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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 (...)

  • Les vidéos

    21 avril 2011, par

    Comme les documents de type "audio", Mediaspip affiche dans la mesure du possible les vidéos grâce à la balise html5 .
    Un des inconvénients de cette balise est qu’elle n’est pas reconnue correctement par certains navigateurs (Internet Explorer pour ne pas le nommer) et que chaque navigateur ne gère en natif que certains formats de vidéos.
    Son avantage principal quant à lui est de bénéficier de la prise en charge native de vidéos dans les navigateur et donc de se passer de l’utilisation de Flash et (...)

  • Personnaliser en ajoutant son logo, sa bannière ou son image de fond

    5 septembre 2013, par

    Certains thèmes prennent en compte trois éléments de personnalisation : l’ajout d’un logo ; l’ajout d’une bannière l’ajout d’une image de fond ;

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  • FFmpeg decode H264 video too slowly

    17 décembre 2012, par user1158196

    I am currently working on a project on iPhone using FFMpeg. I can decode all the formats I need but when I want to play a h264 video, ffmpeg decodes frames too slowly.

    I tried to see where the problem is. I think that the options from the compilation of the library are good, decoding and displaying the frames are made ​​on different threads. In the end, it seems that it is the function avcodec_decode_video2 that takes too long (3 to 4 seconds to decode 30 frames).

  • Naive Sorenson Video 1 Encoder

    12 septembre 2010, par Multimedia Mike — General

    (Yes, the word is “naive” — or rather, “naïve” — not “native”. People always try to correct me when I use the word. Indeed, it should actually be written with 2 dots over the ‘i’ but who has a keyboard that can easily do that ?)

    At the most primitive level, programming a video encoder is about writing out a sequence of bits that the corresponding video decoder will understand. It’s sort of like creating a program — represented as a stream of opcodes — that will run on a given microprocessor or virtual machine. In fact, reading a video codec bitstream specification will reveal a lot of terminology along the lines of “transmitting information to the decoder” or “signaling the decoder to do xyz.”

    Creating a good encoder that will deliver decent quality at a reasonable bitrate is difficult. Creating a naive encoder that produces a technically compliant bitstream, not so much.



    When I wrote an FFmpeg encoder for Sorenson Video 1 (SVQ1), the first step was to just create a minimally compliant bitstream. The coarsest encoding mode that SVQ1 allows is to encode the average (mean) of each 16×16 block of samples. So I created an encoder that just encoded the mean of each block. Apple’s QuickTime Player was able to play the resulting video in all of its blocky glory. The result rather reminds me of the Super Nintendo’s mosaic effect.

    Level 5 blocks (mean-only 16×16 encoding) :



    Level 3 blocks (mean-only 8×8 encoding) :



    It’s one thing for your own decoder (in this case, FFmpeg’s own decoder) to be able to decode the data. The big test is whether the official decoder (in this case, Apple QuickTime Player) can decode the file.



    Now that’s a good feeling. After establishing that sort of baseline, it’s possible to adapt more and more features of the codec.

  • Kaleidoscope-like video, what happened ? [closed]

    11 avril 2012, par ghost

    I have used dolphin-player (http://code.google.com/p/dolphin-player/), it is based on ffplay with libsdl, all movies are in 3 pictures like these these.

    can anyone know what the problem is, and how to repair it in code ?
    (Source code here)

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