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• fluent-ffmpeg generating incorrect framerate

  25 novembre 2013, par ZakThompson

  I'm having a strange issue converting images to a video. I am using the excellent fluent-ffmpeg module for a node.js server. I have 179 jpg images which I wish to convert to a 30fps video (should be about 6s). I have successfully done so using the following ffmpeg command :

  ffmpeg -r 30 -i frame%03d.jpg -c:v libx264 out.mp4

  This outputs the following when inspected by ffmpeg :

  ffmpeg -i out.mp4
  
  
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'out.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf54.63.104
  
    Duration: 00:00:06.00, start: 0.000000, bitrate: 1631 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuvj420p, 640x480 [SAR 1:1 DAR 4:3], 1627 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc
  
      Metadata:
  
         handler_name    : VideoHandler

  Now, I am attempting to do the same thing with fluent-ffmpeg :

  var proc = new ffmpeg({ source: 'frame%03d.jpg', nolog: true })
  
    .addOptions(['-c:v libx264','-r 30'])
  
    .saveToFile('test.mp4', function(retcode, error){
  
      console.log('file has been converted succesfully');
  
    });

  Should be exactly the same, right ? But here is what I'm getting :

  ffmpeg -i test.mp4
  
  
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf54.63.104
  
    Duration: 00:00:07.20, start: 0.000000, bitrate: 1556 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuvj420p, 640x480 [SAR 1:1 DAR 4:3], 1553 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc
  
      Metadata:
  
        handler_name    : VideoHandler

  Now what's most interesting here is that although both were made from the same set of images and both supposedly have the same frame rate, the one made with fluent-ffmpeg has a duration of 7.20s, a full 1.20 longer than the first one. Upon comparing the two videos, it seems the fluent-ffmpeg one is actually at 25fps even though it reports 30.

  Note that I have tried properly adding the two flags using the methods (.withVideoCodec, .withFps) with the same result, I merely resorted to adding the arguments manually in an attempt to make it exactly the same as my original command.

  If anybody here has experience with this module and/or has any suggestions, it would be greatly appreciated !

• Streaming video from nodejs to an open player

  27 août 2013, par Matthew Young

  Odd ball question for somebody just getting started with html5 players and streaming video....

  When using YouTube long videos can be scrolled towards then end then played from there. Assuming YouTube first pulls down metadata like total video start/stop points and a bunch of thumbnails for scrolling.

  Is this possible with an open html5 video player (like projekkter) ? Reason asking is that I have video data inside a mongo database that I would like to stream similar to the YouTube player.

  Inside mongo I have a bunch of smaller h264 files each in a document : actual raw h264 usually 1000kb (max 2 seconds), creation timestamp (long), and potentially a converted format (like mp4) for known clients. Idea is to query off a time range and order by creation time then piping the results into readable stream. There is a nice ffmpeg module to take streams and reformat if needed. Thought about piping the stream to the client with binaryjs and appending it into the player.

  But the source directives in the documentation are usually URLs plus I need to lock down the start/stop point for the total video being played plus thumbnails.

• Convert static file to h264 stream with FFmpeg [on hold]

  28 août 2013, par Vprnl

  I'm building a NodeJS application that converts a static videofile to a streamable video which is being sent to a client (iPad or browser) on the fly (using the fluent-ffmpeg module).

  Everything is set and all I need now is to configure ffmpeg correctly. But I'm having a lot of problems with ffmpeg.

  With my current settings, I hear audio right away, but the picture starts a couple of seconds later. Then, my 30 second test file has been compressed to 3 seconds of high speed imagery.

  How can I configure my ffmpeg so it will stream the mp4 correctly (in one pass through of course). It seems it is streaming raw h264, if that is the case how can I force the mp4 container. I thought I was doing that by using '-f mp4'

  my correct settings are :

     '-crf 22','-c:v libx264','-f mp4','-movflags','faststart+frag_keyframe'

  I've also tried :

   '-r 30','-crf 30','-analyzeduration 0','-probesize 1000','-rc_lookahead 0','-fflags nobuffer','-g 75','-ss 0','-threads 0','-vcodec libx264','-qcomp 0.6','-qmin 10','-qmax 51','-qdiff 4','-b:v 400k','-maxrate 400k','-bufsize 800k','-acodec mp3','-ab 192k','-ar 44100','-tune zerolatency','-f mp4','-movflags','faststart+frag_keyframe'

  As you can see by the amount of options I've tried, I'm getting pretty desperate. I'm basically just running around in the dark.

  I don't think it matters much but these are my request headers :

                      res.writeHead(200, { // NOTE: a partial http response
  
                          'Content-Type':'video/mp4',
  
                          'Content-Length':stat.size,
  
                          'Content-Range':'bytes '+start+'-'+end+'/'+stat.size,
  
                          'Transfer-Encoding':'chunked'
  
                      });