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  • MediaSPIP 0.1 Beta version

    25 avril 2011, par

    MediaSPIP 0.1 beta is the first version of MediaSPIP proclaimed as "usable".
    The zip file provided here only contains the sources of MediaSPIP in its standalone version.
    To get a working installation, you must manually install all-software dependencies on the server.
    If you want to use this archive for an installation in "farm mode", you will also need to proceed to other manual (...)

  • 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 (...)

  • HTML5 audio and video support

    13 avril 2011, par

    MediaSPIP uses HTML5 video and audio tags to play multimedia files, taking advantage of the latest W3C innovations supported by modern browsers.
    The MediaSPIP player used has been created specifically for MediaSPIP and can be easily adapted to fit in with a specific theme.
    For older browsers the Flowplayer flash fallback is used.
    MediaSPIP allows for media playback on major mobile platforms with the above (...)

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  • Revision 38ff3e328f : Rate control adjustment. Small adjustment to the active Q range calculations. T

    23 avril 2014, par Paul Wilkins

    Changed Paths :
     Modify /vp9/encoder/vp9_ratectrl.c



    Rate control adjustment.

    Small adjustment to the active Q range calculations.
    These changes should slightly extend the available Q range
    for KF/GF/ARF and narrow it for other frames.

    The results for this change in isolation are broadly positive
    for SSIM and average PSNR and slightly up but mixed for opsnr.

    derf +0.293% opsnr, +1.286% SSIM
    std-hd + 0.528% opsnr, + 1.746% SSIM
    yt +0.056% opsnr, +0.457% SSIM
    yt-hd -0.147% opsnr, + 0.226% SSIM

    Change-Id : If065280342027ecc5d44b49fc1d440dfef041002

  • avfilter/vf_drawtext : add expression variables to control font ascent/descent

    26 mai 2023, par yethie
    avfilter/vf_drawtext : add expression variables to control font ascent/descent

    The following new variables can be used in the x and y expressions : font_a, font_d, top_a, bottom_d.
    • [DH] doc/filters.texi
    • [DH] libavfilter/vf_drawtext.c

  • Is it possible to use the signalstats YAVG filter in FFMPEG to control the gamma correction in a video ? [migrated]

    27 décembre 2023, par tuqueque

    I don't know if this is even possible, but something tells me it is… You see, I want to dynamically control the gamma correction in FFMPEG/FFPLAY depending on how bright/dark the frame being reproduced in a video/movie is…

    


    For context, there's a filter in FFMPEG/FFPLAY/FFPROBE called signalstats that reports various useful sets of info about the video being processed/reproduced/analized. There's a YAVG parameter in the signalstats filter that returns the average luma level of the frame (https://ffmpeg.org/ffmpeg-filters.html#signalstats-1) . This is what I want to use to determine/calculate the gamma value to use in the eq filter gamma (https://ffmpeg.org/ffmpeg-filters.html#eq)… For example, in the end, I would like to use a formula like "1-(YAVG/50)+1"…

    


    With the signalstats YAVG filter/parameter I've managed to do these unrelated exercises :

    


    Analyze (with FFPROBE) a video and write a log file with the YAVG value for each frame :

    


    ffprobe -f lavfi movie=VIDEO_INPUT,signalstats -show_entries frame_tags=lavfi.signalstats.YAVG -of csv="p=0" > YAVG.log


    


    I have been able to also play a video (with FFPLAY) and show in the upper-left corner the YAVG values for each frame being reproduced :

    


    First, we need to create a text file in the home folder called in this case "signalstat_drawtext.txt" with the following content :

    


        %{metadata:lavfi.signalstats.YAVG}


    


    Then, we run this command :

    


        ffplay VIDEO_INPUT -vf signalstats,drawtext=fontfile=FreeSerif.ttf:fontcolor=lime:textfile=signalstat_drawtext.txt


    


    However, I haven't been able to find/guess how to use the YAVG output to control (in realtime) the gamma value in the eq filter… I think it's possible, I just don't know how to write the command.

    


    Using FFPLAY, I would imagine something like this :

    


    ffplay VIDEO_INPUT -vf signalstats,eq=gamma="1-(metadata:lavfi.signalstats.YAVG/50)+1":eval=frame


    


    But of course, this doesn't work and I'm sure I'm just writing nonsense.

    


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