AVCam save full screen captured image

问题

I am using AVCam made by apple for my custom camera view. Honestly it is not to simple to understand what's going on in the class AVCamViewController if you see it at first time.

Right now I am interested how they set frame of captured image. I tried to found where some fames setters or something like this, but I have not found any.

I searched in Google and found answer here AVCam not in fullscreen

But when I implemented that solution I just realised that it just made live camera preview layer with the same size as my view, but when app saves image in the method - (IBAction)snapStillImage:(id)sender in the gallery images still was with 2 stripes from left and right.

My question is how can I remove this stripes or in which line in source code apple set this stuff?

Also as additional sub-question how can I set type create just photo, because the app requests me "Microphone settings" and I don't need it just need make a photo and that's it.

This code from apple sources will save image to the photo library.

- (IBAction)snapStillImage:(id)sender
{
    dispatch_async([self sessionQueue], ^{
        // Update the orientation on the still image output video connection before capturing.
        [[[self stillImageOutput] connectionWithMediaType:AVMediaTypeVideo] setVideoOrientation:[[(AVCaptureVideoPreviewLayer *)[[self previewView] layer] connection] videoOrientation]];

        // Flash set to Auto for Still Capture
        [AVCamViewController setFlashMode:AVCaptureFlashModeAuto forDevice:[[self videoDeviceInput] device]];

        // Capture a still image.
        [[self stillImageOutput] captureStillImageAsynchronouslyFromConnection:[[self stillImageOutput] connectionWithMediaType:AVMediaTypeVideo] completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {

            if (imageDataSampleBuffer)
            {
                NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];

                UIImage *image = [[UIImage alloc] initWithData:imageData];

                UIImage *proccessingImage = [SAPAdjustImageHelper adjustImage:image];

                NSNumber *email_id = [SAPCoreDataEmailHelper currentEmailId];

                [SAPFileManagerHelper addImage:proccessingImage toFolderWithEmailId:email_id];
            }
        }];
    });
}

回答1:

Are you setting the session preset?

You can use your session with the session preset set in AVCaptureSessionPresetPhoto.

For the another subquestion: You need to add only the AVCaptureStillImageOutput output.

How to set the session Preset?

[session setSessionPreset:AVCaptureSessionPresetPhoto];

How to configure the session to use only StillImageOutput to take photos and ?

- (void)viewDidLoad
{
    [super viewDidLoad];

    // Create the AVCaptureSession
    AVCaptureSession *session = [[AVCaptureSession alloc] init];
    [self setSession:session];

    // Setup the preview view
    [[self previewView] setSession:session];

    // Setup the session Preset          
    [session setSessionPreset:AVCaptureSessionPresetPhoto];

    // Check for device authorization
    [self checkDeviceAuthorizationStatus];

    dispatch_queue_t sessionQueue = dispatch_queue_create("session queue", DISPATCH_QUEUE_SERIAL);
    [self setSessionQueue:sessionQueue];

    dispatch_async(sessionQueue, ^{
        //[self setBackgroundRecordingID:UIBackgroundTaskInvalid];

        NSError *error = nil;

        AVCaptureDevice *videoDevice = [AVCamViewController deviceWithMediaType:AVMediaTypeVideo preferringPosition:AVCaptureDevicePositionBack];
        AVCaptureDeviceInput *videoDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error];

        if (error)
        {
            NSLog(@"%@", error);
        }

        if ([session canAddInput:videoDeviceInput])
        {
            [session addInput:videoDeviceInput];
            [self setVideoDeviceInput:videoDeviceInput];

            dispatch_async(dispatch_get_main_queue(), ^{
                // Why are we dispatching this to the main queue?
                // Because AVCaptureVideoPreviewLayer is the backing layer for AVCamPreviewView and UIView can only be manipulated on main thread.
                // Note: As an exception to the above rule, it is not necessary to serialize video orientation changes on the AVCaptureVideoPreviewLayer’s connection with other session manipulation.

                [[(AVCaptureVideoPreviewLayer *)[[self previewView] layer] connection] setVideoOrientation:(AVCaptureVideoOrientation)[self interfaceOrientation]];
            });
        }

AVCaptureStillImageOutput *stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
        if ([session canAddOutput:stillImageOutput])
        {
            [stillImageOutput setOutputSettings:@{AVVideoCodecKey : AVVideoCodecJPEG}];
            [session addOutput:stillImageOutput];
            [self setStillImageOutput:stillImageOutput];
        }
    });
}

回答2:

The blacks fields are needed to keep the aspect ratio, if want to avoid them you should change the videoGravity in the AVCaptureVideoPreviewLayer, or in the contentMode of the UIImageView displaying the captured image.
This is an expected behavior, don't understand your concern.

来源：https://stackoverflow.com/questions/25685179/avcam-save-full-screen-captured-image