快速压缩视频大小，然后快速附加到电子邮件 [英] Compress video size before attach to an email in swift

问题描述

以前，我问过如何附加视频然后通过电子邮件发送。现在工作了。

Previous, I have ask for how to attach video then send via email. Now it working. Advised by some friend from this website.

我发现了一个新问题，即视频大小比相同iOS文件中通过默认电子邮件应用程序发送的视频大得多。

I found new problem that video size is very large and larger than send with default email app in iOS for same video file.

在附加到电子邮件应用程序之前，请先告诉我如何压缩视频文件。

Please advice me how to compress video file before attach to an email application.

谢谢大家。

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject : AnyObject]) {

    if let myImage = info[UIImagePickerControllerOriginalImage] as? UIImage {

        image = info[UIImagePickerControllerOriginalImage] as! UIImage
        self.dismissViewControllerAnimated(false, completion: nil)
        sendmail()

    }
    else {
        //picker.videoQuality = UIImagePickerControllerQualityTypeLow
        videoURL = info[UIImagePickerControllerMediaURL] as! NSURL
        self.dismissViewControllerAnimated(true, completion: nil)
        sendmailVDO()
    }

}

推荐答案

下面是压缩视频的代码，大小为实际大小的一半

Below is the code for Compress video by half of the actual size

var assetWriter:AVAssetWriter?
var assetReader:AVAssetReader?
let bitrate:NSNumber = NSNumber(value:250000)

func compressFile(urlToCompress: URL, outputURL: URL, completion:@escaping (URL)->Void){
    //video file to make the asset

    var audioFinished = false
    var videoFinished = false

    let asset = AVAsset(url: urlToCompress);

    let duration = asset.duration
    let durationTime = CMTimeGetSeconds(duration)

    print("Video Actual Duration -- \(durationTime)")

    //create asset reader
    do{
        assetReader = try AVAssetReader(asset: asset)
    } catch{
        assetReader = nil
    }

    guard let reader = assetReader else{
        fatalError("Could not initalize asset reader probably failed its try catch")
    }

    let videoTrack = asset.tracks(withMediaType: AVMediaType.video).first!
    let audioTrack = asset.tracks(withMediaType: AVMediaType.audio).first!

    let videoReaderSettings: [String:Any] =  [(kCVPixelBufferPixelFormatTypeKey as String?)!:kCVPixelFormatType_32ARGB ]

    // ADJUST BIT RATE OF VIDEO HERE

    let videoSettings:[String:Any] = [
        AVVideoCompressionPropertiesKey: [AVVideoAverageBitRateKey:self.bitrate],
        AVVideoCodecKey: AVVideoCodecType.h264,
        AVVideoHeightKey: videoTrack.naturalSize.height,
        AVVideoWidthKey: videoTrack.naturalSize.width
    ]


    let assetReaderVideoOutput = AVAssetReaderTrackOutput(track: videoTrack, outputSettings: videoReaderSettings)
    let assetReaderAudioOutput = AVAssetReaderTrackOutput(track: audioTrack, outputSettings: nil)


    if reader.canAdd(assetReaderVideoOutput){
        reader.add(assetReaderVideoOutput)
    }else{
        fatalError("Couldn't add video output reader")
    }

    if reader.canAdd(assetReaderAudioOutput){
        reader.add(assetReaderAudioOutput)
    }else{
        fatalError("Couldn't add audio output reader")
    }

    let audioInput = AVAssetWriterInput(mediaType: AVMediaType.audio, outputSettings: nil)
    let videoInput = AVAssetWriterInput(mediaType: AVMediaType.video, outputSettings: videoSettings)
    videoInput.transform = videoTrack.preferredTransform
    //we need to add samples to the video input

    let videoInputQueue = DispatchQueue(label: "videoQueue")
    let audioInputQueue = DispatchQueue(label: "audioQueue")

    do{
        assetWriter = try AVAssetWriter(outputURL: outputURL, fileType: AVFileType.mov)
    }catch{
        assetWriter = nil
    }
    guard let writer = assetWriter else{
        fatalError("assetWriter was nil")
    }

    writer.shouldOptimizeForNetworkUse = true
    writer.add(videoInput)
    writer.add(audioInput)


    writer.startWriting()
    reader.startReading()
    writer.startSession(atSourceTime: kCMTimeZero)


    let closeWriter:()->Void = {
        if (audioFinished && videoFinished){
            self.assetWriter?.finishWriting(completionHandler: {
                print("------ Finish Video Compressing")
                self.checkFileSize(sizeUrl: (self.assetWriter?.outputURL)!, message: "The file size of the compressed file is: ")

                completion((self.assetWriter?.outputURL)!)
            })

            self.assetReader?.cancelReading()
        }
    }


    audioInput.requestMediaDataWhenReady(on: audioInputQueue) {
        while(audioInput.isReadyForMoreMediaData){
            let sample = assetReaderAudioOutput.copyNextSampleBuffer()
            if (sample != nil){
                audioInput.append(sample!)
            }else{
                audioInput.markAsFinished()
                DispatchQueue.main.async {
                    audioFinished = true
                    closeWriter()
                }
                break;
            }
        }
    }

    videoInput.requestMediaDataWhenReady(on: videoInputQueue) {
        //request data here
        while(videoInput.isReadyForMoreMediaData){
            let sample = assetReaderVideoOutput.copyNextSampleBuffer()
            if (sample != nil){
                let timeStamp = CMSampleBufferGetPresentationTimeStamp(sample!)
                let timeSecond = CMTimeGetSeconds(timeStamp)
                let per = timeSecond / durationTime
                print("Duration --- \(per)")
                DispatchQueue.main.async {
                    self.progress.progress = Float(per)
                }
                videoInput.append(sample!)
            }else{
                videoInput.markAsFinished()
                DispatchQueue.main.async {
                    videoFinished = true
                    self.progress.progress = 1.0
                    closeWriter()
                }
                break;
            }
        }
    }
}

您还可以显示视频压缩的进度。

You can also display the progress of video compression.

这篇关于快速压缩视频大小，然后快速附加到电子邮件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！