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• Extract playable parts from unfinished torrent video ?

  9 avril 2016, par MostafaZ4

  Torrents download files by pieces.
  Is it possible to extract downloaded parts from unfinished torrent of a movie into a video that contains only the downloaded parts ??

• Create thumbnails of sections of a torrent stream

  14 juillet 2015, par Ortixx

  I’m trying to create a little application in nodejs using the torrent-stream library to create thumbnails of a video without actually having to download the entire file. I was thinking of downloading only 10 parts, out of which I would extract an image, but then the encoding comes into play : without an I-frame I cannot extract an image out of the stream, and there is no way of me knowing where the I-frame is.

  So any ideas on how to do this ? Basically I was hoping to create 10 tiny files which I could then open in ffmpeg in order to save a thumbnail (this would give me 10 thumbnails which is want I want). I’m just not sure how to handle the stream.

• Swift - Workaround/Alternative to M3u8 to play mp4 segment or merge segments into mp4

  14 mai 2020, par STerrier

  I used AVAssetExportSession to download a session URL but the issue that you can't download live stream so to get around it, the live stream is split into 10 seconds mp4 segments that are downloaded using an m3u8 to create the URLs. I then use AVAssetExportSession to merge those mp4 segments.

  



  I can merge those clips one by one into one mp4 file which is what I want but as the file gets bigger, the longer it takes as I am dealing with thousands of segments which becomes unpractical.

  



  I thought about using AVplayerLooper but I cannot scrub, rewind or forward through the mp4 segment like a single video.

  



  Is there a way to combine the mp4 clips together to play as one video as the m3u8 does without merging ? or is there a fast way to merge videos ?

  



  Note : The server uses FFmpeg but I am not allowed to use FFmpeg or pods in the app.

  



  below is the function to merge videos

  



  var mp4Array: [AVAsset] = []
var avAssetExportSession: AVAssetExportSession?

var firstAsset: AVAsset?
var secondAsset: AVAsset?

func mergeVideos() {

    firstAsset = mp4Array.first
    secondAsset = mp4Array[1]

    guard let firstAsset = firstAsset, let secondAsset = secondAsset else { return }
    let mixComposition = AVMutableComposition()

    guard let firstTrack = mixComposition.addMutableTrack(withMediaType: .video, preferredTrackID: Int32(kCMPersistentTrackID_Invalid)) else {return}

    do {

        try firstTrack.insertTimeRange(CMTimeRangeMake(start: CMTime.zero, duration: firstAsset.duration),
                                       of: firstAsset.tracks(withMediaType: .video)[0],
                                       at: CMTime.zero)

    } catch {
        print("Couldn't load track 1")
        return
    }

    guard let secondTrack = mixComposition.addMutableTrack(withMediaType: .video, preferredTrackID: Int32(kCMPersistentTrackID_Invalid)) else {return}

    do {
        try secondTrack.insertTimeRange(CMTimeRangeMake(start: CMTime.zero, duration: secondAsset.duration),
                                        of: secondAsset.tracks(withMediaType: .video)[0],
                                        at: firstAsset.duration)
    } catch {
        print("couldn't load track 2")
        return
    }

    let mainInstruction = AVMutableVideoCompositionInstruction()
    mainInstruction.timeRange = CMTimeRangeMake(start: CMTime.zero, duration: CMTimeAdd(firstAsset.duration, secondAsset.duration))

    let firstAssetInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: firstTrack)
    firstAssetInstruction.setOpacity(0.0, at: firstAsset.duration)

    let secondAssetInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: secondTrack)

    mainInstruction.layerInstructions = [firstAssetInstruction, secondAssetInstruction]
    let mainComposition = AVMutableVideoComposition()
    mainComposition.instructions = [mainInstruction]
    mainComposition.frameDuration = CMTimeMake(value: 1, timescale: 30)
    mainComposition.renderSize = firstTrack.naturalSize

    guard let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else { return }
    let url = documentDirectory.appendingPathComponent("MergedVideos/mergeVideo\(videoInt).mp4")

    guard let exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality) else {return}

    exporter.outputURL = url
    exporter.outputFileType = AVFileType.mp4
    exporter.shouldOptimizeForNetworkUse = true
    exporter.videoComposition = mainComposition

    exporter.exportAsynchronously {

        if exporter.status == .completed {
            let avasset = AVAsset(url:url)
            self.mergeUrl = avasset
            if self.mp4Array.count > 1{
                print("This add the merged video to the front of the mp4array")
                self.mp4Array.remove(at: 1)
                self.mp4Array.removeFirst()
                self.videoInt = self.videoInt + 1
                self.mp4Array.append(self.mergeUrl!)
                self.mp4Array.bringToFront(item: self.mp4Array.last!)
            }

            if (self.mp4Array.count > 1){
                if self.mergeUrl != nil {
                    self.mergeVideos()
                }
            } else {
                var numberofvideosdeleted = 0
                while (numberofvideosdeleted < self.videoInt - 1){
                    do {
                        print("deleting")
                        let url = documentDirectory.appendingPathComponent("MergedVideos/mergeVideo\(numberofvideosdeleted).mp4")
                        try FileManager.default.removeItem(at: url)
                        numberofvideosdeleted = numberofvideosdeleted + 1
                    } catch {
                        print("Error removing videos")
                    }
                }

                self.deleteCurrentSegementsInFolder()
            }
        }
    }
}