Setting the orientation of video with AV Foundation

Q:  How do I set the orientation of video with AV Foundation?

A: AV Foundation Capture

You can set an orientation on a AVCaptureConnection to specify how you want the images oriented in the AVCaptureOutput output destination (AVCaptureMovieFileOutput, AVCaptureStillImageOutput or AVCaptureVideoDataOutput) or AVCaptureVideoPreviewLayer for the connection.

Use the AVCaptureConnection supportsVideoOrientation property (getter= isVideoOrientationSupported) to determine whether the object supports changing the orientation of the video, and the videoOrientation property to specify how you want the images oriented in the the output destination or preview layer. For example, here's a code snippet showing how to set the videoOrientation for a AVCaptureStillImageOutput's AVCaptureConnection to AVCaptureVideoOrientationLandscapeLeft:

Listing 1  Setting the videoOrientation for a AVCaptureStillImageOutput's AVCaptureConnection.

#import <AVFoundation/AVFoundation.h>

AVCaptureStillImageOutput *stillImageOutput = <#A still image output#>;

AVCaptureConnection *connection =

    [stillImageOutput connectionWithMediaType:AVMediaTypeVideo];

if ([connection isVideoOrientationSupported])

{

    [connection setVideoOrientation: AVCaptureVideoOrientationLandscapeLeft];

}

Applications that do not take into consideration the video track transform and still image exif metadata may not display these media items in the proper orientation.

AVCaptureVideoDataOutput clients may receive physically rotated CVPixelBuffers in their -captureOutput:didOutputSampleBuffer:fromConnection: delegate callback. All 4 AVCaptureVideoOrientation modes are supported, and rotation is hardware accelerated. To request buffer rotation, a client calls -setVideoOrientation: on the AVCaptureVideoDataOutput's video AVCaptureConnection.

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