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Autres articles (97)

  • Websites made ​​with MediaSPIP

    2 mai 2011, par

    This page lists some websites based on MediaSPIP.

  • Creating farms of unique websites

    13 avril 2011, par

    MediaSPIP platforms can be installed as a farm, with a single "core" hosted on a dedicated server and used by multiple websites.
    This allows (among other things) : implementation costs to be shared between several different projects / individuals rapid deployment of multiple unique sites creation of groups of like-minded sites, making it possible to browse media in a more controlled and selective environment than the major "open" (...)

  • Organiser par catégorie

    17 mai 2013, par

    Dans MédiaSPIP, une rubrique a 2 noms : catégorie et rubrique.
    Les différents documents stockés dans MédiaSPIP peuvent être rangés dans différentes catégories. On peut créer une catégorie en cliquant sur "publier une catégorie" dans le menu publier en haut à droite ( après authentification ). Une catégorie peut être rangée dans une autre catégorie aussi ce qui fait qu’on peut construire une arborescence de catégories.
    Lors de la publication prochaine d’un document, la nouvelle catégorie créée sera proposée (...)

Sur d’autres sites (4092)

  • Making Sure The PNG Gets There

    14 juin 2013, par Multimedia Mike — General

    Rewind to 1999. I was developing an HTTP-based remote management interface for an embedded device. The device sat on an ethernet LAN and you could point a web browser at it. The pitch was to transmit an image of the device’s touch screen and the user could click on the picture to interact with the device. So we needed an image format. If you were computing at the time, you know that the web was insufferably limited back then. Our choice basically came down to GIF and JPEG. Being the office’s annoying free software zealot, I was championing a little known up and coming format named PNG.

    So the challenge was to create our own PNG encoder (incorporating a library like libpng wasn’t an option for this platform). I seem to remember being annoyed at having to implement an integrity check (CRC) for the PNG encoder. It’s part of the PNG spec, after all. It just seemed so redundant. At the time, I reasoned that there were 5 layers of integrity validation in play.

    I don’t know why, but I was reflecting on this episode recently and decided to revisit it. Here are all the encapsulation layers of a PNG file when flung over an ethernet network :


    PNG Network Encapsulation

    So there are up to 5 encapsulations for the data in this situation. At the innermost level is the image data which is compressed with the zlib DEFLATE method. At first, I thought that this also had a CRC or checksum. However, in researching this post, I couldn’t find any evidence of such an integrity check. Further, I don’t think we bothered to compress the PNG data in this project long ago. It was a small image, monochrome, and transferring via LAN, so the encoder could get away with signaling uncompressed data.

    The graphical data gets wrapped up in a PNG chunk and all PNG chunks have a CRC. To transmit via the network, it goes into a TCP frame, which also has a checksum. That goes into an IP packet. I previously believed that this represented another integrity check. While an IP frame does have a checksum, the checksum only covers the IP header and not the payload. So that doesn’t really count towards this goal.

    Finally, the data gets encapsulated into an ethernet frame which has — you guessed it — a CRC.

    I see that other link layer protocols like PPP and wireless ethernet (802.11) also feature frame CRCs. So I guess what I’m saying is that, if you transfer a PNG file over the network, you can be confident that the data will be free of any errors.

  • Stream video and commands on same connection or split connections ?

    10 mai 2013, par bizzehdee

    Background

    I am in the middle of writing a client/server app that i will install on every machine within my office (roughly 30 - 35 machines). I currently have the client connecting to the server and it has an ability to send mouse movement, mouse clicks, key strokes and execute certain commands. The next step is to stream back a video output of the screen, i am using the GDI method from Fastest method of screen capturing to capture the entire screen and will be using the x264 encoder to compress the frames and transmit them back to the client which will then decode and display the stream.

    Question

    is it best (by means of reducing lag, ensuring all commands are delivered as fast as possible and that streaming is as live as possible) that i transmit back along the same connection that i established for the commands, or, should i establish a separate connection on the same port, or on a different port to stream back the video ?

    P.S.

    i am aware that VNC, RD and other things such as TeamViewer already exist and already do this sort of thing, but none of these support all the requirements needed for what we need within this system.

  • Anomalie #2880 (Nouveau) : Gestion du portfolio

    22 octobre 2012, par Charles De Clercq

    Concerne : ajouter une image ou un document dans un article Lorsque j’ajoute un archive zippée contenant des illustrations, il y a la possibilité de cocher la case pour ajouter les fichiers (jpg en l’occurrence) dans le portfolio. Bug constaté : les fichiers sont d’office ajoutés au portfolio que la (...)

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