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The Slip - Artworks
26 septembre 2011, par
Mis à jour : Septembre 2011
Langue : English
Type : Texte
Autres articles (101)
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Websites made with MediaSPIP
2 mai 2011, parThis page lists some websites based on MediaSPIP.
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Publier sur MédiaSpip
13 juin 2013Puis-je poster des contenus à partir d’une tablette Ipad ?
Oui, si votre Médiaspip installé est à la version 0.2 ou supérieure. Contacter au besoin l’administrateur de votre MédiaSpip pour le savoir -
Configuration spécifique d’Apache
4 février 2011, parModules spécifiques
Pour la configuration d’Apache, il est conseillé d’activer certains modules non spécifiques à MediaSPIP, mais permettant d’améliorer les performances : mod_deflate et mod_headers pour compresser automatiquement via Apache les pages. Cf ce tutoriel ; mode_expires pour gérer correctement l’expiration des hits. Cf ce tutoriel ;
Il est également conseillé d’ajouter la prise en charge par apache du mime-type pour les fichiers WebM comme indiqué dans ce tutoriel.
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Sur d’autres sites (9473)
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lavfi/psnr : rename ’s’ parameter to match documentation
9 juillet 2013, par Paul B Mahol -
x86 : h264_idct : Update comments to match 8/10-bit depth optimization split
6 octobre 2013, par Diego Biurrun -
Encode h264 to match existing stream
6 juin 2013, par Diego SánchezIn 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 :
- Demux the original ts and extract h.264 NAL packets.
- When I find the first "user data unregistered" SEI packet, I parse it and find a bunch of x264 parameters.
- 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.
- 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