基于AVFoundation实现视频录制的两种方式

目录

• 一、前言
• 二、方案一：AVCaptureSession + AVCaptureMovieFileOutput
  • 1.创建AVCaptureSession
  • 2.设置音频、视频输入
  • 3.设置文件输出源
  • 4.添加视频预览层
  • 5. 开始采集
  • 6. 开始录制
  • 7.停止录制
  • 8.停止采集
• 三、方案二：AVCaptureSession + AVAssetWriter

一、前言

AVCaptureSession 是 AVFoundation 的核心类，用于管理捕获对象 AVCaptureInput 的视频和音频的输入，协调捕获的输出 AVCaptureOutput。

AVCaptureOutput 的输出有两种方法：

• 一种是直接以 movieFileUrl 方式输出；
• 一种是以原始数据流 data 的方式输出

流程对比图如下：

下面详细讲解两种录制视频的方案：

二、方案一：AVCaptureSession + AVCaptureMovieFileOutput1.创建AVCaptureSession

//导入 AVFoundation.framework #import //声明属性@property (nonatomic, strong) AVCaptureSession *captureSession;//懒加载 AVCapturesession- (AVCaptureSession *)captureSession {    if (!_captureSession) {        _captureSession = [[AVCaptureSession alloc] init];                //设置分辨率        if ([_captureSession canSetSessionPreset:AVCaptureSessionPresetHigh]) {            [_captureSession setSessionPreset:AVCaptureSessionPresetHigh];        }    }    return _captureSession;}

注意：AVCaptureSession 的调用是会阻塞线程的，建议单独开辟子线程处理。

2.设置音频、视频输入

//声明属性@property (nonatomic, strong) AVCaptureDeviceInput *videoInput;@property (nonatomic, strong) AVCaptureDeviceInput *audioInput;//设置视频，音频输入源- (void)setCaptureDeviceInput {    //1. 视频输入源    //获取视频输入设备， 默认后置摄像头    AVCaptureDevice *videoCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];        NSError *error = nil;    self.videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoCaptureDevice error:&error];        if ([self.captureSession canAddInput:self.videoInput]) {        [self.captureSession addInput:self.videoInput];    }            //2. 音频输入源    AVCaptureDevice *audioCaptureDevice = [[AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio] firstObject];    self.audioInput = [AVCaptureDeviceInput deviceInputWithDevice:audioCaptureDevice error:&error];    if ([self.captureSession canAddInput:self.audioInput]) {        [self.captureSession addInput:self.audioInput];    }    }

3.设置文件输出源

//声明属性@property (nonatomic, strong) AVCaptureMovieFileOutput *movieFileOutput;@property (nonatomic, strong) AVCaptureVideoPreviewLayer *previewLayer;//设置文件输出源- (void)setDeviceFileOutput {        //初始化文件输出对象    self.movieFileOutput = [[AVCaptureMovieFileOutput alloc] init];        //捕获会话中特定捕获输入对象和捕获输出对象之间的连接    AVCaptureConnection *captureConnection = [self.movieFileOutput connectionWithMediaType:AVMediaTypeVideo];        //设置防抖    if ([captureConnection isVideoStabilizationSupported]) {        captureConnection.preferredVideoStabilizationMode = AVCaptureVideoStabilizationModeAuto;    }        //预览图层和视频方向保持一致    captureConnection.videoOrientation = [self.previewLayer connection].videoOrientation;        //添加文件输出源    if ([self.captureSession canAddOutput:self.movieFileOutput]) {        [self.captureSession addOutput:self.movieFileOutput];    }    }

4.添加视频预览层

- (void)setVideoPreviewLayer {    self.previewLayer.frame = [UIScreen mainScreen].bounds;        [self.superView.layer addSubLayer:self.previewLayer];}- (AVCaptureVideoPreviewLayer *)previewLayer {    if (!_previewLayer) {        _previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:self.captureSession];        _previewLayer.masksToBounds = YES;        _previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;//填充模式    }    return _previewLayer;}

5. 开始采集

//声明属性@property (nonatomic, strong) dispatch_queue_t sessionQueue;//开始采集- (void)startCapture {self.sessionQueue = dispatch_queue_create("com.capturesession.queue", DISPATCH_QUEUE_CONCURRENT);    if (![self.captureSession isRunning]) {        __weak __typeof(self) weakSelf = self;                dispatch_async(self.sessionQueue, ^{            [weakSelf.captureSession startRunning];        });            }}

6. 开始录制

//开始录制- (void)startRecord {        [self.movieFileOutput startRecordingToOutputFileURL:[self createVideoPath] recordingDelegate:self];}

当实际的录制开始或停止时，系统会有代理回调。当开始录制之后，这时可能还没有真正写入，真正开始写入会回调下面代理，停止录制也是如此，所以如果你需要对录制视频起始点操作，建议通过系统的回调代理：

//实现协议 中的方法#pragma mark _ AVCaptureFileOutputRecordingDelegate//起始点 - 开始录制- (void)captureOutput:(AVCaptureFileOutput *)output didStartRecordingToOutputFileAtURL:(NSURL *)fileURL fromConnections:(NSArray *)connections {    }//结束录制-(void)captureOutput:(AVCaptureFileOutput *)captureOutput didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL fromConnections:(NSArray *)connections error:(NSError *)error{    NSLog(@"视频录制完成. 文件路径：%@",[outputFileURL absoluteString]);}

7.停止录制

//停止录制- (void)stopRecord {    if ([self.movieFileOutput isRecording]) {        [self.movieFileOutput stopRecording];    }}

8.停止采集

//停止采集- (void)stopCapture {    if ([self.captureSession isRunning]) {        __weak __typeof(self) weakSelf = self;        dispatch_async(self.sessionQueue, ^{            [weakSelf.captureSession stopRunning];            weakSelf.captureSession = nil;        });    }}

三、方案二：AVCaptureSession + AVAssetWriter

方案二及更多内容，请访问： 基于AVFoundation实现视频录制的两种方式

本文来自博客园，作者：reyzhang，转载请注明原文链接：https://www.cnblogs.com/reyzhang/p/16646673.html