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Autres articles (32)

  • 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.

  • ANNEXE : Les plugins utilisés spécifiquement pour la ferme

    5 mars 2010, par

    Le site central/maître de la ferme a besoin d’utiliser plusieurs plugins supplémentaires vis à vis des canaux pour son bon fonctionnement. le plugin Gestion de la mutualisation ; le plugin inscription3 pour gérer les inscriptions et les demandes de création d’instance de mutualisation dès l’inscription des utilisateurs ; le plugin verifier qui fournit une API de vérification des champs (utilisé par inscription3) ; le plugin champs extras v2 nécessité par inscription3 (...)

  • Contribute to translation

    13 avril 2011

    You can help us to improve the language used in the software interface to make MediaSPIP more accessible and user-friendly. You can also translate the interface into any language that allows it to spread to new linguistic communities.
    To do this, we use the translation interface of SPIP where the all the language modules of MediaSPIP are available. Just subscribe to the mailing list and request further informantion on translation.
    MediaSPIP is currently available in French and English (...)

Sur d’autres sites (5368)

  • Anomalie #4532 (Nouveau) : Parse error en php 8

    26 juillet 2020, par Franck D

    Hello

    Spip et plugin_dist à jour de ce jour !
    easyphp (windows 10 (1909))
    easyphp
    Apache 2.4.43 x64
    PHP 8.0.0 alpha3 x64
    MySQL 8.0.20 x64

    Avant même de pouvoir faire l’installation, quand je vais sur le site, j’ai :
    Parse error : syntax error, unexpected token "match", expecting "(" in C :\Program Files (x86)\EasyPHP-Devserver-17\eds-www\test13\ecrire\inc\filtres.php on line 3114

    Je pense que le changement vient de :
    https://wiki.php.net/rfc/match_expression_v2

  • Fastest way to extract raw Y' plane data from Y'Cb'Cr encoded video ?

    20 février 2024, par memeko

    I have a use-case where I'm extracting I-Frames from videos and turning them into perceptual hashes for later analysis.

    


    ⠀

    


    I'm currently using ffmpeg to do this with a command akin to :

    


    ffmpeg -skip_frame nokey -i 'in%~1.mkv' -vsync vfr -frame_pts true -vf 'keyframes/_Y/out%~1/%%06d.bmp'

    


    and then reading in the data from the resulting images.

    


    ⠀

    


    This is a bit wasteful as, to my understanding, ffmpeg does implicit YUV -> RGB colour-space conversion and I'm also needlessly saving intermediate data to disk.

    


    Most modern video codecs utilise chroma subsampling and have frames encoded in a Y'CbCr colour-space, where Y' is the luma component, and Cb Cr are the blue-difference, red-difference chroma components.

    


    Which in something like YUV420p used in h.264/h.265 video codecs is encoded as such :

    


    single YUV420p encoded frame

    


    Where each Y' value is 8 bits long and corresponds to a pixel.

    


    ⠀

    


    As I use gray-scale data for generating the perceptual hashes anyway, I was wondering if there is a way to simply grab just the raw Y' values from any given I-Frame into an array and skip all of the unnecessary conversions and extra steps ?

    


    (as the luma component is essentially equivalent to the grayscale data i need for generating hashes)

    


    I came across the -vf 'extractplanes=y' filter in ffmpeg that seems like it might do just that, but according to source :

    


    


    "...what is extracted by 'extractplanes' is not raw data of the (for example) Y plane. Each extracted is converted to grayscale. That is, the converted video data has YUV (or RGB) which is different from the input."

    


    


    which makes it seem like it's touching chroma components and doing some conversion anyway, in testing applying this filter didn't affect the processing time of the I-Frame extraction either.

    


    ⠀

    


    My script is currently written in Python, but I am in the process of migrating it to C++, so I would prefer any solutions pertaining to the latter.

    


    ffmpeg seems like the ideal candidate for this task, but I really am looking for whatever solution that would ingest the data fastest, preferably saving directly to RAM, as I'll be processing a large number of video files and discarding I-Frame luma pixel data once a hash has been generated.

    


    I would also like to associate each I-Frame with its corresponding frame number in the video.

    


  • Android Video color effect issue using FFMPEG [on hold]

    8 juin 2016, par umesh mishra

    I m facing one problem. when we use library for effect that i have mentioned below video is created only 1/3 of actual video size. please tell me what is issue. and also doesn’t work on marshmallow.
    https://github.com/krazykira/VidEffects/wiki/Permanent-video-effects

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