iOS 关于视频录制实现 (仿微信)

项目demo
tips:建议参照我的demo进行了解,如果有帮助到你的话请帮我点亮 star, 谢谢啦~

类似于微信的 点击拍照 , 长按拍视频的功能.
导入框架

#import 

在需要进行录屏的时候,创建 视频流 和 音频流 的 输入输出流, 代码如下:

 NSArray *devicesVideo = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    NSArray *devicesAudio = [AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio];

    self.videoInput = [AVCaptureDeviceInput deviceInputWithDevice:devicesVideo[0] error:nil];

    AVCaptureDeviceInput *audioInput = [AVCaptureDeviceInput deviceInputWithDevice:devicesAudio[0] error:nil];

    self.videoDevice = devicesVideo[0];

    self.videoDataOut = [[AVCaptureVideoDataOutput alloc] init];
    self.videoDataOut.videoSettings = @{(__bridge NSString *)kCVPixelBufferPixelFormatTypeKey:@(kCVPixelFormatType_32BGRA)};
    self.videoDataOut.alwaysDiscardsLateVideoFrames = YES;
    [self.videoDataOut setSampleBufferDelegate:self queue:self.recodingQueue];

    self.audioDataOut = [[AVCaptureAudioDataOutput alloc] init];
    [self.audioDataOut setSampleBufferDelegate:self queue:self.recodingQueue];

在进行录像的时候,主要使用 AVCaptureVideoPreviewLayer 所创建的实例进行展示,它的创建需要上述所创建的数据流

    self.videoSession = [[AVCaptureSession alloc] init];

    if ([self.videoSession canSetSessionPreset:AVCaptureSessionPreset1280x720]) {
        self.videoSession.sessionPreset = AVCaptureSessionPreset1280x720;
    }
    if ([self.videoSession canAddInput:self.videoInput]) {
        [self.videoSession addInput:self.videoInput];
    }
    if ([self.videoSession canAddInput:audioInput]) {
        [self.videoSession addInput:audioInput];
    }
    if ([self.videoSession canAddOutput:self.videoDataOut]) {
        [self.videoSession addOutput:self.videoDataOut];
    }
    if ([self.videoSession canAddOutput:self.audioDataOut]) {
        [self.videoSession addOutput:self.audioDataOut];
    }
    self.videoPreLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.videoSession];
    self.videoPreLayer.frame = self.videoView.bounds;
    self.videoPreLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
    [self.videoView.layer addSublayer:self.videoPreLayer];
    [self.videoSession startRunning];

在 startRunning 之后,这个时候在你的屏幕上已经可以看到摄像头的实时画面了,同时不断触发代理方法,接下来要开始录制,先要创建录制对象

    //这里的 assetUrl 是存储到本地的地址,在录制的过程中,可以将实时数据存储到本地
    _assetWriter = [AVAssetWriter assetWriterWithURL:assetUrl fileType:AVFileTypeMPEG4 error:nil];
    //默认横屏录入的,所以这里要旋转 90
    NSDictionary *outputSettings = @{
                                     AVVideoCodecKey : AVVideoCodecH264,
                                     AVVideoWidthKey : @(self.recordH),
                                     AVVideoHeightKey : @(self.recordW),
                                     AVVideoScalingModeKey:AVVideoScalingModeResizeAspectFill,
                                     //                          AVVideoCompressionPropertiesKey:codecSettings
                                     };
    _assetWriterVideoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:outputSettings];
    _assetWriterVideoInput.expectsMediaDataInRealTime = YES;

    CGFloat rate = M_PI / 2.0;

    _assetWriterVideoInput.transform = CGAffineTransformMakeRotation(rate);


    NSDictionary *audioOutputSettings = @{
                                          AVFormatIDKey:@(kAudioFormatMPEG4AAC),
                                          AVEncoderBitRateKey:@(64000),
                                          AVSampleRateKey:@(44100),
                                          AVNumberOfChannelsKey:@(1),
                                          };

    _assetWriterAudioInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:audioOutputSettings];
    _assetWriterAudioInput.expectsMediaDataInRealTime = YES;


    NSDictionary *SPBADictionary = @{
                                     (__bridge NSString *)kCVPixelBufferPixelFormatTypeKey : @(kCVPixelFormatType_32BGRA),
                                     (__bridge NSString *)kCVPixelBufferWidthKey : @(self.recordW),
                                     (__bridge NSString *)kCVPixelBufferHeightKey  : @(self.recordH),
                                     (__bridge NSString *)kCVPixelFormatOpenGLESCompatibility : ((__bridge NSNumber *)kCFBooleanTrue)
                                     };
    _assetWriterPixelBufferInput = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:_assetWriterVideoInput sourcePixelBufferAttributes:SPBADictionary];
    if ([_assetWriter canAddInput:_assetWriterVideoInput]) {
        [_assetWriter addInput:_assetWriterVideoInput];
    }else {
        NSLog(@"不能添加视频writer的input \(assetWriterVideoInput)");
    }
    if ([_assetWriter canAddInput:_assetWriterAudioInput]) {
        [_assetWriter addInput:_assetWriterAudioInput];
    }else {
        NSLog(@"不能添加视频writer的input \(assetWriterVideoInput)");
    }

在摄像头使用的过程中会不断触发代理方法,我们在代理方法里面就可以开启或者关闭视频的录制了

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {
   //这里就是取得摄像头数据的某一帧,当 长按 时间非常短的时候,我们就可以取这个图片为实时拍摄的照片了
    UIImage * image = [self imageFromSampleBuffer:sampleBuffer];
    if (image && !self.isGetShootImg) {
        self.shootImage = image;
    }
    if (!_recoding) return;

    @autoreleasepool {
        _currentSampleTime = CMSampleBufferGetOutputPresentationTimeStamp(sampleBuffer);
        if (_assetWriter.status != AVAssetWriterStatusWriting) {
            [_assetWriter startWriting];
            [_assetWriter startSessionAtSourceTime:_currentSampleTime];
        }
        if (captureOutput == _videoDataOut) {
            if (_assetWriterPixelBufferInput.assetWriterInput.isReadyForMoreMediaData) {
                CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
                BOOL success = [_assetWriterPixelBufferInput appendPixelBuffer:pixelBuffer withPresentationTime:_currentSampleTime];
                if (!success) {
                    NSLog(@"Pixel Buffer没有append成功");
                }
            }
        }
        if (captureOutput == _audioDataOut) {
            [_assetWriterAudioInput appendSampleBuffer:sampleBuffer];
        }
    }
}

注: 关于 点击拍照 功能的实现, 我之前尝试过在 点击结束 的时候直接截图,但是, self.videoPreLayer 的位置截取到的只是黑色背景,所以转而采用了这种方法. 如果有更好的建议请留言交流.