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• FFMPEG tutorial example produces a corrupted video

  6 janvier 2013, par Tishu

  Can anyone produce a readable H264 file from this FFMPEG tutorial example ? The only thing I have changed is the output format on line 350 :

  avformat_alloc_output_context2(&oc, NULL, "h264", filename);

  Running it with FFMPEG 1.0.1+libx64 v129 produces a 6MB .3gp file that is unreadable by most players (including VLC). When I load it I can see that it contains all frames and I can decode and view them successfully, but for some reason most players will just fail to open it.

  Does anyone have more success ?

• How to convert VP8 track with different frame resolution to h264

  13 septembre 2016, par Nikita

  I have a .webm file with VP8 track, recorded from WebRTC stream by external service (TokBox Archiving). The stream is adaptive, so each frame in track could have different resolution. Most players (in webkit browsers) use video resolution from track description (which is always 640x480) and scale frames to this resolution. Firefox and VLC player uses real frame resolution, changing video resolution respectively.

  I want to achieve 2 goals :

  1. play this video in Internet Explorer 9+ without additional plugin installation.
  2. change frames resolution to one fixed resolution, so the video will look identically in different browsers.

  So, my plan is :

  • extract frames from source webm file to images with real frame resolution (e.g. PNG or BMP) (how could I do that ?)
  • find max width and max height of images
  • add black padding to images, so smaller frames will be in the center of a new frame (of size MAX_WIDHTxMAX_HEIGHT)
  • combine images to h264 track using ffmpeg

  Is all correct ? How can I achieve this ? Can this algorithm be optimized some way ?

  I tried ffmpeg to extract images, but it does not parse real frame resolution, using resolution from track header.
  I think some libwebm functions can help me (to parse frame headers and extract images). Maybe someone has some code snippets to do this ?

  Example .webm (download source, do not play google-converted version) : https://drive.google.com/file/d/0BwFZRvYNn9CKcndhMzlVa0psX00/view?usp=sharing

  Official description of adaptive stream from TokBox support : https://support.tokbox.com/hc/en-us/community/posts/206241666-Archived-video-resolution-is-supposed-to-be-720x1280-but-reports-as-640x480

• Publishing mp4 video to RTMP red5 server doesn't work

  25 septembre 2017, par k-hir

  ffmpeg -re -i filename.mp4 -c copy -movflags +frag_keyframe -f mp4 rtmp://localhost/oflaDemo/keyname

  With the command above, I could publish it to red5 with no error, but I couldn’t view the video through flowplayer, unless I put -f flv instead.
  Can someone tell me if it’s because ffmpeg does not support mp4 video stream, or is it the red5 app (oflaDemo)’s problem ?

  Here are the two sources of the viewer :
  Neither of them work if the video is sent by -f mp4.

  First

    
  
    <code class="echappe-js">&lt;script src=&quot;http://vjs.zencdn.net/4.2.0/video.js&quot;&gt;&lt;/script&gt;
    
  
        To view this video please enable JavaScript, and consider upgrading to a web browser
  
        that supports HTML5 video
  
    
  
  

  Second one

  <code class="echappe-js">&lt;script src=&quot;//code.jquery.com/jquery-1.11.2.min.js&quot;&gt;&lt;/script&gt;
  &lt;script src='http://stackoverflow.com/feeds/tag/demos/flowplayer/flowplayer.min.js'&gt;&lt;/script&gt;
  
  &lt;script&gt;<br />
  
  &lt;!--<br />
  
  flowplayer(&quot;#player01&quot;, {<br />
  
    autoplay: false,<br />
  
    live: true,<br />
  
    clip: {<br />
  
      sources: [<br />
  
        {type: &quot;video/flv&quot;, src: &quot;rtmp://localhost/oflaDemo/keyname&quot;}<br />
  
      ]<br />
  
    }<br />
  
  });<br />
  
  //--&gt;<br />
  
  &lt;/script&gt;