我想将拍摄的视频从横向旋转为纵向，我的代码如下:

if self.isDeviceRotatedToLandscape
        {
            let outputPath : NSString = NSString(format: "%@%@", NSTemporaryDirectory(), "output2.mov")
            let outputURL : NSURL = NSURL(fileURLWithPath: outputPath as String)!
            let fileManager : NSFileManager = NSFileManager.defaultManager()
            if(fileManager.fileExistsAtPath(outputPath as String))
            {
                let asset : AVURLAsset = AVURLAsset(URL: outputURL, options: nil)

                if let clipVideoTrack: AVAssetTrack = asset.tracksWithMediaType(AVMediaTypeVideo)[0] as? AVAssetTrack
                {

            var FirstlayerInstruction:AVMutableVideoCompositionLayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: clipVideoTrack)
            if let FirstAssetTrack:AVAssetTrack = asset.tracksWithMediaType(AVMediaTypeVideo)[0] as? AVAssetTrack
            {
                let FirstAssetTrack_ = UIImageOrientation.Up
                var isFirstAssetPortrait_ = false
                var FirstAssetScaleToFitRatio:CGFloat = 1.0
                var FirstAssetScaleFactor:CGAffineTransform = CGAffineTransformMakeScale(FirstAssetScaleToFitRatio, FirstAssetScaleToFitRatio)

                FirstlayerInstruction.setTransform(CGAffineTransformConcat(CGAffineTransformConcat(FirstAssetTrack.preferredTransform,FirstAssetScaleFactor), CGAffineTransformMakeTranslation(0, 160)), atTime: kCMTimeZero)
                FirstlayerInstruction.setOpacity(0.0, atTime: asset.duration)
                var MainInstruction:AVMutableVideoCompositionInstruction = AVMutableVideoCompositionInstruction()
                MainInstruction.layerInstructions = [FirstlayerInstruction]
                var MainCompositionInst: AVMutableVideoComposition = AVMutableVideoComposition()
                MainCompositionInst.instructions = [MainInstruction]
                MainCompositionInst.frameDuration = CMTimeMake(1, 30)
                MainCompositionInst.renderSize = CGSizeMake(612,612)

                let exportPath : NSString = NSString(format: "%@%@", NSTemporaryDirectory(), "output1212.mov")

                var exportUrl: NSURL = NSURL.fileURLWithPath(exportPath as! String)!
                let fileManager : NSFileManager = NSFileManager.defaultManager()
                if(fileManager.fileExistsAtPath(exportPath as String))
                {
                    var error:NSError? = nil
                    if(fileManager.removeItemAtPath(exportPath as String, error: &error))
                    {
                        //Error - handle if requried
                    }
                }

                var exporter = AVAssetExportSession(asset: asset, presetName: AVAssetExportPresetHighestQuality)
                exporter.videoComposition = MainCompositionInst
                exporter.outputFileType = AVFileTypeQuickTimeMovie
                exporter.outputURL = exportUrl
                exporter.exportAsynchronouslyWithCompletionHandler({ () -> Void in

                    print("hi")

                    UISaveVideoAtPathToSavedPhotosAlbum(exportPath as String, self, nil, nil)


                })


                    }
                }
            }
        }

但视频甚至没有创建并保存到照片应用程序。我不知道哪里错了。请帮忙解决这个问题，我卡住了，需要尽快解决

最佳答案

实际上问题出在 CGAffineTransform 中，需要根据横向左侧或右侧设置它，并且它按方面工作。 代码如下:

if isDeviceRotatedToLandscape
    {

        let outputPath : NSString = NSString(format: "%@%@", NSTemporaryDirectory(), "output2.mov")

        let outputURL : NSURL = NSURL(fileURLWithPath: outputPath as String)!

        let fileManager : NSFileManager = NSFileManager.defaultManager()

        if(fileManager.fileExistsAtPath(outputPath as String))
        {
            let asset : AVURLAsset = AVURLAsset(URL: outputURL, options: nil)

            if let clipVideoTrack: AVAssetTrack = asset.tracksWithMediaType(AVMediaTypeVideo)[0] as? AVAssetTrack
            {

                var videoComposition: AVMutableVideoComposition = AVMutableVideoComposition()
                videoComposition.frameDuration = CMTimeMake(1, 30)

                print(clipVideoTrack.naturalSize.height)

                videoComposition.renderSize = CGSizeMake(612,612)

                var instruction: AVMutableVideoCompositionInstruction = AVMutableVideoCompositionInstruction()
                instruction.timeRange = CMTimeRangeMake(kCMTimeZero, CMTimeMakeWithSeconds(60, 30))
                var transformer: AVMutableVideoCompositionLayerInstruction =
                AVMutableVideoCompositionLayerInstruction(assetTrack: clipVideoTrack)

                var t1: CGAffineTransform = CGAffineTransformMakeTranslation(isDeviceLandscapeLeft ? 0 : 612, isDeviceLandscapeLeft ? 612 : 0)

                var t2: CGAffineTransform?
                t2 = CGAffineTransformRotate(t1, CGFloat(isDeviceLandscapeLeft ? -M_PI_2 : M_PI_2))

                var finalTransform: CGAffineTransform = t2!

                transformer.setTransform(finalTransform, atTime: kCMTimeZero)

                instruction.layerInstructions = NSArray(object: transformer) as [AnyObject]

                videoComposition.instructions = NSArray(object: instruction) as [AnyObject]


                let exportPath : NSString = NSString(format: "%@%@", NSTemporaryDirectory(), "output22.mov")

                var exportUrl: NSURL = NSURL.fileURLWithPath(exportPath as! String)!
                if(fileManager.fileExistsAtPath(exportPath as String))
                {
                    var error:NSError? = nil
                    if(fileManager.removeItemAtPath(exportPath as String, error: &error))
                    {
                        //Error - handle if requried
                    }
                }

                var exporter = AVAssetExportSession(asset: asset, presetName: AVAssetExportPresetHighestQuality)
                exporter.videoComposition = videoComposition
                exporter.outputFileType = AVFileTypeQuickTimeMovie
                exporter.outputURL = exportUrl
                exporter.exportAsynchronouslyWithCompletionHandler({ () -> Void in

                    dispatch_async(dispatch_get_main_queue()) {
                        () -> Void in
                          UISaveVideoAtPathToSavedPhotosAlbum(exportPath as String, self, nil, nil)

                    }
                })
            }
        }
    }

关于ios - 如何旋转视频？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32003222/