问题

领导看了前面做的拍照，问了句"哪来的声音",

"系统的，自带的，你看系统的拍照也有声音"

"有办法能去掉吗？挺糟心的"

"我试试"

思路

路漫漫其修远兮，吾在度娘+SDK中求索

拍砖AVCaptureVideoDataOutput, 代理方法中将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、取到设备输入添加到session、初始化videoOutput添加入session

AVCaptureDevice *device = [self cameraDevice];
if (!device) {
    NSLog(@"取得后置摄像头出问题");
    return;;
}

NSError *error = nil;
self.videoInput = [[AVCaptureDeviceInput alloc] initWithDevice:device error:nil];

// 设备添加到会话中
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, 该方法有所调整，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自己调整

- (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;
}

图有了，收工。怎么用图，业务该干活了