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• Generate frame images from video and compile them back to the video in-memory

  24 septembre 2020, par gumkins

  I have to remove some repeating frames from the beginning of a video file.

  


  For that I'm generating frame images from the video

  


  ffmpeg -i input.mp4 -qscale:v 2 frame_%04d.jpg

  


  This command generates a set of files with index in name. Then I'm analyzing frames against some criteria programmaticaly, removing useless ones and compiling the rest back to the video file

  


  ffmpeg -r 60 -start_number 0 -i "frame_%04d.jpg" -c:v libx264 -vf "fps=25,format=yuv420p" out.mp4

  


  What I don't like in this schema that IO operations take part in the process. I would like to generate an array of buffers with binary data, then process it with Javascript and then pipe filtered ones back to ffmpeg without using the file system.

  


  Does ffmpeg have such possibility ?

  


• IE9+ not playing portrait video in HTML5 video tag

  12 avril 2017, par ptrn

  For some reason I can’t get IE9/10 to play video that is taller than wide, when using HTML5 video tags.

  Demo :
  http://s.l6.no/demo/video+html5/

  The demo shows one video scaled down from 1280x720, which plays perfectly fine in all tested browsers, and one video scaled down from 720x1280 which plays for all browsers but IE9/10.

  Tested and works for :

  • Chrome 26, Windows 7 64-bit
  • Chromium 24, Ubuntu 64-bit
  • Firefox 14, Windows 7 64-bit

  Tested and does not work for :

  • Internet Explorer 9, Windows 7 64-bit
  • Internet Explorer 10, Windows 7 64-bit

  I’m using FFmpeg to code the videos to MP4(x264) and WebM(VP8), with the current command dummed down to this :

  ffmpeg -i in.mp4 -vcodec libx264 -pix_fmt yuv420p -y -b:v 4000k out.mp4

  The lack of profile settings would be my first point, but since the other video is playing just fine, I can’t see why it should matter.

  Any ideas ?

  Edit : soft rotating the video isn’t really an option, as the user is to be able to download the video to play offline. I could transcode an extra version just for IE, but come on, there’s gotta be another way, no ?

• IE9+ not playing portait video in HTML5 video tag

  12 avril 2013, par ptrn

  For some reason I can't get IE9/10 to play video that is taller than wide, when using HTML5 video tags.

  Demo :
  http://s.l6.no/demo/video+html5/

  The demo shows one video scaled down from 1280x720, which plays perfectly fine in all tested browsers, and one video scaled down from 720x1280 which plays for all browsers but IE9/10.

  Tested and works for :

  • Chrome 26, Windows 7 64-bit
  • Chromium 24, Ubuntu 64-bit
  • Firefox 14, Windows 7 64-bit

  Tested and does not work for :

  • Internet Explorer 9, Windows 7 64-bit
  • Internet Explorer 10, Windows 7 64-bit

  I'm using FFmpeg to code the videos to MP4(x264) and WebM(VP8), with the current command dummed down to this :

  ffmpeg -i in.mp4 -vcodec libx264 -pix_fmt yuv420p -y -b:v 4000k out.mp4

  The lack of profile settings would be my first point, but since the other video is playing just fine, I can't see why it should matter.

  Any ideas ?

  Edit : soft rotating the video isn't really an option, as the user is to be able to download the video to play offline. I could transcode an extra version just for IE, but come on, there's gotta be another way, no ?