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Autres articles (58)

  • MediaSPIP : Modification des droits de création d’objets et de publication définitive

    11 novembre 2010, par

    Par défaut, MediaSPIP permet de créer 5 types d’objets.
    Toujours par défaut les droits de création et de publication définitive de ces objets sont réservés aux administrateurs, mais ils sont bien entendu configurables par les webmestres.
    Ces droits sont ainsi bloqués pour plusieurs raisons : parce que le fait d’autoriser à publier doit être la volonté du webmestre pas de l’ensemble de la plateforme et donc ne pas être un choix par défaut ; parce qu’avoir un compte peut servir à autre choses également, (...)

  • Les autorisations surchargées par les plugins

    27 avril 2010, par

    Mediaspip core
    autoriser_auteur_modifier() afin que les visiteurs soient capables de modifier leurs informations sur la page d’auteurs

  • Déploiements possibles

    31 janvier 2010, par

    Deux types de déploiements sont envisageable dépendant de deux aspects : La méthode d’installation envisagée (en standalone ou en ferme) ; Le nombre d’encodages journaliers et la fréquentation envisagés ;
    L’encodage de vidéos est un processus lourd consommant énormément de ressources système (CPU et RAM), il est nécessaire de prendre tout cela en considération. Ce système n’est donc possible que sur un ou plusieurs serveurs dédiés.
    Version mono serveur
    La version mono serveur consiste à n’utiliser qu’une (...)

Sur d’autres sites (6011)

  • lavc : drop encode() support for video.

    23 février 2012, par Anton Khirnov

    lavc : drop encode() support for video.

  • Theatrical quality ffmpeg/x264 encoding of a high-motion 1080p video

    2 décembre 2011, par Ian

    I've been struggling with encoding videos using FFMPEG and x264. The output stutters when played back in Quicktime, while in VLC it shows a lot of compression artifacts at the same places Quicktime stutters. So it seems like Quicktime is stuttering because it's trying to suppress the corruption/artifacts.

    The videos have a lot of random motion in them, including frames where 75% of the pixels will change at a random interval (the video is software generated so it's truly pseudo-random). The compression seems to be choking in these places where it's likely detecting a "scene cut" incorrectly. It also seems to choke at regular intervals where I guess it's doing a keyframe.

    I've based my encoding preset off of the x264-hq preset that comes with FFMPEG. I've tried turning off scene cut detection, and playing with the keyint/g and keyint_min options. Setting g to 1 makes it work, but blows out the filesize. I've tried the lossless presets, but they won't playback at all in Quicktime. Oddly, I haven't had any problems when working with a lower-resolution test video (1440x810).

    Here's the preset I have right now, which works, but yields a file that's approximately 60% larger than the (non-working) hq preset yields. Is there any way to improve upon this ? The filesize doesn't matter much, I just want something that will playback anywhere and be very high quality.

    coder=1
flags=+loop
cmp=+chroma
partitions=+parti8x8+parti4x4+partp8x8+partp4x4+partb8x8
me_method=umh
subq=8
me_range=16
g=1
keyint_min=1
sc_threshold=0
i_qfactor=0.71
b_strategy=1crf=20
qcomp=0.6
qmin=20
qmax=51
qdiff=4
bf=16
refs=4
trellis=1
flags2=+dct8x8+wpred+bpyramid+mixed_refs
wpredp=2

    Here's the command :

    ffmpeg \
  -r 60 -i "frame-%06d.tiff" \
  -vcodec libx264 -vpre my_preset \
  -threads 0 \
  -r 60 -an -f out.mp4

  • Theatrical quality ffmpeg/x264 encoding of a high-motion 1080p video

    2 décembre 2011, par Ian

    I've been struggling with encoding videos using FFMPEG and x264. The output stutters when played back in Quicktime, while in VLC it shows a lot of compression artifacts at the same places Quicktime stutters. So it seems like Quicktime is stuttering because it's trying to suppress the corruption/artifacts.

    The videos have a lot of random motion in them, including frames where 75% of the pixels will change at a random interval (the video is software generated so it's truly pseudo-random). The compression seems to be choking in these places where it's likely detecting a "scene cut" incorrectly. It also seems to choke at regular intervals where I guess it's doing a keyframe.

    I've based my encoding preset off of the x264-hq preset that comes with FFMPEG. I've tried turning off scene cut detection, and playing with the keyint/g and keyint_min options. Setting g to 1 makes it work, but blows out the filesize. I've tried the lossless presets, but they won't playback at all in Quicktime. Oddly, I haven't had any problems when working with a lower-resolution test video (1440x810).

    Here's the preset I have right now, which works, but yields a file that's approximately 60% larger than the (non-working) hq preset yields. Is there any way to improve upon this ? The filesize doesn't matter much, I just want something that will playback anywhere and be very high quality.

    coder=1
flags=+loop
cmp=+chroma
partitions=+parti8x8+parti4x4+partp8x8+partp4x4+partb8x8
me_method=umh
subq=8
me_range=16
g=1
keyint_min=1
sc_threshold=0
i_qfactor=0.71
b_strategy=1crf=20
qcomp=0.6
qmin=20
qmax=51
qdiff=4
bf=16
refs=4
trellis=1
flags2=+dct8x8+wpred+bpyramid+mixed_refs
wpredp=2

    Here's the command :

    ffmpeg \
  -r 60 -i "frame-%06d.tiff" \
  -vcodec libx264 -vpre my_preset \
  -threads 0 \
  -r 60 -an -f out.mp4

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