AVCaptureSession亮度

Question

我正在开发一个镜像应用程序使用前置摄像头与AVFoundation。我已经完成了向UIView显示相机屏幕。但是我如何调整亮度呢？这些代码如下：

-(void)AVCaptureInit {   
    mCameraAVSession = [[AVCaptureSession alloc] init];
    [mCameraAVSession setSessionPreset:AVCaptureSessionPresetPhoto];

    mCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    for (AVCaptureDevice *device in devices) {
        if ([device position] == AVCaptureDevicePositionFront) {
            mCaptureDevice = device;
            break;
        }
    }

    //if ([mCaptureDevice hasTorch] && [mCaptureDevice hasFlash])
    {
        [mCaptureDevice lockForConfiguration:nil];
        // [mCaptureDevice setTorchMode:AVCaptureTorchModeOn];
        //[mCaptureDevice setExposurePointOfInterest:0.5];

        [mCaptureDevice setExposureMode:AVCaptureExposureModeManual];

        [mCaptureDevice unlockForConfiguration];
    }



    // [inputDevice setTorchModeOnWithLevel:0.5 error:NULL];

    NSError *error;
    AVCaptureDeviceInput *deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:mCaptureDevice error:&error];

    if ([mCameraAVSession canAddInput:deviceInput]) {
        [mCameraAVSession addInput:deviceInput];
    }

    AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:mCameraAVSession];
    [previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
    CALayer *rootLayer = [mCameraView layer];
    [rootLayer setMasksToBounds:YES];
    CGRect frame = mCaptureView.frame;
    [previewLayer setFrame:frame];
    [rootLayer insertSublayer:previewLayer atIndex:0];

    mCameraImageOutput = [[AVCaptureStillImageOutput alloc] init];
    NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:AVVideoCodecJPEG, AVVideoCodecKey, nil];
    [mCameraImageOutput setOutputSettings:outputSettings];


    [mCameraAVSession addOutput:mCameraImageOutput];

    [mCameraAVSession startRunning];

    [self setVisible:mCaptureImage IsVisible:NO];
}

任何人都说通过曝光来调整亮度是可能的，但我不知道如何使用。特别是，我想调整相机的亮度，当我捏。

Answer 1

手动(自定义)相机曝光描述在WWDC2014会话508和手动AVCam示例代码中。

通过运行AVCamManual、点击曝光>自定义并拖动曝光滑块，为您自己尝试。

在代码中，它归结为将AVCaptureDevice exposureMode设置为AVCaptureExposureModeCustom并调用

if ([mCaptureDevice lockForConfiguration:&error]) {
    [mCaptureDevice setExposureModeCustomWithDuration:exposureDuration ISO:AVCaptureISOCurrent completionHandler:nil];
    [mCaptureDevice unlockForConfiguration];
}

附注：我不知道你从哪里来的AVCaptureExposureModeManual。它似乎不存在。