Question

我正在尝试从AVCaptureStillImageOutput捕获像素数据，并注意到在将图像裁剪为CGImage时，它会重新定向。为了测试这一点，我将临时图像输出到照片库。现在我注意到，即使在裁剪图像之前，它的缩略图也会旋转，而完整图像则不会。（当我将UIImage传递给需要适当尺寸图像的自定义pixelDataManager时，这会成为一个问题。）

设置captureVideoPreviewLayer.orientation = AVCaptureVideoOrientationPortrait;和[videoConnection setVideoOrientation:AVCaptureVideoOrientationPortrait];似乎没有任何改变。

有什么想法??? 我会把它分成几个部分......

1）设置会话，输入和输出：

    // Create a capture session
    AVCaptureSession *session = [[AVCaptureSession alloc] init];
    session.sessionPreset = AVCaptureSessionPresetMedium;

    AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];

    // Add capture layer to visible view    
    captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResize;
    captureVideoPreviewLayer.frame = screenBounds;
    captureVideoPreviewLayer.bounds = screenBounds;
    captureVideoPreviewLayer.orientation = AVCaptureVideoOrientationPortrait;
    [self.vImagePreview.layer addSublayer:captureVideoPreviewLayer];

    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    // Setup error handling
    NSError *error = nil;
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
    if (!input) {
        // Handle the error appropriately.
        NSLog(@"ERROR: trying to open camera: %@", error);
    }
    [session addInput:input];

    // Start session
    [session startRunning];

    // Output image data 
    stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
    NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
    [stillImageOutput setOutputSettings:outputSettings];

    [session addOutput:stillImageOutput];

2）设置视频连接：

AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in stillImageOutput.connections)
{
    for (AVCaptureInputPort *port in [connection inputPorts])
    {
        if ([[port mediaType] isEqual:AVMediaTypeVideo] )
        {
            videoConnection = connection;
            break;
        }
    }
    if (videoConnection) { break; }
}

if ([videoConnection isVideoOrientationSupported])
{
    [videoConnection setVideoOrientation:AVCaptureVideoOrientationPortrait];
}

3）输出捕获的图像：

NSLog(@"about to request a capture from: %@", stillImageOutput);
[stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error)
{         
    NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
    UIImage *image = [[UIImage alloc] initWithData:imageData];
    UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
    //......
}

Answer 1

当你这样做时，虽然图像是作为UIImage提供给你的，但它实际上是使用底层的Quartz CGImage数据，它具有不同的原点（我认为是左下角），这意味着当你使用图像时它会被旋转到了一边。

我找到了一个C函数，你可以用UIImage作为参数调用它来修复它并返回固定的UIImage。

http://blog.logichigh.com/2008/06/05/uiimage-fix/

AVCaptureStillImageOutput的UIImage方向不正确

1 个答案: