关于ios:iOS拍照定制之AVCaptureVideoDataOutput

领导看了后面做的拍照，问了句"哪来的声音",

"零碎的，自带的，你看零碎的拍照也有声音"

"有方法能去掉吗？挺糟心的"

"我试试"

路漫漫其修远兮，吾在度娘+SDK中求索

拍砖AVCaptureVideoDataOutput, 代理办法中将CMSampleBufferRef转成UIImage

上码

• session设置不提
• layer设置可参考上篇 [iOS拍照定制之AVCapturePhotoOutput] 以及 上上篇[iOS写在定制相机之前]
• 获取摄像头、取到设施输出增加到session、初始化videoOutput增加入session

AVCaptureDevice *device = [self cameraDevice];if (!device) {    NSLog(@"获得后置摄像头出问题");    return;;}NSError *error = nil;self.videoInput = [[AVCaptureDeviceInput alloc] initWithDevice:device error:nil];// 设施增加到会话中if ([self.captureSession canAddInput:self.videoInput]) {    [self.captureSession addInput:self.videoInput];}[self.videoOutput setSampleBufferDelegate:self queue:self.videoQueue];if ([self.captureSession canAddOutput:self.videoOutput]) {    [self.captureSession addOutput:self.videoOutput];}// 懒加载- (AVCaptureVideoDataOutput *)videoOutput {    if (!_videoOutput) {        _videoOutput = [[AVCaptureVideoDataOutput alloc] init];        _videoOutput.alwaysDiscardsLateVideoFrames = YES;        _videoOutput.videoSettings = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA]                                                                 forKey:(id)kCVPixelBufferPixelFormatTypeKey];    }    return _videoOutput;}- (dispatch_queue_t)videoQueue {    if (!_videoQueue) {        _videoQueue = dispatch_queue_create("queue", DISPATCH_QUEUE_SERIAL);    }    return _videoQueue;}

• 代理AVCaptureVideoDataOutputSampleBufferDelegate

- (void)captureOutput:(AVCaptureOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {    @autoreleasepool {        if (connection == [self.videoOutput connectionWithMediaType:AVMediaTypeVideo]) { // 视频            @synchronized (self) {                UIImage *image = [self bufferToImage:sampleBuffer rect:self.scanView.scanRect];                self.uploadImg = image;            }        }    }}

• CMSampleBufferRef转成UIImage, 该办法有所调整，截图整张图中的某一部分，按需设置。具体获取指定区域图片需本人调整

- (UIImage *)bufferToImage:(CMSampleBufferRef)sampleBuffer rect:(CGRect)rect {    // Get a CMSampleBuffer's Core Video image buffer for the media data    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);    // Lock the base address of the pixel buffer    CVPixelBufferLockBaseAddress(imageBuffer, 0);    // Get the number of bytes per row for the pixel buffer    void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer);    // Get the number of bytes per row for the pixel buffer    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);    // Get the pixel buffer width and height    size_t width = CVPixelBufferGetWidth(imageBuffer);    size_t height = CVPixelBufferGetHeight(imageBuffer);    // Create a device-dependent RGB color space    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();    // Create a bitmap graphics context with the sample buffer data    CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8,                                                 bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);    // Create a Quartz image from the pixel data in the bitmap graphics context    CGImageRef quartzImage = CGBitmapContextCreateImage(context);    // Unlock the pixel buffer    CVPixelBufferUnlockBaseAddress(imageBuffer,0);    // Free up the context and color space    CGContextRelease(context);    CGColorSpaceRelease(colorSpace);        // 获取指定区域图片    CGRect dRect;    CGSize msize = UIScreen.mainScreen.bounds.size;    msize.height = msize.height - 150;    CGFloat x = width * rect.origin.x / msize.width;    CGFloat y = height * rect.origin.y / msize.height;    CGFloat w = width * rect.size.width / msize.width;    CGFloat h = height * rect.size.height / msize.height;    dRect = CGRectMake(x, y, w, h);        CGImageRef partRef = CGImageCreateWithImageInRect(quartzImage, dRect);        // Create an image object from the Quartz image    UIImage *image = [UIImage imageWithCGImage:partRef];    // Release the Quartz image    CGImageRelease(partRef);    CGImageRelease(quartzImage);        return image;}