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Autres articles (25)

  • La file d’attente de SPIPmotion

    28 novembre 2010, par

    Une file d’attente stockée dans la base de donnée
    Lors de son installation, SPIPmotion crée une nouvelle table dans la base de donnée intitulée spip_spipmotion_attentes.
    Cette nouvelle table est constituée des champs suivants : id_spipmotion_attente, l’identifiant numérique unique de la tâche à traiter ; id_document, l’identifiant numérique du document original à encoder ; id_objet l’identifiant unique de l’objet auquel le document encodé devra être attaché automatiquement ; objet, le type d’objet auquel (...)

  • Submit bugs and patches

    13 avril 2011

    Unfortunately a software is never perfect.
    If you think you have found a bug, report it using our ticket system. Please to help us to fix it by providing the following information : the browser you are using, including the exact version as precise an explanation as possible of the problem if possible, the steps taken resulting in the problem a link to the site / page in question
    If you think you have solved the bug, fill in a ticket and attach to it a corrective patch.
    You may also (...)

  • Contribute to documentation

    13 avril 2011

    Documentation is vital to the development of improved technical capabilities.
    MediaSPIP welcomes documentation by users as well as developers - including : critique of existing features and functions articles contributed by developers, administrators, content producers and editors screenshots to illustrate the above translations of existing documentation into other languages
    To contribute, register to the project users’ mailing (...)

Sur d’autres sites (5194)

  • avformat/cdxl : improve frame rate guessing for standard cdxl

    5 février 2021, par Paul B Mahol
    avformat/cdxl : improve frame rate guessing for standard cdxl

    Use audio size and sample rate to get real frame rate.
    
Also make seeking more robust.
    • [DH] libavformat/cdxl.c
    • [DH] tests/ref/fate/cdxl-bitline-ham6
    • [DH] tests/ref/fate/cdxl-demux
    • [DH] tests/ref/fate/cdxl-ham6
    • [DH] tests/ref/fate/cdxl-ham8
    • [DH] tests/ref/fate/cdxl-pal8
    • [DH] tests/ref/fate/cdxl-pal8-small

  • ffmpeg convert white color to alpha

    11 janvier 2021, par tony

    Hello i took a picture with my camera :a drawing of a square frame on a white paper ; i'm trying to convert the white to transparent and keep the black color frame.

    


    So i started making 1 palette with only 2 colors to make the colors uniform and 1 palette to add the transparency

    


    ffmpeg -f lavfi -i "color=color=white:100x100" -f lavfi -i "color=color=black:100x100" -filter_complex "[0][1]hstack" -frames:v 1 blackwhite.png`
ffmpeg -i blackwhite.png -filter_complex "[0]split[a][b];[a]palettegen[pal1];[b]palettegen=reserve_transparent=on:transparency_color=white[pal2]" -map [pal1] palette1.png -map [pal2] palette2.png


    


    then i mapped the image png of the frame to convert the white to transparent and overlayed the result to a red background

    


    ffmpeg -i image.png -i palette1.png -i palette2.png -i background.png -filter_complex "[0:v][1:v]paletteuse=dither=bayer[a],[a]split[a1][a2];[a1][2:v]paletteuse=alpha_threshold=128[c];[3:v][c]overlay[d]" -map [a2] -c:v png out.png -map [d] -c:v png out1.png


    


    the png mapped to the first palette (as a test) comes as it should be, pure black and white,the second comes with no transparency at all and covers the background
what am i doing wrong ?

    


  • ffmpeg convert white background to transparent

    7 janvier 2021, par tony

    Hello i took a picture of a framed sheet with my camera and i'm trying to convert the white background to transparent without using the colorkey filter. It is meant to be for a video using a number of frames overlayed to a static background but i started with only one png to see if it works.

    


    So i started making 1 palette with only 2 colors with -f lavfi (black and white) and 1 palette to add the transparency

    


    ffmpeg -i blackwhite.png -filter_complex "[0:v]split[a][b];[a]palettegen=max_colors=4[out1];\
                            [b]palettegen=max_colors=4:reserve_transparent=on:\
                            transparency_color=#FFFFFF[out2]" \
    -c:v png \
    -map [out1] paletteNormal.png \
    -map [out2] paletteTransparent.png 


    


    then i mapped the png that i want to convert to the first palette to make uniform colors and then to the second to add the transparency and i overlayed the result to a background image that should be red

    


    ffmpeg -i image.png -i paletteNormal.png -i paletteTransparent.png -i background.png \
     -filter_complex "[0:v][1:v]paletteuse=dither=bayer[a],\
     [a]split[a1][a2]; \
     [a1][2:v]paletteuse=alpha_threshold=128[c];[3:v][c]overlay[d]" \
    -map [a2] -c:v png out.png \
    -map [d] -c:v png out1.png


    


    the png mapped to the first palette comes as it should be, pure black and white
the second comes with no transparency at all and covers the background
i tried different combinations like to make the second palette of 255colors..... nothing

    


    what am i doing wrong ? i know it can be done
i went to this site and i made an alpha channel in 5 seconds with a lot of grief and rage.linkOfPain

    


    p.s for a video from png frames what codec should i use ?

    


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