Duet - 并排合并 2 个视频

Question

注意：-并排合并视频而不会降低视频质量

我认为这是一个非常非常重要的问题，经过大量搜索和谷歌搜索，没有找到任何与此问题相关的有用材料。

我正在做一个项目，我需要将视频并排合并到一个文件中。

我已经完成使用 AVFoundation 合并视频，但问题是 FIRST 视频显示为第二个视频的叠加层（与 SMULE 应用程序/卡拉 OK 应用程序或 Tiktok 应用程序相同的合并不正确）。

func mergeVideosFilesWithUrl(savedVideoUrl: URL, newVideoUrl: URL, audioUrl:URL)
    {
        let savePathUrl : NSURL = NSURL(fileURLWithPath: NSHomeDirectory() + "/Documents/camRecordedVideo.mp4")
        do { // delete old video
            try FileManager.default.removeItem(at: savePathUrl as URL)
        } catch { print(error.localizedDescription) }

        var mutableVideoComposition : AVMutableVideoComposition = AVMutableVideoComposition()
        var mixComposition : AVMutableComposition = AVMutableComposition()

        let aNewVideoAsset : AVAsset = AVAsset(url: newVideoUrl)
        let asavedVideoAsset : AVAsset = AVAsset(url: savedVideoUrl)

        let aNewVideoTrack : AVAssetTrack = aNewVideoAsset.tracks(withMediaType: AVMediaType.video)[0]
        let aSavedVideoTrack : AVAssetTrack = asavedVideoAsset.tracks(withMediaType: AVMediaType.video)[0]

        let mutableCompositionNewVideoTrack : AVMutableCompositionTrack = mixComposition.addMutableTrack(withMediaType: AVMediaType.video, preferredTrackID: kCMPersistentTrackID_Invalid)!
        do{
            try mutableCompositionNewVideoTrack.insertTimeRange(CMTimeRangeMake(start: CMTime.zero, duration: aNewVideoAsset.duration), of: aNewVideoTrack, at: CMTime.zero)
        }catch {  print("Mutable Error") }

        let mutableCompositionSavedVideoTrack : AVMutableCompositionTrack = mixComposition.addMutableTrack(withMediaType: AVMediaType.video, preferredTrackID: kCMPersistentTrackID_Invalid)!
        do{
            try mutableCompositionSavedVideoTrack.insertTimeRange(CMTimeRangeMake(start: CMTime.zero, duration: asavedVideoAsset.duration), of: aSavedVideoTrack , at: CMTime.zero)
        }catch{ print("Mutable Error") }

        let mainInstruction = AVMutableVideoCompositionInstruction()
        mainInstruction.timeRange = CMTimeRangeMake(start: CMTime.zero, duration: CMTimeMaximum(aNewVideoAsset.duration, asavedVideoAsset.duration) )

        let newVideoLayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: mutableCompositionNewVideoTrack)
        let newScale : CGAffineTransform = CGAffineTransform.init(scaleX: 0.7, y: 0.7)
        let newMove : CGAffineTransform = CGAffineTransform.init(translationX: 230, y: 230)
        newVideoLayerInstruction.setTransform(newScale.concatenating(newMove), at: CMTime.zero)

        let savedVideoLayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: mutableCompositionSavedVideoTrack)
        let savedScale : CGAffineTransform = CGAffineTransform.init(scaleX: 1.2, y: 1.5)
        let savedMove : CGAffineTransform = CGAffineTransform.init(translationX: 0, y: 0)
        savedVideoLayerInstruction.setTransform(savedScale.concatenating(savedMove), at: CMTime.zero)

        mainInstruction.layerInstructions = [newVideoLayerInstruction, savedVideoLayerInstruction]


        mutableVideoComposition.instructions = [mainInstruction]
        mutableVideoComposition.frameDuration = CMTimeMake(value: 1, timescale: 30)
        mutableVideoComposition.renderSize = CGSize(width: 1240 , height: self.camPreview.frame.height)

        finalPath = savePathUrl.absoluteString
        let assetExport: AVAssetExportSession = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)!
        assetExport.videoComposition = mutableVideoComposition
        assetExport.outputFileType = AVFileType.mov

        assetExport.outputURL = savePathUrl as URL
        assetExport.shouldOptimizeForNetworkUse = true

        assetExport.exportAsynchronously { () -> Void in
            switch assetExport.status {

            case AVAssetExportSession.Status.completed:
                print("success")
            case  AVAssetExportSession.Status.failed:
                print("failed \(assetExport.error)")
            case AVAssetExportSession.Status.cancelled:
                print("cancelled \(assetExport.error)")
            default:
                print("complete")
            }
        }

    }

这是我的输出

我想要什么

因为我不知道制作 SIDE BY SIDE VIDEO/DUET VIDEO 的最佳方法是什么……至于现在，我使用了 AVFoundation。我没有使用任何 3rd 方框架或任何 POD。

我想问一下，实现这一点的最佳方法是什么？视频应该合并在服务器端还是应用程序？还有我应该使用哪种方法？

任何帮助都将受到高度赞赏。谢谢

Answer 1

为此，我将创建一个包含 2 个轨道的新 AVMutableComposition 对象，并在每个轨道上设置变换以将它们并排放置：

let composition = AVMutableComposition(urlAssetInitializationOptions: <your options>)
let videoTrackA = composition.addMutableTrack(withMediaType:.video, preferredTrackID:kCMPersistentTrackID_Invalid);
let videoTrackB = composition.addMutableTrack(withMediaType:.video, preferredTrackID:kCMPersistentTrackID_Invalid);

videoTrackA.preferredTransform = CGAffineTransform(translationX: <yourX_for_A>, y:0.0)
videoTrackB.preferredTransform = CGAffineTransform(translationX: <yourX_for_B>, y:0.0)

那么。保存使用：

let exporter = AVAssetExportSession(asset:<yourAsset>, presetName:<yourPresetName>)
exporter.exportAsynchronously(completionHandler: <yourCompletionHandler>)

（Swift 代码未测试）。

Answer 2

其实AVAssetExportSession是为了简单的需求，对你的情况来说太简单了。

您必须使用AVAssetWriter。

您将AVAssetWriterInput 添加到您的AVAssetWriter。

您可以使用AVAssetWriterInput 的transform 属性配置其转换。

然后，您使用 append 调用为您的 AVAssetWriterInput 提供 CMSampleBuffer（每个图像缓冲区）。

有关详细示例，请参阅完整的 Apple 文档：https://developer.apple.com/library/archive/documentation/AudioVideo/Conceptual/AVFoundationPG/Articles/05_Export.html#//apple_ref/doc/uid/TP40010188-CH9-SW2

Answer 3

这取决于您的视频帧大小（渲染大小）的宽度，如果您的帧渲染宽度是 800。您必须将第二个合并视频转换为 400（一半）。同样，您必须缩小或放大。如下示例代码sn-p所示。

        var renderSize = CGSize(width: 800, height: 534) // 534
        let assetInfo = AVMutableComposition.orientationFromTransform(firstTrack.preferredTransform)
        renderSize = assetInfo.isPortrait ? CGSize(width: renderSize.height, height: renderSize.width) : CGSize(width: renderSize.width, height: renderSize.height)
        
        let scaleRatioX = (renderSize.width / 2) / firstTrack.naturalSize.width
        let scaleRatioY = (renderSize.height) / firstTrack.naturalSize.height
        
        let scaleRatio2X = (renderSize.width / 2) / secondTrack.naturalSize.width
        let scaleRatio2Y = renderSize.height / secondTrack.naturalSize.height
        
        print("Scale Video 1 : \(scaleRatioX), \(scaleRatioY)") // print("Scale Video 1 : \(scaleRatioY), \(scaleRatioX)")
        print("Scale Video 2 : \(scaleRatio2X), \(scaleRatio2Y)")
        
//        let scale  = CGAffineTransform(scaleX: scaleRatioY, y: scaleRatioX) // 1, 1
        let scale  = CGAffineTransform(scaleX: scaleRatioX, y: scaleRatioY)
        let move = CGAffineTransform(translationX: 0, y: 0)

        firstlayerInstruction.setTransform(scale.concatenating(move), at: .zero)
        let secondlayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: secondTrack)

        let secondScale = CGAffineTransform(scaleX: scaleRatio2X, y: scaleRatio2Y) // 0.13, 0.13
        let secondMove = CGAffineTransform(translationX: 400, y: 0) // 160, 0
        secondlayerInstruction.setTransform(secondScale.concatenating(secondMove), at: .zero)