")
return
}
videoFileWriter.startSession(atSourceTime: CMSampleBufferGetOutputPresentationTimeStamp(earliestRecordedSampleBuffer))
videoWriterInput.requestMediaDataWhenReady(on: recordingClipQueue) {
while videoWriterInput.isReadyForMoreMediaData {
if self.backfillSampleBufferList.count > 0 {
let sampleBufferToAppend = self.backfillSampleBufferList.first!.deepCopy()
let appendSampleBufferSucceeded = videoWriterInput.append(sampleBufferToAppend)
if !appendSampleBufferSucceeded {
print("Failed to append sample buffer to asset writer input: \(videoFileWriter.error!)")
print("Video file writer status: \(videoFileWriter.status.rawValue)")
}
self.backfillSampleBufferList.remove(at: 0)
} else {
videoWriterInput.markAsFinished()
videoFileWriter.finishWriting {
print("Saved clip to \(clipURL)")
}
break
}
}
}
}
// MARK: AVCaptureVideoDataOutputSampleBufferDelegate
func captureOutput(_ captureOutput: AVCaptureOutput!,
didOutputSampleBuffer sampleBuffer: CMSampleBuffer!,
from connection: AVCaptureConnection!) {
guard let buffer = sampleBuffer else {
print("Captured sample buffer was nil.")
return
}
let sampleBufferCopy = buffer.deepCopy()
backfillSampleBufferList.append(sampleBufferCopy)
if backfillSizeInSeconds() > 3.0 {
session.stopRunning()
createClipFromBackfill()
}
}
func captureOutput(_ captureOutput: AVCaptureOutput!,
didDrop sampleBuffer: CMSampleBuffer!,
from connection: AVCaptureConnection!) {
print("Sample buffer dropped.")
}
}
import UIKit
import AVFoundation
import Photos
class ViewController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate {
private let recordingClipQueue = DispatchQueue(label: "com.example.recordingClipQueue")
private let videoDataOutputQueue = DispatchQueue(label: "com.example.videoDataOutputQueue")
private let session = AVCaptureSession()
private var backfillSampleBufferList = [CMSampleBuffer]()
override func viewDidLoad() {
super.viewDidLoad()
session.sessionPreset = AVCaptureSessionPreset640x480
let videoDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo);
let videoDeviceInput: AVCaptureDeviceInput;
do {
videoDeviceInput = try AVCaptureDeviceInput(device: videoDevice)
} catch {
print("Error creating device input from video device: \(error).")
return
}
guard session.canAddInput(videoDeviceInput) else {
print("Could not add video device input to capture session.")
return
}
session.addInput(videoDeviceInput)
let videoDataOutput = AVCaptureVideoDataOutput()
videoDataOutput.videoSettings = [ kCVPixelBufferPixelFormatTypeKey as NSString : Int(kCMPixelFormat_32BGRA) ]
videoDataOutput.alwaysDiscardsLateVideoFrames = true
videoDataOutput.setSampleBufferDelegate(self, queue: videoDataOutputQueue)
guard session.canAddOutput(videoDataOutput) else {
print("Could not add video data output to capture session.")
return
}
session.addOutput(videoDataOutput)
videoDataOutput.connection(withMediaType: AVMediaTypeVideo).isEnabled = true
session.startRunning()
}
private func backfillSizeInSeconds() -> Double {
if backfillSampleBufferList.count < 1 {
return 0.0
}
let earliestSampleBuffer = backfillSampleBufferList.first!
let latestSampleBuffer = backfillSampleBufferList.last!
let earliestSampleBufferPTS = CMSampleBufferGetOutputPresentationTimeStamp(earliestSampleBuffer).value
let latestSampleBufferPTS = CMSampleBufferGetOutputPresentationTimeStamp(latestSampleBuffer).value
let timescale = CMSampleBufferGetOutputPresentationTimeStamp(latestSampleBuffer).timescale
return Double(latestSampleBufferPTS - earliestSampleBufferPTS) / Double(timescale)
}
private func createClipFromBackfill() {
guard backfillSampleBufferList.count > 0 else {
print("createClipFromBackfill() called before any samples were recorded.")
return
}
let clipURL = URL(fileURLWithPath:
NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] +
"/recorded_clip.mp4")
if FileManager.default.fileExists(atPath: clipURL.path) {
do {
try FileManager.default.removeItem(atPath: clipURL.path)
} catch {
print("Could not delete existing clip file: \(error).")
}
}
var _videoFileWriter: AVAssetWriter?
do {
_videoFileWriter = try AVAssetWriter(url: clipURL, fileType: AVFileTypeMPEG4)
} catch {
print("Could not create video file writer: \(error).")
return
}
guard let videoFileWriter = _videoFileWriter else {
print("Video writer was nil.")
return
}
let settingsAssistant = AVOutputSettingsAssistant(preset: AVOutputSettingsPreset640x480)!
guard videoFileWriter.canApply(outputSettings: settingsAssistant.videoSettings, forMediaType: AVMediaTypeVideo) else {
print("Video file writer could not apply video output settings.")
return
}
let earliestRecordedSampleBuffer = backfillSampleBufferList.first!
let _formatDescription = CMSampleBufferGetFormatDescription(earliestRecordedSampleBuffer)
guard let formatDescription = _formatDescription else {
print("Earliest recording pixel buffer format description was nil.")
return
}
let videoWriterInput = AVAssetWriterInput(mediaType: AVMediaTypeVideo,
outputSettings: settingsAssistant.videoSettings,
sourceFormatHint: formatDescription)
guard videoFileWriter.canAdd(videoWriterInput) else {
print("Could not add video writer input to video file writer.")
return
}
videoFileWriter.add(videoWriterInput)
let pixelAdapterBufferAttributes = [ kCVPixelBufferPixelFormatTypeKey as String : Int(kCMPixelFormat_32BGRA) ]
let pixelAdapter = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: videoWriterInput,
sourcePixelBufferAttributes: pixelAdapterBufferAttributes)
guard videoFileWriter.startWriting() else {
print("Video file writer not ready to write file.")
return
}
videoFileWriter.startSession(atSourceTime: CMSampleBufferGetOutputPresentationTimeStamp(earliestRecordedSampleBuffer))
videoWriterInput.requestMediaDataWhenReady(on: recordingClipQueue) {
while videoWriterInput.isReadyForMoreMediaData {
if self.backfillSampleBufferList.count > 0 {
let sampleBufferToAppend = self.backfillSampleBufferList.first!.deepCopy()
let appendSampleBufferSucceeded = pixelAdapter.append(CMSampleBufferGetImageBuffer(sampleBufferToAppend)!,
withPresentationTime: CMSampleBufferGetOutputPresentationTimeStamp(sampleBufferToAppend))
if !appendSampleBufferSucceeded {
print("Failed to append sample buffer to asset writer input: \(videoFileWriter.error!)")
print("Video file writer status: \(videoFileWriter.status.rawValue)")
}
self.backfillSampleBufferList.remove(at: 0)
} else {
videoWriterInput.markAsFinished()
videoFileWriter.finishWriting {
print("Saving clip to \(clipURL)")
}
break
}
}
}
}
// MARK: AVCaptureVideoDataOutputSampleBufferDelegate
func captureOutput(_ captureOutput: AVCaptureOutput!,
didOutputSampleBuffer sampleBuffer: CMSampleBuffer!,
from connection: AVCaptureConnection!) {
guard let buffer = sampleBuffer else {
print("Captured sample buffer was nil.")
return
}
let sampleBufferCopy = buffer.deepCopy()
backfillSampleBufferList.append(sampleBufferCopy)
if backfillSizeInSeconds() > 3.0 {
session.stopRunning()
createClipFromBackfill()
}
}
func captureOutput(_ captureOutput: AVCaptureOutput!,
didDrop sampleBuffer: CMSampleBuffer!,
from connection: AVCaptureConnection!) {
print("Sample buffer dropped.")
}
}
import CoreVideo
extension CVPixelBuffer {
func deepCopy() -> CVPixelBuffer {
precondition(CFGetTypeID(self) == CVPixelBufferGetTypeID(), "deepCopy() cannot copy a non-CVPixelBuffer")
var _copy : CVPixelBuffer?
CVPixelBufferCreate(
nil,
CVPixelBufferGetWidth(self),
CVPixelBufferGetHeight(self),
CVPixelBufferGetPixelFormatType(self),
CVBufferGetAttachments(self, CVAttachmentMode.shouldPropagate),
&_copy)
guard let copy = _copy else {
print("Pixel buffer copy was nil.")
fatalError()
}
CVBufferPropagateAttachments(self, copy)
CVPixelBufferLockBaseAddress(self, CVPixelBufferLockFlags.readOnly)
CVPixelBufferLockBaseAddress(copy, CVPixelBufferLockFlags(rawValue: 0))
let sourceBaseAddress = CVPixelBufferGetBaseAddress(self)
let copyBaseAddress = CVPixelBufferGetBaseAddress(copy)
memcpy(copyBaseAddress, sourceBaseAddress, CVPixelBufferGetHeight(self) * CVPixelBufferGetBytesPerRow(self))
CVPixelBufferUnlockBaseAddress(copy, CVPixelBufferLockFlags(rawValue: 0))
CVPixelBufferUnlockBaseAddress(self, CVPixelBufferLockFlags.readOnly)
return copy
}
}
import CoreMedia
extension CMSampleBuffer {
func deepCopy() -> CMSampleBuffer {
let _pixelBuffer = CMSampleBufferGetImageBuffer(self)
guard let pixelBuffer = _pixelBuffer else {
print("Pixel buffer to copy was nil.")
fatalError()
}
let pixelBufferCopy = pixelBuffer.deepCopy()
let _formatDescription = CMSampleBufferGetFormatDescription(self)
guard let formatDescription = _formatDescription else {
print("Format description to copy was nil.")
fatalError()
}
var timingInfo = kCMTimingInfoInvalid
let getTimingInfoResult = CMSampleBufferGetSampleTimingInfo(self, 0, &timingInfo)
guard getTimingInfoResult == noErr else {
print("Could not get timing info to copy: \(getTimingInfoResult).")
fatalError()
}
timingInfo.presentationTimeStamp = CMSampleBufferGetOutputPresentationTimeStamp(self)
var _copy : CMSampleBuffer?
let createCopyResult = CMSampleBufferCreateForImageBuffer(kCFAllocatorDefault,
pixelBufferCopy,
true,
nil,
nil,
formatDescription,
&timingInfo,
&_copy);
guard createCopyResult == noErr else {
print("Error creating copy of sample buffer: \(createCopyResult).")
fatalError()
}
guard let copy = _copy else {
print("Copied sample buffer was nil.")
fatalError()
}
return copy
}
}
经过更多的研究和实验，似乎使用AvassetWriterInputPixelBufferAdapter将我存储的CMSampleBuffers的CVPixelBuffers附加到AVAssetWriterInput工作时不会产生错误 下面是ViewController.swift实现的修改版本，它使用AvassetWriterInputPixelBufferAdapter附加像素缓冲区 ViewController.swift
import UIKit
import AVFoundation
class ViewController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate {
private let recordingClipQueue = DispatchQueue(label: "com.example.recordingClipQueue")
private let videoDataOutputQueue = DispatchQueue(label: "com.example.videoDataOutputQueue")
private let session = AVCaptureSession()
private var backfillSampleBufferList = [CMSampleBuffer]()
override func viewDidLoad() {
super.viewDidLoad()
session.sessionPreset = AVCaptureSessionPreset640x480
let videoDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo);
let videoDeviceInput: AVCaptureDeviceInput;
do {
videoDeviceInput = try AVCaptureDeviceInput(device: videoDevice)
} catch {
print("Error creating device input from video device: \(error).")
return
}
guard session.canAddInput(videoDeviceInput) else {
print("Could not add video device input to capture session.")
return
}
session.addInput(videoDeviceInput)
let videoDataOutput = AVCaptureVideoDataOutput()
videoDataOutput.videoSettings = [ kCVPixelBufferPixelFormatTypeKey as NSString : Int(kCMPixelFormat_32BGRA) ]
videoDataOutput.alwaysDiscardsLateVideoFrames = true
videoDataOutput.setSampleBufferDelegate(self, queue: videoDataOutputQueue)
guard session.canAddOutput(videoDataOutput) else {
print("Could not add video data output to capture session.")
return
}
session.addOutput(videoDataOutput)
videoDataOutput.connection(withMediaType: AVMediaTypeVideo).isEnabled = true
session.startRunning()
}
private func backfillSizeInSeconds() -> Double {
if backfillSampleBufferList.count < 1 {
return 0.0
}
let earliestSampleBuffer = backfillSampleBufferList.first!
let latestSampleBuffer = backfillSampleBufferList.last!
let earliestSampleBufferPTS = CMSampleBufferGetOutputPresentationTimeStamp(earliestSampleBuffer).value
let latestSampleBufferPTS = CMSampleBufferGetOutputPresentationTimeStamp(latestSampleBuffer).value
let timescale = CMSampleBufferGetOutputPresentationTimeStamp(latestSampleBuffer).timescale
return Double(latestSampleBufferPTS - earliestSampleBufferPTS) / Double(timescale)
}
private func createClipFromBackfill() {
guard backfillSampleBufferList.count > 0 else {
print("createClipFromBackfill() called before any samples were recorded.")
return
}
let clipURL = URL(fileURLWithPath:
NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] +
"/recorded_clip.mp4")
if FileManager.default.fileExists(atPath: clipURL.path) {
do {
try FileManager.default.removeItem(atPath: clipURL.path)
} catch {
print("Could not delete existing clip file: \(error).")
}
}
var _videoFileWriter: AVAssetWriter?
do {
_videoFileWriter = try AVAssetWriter(url: clipURL, fileType: AVFileTypeQuickTimeMovie)
} catch {
print("Could not create video file writer: \(error).")
return
}
guard let videoFileWriter = _videoFileWriter else {
print("Video writer was nil.")
return
}
let settingsAssistant = AVOutputSettingsAssistant(preset: AVOutputSettingsPreset640x480)!
guard videoFileWriter.canApply(outputSettings: settingsAssistant.videoSettings, forMediaType: AVMediaTypeVideo) else {
print("Video file writer could not apply video output settings.")
return
}
let earliestRecordedSampleBuffer = backfillSampleBufferList.first!
let _formatDescription = CMSampleBufferGetFormatDescription(earliestRecordedSampleBuffer)
guard let formatDescription = _formatDescription else {
print("Earliest recording pixel buffer format description was nil.")
return
}
let videoWriterInput = AVAssetWriterInput(mediaType: AVMediaTypeVideo,
outputSettings: settingsAssistant.videoSettings,
sourceFormatHint: formatDescription)
guard videoFileWriter.canAdd(videoWriterInput) else {
print("Could not add video writer input to video file writer.")
return
}
videoFileWriter.add(videoWriterInput)
guard videoFileWriter.startWriting() else {
print("Video file writer not ready to write file.")
return
}
videoFileWriter.startSession(atSourceTime: CMSampleBufferGetOutputPresentationTimeStamp(earliestRecordedSampleBuffer))
videoWriterInput.requestMediaDataWhenReady(on: recordingClipQueue) {
while videoWriterInput.isReadyForMoreMediaData {
if self.backfillSampleBufferList.count > 0 {
let sampleBufferToAppend = self.backfillSampleBufferList.first!.deepCopy()
let appendSampleBufferSucceeded = videoWriterInput.append(sampleBufferToAppend)
if !appendSampleBufferSucceeded {
print("Failed to append sample buffer to asset writer input: \(videoFileWriter.error!)")
print("Video file writer status: \(videoFileWriter.status.rawValue)")
}
self.backfillSampleBufferList.remove(at: 0)
} else {
videoWriterInput.markAsFinished()
videoFileWriter.finishWriting {
print("Saved clip to \(clipURL)")
}
break
}
}
}
}
// MARK: AVCaptureVideoDataOutputSampleBufferDelegate
func captureOutput(_ captureOutput: AVCaptureOutput!,
didOutputSampleBuffer sampleBuffer: CMSampleBuffer!,
from connection: AVCaptureConnection!) {
guard let buffer = sampleBuffer else {
print("Captured sample buffer was nil.")
return
}
let sampleBufferCopy = buffer.deepCopy()
backfillSampleBufferList.append(sampleBufferCopy)
if backfillSizeInSeconds() > 3.0 {
session.stopRunning()
createClipFromBackfill()
}
}
func captureOutput(_ captureOutput: AVCaptureOutput!,
didDrop sampleBuffer: CMSampleBuffer!,
from connection: AVCaptureConnection!) {
print("Sample buffer dropped.")
}
}
import UIKit
import AVFoundation
import Photos
class ViewController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate {
private let recordingClipQueue = DispatchQueue(label: "com.example.recordingClipQueue")
private let videoDataOutputQueue = DispatchQueue(label: "com.example.videoDataOutputQueue")
private let session = AVCaptureSession()
private var backfillSampleBufferList = [CMSampleBuffer]()
override func viewDidLoad() {
super.viewDidLoad()
session.sessionPreset = AVCaptureSessionPreset640x480
let videoDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo);
let videoDeviceInput: AVCaptureDeviceInput;
do {
videoDeviceInput = try AVCaptureDeviceInput(device: videoDevice)
} catch {
print("Error creating device input from video device: \(error).")
return
}
guard session.canAddInput(videoDeviceInput) else {
print("Could not add video device input to capture session.")
return
}
session.addInput(videoDeviceInput)
let videoDataOutput = AVCaptureVideoDataOutput()
videoDataOutput.videoSettings = [ kCVPixelBufferPixelFormatTypeKey as NSString : Int(kCMPixelFormat_32BGRA) ]
videoDataOutput.alwaysDiscardsLateVideoFrames = true
videoDataOutput.setSampleBufferDelegate(self, queue: videoDataOutputQueue)
guard session.canAddOutput(videoDataOutput) else {
print("Could not add video data output to capture session.")
return
}
session.addOutput(videoDataOutput)
videoDataOutput.connection(withMediaType: AVMediaTypeVideo).isEnabled = true
session.startRunning()
}
private func backfillSizeInSeconds() -> Double {
if backfillSampleBufferList.count < 1 {
return 0.0
}
let earliestSampleBuffer = backfillSampleBufferList.first!
let latestSampleBuffer = backfillSampleBufferList.last!
let earliestSampleBufferPTS = CMSampleBufferGetOutputPresentationTimeStamp(earliestSampleBuffer).value
let latestSampleBufferPTS = CMSampleBufferGetOutputPresentationTimeStamp(latestSampleBuffer).value
let timescale = CMSampleBufferGetOutputPresentationTimeStamp(latestSampleBuffer).timescale
return Double(latestSampleBufferPTS - earliestSampleBufferPTS) / Double(timescale)
}
private func createClipFromBackfill() {
guard backfillSampleBufferList.count > 0 else {
print("createClipFromBackfill() called before any samples were recorded.")
return
}
let clipURL = URL(fileURLWithPath:
NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] +
"/recorded_clip.mp4")
if FileManager.default.fileExists(atPath: clipURL.path) {
do {
try FileManager.default.removeItem(atPath: clipURL.path)
} catch {
print("Could not delete existing clip file: \(error).")
}
}
var _videoFileWriter: AVAssetWriter?
do {
_videoFileWriter = try AVAssetWriter(url: clipURL, fileType: AVFileTypeMPEG4)
} catch {
print("Could not create video file writer: \(error).")
return
}
guard let videoFileWriter = _videoFileWriter else {
print("Video writer was nil.")
return
}
let settingsAssistant = AVOutputSettingsAssistant(preset: AVOutputSettingsPreset640x480)!
guard videoFileWriter.canApply(outputSettings: settingsAssistant.videoSettings, forMediaType: AVMediaTypeVideo) else {
print("Video file writer could not apply video output settings.")
return
}
let earliestRecordedSampleBuffer = backfillSampleBufferList.first!
let _formatDescription = CMSampleBufferGetFormatDescription(earliestRecordedSampleBuffer)
guard let formatDescription = _formatDescription else {
print("Earliest recording pixel buffer format description was nil.")
return
}
let videoWriterInput = AVAssetWriterInput(mediaType: AVMediaTypeVideo,
outputSettings: settingsAssistant.videoSettings,
sourceFormatHint: formatDescription)
guard videoFileWriter.canAdd(videoWriterInput) else {
print("Could not add video writer input to video file writer.")
return
}
videoFileWriter.add(videoWriterInput)
let pixelAdapterBufferAttributes = [ kCVPixelBufferPixelFormatTypeKey as String : Int(kCMPixelFormat_32BGRA) ]
let pixelAdapter = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: videoWriterInput,
sourcePixelBufferAttributes: pixelAdapterBufferAttributes)
guard videoFileWriter.startWriting() else {
print("Video file writer not ready to write file.")
return
}
videoFileWriter.startSession(atSourceTime: CMSampleBufferGetOutputPresentationTimeStamp(earliestRecordedSampleBuffer))
videoWriterInput.requestMediaDataWhenReady(on: recordingClipQueue) {
while videoWriterInput.isReadyForMoreMediaData {
if self.backfillSampleBufferList.count > 0 {
let sampleBufferToAppend = self.backfillSampleBufferList.first!.deepCopy()
let appendSampleBufferSucceeded = pixelAdapter.append(CMSampleBufferGetImageBuffer(sampleBufferToAppend)!,
withPresentationTime: CMSampleBufferGetOutputPresentationTimeStamp(sampleBufferToAppend))
if !appendSampleBufferSucceeded {
print("Failed to append sample buffer to asset writer input: \(videoFileWriter.error!)")
print("Video file writer status: \(videoFileWriter.status.rawValue)")
}
self.backfillSampleBufferList.remove(at: 0)
} else {
videoWriterInput.markAsFinished()
videoFileWriter.finishWriting {
print("Saving clip to \(clipURL)")
}
break
}
}
}
}
// MARK: AVCaptureVideoDataOutputSampleBufferDelegate
func captureOutput(_ captureOutput: AVCaptureOutput!,
didOutputSampleBuffer sampleBuffer: CMSampleBuffer!,
from connection: AVCaptureConnection!) {
guard let buffer = sampleBuffer else {
print("Captured sample buffer was nil.")
return
}
let sampleBufferCopy = buffer.deepCopy()
backfillSampleBufferList.append(sampleBufferCopy)
if backfillSizeInSeconds() > 3.0 {
session.stopRunning()
createClipFromBackfill()
}
}
func captureOutput(_ captureOutput: AVCaptureOutput!,
didDrop sampleBuffer: CMSampleBuffer!,
from connection: AVCaptureConnection!) {
print("Sample buffer dropped.")
}
}
导入UIKit
进口AVF基金会
导入照片
类ViewController:UIViewController、AVCaptureVideoDataOutputSampleBufferDelegate{
private let recordingClipQueue=DispatchQueue（标签：“com.example.recordingClipQueue”）
私有let videoDataOutputQueue=DispatchQueue（标签：“com.example.videoDataOutputQueue”）
private let session=AVCaptureSession（）
私有变量回填SampleBufferList=[CMSampleBuffer]（）
重写func viewDidLoad（）{
super.viewDidLoad（）
session.sessionPreset=AVCaptureSessionPreset640x480
让videoDevice=AVCaptureDevice.defaultDevice（带MediaType:AVMediaTypeVideo）；
让视频设备输入：AVCaptureDeviceInput；
做{
videoDeviceInput=尝试AVCaptureDeviceInput（设备：videoDevice）
}抓住{
打印（“从视频设备创建设备输入时出错：\（错误）。”）
返回
}
保护会话。canAddInput（视频设备输入）else{
打印（“无法将视频设备输入添加到捕获会话。”）
返回
}
会话.添加输入（视频设备输入）
让videoDataOutput=AVCaptureVideoDataOutput（）
videoDataOutput.videoSettings=[kCVPixelBufferPixelFormatTypeKey作为NSString:Int（kCMPixelFormat_32BGRA）]
videoDataOutput.alwaysDiscardsLateVideoFrames=true
videoDataOutput.setSampleBufferDelegate（self，队列：videoDataOutputQueue）
保护会话.canAddOutput（视频数据输出）else{
打印（“无法将视频数据输出添加到捕获会话。”）
返回
}
session.addOutput（videoDataOutput）
videoDataOutput.connection（withMediaType:AVMediaTypeVideo）.isEnabled=true
会议.启动耳轴（）
}
private func backfillSizeInSeconds（）->Double{
如果回填SampleBufferList.count<1{
返回0.0
}
让EarliesSampleBuffer=backfillSampleBufferList.first！
让latestSampleBuffer=backfillSampleBufferList.last！
让earliestSampleBufferPTS=CMSampleBufferGetOutputPresentationTimeStamp（earliestSampleBuffer）.value
让latestSampleBufferPTS=CMSampleBufferGetOutputPresentationTimeStamp（latestSampleBuffer）.value
让timescale=CMSampleBufferGetOutputPresentationTimeStamp（latestSampleBuffer）。timescale
返回双精度（latestSampleBufferPTS-earliestSampleBufferPTS）/双精度（时间刻度）
}
私有函数createClipFromBackfill（）{
guard backfillSampleBufferList.count>0其他{
打印（“在记录任何样本之前调用createClipFromBackfill（）”）
返回
}
让clipURL=URL（fileURLWithPath:
NSSearchPathForDirectoriesInDomains（.documentDirectory、.userDomainMask，true）[0]+
“/recorded\u clip.mp4”）
如果FileManager.default.fileExists（atPath:clipURL.path）{
做{
请尝试FileManager.default.removietem（atPath:clipURL.path）
}抓住{
打印（“无法删除现有剪辑文件：\（错误）。”）
}
}
var_videoFileWriter:AVAssetWriter？
做{
_videoFileWriter=尝试AVAssetWriter（url:clipURL，文件类型：AVFileTypeMPEG4）
}抓住{
打印（“无法创建视频文件编写器：\（错误）。”）
返回
}
guard let videoFileWriter=\u videoFileWriter else{
打印（“视频编写器为零”）
返回
}
让SettingsAsistant=AvoutputSettingsAsistant（预设：AVOutputSettingsPreset640x480）！
guard videoFileWriter.canApply（输出设置：SettingsAsistant.videoSettings，forMediaType:AVMediaTypeVideo）其他{
打印（“视频文件编写器无法应用视频输出设置。”）
返回
}
让EarliesTreRecordedSampleBuffer=backfillSampleBufferList.first！
let _formatDescription=CMSampleBufferGetFormatDescription（EarliesTreRecordedSampleBuffer）
guard let formatDescription=\u formatDescription else{
打印（“最早的记录像素缓冲区格式说明为零。”）
返回
}
让videoWriterInput=AVAssetWriterInput（mediaType:AVMediaTypeVideo，
输出设置：设置SASS