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Médias (1)

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Autres articles (26)

  • Submit enhancements and plugins

    13 avril 2011

    If you have developed a new extension to add one or more useful features to MediaSPIP, let us know and its integration into the core MedisSPIP functionality will be considered.
    You can use the development discussion list to request for help with creating a plugin. As MediaSPIP is based on SPIP - or you can use the SPIP discussion list SPIP-Zone.

  • Emballe médias : à quoi cela sert ?

    4 février 2011, par

    Ce plugin vise à gérer des sites de mise en ligne de documents de tous types.
    Il crée des "médias", à savoir : un "média" est un article au sens SPIP créé automatiquement lors du téléversement d’un document qu’il soit audio, vidéo, image ou textuel ; un seul document ne peut être lié à un article dit "média" ;

  • Other interesting software

    13 avril 2011, par

    We don’t claim to be the only ones doing what we do ... and especially not to assert claims to be the best either ... What we do, we just try to do it well and getting better ...
    The following list represents softwares that tend to be more or less as MediaSPIP or that MediaSPIP tries more or less to do the same, whatever ...
    We don’t know them, we didn’t try them, but you can take a peek.
    Videopress
    Website : http://videopress.com/
    License : GNU/GPL v2
    Source code : (...)

Sur d’autres sites (5086)

  • FFMPEG - Merging Videos with Transparency

    4 juillet 2013, par user1829136

    I am trying to merge two videos together, both have transparency, using the command

    ffmpeg.exe -i person2.mov -vf "[in] scale=iw/2:ih/2,fade=out:300:30:alpha=1, pad=2*iw:ih [left] ; movie=person2.mov, scale=iw/2:ih/2,fade=out:300:30:alpha=1 [right] ; [left][right] overlay=main_w/3:0,fade=out:300:30:alpha=1 [out]" -b:v 768k Output_people.mov

    By doing that I get the following output :

    http://i263.photobucket.com/albums/ii122/Fernando461/Untitled.png

    As you can see, it was possible to get the two videos to be on top of each other. But then, when I try to merge this video (Output_people.mov) with another video, it doesn't have the same transparency. Is it possible to keep transparency in the outcome ?

    Edit 1 :

    This is the output I get : https://www.dropbox.com/s/gpid1pptfio31gd/ffmpeg-20130701-193206.log

    And by "it doesn't have the same transparecy" I meant that the background is black instead of being transparent, so if I put one video on top of each other, the one in the back is covered by a black part of the one in the front.

    Edit 2 :
    Adding -vcodec qtrle to the code worked. Thanks mark4o !

  • Révision 20656 : L’histoire amusante de imagepalettetotruecolor()

    18 juin 2013, par da@weeno.net

    La fonction imagepalettetotruecolor() a été introduite par ARNO* avec
    la révision r8317 en janvier 2007 (et améliorée par la suite).

    Six ans et demi après, une fonction du même nom est introduite dans
    PHP 5.5. Par chance, elle a exactement le même comportement que la
    nôtre. La seule différence c’est qu’elle renvoie un booleen alors que
    nous on ne renvoie rien, donc dans ce sens ça ne pose pas de problème.

    On ajoute donc simplement une condition sur function_exists(). De cette
    manière c’est notre fonction qui sera toujours utilisée sur les versions
    de PHP actuelles, puis la fonction native sera utilisée sur les sites
    tournant avec PHP 5.5 et suivantes. (Ferme #3016.)

    Il suffira ensuite de supprimer notre fonction dans quelques années quand
    la version minimum de PHP pour faire tourner SPIP sera 5.5 ou supérieure.

  • Encode h264 to match existing stream

    6 juin 2013, par Diego Sánchez

    In short : I have to encode a tiny amount of video frames and stitch them in front of a much bigger h.264 stream without reencoding said stream.

    The details : I receive a multi GB transport stream containing a h.264 es and an audio es. Currently the h.264 streams are always generated using x264, and I can assume this will be the case in the future. Now I have to prepend some video frames to this stream, but am not allowed to decode/encode the whole stream ; which leaves me with the only option to find out the exact parameters I need to pass x264_encoder_open so both streams match.

    Currently what I'm doing is :

    1. Demux the original ts and extract h.264 NAL packets.
    2. When I find the first "user data unregistered" SEI packet, I parse it and find a bunch of x264 parameters.
    3. Use libavcodec to start decoding the video. That gives me the dimensions of the picture and the h264 profile and level in the AVCodecContext structure.
    4. Match all of that as best as I can in the x264_param_t structure.

    I can do some encoding with that, and the encoded video plays correctly up to the join point. When VLC is reaching the stitch point it starts throwing out the following sequence of messages and soon after stops playing :

    [h264 @ 0x7fe36cd75be0] decode_slice_header error
    
[h264 @ 0x7fe36cd75be0] no frame!
    
[h264 @ 0x7fe36ccc9080] Width/height changing with threads is not implemented. Update your Libav version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.

    which clearly shows that my encoded frames do not match the original ones. I've been browsing the source code and can't seem to find a way of doing this. What I have currently (besides not working), involves a lot of guesswork, so even if I could make it work with the handful of example files I have, I would be scared to deploy this in production servers.

    So the obvious question is : Is there a safe, formal way of doing this ?

    Thanks in Advance

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