Question

我正在使用AVCapture捕获视频并保存。但我需要提供缩放比例缩放或缩放按钮等缩放选项。此外，视频应以完全相同的方式保存，我的意思是在放大时，应该保存缩放。任何帮助，链接表示赞赏。我设置AVCapture会话的代码是：

- (void)setupAVCapture{
session = [[AVCaptureSession alloc] init];
session.automaticallyConfiguresApplicationAudioSession=YES;
[session beginConfiguration];
session.sessionPreset = AVCaptureSessionPresetMedium;
AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
captureVideoPreviewLayer.frame = self.view.bounds;

[self.view.layer addSublayer:captureVideoPreviewLayer];
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

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];

movieFileOutput = [[AVCaptureMovieFileOutput alloc] init];

[session addOutput:movieFileOutput];
[session commitConfiguration];
[session startRunning];

 }

Answer 1

我也遇到了同样的问题，我用这两个步骤解决了这个问题：

在相机预览视图控制器中添加类似的PinchGestureRecognizer事件

- (IBAction)handlePinchGesture:(UIPinchGestureRecognizer *)gestureRecognizer{

if([gestureRecognizer isMemberOfClass:[UIPinchGestureRecognizer class]])
{

        effectiveScale = beginGestureScale * ((UIPinchGestureRecognizer *)gestureRecognizer).scale;
        if (effectiveScale < 1.0)
            effectiveScale = 1.0;
        CGFloat maxScaleAndCropFactor = [[self.stillImageOutput connectionWithMediaType:AVMediaTypeVideo] videoMaxScaleAndCropFactor];
        if (effectiveScale > maxScaleAndCropFactor)
            effectiveScale = maxScaleAndCropFactor;
        [CATransaction begin];
        [CATransaction setAnimationDuration:.025];
        [self.previewView.layer setAffineTransform:CGAffineTransformMakeScale(effectiveScale, effectiveScale)];
        [CATransaction commit];

    if ([[self videoDevice] lockForConfiguration:nil]) {
        [[self videoDevice] setVideoZoomFactor:effectiveScale];
        [[self videoDevice] unlockForConfiguration];
    }}}}

**请注意，保持视频设备缩放级别的关键方法是[device setVideoZoomFactor：]

2-在录制按钮的IBAction中，添加此代码以捕获视频（录制），然后将录制的视频保存在具有特定名称的特定路径中

- (IBAction)recordButtonClicked:(id)sender {

dispatch_async([self sessionQueue], ^{
    if (![[self movieFileOutput] isRecording])
    {
        [self setLockInterfaceRotation:YES];

        if ([[UIDevice currentDevice] isMultitaskingSupported])
        {
            // Setup background task. This is needed because the captureOutput:didFinishRecordingToOutputFileAtURL: callback is not received until the app returns to the foreground unless you request background execution time. This also ensures that there will be time to write the file to the assets library when the app is backgrounded. To conclude this background execution, -endBackgroundTask is called in -recorder:recordingDidFinishToOutputFileURL:error: after the recorded file has been saved.
            [self setBackgroundRecordingID:[[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:nil]];
        }

        // Update the orientation on the movie file output video connection before starting recording.
        // Start recording to a temporary file.
        NSString *outputFilePath = [NSTemporaryDirectory() stringByAppendingPathComponent:[@"movie" stringByAppendingPathExtension:@"mov"]];
        [[self movieFileOutput] startRecordingToOutputFileURL:[NSURL fileURLWithPath:outputFilePath] recordingDelegate:self];
    }
    else
    {

        [[self movieFileOutput] stopRecording];

    }
});
}

我希望能帮到你

Answer 2

将 UIPinchGestureRecognizer 对象添加到您的处理并处理回调，如下所示：

- (void) zoomPinchGestureRecognizerAction: (UIPinchGestureRecognizer *) sender {
    static CGFloat initialVideoZoomFactor = 0;

    if (sender.state == UIGestureRecognizerStateBegan) {

        initialVideoZoomFactor = _captureDevice.videoZoomFactor;

    } else {

        CGFloat scale = MIN(MAX(1, initialVideoZoomFactor * sender.scale), 4);

        [CATransaction begin];
        [CATransaction setAnimationDuration: 0.01];
        _previewLayer.affineTransform = CGAffineTransformMakeScale(scale, scale);
        [CATransaction commit];

        if ([_captureDevice lockForConfiguration: nil] == YES) {
            _captureDevice.videoZoomFactor = scale;
            [_captureDevice unlockForConfiguration];
        }
    }
}

在iOS中使用AVCapture捕获视频时缩放

2 个答案: