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• doc : restore default.css

  20 juillet 2014, par Clément Bœsch

  doc : restore default.css
  This partially reverts 9ce64ba111221a37bdd78204b67330a6120f6c50.
  FATE still needs it until its design is updated to the new website
  
  version.
  

  • [DH] doc/default.css

• FFMPEG frames are choppy when piping images to mp4

  15 décembre 2020, par Michael Joseph Aubry

  I'm working to optimize my rendering technique, it has some noticeable frame drops here and there. It's hard to tell, if you take a look at this recording you will see what I mean https://share.getcloudapp.com/6quxYe5O

  


  My technique involves hardcoding a default FPS to be 25 and to use that to take a screenshot of the video every (25 / 1000) = 0.4 ms inside a Chrome instance.

  


  When I run ffmpeg -i ORIGINAL_VIDEO I get this output

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'https://s3.us-west-1.amazonaws.com/storycreator.clips/e7d87660-51a8-11ea-a753-8f195b459e44':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
  Duration: 00:00:20.36, start: 0.000000, bitrate: 6095 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 6092 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : L-SMASH Video Handler


  


  When I run it on the newly made video from the screenshots here is the ffmpeg output.

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'https://s3.us-west-2.amazonaws.com/storycreator.testing/4aa5e5c0-3e89-11eb-a8b5-a38609fab693.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
  Duration: 00:00:15.04, start: 0.000000, bitrate: 4775 kb/s
    Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 16000 Hz, stereo, fltp, 83 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
    Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1080x1080 [SAR 1:1 DAR 1:1], 4698 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : VideoHandler


  


  Some slight differences. You can see the bitrate drops from 6095 to 4775. You will also notice audio was attached in the new one. The video size changed — this was intentional.

  


  You also notice it go from 6092 kb/s to 4698 kb/s not sure what that means, open to clarification. Another change before that is [SAR 1:1 DAR 16:9] to [SAR 1:1 DAR 1:1] not sure what that is.

  


  The last major difference I notice is handler_name    : L-SMASH Video Handler to handler_name    : VideoHandler. Very curious about those properties as a learning bit.

  


  Not sure out of those changes which one is the most important for smooth playback like the original. I assume its bitrate.

  


• How to read and send a compressed video, frame by frame ?

  2 mars 2018, par fei shawnshanks

  How to read and send a compressed video, frame by frame ?

  I plan to design a video transport protocol, which should send and receive a video frame by frame, at the same time has distinguish between I frames and P frames.