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La conservation du net art au musée. Les stratégies à l’œuvre
26 mai 2011
Mis à jour : Juillet 2013
Langue : français
Type : Texte
Autres articles (55)
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XMP PHP
13 mai 2011, parDixit Wikipedia, XMP signifie :
Extensible Metadata Platform ou XMP est un format de métadonnées basé sur XML utilisé dans les applications PDF, de photographie et de graphisme. Il a été lancé par Adobe Systems en avril 2001 en étant intégré à la version 5.0 d’Adobe Acrobat.
Étant basé sur XML, il gère un ensemble de tags dynamiques pour l’utilisation dans le cadre du Web sémantique.
XMP permet d’enregistrer sous forme d’un document XML des informations relatives à un fichier : titre, auteur, historique (...) -
Use, discuss, criticize
13 avril 2011, parTalk to people directly involved in MediaSPIP’s development, or to people around you who could use MediaSPIP to share, enhance or develop their creative projects.
The bigger the community, the more MediaSPIP’s potential will be explored and the faster the software will evolve.
A discussion list is available for all exchanges between users. -
Installation en mode ferme
4 février 2011, parLe mode ferme permet d’héberger plusieurs sites de type MediaSPIP en n’installant qu’une seule fois son noyau fonctionnel.
C’est la méthode que nous utilisons sur cette même plateforme.
L’utilisation en mode ferme nécessite de connaïtre un peu le mécanisme de SPIP contrairement à la version standalone qui ne nécessite pas réellement de connaissances spécifique puisque l’espace privé habituel de SPIP n’est plus utilisé.
Dans un premier temps, vous devez avoir installé les mêmes fichiers que l’installation (...)
Sur d’autres sites (4682)
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Revision 17292 : Update Skeleton/OggIndex support to Skeleton 4.0. ffmpeg2theora now ...
16 juin 2010, par j — LogUpdate Skeleton/OggIndex ? support to Skeleton 4.0.
ffmpeg2theora now writes Skeleton 4.0 with index by default.
Patch by Chris Pearce -
can't read mp4 in opencv3.2 (ubuntu, python3)
28 mars 2017, par lhkI’ve ran into a problem with my opencv installation, it is unable to open an mp4 video. My system is ubuntu 16.04, 64bit, opencv3.2 used from python 3.5.
VideoCapture.read
returnsFalse
andNone
.There are other questions with this problem, but they target different platforms or different opencv versions.
Apparently, I’m missing the proper codec.
So I ranmake uninstall
from my build directory, purgedopencv*
with apt and built from source again. This time making sure thatffmpeg
was installed before the compilation.Here are my steps :
- clone opencv and opencv_contrib
cd opencv/
mkdir build
cd build
cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D INSTALL_PYTHON_EXAMPLES=ON -D INSTALL_C_EXAMPLES=OFF -D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules -D BUILD_EXAMPLES=ON ..
make -j 8
sudo make install
I checked the output of cmake, ffmpeg is there :
Video I/O:
-- DC1394 1.x: NO
-- DC1394 2.x: NO
-- FFMPEG: YES
-- avcodec: YES (ver 56.60.100)
-- avformat: YES (ver 56.40.101)
-- avutil: YES (ver 54.31.100)
-- swscale: YES (ver 3.1.101)
-- avresample: NO
-- GStreamer: NO
-- OpenNI: NO
-- OpenNI PrimeSensor Modules: NO
-- OpenNI2: NO
-- PvAPI: NO
-- GigEVisionSDK: NO
-- Aravis SDK: NO
-- UniCap: NO
-- UniCap ucil: NO
-- V4L/V4L2: NO/YES
-- XIMEA: NO
-- Xine: NO
-- gPhoto2: NOBut the problem persists. How can I fix this ?
UPDATE
I had to manually remove some .so files from /usr/local.
Then I installed all avi related codecs I could find.
https://wiki.ubuntuusers.de/Codecs/
plus libavcodec-extra and ffmpegThen I recompiled and now it works.
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ffmpeg for archival and convertibility
27 juillet 2021, par SatyaI've got a couple hundred gigs of *.dv files. I'd like to convert them to H.264 or something else or even leave them alone. The purpose is archival, with an eye to maximum convertibility especially to DVD. The content is family videos.


Would this be fine ?


ffmpeg -i input.dv \
 -c:v libx264 -preset slower \
 -crf 17 \
 -pix_fmt yuv420p \
 output.mp4



I went with the
slower
preset because encoding time isn't an issue and I'd like a smaller file size. crf 17 is for least-lossy while being widely playable. I read somewhere that yuv420p is needed for some Quicktime players.

Should I throw in
-c:a aac
for AAC audio ? The audio is voice only, no need for music-hall quality.

I looked at https://trac.ffmpeg.org/wiki/Encode/H.264 for previous research and that's where I got those settings, but it is silent on the audio settings.


Edited : My priorities, in order of importance, are :


- 

- Compatibility
- Losslessness (doesn't have to be 100% lossless, hence crf of 17 and not 0)
- File size








Most of the input files say this :


[lavf] stream 0: video (dvvideo), -vid 0
[lavf] stream 1: audio (pcm_s16le), -aid 0
VIDEO: [dvsd] 720x480 0bpp 29.970 fps 25000.0 kbps (3051.8 kbyte/s)
Selected video codec: [ffdv] vfm: ffmpeg (FFmpeg DV)
AUDIO: 32000 Hz, 2 ch, s16le, 1024.0 kbit/100.00% (ratio: 128000->128000)
Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)



Output from ffmpeg :


Stream #0:1: Audio: pcm_s16le, 32000 Hz, stereo, s16, 1024 kb/s