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• Video buffering/streaming with node-fluent-ffmpeg

  24 février 2018, par Salies

  I want to turn AC3-audio videos playable on browsers. For this, I decided to use fluent-ffmpeg to real-time convert the videos and stream them. It works as livestreaming/piping pretty well, but you can’t even go back in the videos.

  app.get('/video', function (req, res) {
  
    var path = 'show.mkv';
  
    ffmpeg(path)
  
      .outputOptions(arr)
  
      .on('end', function () {
  
        console.log('file has been converted succesfully');
  
      })
  
      .on('error', function (err) {
  
        console.log('an error happened: ' + err.message);
  
      })
  
      .pipe(res);
  
  });

  So I need to build a sort of buffer for the conversion, this is, to let the user go back and forth in the video. I’ve found some code that does exactly what I need, although it doesn’t convert :

  app.get('/video', function(req, res) {
  
    const path = 'assets/sample.mp4'
  
    const stat = fs.statSync(path)
  
    const fileSize = stat.size
  
    const range = req.headers.range
  
  
  
    if (range) {
  
      const parts = range.replace(/bytes=/, "").split("-")
  
      const start = parseInt(parts[0], 10)
  
      const end = parts[1]
  
        ? parseInt(parts[1], 10)
  
        : fileSize-1
  
  
  
      const chunksize = (end-start)+1
  
      const file = fs.createReadStream(path, {start, end})
  
      const head = {
  
        'Content-Range': `bytes ${start}-${end}/${fileSize}`,
  
        'Accept-Ranges': 'bytes',
  
        'Content-Length': chunksize,
  
        'Content-Type': 'video/mp4',
  
      }
  
  
  
      res.writeHead(206, head)
  
      file.pipe(res)
  
    } else {
  
      const head = {
  
        'Content-Length': fileSize,
  
        'Content-Type': 'video/mp4',
  
      }
  
      res.writeHead(200, head)
  
      fs.createReadStream(path).pipe(res)
  
    }
  
  })

  (from https://github.com/daspinola/video-stream-sample)

  I’ve been trying to make fluent-ffmpeg work with buffering, with no success, and I pretty much have no clue on what to do. If buffering isn’t possible, is there an similar alternative excpect for pre-converting the videos ? Thanks already.

• Seeking in Libav / FFMPEG a DASH stream

  23 janvier 2018, par Glen Rhodes

  Recently, the functionality for playing DASH format files (mpd) was added to Libav. I’m trying to determine the best way to seek forward in the stream.

  When I use av_seek_frame, it does go to the correct time, but there’s a considerable delay which makes me think it’s not properly jumping to a segment / byte offset in the HTTP request, but rather just downloading with all its might until it arrives at the correct timestamp.

  int ret = av_seek_frame(is->pFormatCtx, stream_index, seek_target, is->seek_flags);

  When I use avformat_seek_file, it only seems to go forward several seconds before just continuing to play. So if I start playback, and then seek to 50 seconds, it will jump to something like 12. If I do the same seek again, it’ll jump further ahead, but still not 50.. however if it eventually gets to 50, then I do avformat_seek_file, it will successfully jump back to 50 no problem. So it’s like it tries, and gives up.

  int ret = avformat_seek_file(is->pFormatCtx, stream_index, INT64_MIN, tm, INT64_MAX, 0);

  Does anyone know how seeking is managed in the Libav dash playback ?

• Screen Transfer [on hold]

  9 décembre 2013, par sanalism

  I need to develop a program that transfers a users screen and sound to another user over internet. The scenario can be visualized like this :

  There is a teacher in front of his computer and writes some code on his computer (ex:visual studio). He has a microphone. There is two students watching teacher's screen and listening his voice from their own computers.

  There are a few alternatives to get screen capture of a user and transfer it like ffmpeg, aforge or self coded screen capture program by c# (over udp). Tried all alternatives.

  However, the problem is all of them are so slow, or creates bad resolution of video. There should be an alternative way, because some programs reaches a high quality. For example teamviewer, windows remote desktop, logmein can send the screen with a high quality. More over, teamviewer can send sound also.

  Where should I begin to overcome this mission ? Which platform, language, protocol is useful ?