CODEWITHSUNDEEP
iosobjective-ciphoneavcapturesession
Mark Pepper
Mark Pepper

Reputation: 21

How to maintain captured video size when using AVCaptureVideoPreviewLayer

When using AVCaptureSession to show camera image to a small preview layer (AVCaptureVideoPreviewLayer), the image is scaled to fit the layer size.

In order to fill all the preview layer, this scaling is configurable by setting:

previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;

The problem is that this will only resize to fill the layer and as the camera image is very large, the image is resized becoming too small.

what i am looking for is a way to have my preview layer showing the same level of scale of the builtin camera, discarding the remaining image (imagine the device camera masked, only showing a square in the middle of the screen).

I have also tried changing capture Presets by issuing multiple presets, to no avail:

AVCaptureSession *session = [[AVCaptureSession alloc]init];
session.sessionPreset = AVCaptureSessionPresetMedium;

Upvotes: 2

Views: 871

Answers (1)

Leslie Godwin
Leslie Godwin

Reputation: 2661

Here's what you do:

You get the inputVideo size:

AVCaptureDeviceInput *videoDeviceInput = // initialised already in your app

// Here you can get the video dimensions:
CMVideoDimensions dimensions = CMVideoFormatDescriptionGetDimensions(videoDeviceInput.device.activeFormat.formatDescription);

You size the previewLayer to the size of the video feed. Now you have a video layer at a 1:1 scale.

You then just centre the previewLayer within the window.

Upvotes: 1

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