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• How to extract only 3 video frames at 0,5,10 seconds using FFMPEG ? [closed]

  26 mars 2018, par kheya

  Command I am using :

  ffmpeg -i input -c:v libx264 -movflags +faststart -preset slow -crf 22 -b:v 500k -c:a libvo_aacenc -b:a 128k "out.mp4" -r 1 -t 3 -ss 3 -s sqcif "%%1d.jpg"

• ffmpeg + socket.io -> MediaSource video stops after few seconds

  25 avril 2015, par Dmitry S.

  I am trying to transcode a video using ffmpeg and pipe the output through socket.io to client page which appends the data to MediaSource buffer to play. Video starts playing but suddenly stops after a few seconds.
  I assume that ffmpeg throughput is less than real-time which cause the issue. What might be a better way of handling slow streams to play the video ? Some pre-loading could happen, but is it possible to use along with MediaSource ?

  var app = require('http').createServer(handler)
  
  var io = require('socket.io')(app);
  
  var fs = require('fs');
  
  var child = require('child_process');
  
  var util = require('util');
  
  
  
  var args = ['-i', 'pipe:0', '-c:v', 'libvpx', '-b:v', '300k', '-quality', 'good', '-vf', 'scale=640:-2',
  
    '-c:a', 'libvorbis', '-b:a', '128000', '-threads', '0', '-r', '25', '-rc_lookahead', '25', '-f', 'webm',
  
    '-me_method', 'zero', '-flags2', 'fast', '-preset', 'ultrafast', '-analyzeduration', '1000', 'pipe:1'
  
  ];
  
  
  
  app.listen(8080);
  
  
  
  function handler(req, res) {
  
    fs.readFile(__dirname + '/video.html',
  
      function(err, data) {
  
        if (err) {
  
          res.writeHead(500);
  
          return res.end('Error loading video.html');
  
        }
  
  
  
        res.writeHead(200);
  
        res.end(data);
  
        console.log('html sent');
  
      });
  
  }
  
  
  
  io.on('connection', function(socket) {
  
  
  
    console.log('Connected...');
  
  
  
    var in_file = fs.createReadStream("oceans.mp4");
  
    var trans_proc = child.spawn('ffmpeg', args, null);
  
    in_file.pipe(trans_proc.stdin);
  
  
  
    trans_proc.stderr.on('data', function(data) {
  
      console.log(data.toString());
  
    });
  
  
  
    socket.on('VIDEO_STREAM_REQ', function(req) {
  
      console.log(req);
  
  
  
      trans_proc.stdout.addListener('data', function(data) {
  
        console.log(data.length);
  
        socket.emit('VS', data);
  
      });
  
  
  
    });
  
  });

    <video autoplay="autoplay"></video>
  
  
  
    <code class="echappe-js">&lt;script src=&quot;https://cdn.socket.io/socket.io-1.3.5.js&quot;&gt;&lt;/script&gt;
  &lt;script&gt;<br />
  
      window.URL = window.URL || window.webkitURL;<br />
  
  <br />
  
      window.MediaSource = window.MediaSource || window.WebKitMediaSource;<br />
  
      if (!!!window.MediaSource) {<br />
  
        alert('MediaSource API is not available');<br />
  
      }<br />
  
      console.log('MediaSource API' + window.MediaSource);<br />
  
  <br />
  
      var mediaSource = new MediaSource();<br />
  
      var video = document.getElementById('v');<br />
  
      var i = 0;<br />
  
  <br />
  
      video.src = window.URL.createObjectURL(mediaSource);<br />
  
  <br />
  
      mediaSource.addEventListener('webkitsourceopen', function(e) {<br />
  
        console.log('mediaSource readyState: ' + this.readyState);<br />
  
      }, false);<br />
  
  <br />
  
      mediaSource.addEventListener('webkitsourceended', function(e) {<br />
  
        console.log('mediaSource readyState: ' + this.readyState);<br />
  
      }, false);<br />
  
  <br />
  
      var queue = [];<br />
  
  <br />
  
      mediaSource.addEventListener('sourceopen', function(e) {<br />
  
        console.log('mediaSource readyState: ' + this.readyState);<br />
  
  <br />
  
        console.log('listener fired');<br />
  
        var sourceBuffer = mediaSource.addSourceBuffer('video/webm; codecs=&quot;vorbis,vp8&quot;');<br />
  
  <br />
  
        var socket = io.connect('http://localhost:8080');<br />
  
  <br />
  
        socket.emit('VIDEO_STREAM_REQ', 'REQUEST');<br />
  
  <br />
  
        socket.on('VS', function(data) {<br />
  
          queue.push(new Uint8Array(data));<br />
  
  <br />
  
          if (queue.length &gt; 3 &amp;amp;&amp;amp; !sourceBuffer.updating)<br />
  
            sourceBuffer.appendBuffer(queue.shift());<br />
  
  <br />
  
  <br />
  
          i = i + 1;<br />
  
          console.log(queue.length);<br />
  
        });<br />
  
  <br />
  
        sourceBuffer.addEventListener('updateend', function() {<br />
  
          console.log(queue.length);<br />
  
          if (queue.length) {<br />
  
            sourceBuffer.appendBuffer(queue.shift());<br />
  
          }<br />
  
        }, false);<br />
  
  <br />
  
      });<br />
  
    &lt;/script&gt;
  

• ffmpeg produces video of 0 seconds on adding text

  7 mars 2018, par Anuj TBE

  I’m using ffmpeg to add text over video.

  ffmpeg -i /path_to_video_input/1520425717.mp4 -vf\
  
   "drawtext=text='This is text':x=10:y=H-th-10:fontsize=42:fontcolor=#FFFFFF"\
  
   /path_to_video_input/1520425717.mp4 -y

  Text is added to the video but video length is reduced to 0 seconds and shows only one frame.

  How to keep the length of video as original and add the text throughout the video ?