音视频之视频采集

视频采集

AVFoundation 完成视频采集,做个笔记吧.

初始化页面布局

UILabel *titleLabel = [[UILabel alloc] init];
titleLabel.text = @"音视频采集";
[self.view addSubview:titleLabel];
[titleLabel mas_makeConstraints:^(MASConstraintMaker *make) {
    make.top.equalTo(self.view).offset(30);
    make.centerX.equalTo(self.view);
}];

UIButton *beginInputVideo = [UIButton buttonWithType:UIButtonTypeCustom];
[beginInputVideo setTitle:@"开始视频采集" forState:UIControlStateNormal];
[beginInputVideo setTitle:@"停止视频采集" forState:UIControlStateSelected];
beginInputVideo.backgroundColor = [UIColor orangeColor];
[beginInputVideo addTarget:self action:@selector(beginInputVideoClcik:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:beginInputVideo];
[beginInputVideo mas_makeConstraints:^(MASConstraintMaker *make) {
    make.top.equalTo(titleLabel.mas_bottom).offset(20);
    make.centerX.equalTo(titleLabel);
    make.width.equalTo(@150);
}];

self.captureVideoPreviewView = [[UIView alloc] init];
self.captureVideoPreviewView.backgroundColor = [UIColor whiteColor];
[self.view addSubview:self.captureVideoPreviewView];
[self.captureVideoPreviewView mas_makeConstraints:^(MASConstraintMaker *make) {
    make.top.equalTo(beginInputVideo.mas_bottom).offset(20);
    make.left.right.bottom.equalTo(self.view);
}];

懒加载需要用的对象

/** 图像sesson */ 
@property (nonatomic, strong) AVCaptureSession *captureSession;

/** 采集数据用的相机设备 */
@property (nonatomic, strong) AVCaptureDevice *inputCamera;

/** 输入 */
@property (nonatomic, strong) AVCaptureDeviceInput *captureDeviceInput;

/** 输出 */
@property (nonatomic, strong) AVCaptureVideoDataOutput *captureVideoDataOutput;

/** 相机采集页面的layer */
@property (nonatomic, strong) AVCaptureVideoPreviewLayer *captureVideoPreviewLayer;

/** 相机采集页面View */
@property (nonatomic, strong) UIView *captureVideoPreviewView;

下面是懒加载的代码

- (AVCaptureSession *)captureSession {
    if (!_captureSession) {
        _captureSession = [[AVCaptureSession alloc] init];
        // 设置session显示分辨率, 用于设置output输出流的bitrate或者说画面质量
        [_captureSession setSessionPreset:AVCaptureSessionPresetHigh];
        /*
         AVCaptureSessionPresetHigh  质量最高
         AVCaptureSessionPresetPhoto Photo模式不能输出视频
         AVCaptureSessionPresetMedium 中等质量
         AVCaptureSessionPresetLow 最低质量
         AVCaptureSessionPreset320x240 320x240大小（不支持IPhone）
         AVCaptureSessionPreset352x288 （支持iPhone）
         AVCaptureSessionPreset640x480（支持iPhone）等等...
         */
        if ([_captureSession canAddInput:self.captureDeviceInput]) {
            [_captureSession addInput:self.captureDeviceInput];
        }
        if ([_captureSession canAddOutput:self.captureVideoDataOutput]) {
            [_captureSession addOutput:self.captureVideoDataOutput];
        }
    }
    return _captureSession;
}
- (AVCaptureDevice *)inputCamera {
    if (!_inputCamera) {
        NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
        for (AVCaptureDevice *device in devices) {
            if ([device position] == AVCaptureDevicePositionBack) {
                _inputCamera = device;
            }
        }
    }
    return _inputCamera;
}

- (AVCaptureDeviceInput *)captureDeviceInput {
    if (!_captureDeviceInput) {
        NSError *error;
        _captureDeviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:self.inputCamera error:&error];
        NSLog(@"%@", error);
    }
    return _captureDeviceInput;
}

- (AVCaptureVideoDataOutput *)captureVideoDataOutput {
    if (!_captureVideoDataOutput) {
        _captureVideoDataOutput = [[AVCaptureVideoDataOutput alloc] init];
        _captureVideoDataOutput.alwaysDiscardsLateVideoFrames = YES;
        [_captureVideoDataOutput setAlwaysDiscardsLateVideoFrames:NO];
        [_captureVideoDataOutput setVideoSettings:[NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_420YpCbCr8BiPlanarFullRange] forKey:(id)kCVPixelBufferPixelFormatTypeKey]];
        [_captureVideoDataOutput setSampleBufferDelegate:self queue:encodeQueue];
        AVCaptureConnection *captureConnection = [_captureVideoDataOutput connectionWithMediaType:AVMediaTypeVideo];
        [captureConnection setVideoOrientation:AVCaptureVideoOrientationPortrait | AVCaptureVideoOrientationLandscapeRight | AVCaptureVideoOrientationLandscapeLeft];
    }
    return _captureVideoDataOutput;
}

- (AVCaptureVideoPreviewLayer *)captureVideoPreviewLayer {
    if (!_captureVideoPreviewLayer) {
        _captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];
        /*
         AVLayerVideoGravityResizeAspect        // 适合层范围内(完全显示,可能有黑边)
         AVLayerVideoGravityResizeAspectFill    // 填充层边界(平铺,不拉伸,但是会被裁剪,内容可能显示不全)
         AVLayerVideoGravityResize              // 拉伸填充层边界(拉伸填充视图)
         */
        [_captureVideoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspect];
    }
    return _captureVideoPreviewLayer;
}

开始视频采集

- (void)beginInputVideo {

    self.captureVideoPreviewLayer.frame = self.captureVideoPreviewView.bounds;
    
    self.captureVideoPreviewLayer.backgroundColor = [UIColor blackColor].CGColor;
    
    [self.captureVideoPreviewView.layer addSublayer:self.captureVideoPreviewLayer];
    
    [self.captureSession startRunning];
    
}

采集到视频数据的回调

/**
 采集到数据的回调

 @param output outPut对象
 @param sampleBuffer 数据
 @param connection 链接
 */
- (void)captureOutput:(AVCaptureOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {
    NSLog(@"%@", sampleBuffer);
}

注: 如发现问题,请留言.谢谢.