You need to mirror the orientation of the video and turn the knob when using the front camera

Question

I cannot figure out how to handle the video capture orientation on the front panel. I have all the turns that are processed for the rear camera when capturing video and images and all the turns that are processed for the front camera when shooting, as well as for saving captured videos and images with the correct orientation, except for capturing video from the front camera.

The first problem is that in landscape mode the video is not saved correctly with the correct orientation. The second problem is that the saved video is mirrored. Although I know how to handle this mirroring effect for an image using the front camera, I'm not sure what to call to process it for video.

I had a lot of problems trying to find something specifically for this one problem and could not do it. If anyone can point me to a thread that addresses this particular issue, that would be great.

In any case, a method is called here that processes the orientation of the video when the orientation of the device changes. I'm not sure exactly what to add to my code if using the front camera.

/**************************************************************************
    DEVICE ORIENTATION DID CHANGE
    **************************************************************************/
    func deviceOrientationDidChange() {

        println("DEVICE ORIENTATION DID CHANGE CALLED")

        let orientation: UIDeviceOrientation = UIDevice.currentDevice().orientation

        //------ IGNORE THESE ORIENTATIONS ------
        if orientation == UIDeviceOrientation.FaceUp || orientation == UIDeviceOrientation.FaceDown || orientation == UIDeviceOrientation.Unknown || orientation == UIDeviceOrientation.PortraitUpsideDown || self.currentOrientation == orientation {

            println("device orientation does not need to change --- returning...")

            return
        }


        self.currentOrientation = orientation


        //------ APPLY A ROTATION USING THE STANDARD ROTATION TRANSFORMATION MATRIX in R3 ------

        /*

            x       y       z
            ---           ---
        x | cosø    sinø    0 |
        y | -sinø   consø   0 |
        z | 0       0       1 |
            ---           ---

        */


        //----- PERFORM BUTTON AND VIDEO DATA BUFFER ROTATIONS ------
        switch orientation {

        case UIDeviceOrientation.Portrait:

            rotateButtons(self.degrees0)

            if self.usingFrontCamera == true {


            }
            else {

            }

            println("Device Orientation Portrait")

            break

        case UIDeviceOrientation.LandscapeLeft:

            println("Device Orientation LandScapeLeft")

            rotateButtons(self.degrees90)

            if self.usingFrontCamera == true {

                println("Using front camera, rotation in landscape left")

//                if let connection = self.captureConnection {
//                    
//                    connection.videoOrientation = AVCaptureVideoOrientation.LandscapeRight
//                    
//                    println("Capture connection Orientation is LandScape Right")
//                }
//                else {
//                    
//                    println("Capture connection is nil, could not change video orientation")
//                }
            }
            else {

                if let connection = self.captureConnection {

                    connection.videoOrientation = AVCaptureVideoOrientation.LandscapeRight

                    println("Capture connection Orientation is LandScape Right")
                }
                else {

                    println("Capture connection is nil, could not change video orientation")
                }
            }

            break

        case UIDeviceOrientation.LandscapeRight:

            println("Device Orientation LandscapeRight")

            rotateButtons(-self.degrees90)

            if self.usingFrontCamera == true {

                println("Using front camera, rotation in landscape right")

//                if let connection = self.captureConnection {
//                    
//                    connection.videoOrientation = AVCaptureVideoOrientation.LandscapeRight
//                    
//                    println("Capture connection Orientation is LandScape Left")
//                }
//                else {
//                    
//                    println("Capture connection is nil, could not change video orientation")
//                }
            }
            else {

                if let connection = self.captureConnection {

                    connection.videoOrientation = AVCaptureVideoOrientation.LandscapeLeft

                    println("Capture connection Orientation is LandScape Left")
                }
                else {

                    println("Capture connection is nil, could not change video orientation")
                }
            }

            break

        default:

            break
        }
    }

Answer 1

Based on this answer: Saving video in the wrong orientation AVCaptureSession

I ran into the same problem and was able to fix it after this post.

    var videoConnection: AVCaptureConnection?

    for connection in self.fileOutput.connections {

        for port in connection.inputPorts! {

            if port.mediaType == AVMediaTypeVideo {

                videoConnection = connection as? AVCaptureConnection

                if videoConnection!.supportsVideoMirroring {
                    videoConnection!.videoMirrored = true
                }
            }
        }
    }

Please let me know if this helps you James

Answer 2

. .

    func mirrorVideo(inputURL: URL, completion: @escaping (_ outputURL : URL?) -> ())
{
    let videoAsset: AVAsset = AVAsset( url: inputURL )
    let clipVideoTrack = videoAsset.tracks( withMediaType: AVMediaType.video ).first! as AVAssetTrack

    let composition = AVMutableComposition()
    composition.addMutableTrack(withMediaType: AVMediaType.video, preferredTrackID: CMPersistentTrackID())

    let videoComposition = AVMutableVideoComposition()
    videoComposition.renderSize = CGSize(width: clipVideoTrack.naturalSize.height, height: clipVideoTrack.naturalSize.width)
    videoComposition.frameDuration = CMTimeMake(1, 30)

    let transformer = AVMutableVideoCompositionLayerInstruction(assetTrack: clipVideoTrack)

    let instruction = AVMutableVideoCompositionInstruction()
    instruction.timeRange = CMTimeRangeMake(kCMTimeZero, CMTimeMakeWithSeconds(60, 30))
    var transform:CGAffineTransform = CGAffineTransform(scaleX: -1.0, y: 1.0)
    transform = transform.translatedBy(x: -clipVideoTrack.naturalSize.width, y: 0.0)
    transform = transform.rotated(by: CGFloat(Double.pi/2))
    transform = transform.translatedBy(x: 0.0, y: -clipVideoTrack.naturalSize.width)

    transformer.setTransform(transform, at: kCMTimeZero)

    instruction.layerInstructions = [transformer]
    videoComposition.instructions = [instruction]

    // Export

    let exportSession = AVAssetExportSession(asset: videoAsset, presetName: AVAssetExportPreset640x480)!
    let fileName = UniqueIDGenerator.generate().appending(".mp4")
    let filePath = documentsURL.appendingPathComponent(fileName)
    let croppedOutputFileUrl = filePath
    exportSession.outputURL = croppedOutputFileUrl
    exportSession.outputFileType = AVFileType.mp4
    exportSession.videoComposition = videoComposition
    exportSession.exportAsynchronously {
        if exportSession.status == .completed {
            DispatchQueue.main.async(execute: {
                completion(croppedOutputFileUrl)
            })
            return
        } else if exportSession.status == .failed {
            print("Export failed - \(String(describing: exportSession.error))")
        }

        completion(nil)
        return
    }
}

AVCaptureFileOutputRecordingDelegate

   func fileOutput(_ output: AVCaptureFileOutput, didFinishRecordingTo outputFileURL: URL, from connections: [AVCaptureConnection], error: Error?) {
    self.mirrorVideo(inputURL: outputFileURL) { (url) in
        self.delegate!.videoRecordingEnded(videoURL: url!)
    }
}