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Autres articles (53)

  • Websites made ​​with MediaSPIP

    2 mai 2011, par

    This page lists some websites based on MediaSPIP.

  • Creating farms of unique websites

    13 avril 2011, par

    MediaSPIP platforms can be installed as a farm, with a single "core" hosted on a dedicated server and used by multiple websites.
    This allows (among other things) : implementation costs to be shared between several different projects / individuals rapid deployment of multiple unique sites creation of groups of like-minded sites, making it possible to browse media in a more controlled and selective environment than the major "open" (...)

  • Other interesting software

    13 avril 2011, par

    We don’t claim to be the only ones doing what we do ... and especially not to assert claims to be the best either ... What we do, we just try to do it well and getting better ...
    The following list represents softwares that tend to be more or less as MediaSPIP or that MediaSPIP tries more or less to do the same, whatever ...
    We don’t know them, we didn’t try them, but you can take a peek.
    Videopress
    Website : http://videopress.com/
    License : GNU/GPL v2
    Source code : (...)

Sur d’autres sites (7795)

  • Is ffmpeg's chromakey filter broken when matching black/white ?

    7 janvier 2023, par Taylor Brown

    I have a file, colors.png. It looks like this :

    



    Let's say I want to make the red square transparent. When I run ffmpeg -i colors.png -filter_complex "[0]chromakey=0xff0000:similarity=0.1:blend=0.0[out]" -map "[out]" colors-rm-red.png (notice I use similarity=0.1 to make this work), I get exactly that :

    



    How about making the blue square transparent ? ffmpeg -i colors.png -filter_complex "[0]chromakey=0x0000ff:similarity=0.1:blend=0.0[out]" -map "[out]" colors-rm-blue.png works too !

    



    But what about replacing black ? ffmpeg -i colors.png -filter_complex "[0]chromakey=0x000000:similarity=0.1:blend=0.0[out]" -map "[out]" colors-rm-black.png gives me this :

    



    And likewise, replacing white with ffmpeg -i colors.png -filter_complex "[0]chromakey=0xffffff:similarity=0.1:blend=0.0[out]" -map "[out]" colors-rm-white.png gives me the same result :

    



    Why is this ? Even if I use similarity=0.01, which according to the docs "matches only the exact key color", this still doesn't work when I'm trying to make black/white transparent. Is ffmpeg broken, or am I misunderstanding the chromakey filter ?

    


  • Change gray pixel to black pixels in video

    12 janvier 2023, par yabru

    I want to change every gray pixel in my video with the (r,g,b) 158,158,158 to black 0,0,0

    


    I've tried the solution of THIS post, but backwards. I just do not understand the syntax.

    


    ffmpeg -y -I my_video.mp4 -c copy -c:v libx264 -preset ultrafast -vf "yadif,format=rgb24, lutrgb=r='if(eq(val,158),0,val)':g='if(eq(val,158),0,val)':b='if(eq(val,158),0,val)'" my_video_fixed.mp4

    


    ^ doesn't change anything

    


    could anyone help me modify my command (with an explanation of the solution) :)

    


    version : ffmpeg version 5.1.2

    


  • Overlaying one video on another one, and making black pixels transparent

    25 janvier 2023, par Michael A

    I'm trying to use FFMPEG to create a video with one video overlayed on top another.

    



    I have 2 MP4s. I need to make all BLACK pixels in the overlay video transparent so that I can see the main video underneath it.

    



    I found two ways to overlay one video on another :

    



    First, the following positions the overlay in the center, and therefore, hides that portion of the main video beneath it :

    



        ffmpeg -i 1.mp4 -vf "movie=2.mp4 [a]; [in][a] overlay=352:0 [b]" combined.mp4 -y


    



    And, this one, places the overlay video on the left, but it's opacity is set to 50% so at least other one beneath it is visible :

    



    ffmpeg -i 1.mp4 -i 2.mp4 -filter_complex "[0:v]setpts=PTS-STARTPTS[top]; [1:v]setpts=PTS-STARTPTS, format=yuva420p,colorchannelmixer=aa=0.5[bottom]; [top][bottom]overlay=shortest=0" -acodec libvo_aacenc -vcodec libx264 out.mp4 -y


    



    My goal is simply to make all black pixels in the overlay (2.mp4) completely transparent. How can this be done.

    


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