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

问题描述

所以，目前我正在用它来压缩视频：

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 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.

任何减小尺寸的提示？

推荐答案

虽然这些扩展都使用媒体设置进行压缩，但如果您想要关注质量或尺寸，可以将其更改为低或高。

While these extensions both use the medium setting for compression, you can change it to low or high if you want to focus on quality or size.

I使用基于Swift版本的这些扩展程序：

I use these extensions based on Swift version:

对于OP（ Swift 2.2 ）：

extension PreviewVideoViewController: AVCaptureFileOutputRecordingDelegate {
    func captureOutput(captureOutput: AVCaptureFileOutput!, didFinishRecordingToOutputFileAtURL outputFileURL: NSURL!, fromConnections connections: [AnyObject]!, error: NSError!) {
        let data = NSData(contentsOfURL: outputFileURL)
        print("File size before compression: \(Double(data!.length / 1048576)) mb")
        let compressedURL = NSURL.fileURLWithPath(NSTemporaryDirectory() + NSUUID().UUIDString + ".m4v")
        compressVideo(outputFileURL, outputURL: compressedURL) { (session) in
            switch session.status {
            case .Unknown:
                break
            case .Waiting:
                break
            case .Exporting:
                break
            case .Completed:
                let data = NSData(contentsOfURL: compressedURL)
                print("File size after compression: \(Double(data!.length / 1048576)) mb")
            case .Failed:
                break
            case .Cancelled:
                break
            }
        }
    }

    private func compressVideo(inputURL: NSURL, outputURL: NSURL, handler:(session: AVAssetExportSession)-> Void) {
        let urlAsset = AVURLAsset(URL: inputURL, options: nil)
        if let exportSession = AVAssetExportSession(asset: urlAsset, presetName: AVAssetExportPresetMediumQuality) {
            exportSession.outputURL = outputURL
            exportSession.outputFileType = AVFileTypeQuickTimeMovie
            exportSession.shouldOptimizeForNetworkUse = true
            exportSession.exportAsynchronouslyWithCompletionHandler { () -> Void in
                handler(session: exportSession)
            }
        }
    }
}

对于需要 Swift 3.0 的人：

extension PreviewVideoViewController: AVCaptureFileOutputRecordingDelegate {
    func capture(_ captureOutput: AVCaptureFileOutput!, didFinishRecordingToOutputFileAt outputFileURL: URL!, fromConnections connections: [Any]!, error: Error!) {
        guard let data = NSData(contentsOf: outputFileURL as URL) else {
            return
        }

        print("File size before compression: \(Double(data.length / 1048576)) mb")
        let compressedURL = NSURL.fileURL(withPath: NSTemporaryDirectory() + NSUUID().uuidString + ".m4v")
        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 = NSData(contentsOf: compressedURL) else {
                    return
                }

                print("File size after compression: \(Double(compressedData.length / 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 = AVFileTypeQuickTimeMovie
        exportSession.shouldOptimizeForNetworkUse = true
        exportSession.exportAsynchronously { () -> Void in
            handler(exportSession)
        }
    }
}

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