我想对视频应用 CIFilter 并保存该过滤器应用的视频。 [导出耗时太长]答案

【问题标题】：I want to apply CIFilter on video and save that filter applied video. [export taking too much time]我想对视频应用 CIFilter 并保存该过滤器应用的视频。 [导出耗时太长]
【发布时间】：2019-07-06 06:00:57
【问题描述】：

我想对视频应用 CIFilter 并保存该过滤器应用的视频。

我正在使用 AVMutableVideoComposition（也尝试使用 AVVideoComposition）对视频应用过滤器，并且它与 AVPlayer 一起工作正常，但是当我导出过滤后的视频时，本地保存需要太多时间（20 秒视频大约需要 6-8 分钟） .请指导我做错了什么...... 谢谢！

let item = AVPlayerItem(asset: currentAsset!)
    let videoComposition = AVMutableVideoComposition(asset: currentAsset!) { request in
        let filter = CIFilter(name: "CIColorInvert")!
        let source = request.sourceImage.clampedToExtent()
        filter.setValue(source, forKey: kCIInputImageKey)

        let output = filter.outputImage!.cropped(to: request.sourceImage.extent)

        // Provide the filter output to the composition
        request.finish(with: output, context: nil)
    }
    item.videoComposition = videoComposition
    self.player.replaceCurrentItem(with: item)

    let exporter = AVAssetExportSession(asset: item.asset, presetName: AVAssetExportPresetHighestQuality)
    exporter?.videoComposition = videoComposition

    exporter?.outputFileType = .mp4
    let filename = "filename.mp4"

    let documentsDirectory = FileManager.default.urls(for: FileManager.SearchPathDirectory.documentDirectory, in: FileManager.SearchPathDomainMask.userDomainMask).last!
    let outputURL = documentsDirectory.appendingPathComponent(filename)
    exporter?.outputURL = outputURL
    exporter?.exportAsynchronously(completionHandler: {
        guard exporter?.status == .completed else {
            print("export failed: \(exporter?.error)")
            return
        }
        print("done: ",outputURL)
    }
    )

【问题讨论】：

您是否尝试为导出会话创建不同的合成实例？
是的，我已经分别尝试过，但没有成功。
您是否尝试过其他质量预设？这个问题似乎是相关的：stackoverflow.com/questions/51036125
我尝试了所有预设，但仅通过导出视频（无过滤器）其他预设没有导出任何内容。我不明白为什么会这样？

标签： ios swift avvideocomposition

【解决方案1】：

你好，试试在视频文件上应用过滤器

let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
let savedoutputURL = documentsDirectory.appendingPathComponent("Filterd.mov")
try? FileManager.default.removeItem(at: savedoutputURL)

let urlVideofile = Bundle.main.url(forResource: "(your video file name)", withExtension: "mov")

let videoAsset = AVAsset(url: urlVideofile!)

let filter = CIFilter(name: "CIColorInvert")!
let composition = AVVideoComposition(asset: asset, applyingCIFiltersWithHandler: { request in

    let source = request.sourceImage.clampingToExtent()
    filter.setValue(source, forKey: kCIInputImageKey)

    // Crop the invert output to the bounds of the original image
    let output = filter.outputImage!.cropping(to: request.sourceImage.extent)

    // Provide the filter output to the composition
    request.finish(with: output, context: nil)
})
// Simultaneous Video playing although you can use as your's

let playerItem = AVPlayerItem(asset: videoAsset)
playerItem.videoComposition = composition

self.player = AVPlayer(playerItem: playerItem)

self.player.volume = 0.0

self.playerController.player = self.player

 present(self.playerController, animated: true, completion: {
      self.player.play()
})

保存视频

let export = AVAssetExportSession(asset: videoAsset, presetName: AVAssetExportPresetHighestQuality)
    export!.outputFileType = AVFileType.mov
    export!.outputURL = savedoutputURL
    export!.videoComposition = composition

    export?.exportAsynchronously(completionHandler: {

        if export!.status.rawValue == 4 {
            print("Export failed -> Reason: \(export?.error!.localizedDescription))")
            print(export?.error!)
            return
        }
        print("done: ",savedoutputURL)

    })

经过 100% 测试的代码在大约 10 到 15 秒内对 26 秒视频应用过滤器

:)享受

【讨论】：