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Autres articles (47)

  • (Dés)Activation de fonctionnalités (plugins)

    18 février 2011, par

    Pour gérer l’ajout et la suppression de fonctionnalités supplémentaires (ou plugins), MediaSPIP utilise à partir de la version 0.2 SVP.
    SVP permet l’activation facile de plugins depuis l’espace de configuration de MediaSPIP.
    Pour y accéder, il suffit de se rendre dans l’espace de configuration puis de se rendre sur la page "Gestion des plugins".
    MediaSPIP est fourni par défaut avec l’ensemble des plugins dits "compatibles", ils ont été testés et intégrés afin de fonctionner parfaitement avec chaque (...)

  • Le profil des utilisateurs

    12 avril 2011, par

    Chaque utilisateur dispose d’une page de profil lui permettant de modifier ses informations personnelle. Dans le menu de haut de page par défaut, un élément de menu est automatiquement créé à l’initialisation de MediaSPIP, visible uniquement si le visiteur est identifié sur le site.
    L’utilisateur a accès à la modification de profil depuis sa page auteur, un lien dans la navigation "Modifier votre profil" est (...)

  • Automated installation script of MediaSPIP

    25 avril 2011, par

    To overcome the difficulties mainly due to the installation of server side software dependencies, an "all-in-one" installation script written in bash was created to facilitate this step on a server with a compatible Linux distribution.
    You must have access to your server via SSH and a root account to use it, which will install the dependencies. Contact your provider if you do not have that.
    The documentation of the use of this installation script is available here.
    The code of this (...)

Sur d’autres sites (5540)

  • RGB to YUV422 conversion with ffmpeg, incorrect colors

    22 janvier 2016, par user3578571

    I’m trying to convert an 8bit RGB uncompressed to an mpeg2 mxf file (xdcam 422 HD 1080 50i) which is YUV422. With info from the FFMpeg docs and various websites i made the following command :

    ./ffmpeg -y -i test_lines.mov  -pix_fmt yuv422p -vcodec mpeg2video -non_linear_quant 1 -flags +ildct+ilme -top 1 -dc 10 -intra_vlc 1 -qmax 2 -vtag xd5c -rc_max_vbv_use 1 -rc_min_vbv_use 1 -g 12 -b:v 50000k -minrate 50000k -maxrate 50000k -bufsize 8000k -acodec pcm_s24le -ar 48000 -bf 2 -ac 2 lines_HD.mxf

    This gave me a result with the colors much brighter than the original.

    So i tried adding the options -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 1 but this didn’t seem to do anything.

    After adding colormatrix=bt601:bt709 i got a way better image, but slightly darker than the original and it also feels weird specifying this option cause the source is also in the REC709 colorspace, so why specify it differently ?

    Next i regenerated my source image to an YUV codec (prores) and rerun FFMpeg on it with the colors coming out just fine. Therefore i think it has to be an RGB -> YUV problem.
    Does somebody have an idea how to this properly ? I can provide screenshots of the different results on a videoscope as soon as i’m back at the office, if anybody is interested.

    Last, i know there are various topics touching this subject but either they go way over my head FFmpeg wise or bring me to the stage where i already am.

  • Static ffmpeg library windows

    29 novembre 2022, par peter

    Im trying to use the ffmpeg libraries (libavutil, libswscale, ...) in a bigger project by statically linking them, im not interested in the binaries. Now the issue comes down to getting them statically built. I tried searching for pre-compiled builds but without success.

    


    Following the docs, i compiled them on wsl2 for win64 with

    


    ./configure --arch=x86_64 --target-os=mingw32 --cross-prefix=i686-w64-mingw32- --disable-shared --enable-static
make


    


    After that i copied the libavformat/libavformat.a as libavformat.lib (which should be fine since they are cross-compiled ar archives ?) into my project and linked them with CMake.

    


    When compiling smth like

    


    AVFormatContext* pFormatContext = avformat_alloc_context();


    


    i get a linker error saying

    


    lld-link : error : undefined symbol: avformat_alloc_context


    


    When looking at the libs with dumpbin -linkermember libavformat.lib, i can see

    


    >dumpbin -linkermember libavformat.lib
...
  135CD92 _avformat_alloc_context
...


    


    notice the underscore.

    


    Can i not link the cross-compiled *.a files directly into a windows executable ?

    


    Honestly at this point any ideas are welcome.

    


    Thanks

    


  • avcodec/xbmdec : get_nibble() minor speed increase, and binary reduction

    1er février 2021, par Jose Da Silva
    avcodec/xbmdec : get_nibble() minor speed increase, and binary reduction

    Replace av_isxdigit(*ptr) and convert(*ptr) with get_nibble(*ptr) which
    
returns a valid nibble==0x00..0x0f or false==255 for all other values.
    
This way we only need to work with *ptr once instead of twice.
    

    Removing inline av_isxdigit(x) functions also shrinks executable size.
    

    Signed-off-by : Joe Da Silva <digital@joescat.com>
    • [DH] libavcodec/xbmdec.c

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