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• Where can I get 16-bit video sequences ? [on hold]

  9 mai 2017, par govind

  I understand that I can create 16-bit videos from 8-bit ones, but I want to work on actual 16-bit data (for a class project) and not just the bit-shifted pixel values. I just want to extract and work on the 16-bit Luma component from the video.

  https://media.xiph.org/ has 16-bit raw contents but the file size is 500GB. I would like to limit my downloads to 1-2 GB.
  The footnote at https://media.xiph.org/video/derf/ says "These were converted from 16-bit linear RGB to Y’CbCr", can I get the source from which these conversion took place.

  I could create my own content with some custom pattern but that’s not an option since I want to work on natural-looking imagery.

  I do understand that regular monitors can only display 8-bit. I also understand that it’s not a typical StackOverflow question, but I have already spent 2 hours online searching for it. Any links will be appreciated. Thanks in advance.

• Generating Gif from Mp4 directly - ffmpeg

  20 janvier 2016, par senty

  I am trying to generate a gif from an mp4 video file. I want to scale it and crop it while generating.

  I achieved that (cropping & scaling) from mp4 to mp4 with the below line , (so I can extract pngs with ffmpeg and use Imagick to make animated gif), but I believe there is a better way of achieving purely with ffmpeg.

  ffmpeg -i in.mp4 -filter:v "scale=300:ih*300/iw, crop=200:500:50:80" -c:a copy out.mp4

  My question is how to achieve the same this code is doing, but for directly generating gif from mp4.

  ---

  Then I started tweaking with mp4 to gif conversion, but when palette comes in, I couldn’t fully understand what’s going on.

  I found this answer and I made it work, however I couldn’t understand how to adapt scaling & cropping.

  $ ffmpeg -y -ss 30 -t 3 -i in.mp4 \
-vf fps=10,scale=320:-1:flags=lanczos,palettegen palette.png

  $ ffmpeg -ss 30 -t 3 -i in.flv -i palette.png -filter_complex \ "fps=10,scale=320:-1:flags=lanczos[x];[x][1:v]paletteuse" out.gif

  I partially understand what this bit does -y -ss 30 -t 3 -i in.mp4 (getting the first 30 seconds and generating a 3 second gif out of it). But for the next lines, I am completely lost what it is actually doing.

  It’d be amazing if someone can explain what each command does, or refer a link explaining this topic.

• How do I write a simple script which calls ffmpeg and records an audio stream ?

  29 janvier 2016, par user2192778

  I would like to write a script which calls ffmpeg and begins recording an internet radio stream.

  This command is simple :
  ffmpeg -i http://myaudiostream.com output.mp3

  I understand how to make a .bat file, I just don’t know specifically how to code these instructions.

  Can I have some help ?
  I haven’t written a script before, though I understand how it works. I don’t know any of the syntax.