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  • Contribute to a better visual interface

    13 avril 2011

    MediaSPIP is based on a system of themes and templates. Templates define the placement of information on the page, and can be adapted to a wide range of uses. Themes define the overall graphic appearance of the site.
    Anyone can submit a new graphic theme or template and make it available to the MediaSPIP community.

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  • How do I keep black areas black with ffmpeg ?

    20 avril 2017, par P. Dee

    When encoding GoPro videos with ffmpeg using

    ffmpeg -i Goprovideo.mp4 Goprovideo-out.mp4

    I noticed that the videos do not only get much smaller, but also in some cases do black areas lose intensity. So what was black is now grey. Not to an extreme, but slightly noticable.

    How do I keep black areas black with ffmpeg ?

  • How do I keep black areas black with ffmpeg ?

    11 janvier 2018, par Aurelius Schnitzler

    When encoding GoPro videos with ffmpeg using

    ffmpeg -i Goprovideo.mp4 -pix_fmt yuv420p -vf scale=1920:-1,crop=1920:1080:0:362 Goprovideo-out.mp4

    I noticed that the videos do not only get much smaller, but also in some cases do black areas lose intensity. So what was black is now grey. Not to an extreme, but slightly noticable.

    How do I keep black areas black with ffmpeg ?

  • Layer black & white video over background so black pixels are transparent in FFMPEG

    4 février 2018, par Dan Weaver

    I’m trying to blend a video containing black and white animated text over a static background image. I can successfully blend them but no matter what blend mode I use I can’t get the effect I want.

    I’m looking for an effect similar to Photoshop’s ’Add’ blend mode where the color values of each pixel are added together. This results in no change where the top layer (video) has black pixels, effectively making the black background appear transparent.

    This is what I’m trying to achieve :
    enter image description here

    ffmpeg -i text.mp4 -loop 1 -i image.jpg \
    -filter_complex 'blend=all_mode=addition' -t 1 result.mp4

    I tried all the modes of the blend filter but none of them produce this effect. I thought Addition would be the one to work but the resulting video has a pink tint. Maybe there is some mismatch between color channels ?

    How can I get the result I’m looking for ?

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