使用前置摄像头时需要镜像视频方向和手柄旋转
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【中文标题】使用前置摄像头时需要镜像视频方向和手柄旋转【英文标题】：Need to Mirror Video Orientation and Handle Rotation When Using Front Camera 【发布时间】：2015-08-05 01:12:15 【问题描述】：我不太清楚如何处理前置摄像头视频捕捉方向。我在拍摄视频和图片时为后置摄像头处理了所有旋转，在拍照时为前置摄像头处理了所有旋转，以及以正确的方向保存拍摄的视频和图片，前置摄像头视频捕获除外。
第一个问题是在任一横向模式下，视频都无法以正确的方向正确保存。第二个问题是保存的视频是镜像的。虽然我知道如何使用前置摄像头处理图片的这种镜像效果，但我不确定要调用什么来处理视频。
我在试图找到专门针对这一问题的任何东西时遇到了很多麻烦，但未能做到。如果有人能指出我解决这个特定问题的线程，那就太好了。
无论哪种方式，这里都是在设备方向改变时处理视频方向的方法。如果正在使用前置摄像头，我不确定要在我的代码中添加什么。
/**************************************************************************
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
【问题讨论】：
【参考方案1】：基于此答案：Video Saving in the wrong orientation AVCaptureSession
我遇到了同样的问题，并且能够在这篇文章之后修复它。
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
如果对你有帮助，请告诉我詹姆斯
【讨论】：
感谢您的回答。明天我会检查这是否可行，然后会相应地更新问题。 你为我节省了几个小时。所有其他类似的线程只处理预览层而不是文件输出。 仅在预览中显示镜像视频。保存时，它正在保存实际视频。怎么办？ 可以使用self.videoOutput?.connection(with: .video)?.isVideoMirrored = true获取连接【参考方案2】：
接受的答案只会镜像预览中的视频。您需要转换视频。
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
在您的 AVCaptureFileOutputRecordingDelegate
func fileOutput(_ output: AVCaptureFileOutput, didFinishRecordingTo outputFileURL: URL, from connections: [AVCaptureConnection], error: Error?)
self.mirrorVideo(inputURL: outputFileURL) (url) in
self.delegate!.videoRecordingEnded(videoURL: url!)
【讨论】：
有人可以帮我解决第二部分 self.delegate!.videoRecordingEnded(videoURL: url!) 说“'ViewController' 类型的值没有成员类型委托”我正在使用 swift 3【参考方案3】：Kesong 在 Sam 的回答中的评论适用于转换视频本身，而不仅仅是预览。请务必先检查是否支持 videoMirroring，并确保在设置 isVideoMirrored 属性之前禁用自动调整视频镜像，否则应用可能会崩溃。
以下代码适用于 Swift 5。您可以在将 AVCaptureSession 附加到 AVCaptureMovieFileOutput 后使用此代码。
if let videoConnection = movieFileOutput.connection(with: .video)
if videoConnection.isVideoMirroringSupported
if frontCamera //For selfie camera, flip the output video so it doesn't appear mirrored
videoConnection.automaticallyAdjustsVideoMirroring = false
videoConnection.isVideoMirrored = true
else
videoConnection.automaticallyAdjustsVideoMirroring = true
【讨论】：
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