Recherche avancée

Médias (91)

Autres articles (76)

  • Keeping control of your media in your hands

    13 avril 2011, par

    The vocabulary used on this site and around MediaSPIP in general, aims to avoid reference to Web 2.0 and the companies that profit from media-sharing.
    While using MediaSPIP, you are invited to avoid using words like "Brand", "Cloud" and "Market".
    MediaSPIP is designed to facilitate the sharing of creative media online, while allowing authors to retain complete control of their work.
    MediaSPIP aims to be accessible to as many people as possible and development is based on expanding the (...)

  • Les tâches Cron régulières de la ferme

    1er décembre 2010, par

    La gestion de la ferme passe par l’exécution à intervalle régulier de plusieurs tâches répétitives dites Cron.
    Le super Cron (gestion_mutu_super_cron)
    Cette tâche, planifiée chaque minute, a pour simple effet d’appeler le Cron de l’ensemble des instances de la mutualisation régulièrement. Couplée avec un Cron système sur le site central de la mutualisation, cela permet de simplement générer des visites régulières sur les différents sites et éviter que les tâches des sites peu visités soient trop (...)

  • Ecrire une actualité

    21 juin 2013, par

    Présentez les changements dans votre MédiaSPIP ou les actualités de vos projets sur votre MédiaSPIP grâce à la rubrique actualités.
    Dans le thème par défaut spipeo de MédiaSPIP, les actualités sont affichées en bas de la page principale sous les éditoriaux.
    Vous pouvez personnaliser le formulaire de création d’une actualité.
    Formulaire de création d’une actualité Dans le cas d’un document de type actualité, les champs proposés par défaut sont : Date de publication ( personnaliser la date de publication ) (...)

Sur d’autres sites (4968)

  • FFmpeg, low quality merge using overlay filter [closed]

    24 mars, par He2A

    I am currently building a script, part of its functionality is to generate a cover art. I want to limit the scripts dependency to ffmpeg only so please don't suggest to use any other software to do the same.

    


    For this, I am using ffmpeg to generate separate components for the coverart, code is given below :

    


    # Draws transparent circle in correct background
ffmpeg -y -f lavfi -i "color=c=0x20292FFF:s=4000x4000,format=rgba" -filter_complex "geq=r='32':g='41':b='47':a='255*(1-between(hypot(X-2000,Y-2000),0,1150))'" -frames:v 1 -update 1 background.png

# Draws a circle gradient
ffmpeg -y -f lavfi -i "gradients=s=4000x4000:c0=0x33517e:c1=0x645098:c2=0xa53f97:c3=0xdf1177:c4=0xff033e:c5=0x2f4858:n=5:y0=750:x0=750:y1=3250:x1=3250:t=linear,format=rgba" -filter_complex "geq=g='g(X,Y)':a='255*between(hypot(X-2000,Y-2000),0,1200)'" -frames:v 1 -update 1 gradcir.png

# Draws the inner symbol
ffmpeg -y -f lavfi -i "color=c=0x20292FFF:s=4000x4000,format=rgba" -vf "geq=a='255*max(lte((X-2000+(530/3)+25)+sqrt(3)*abs(Y-2000),530)*gte(X-2000+(530/3)+25,0),between(hypot(X-2000,Y-2000),570,630))':r='255*max(lte((X-2000+(530/3)+25)+sqrt(3)*abs(Y-2000),530)*gte(X-2000+(530/3)+25,0),between(hypot(X-2000,Y-2000),570,630))':g='255*max(lte((X-2000+(530/3)+25)+sqrt(3)*abs(Y-2000),530)*gte(X-2000+(530/3)+25,0),between(hypot(X-2000,Y-2000),570,630))':b='255*max(lte((X-2000+(530/3)+25)+sqrt(3)*abs(Y-2000),530)*gte(X-2000+(530/3)+25,0),between(hypot(X-2000,Y-2000),570,630))'" -frames:v 1 shape.png


    


    Now to merge all three pngs, I am using the following command :

    


    ffmpeg -y -i background.png -i gradcir.png -i shape.png -filter_complex "[0][1]overlay[tmp];[tmp][2]overlay" cover.png


    


    All the code works but the problem is that the output is severely low quality with banding and improper merges in the borders of each image.

    


    I believe png is lossless so there shouldn't be any issue with artifacts but still I experimented with different levels of png compression but to no avail. I even tried enforcing rgba format for all three images prior to merging but to no avail.

    


    For now I alleviated the problem by generating all images in 4000x4000 resolution, applying a deband filter and then resizing it to 1000x1000.

    


    ffmpeg -y -i background.png -i gradcir.png -i shape.png -filter_complex "[0][1]overlay[tmp1];[tmp1][2]overlay[tmp2];[tmp2]format=rgb24,scale=2000:2000:flags=spline,deband,scale=1000:1000:flags=lanczos" -frames:v 1 -update 1 cover.png


    


    But the above method is expensive, which is problematic for low performance systems. Can anyone find out what seems to be the issue or suggest some better way to merge it ?

    


  • FFmpeg error - "at least one output file must be specified" [closed]

    7 février 2013, par Derrick Tucker

    I'm having a little trouble, and I feel like the solution is probably starting me in the face.

    ffmpeg -ss 0 -i rawvid.flv -t 33 -vf scale=640x480 -b:21504 test.mpg

    When run, this yells at me that "At least one output file must be specified". I've been knocking me head on the wall for hours now, what am I missing ?

    PS : FFmpeg works fine, and if I remove all of the flags in the statement above, it works.

  • Where can I find modern tutorials for libav, ffmpeg, etc ? [on hold]

    19 décembre 2016, par Marty

    I want to make a quick program in C that will open a video, save each frame as a ppm, and dump motion vectors. All the tutorials I can find are from almost ten years ago and call deprecated or non-existent functions.

    Are there any good online resources, websites, videos, or textbooks that cover a modern approach to doing these types of things ?

Navigation