Swift - 压缩视频文件 [英] Swift - Compressing video files

问题描述

所以，目前我正在使用它来压缩视频:

So, at the moment I am using this to compress video:

func compressVideo(inputURL: NSURL, outputURL: NSURL, handler:(session: AVAssetExportSession)-> Void)
    {
        let urlAsset = AVURLAsset(URL: inputURL, options: nil)

        let exportSession = AVAssetExportSession(asset: urlAsset, presetName: AVAssetExportPresetMediumQuality)

        exportSession!.outputURL = outputURL

        exportSession!.outputFileType = AVFileTypeQuickTimeMovie

        exportSession!.shouldOptimizeForNetworkUse = true

        exportSession!.exportAsynchronouslyWithCompletionHandler { () -> Void in

            handler(session: exportSession!)
        }

    }

当我在 2 秒内录制视频时，大小为 4,3 MB，当我在 6 秒内录制视频时，文件大小为 9,3 MB.

When I recorded a video in 2 seconds, the size was 4,3 MB and when I recorded a video in 6 seconds the file size was 9,3 MB.

有什么减小尺寸的技巧吗?

Any tips to reduce the size?

推荐答案

此扩展侧重于将其导出为较低质量的设置(在本例中为中等)并使用 mp4 容器，而不是 mp4iOS 青睐的 code>mov 容器.这可能会导致质量下降，但您可以尝试使用更高的输出设置和不同的格式来微调输出.

This extension focuses on exporting it to a lower quality setting (in this case Medium) and uses an mp4 container, over the mov container favored by iOS. This can result in a loss of quality, but you can experiment with higher output settings and different formats as you work to fine tune your output.

extension PreviewVideoViewController: AVCaptureFileOutputRecordingDelegate {
    func fileOutput(_ output: AVCaptureFileOutput,
                    didFinishRecordingTo outputFileURL: URL,
                    from connections: [AVCaptureConnection],
                    error: Error?) {
        guard let data = try? Data(contentsOf: outputFileURL) else {
            return
        }

        print("File size before compression: (Double(data.count / 1048576)) mb")

        let compressedURL = NSURL.fileURL(withPath: NSTemporaryDirectory() + UUID().uuidString + ".mp4")
        compressVideo(inputURL: outputFileURL as URL,
                      outputURL: compressedURL) { exportSession in
            guard let session = exportSession else {
                return
            }

            switch session.status {
            case .unknown:
                break
            case .waiting:
                break
            case .exporting:
                break
            case .completed:
                guard let compressedData = try? Data(contentsOf: compressedURL) else {
                    return
                }

                print("File size after compression: (Double(compressedData.count / 1048576)) mb")
            case .failed:
                break
            case .cancelled:
                break
            }
        }
    }


    func compressVideo(inputURL: URL,
                       outputURL: URL,
                       handler:@escaping (_ exportSession: AVAssetExportSession?) -> Void) {
        let urlAsset = AVURLAsset(url: inputURL, options: nil)
        guard let exportSession = AVAssetExportSession(asset: urlAsset,
                                                       presetName: AVAssetExportPresetMediumQuality) else {
            handler(nil)

            return
        }

        exportSession.outputURL = outputURL
        exportSession.outputFileType = .mp4
        exportSession.exportAsynchronously {
            handler(exportSession)
        }
    }
}

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