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Mis à jour : Septembre 2011
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Autres articles (41)
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Websites made with MediaSPIP
2 mai 2011, parThis page lists some websites based on MediaSPIP.
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Creating farms of unique websites
13 avril 2011, parMediaSPIP 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" (...) -
Other interesting software
13 avril 2011, parWe 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 (5712)
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Setting/Installing up OpenCV 2.4.6.1+ on Ubuntu 12.04.02
30 mai 2016, par DamilolaI had previously used OpenCV 2.4.5 with some certain configs and packages on Ubuntu 12.04.1 but had issues upgrading to OpenCV 2.4.6.1 on Ubuntu 12.04.2
I would like to share some ideas (a compilation of noteworthy information gathered from several sources including SO, ubuntu.org, asklinux.org and many other ; and of course by trying several procedures)
Below is what eventually got me through.
NOTE : ensure you uninstall any previous installation of OpenCV, FFMpeg and other dependencies previously installed.
STEP 1 (install ffmpeg and dependencies)
# goto http://sourceforge.net/projects/opencvlibrary/files/opencv-unix/
# download the latest stable opencv such as 2.4.6.1 (http://sourceforge.net/projects/opencvlibrary/files/opencv-unix/2.4.5/opencv-2.4.5.1.tar.gz/download) to current directory (such as home or ~/Document)
# cd /opt
# tar -xvf /OpenCV-2.4.6.1.tar.gz
# cd OpenCV-2.4.6.1
# create a foler under current dir (following previous step, this should be ), called prepare
# cd prepare
# Copy the following script to gedit and save as install.sh to current dir, this should be /prepare
# Check corresponding url used in the script for latest versions of the package and replace as required
# Open terminal and navigate to location used above
# sudo chmod +x install.sh
# ./installecho "Removing any pre-installed ffmpeg, x264, and other dependencies (not all the previously installed dependecies)"
sudo apt-get remove ffmpeg x264 libx264-dev libvpx-dev librtmp0 librtmp-dev libopencv-dev
sudo apt-get update
arch=$(uname -m)
if [ "$arch" == "i686" -o "$arch" == "i386" -o "$arch" == "i486" -o "$arch" == "i586" ]; then
flag=0
else
flag=1
fi
echo "Installing Dependenices"
sudo apt-get install autoconf automake make g++ curl cmake bzip2 python unzip \
build-essential checkinstall git git-core libass-dev libgpac-dev \
libsdl1.2-dev libtheora-dev libtool libva-dev libvdpau-dev libvorbis-dev libx11-dev \
libxext-dev libxfixes-dev pkg-config texi2html zlib1g-dev
echo "downloading yasm (assembler used by x264 and FFmpeg)"
# use git or tarball (not both)
wget http://www.tortall.net/projects/yasm/releases/yasm-1.2.0.tar.gz
tar xzvf yasm-1.2.0.tar.gz
cd yasm-1.2.0
echo "installing yasm"
./configure
make
sudo make install
cd ..
echo 'READ NOTE BELOW which was extracted from http://wiki.serviio.org/doku.php?id=build_ffmpeg_linux'
echo 'New version of x264 contains by default support of OpenCL. If not installed or without sense (example Ubuntu 12.04LTS on VMWare) add to configure additional option --disable-opencl. Without this option ffmpeg could not be configured (ERROR: libx264 not found).'
echo "downloading x264 (H.264 video encoder)"
# use git or tarball (not both)
# git clone http://repo.or.cz/r/x264.git or
git clone git://git.videolan.org/x264.git
cd x264
# wget ftp://ftp.videolan.org/pub/videolan/x264/snapshots/x264-snapshot-20130801-2245-stable.tar.bz2
# tar -xvjf x264-snapshot-20130801-2245-stable.tar.bz2
# cd x264-snapshot-20130801-2245-stable/
echo "Installing x264"
if [ $flag -eq 0 ]; then
./configure --enable-static --disable-opencl
else
./configure --enable-shared --enable-pic --disable-opencl
fi
make
sudo make install
cd ..
echo "downloading fdk-aac (AAC audio encoder)"
# use git or tarball (not both)
git clone --depth 1 git://github.com/mstorsjo/fdk-aac.git
cd fdk-aac
echo "installing fdk-aac"
autoreconf -fiv
./configure --disable-shared
make
sudo make install
cd ..
echo "installing libmp3lame-dev (MP3 audio encoder.)"
sudo apt-get install libmp3lame-dev
echo "downloading libopus (Opus audio decoder and encoder.)"
wget http://downloads.xiph.org/releases/opus/opus-1.0.3.tar.gz
tar xzvf opus-1.0.3.tar.gz
cd opus-1.0.3
echo "installing libopus"
./configure --disable-shared
make
sudo make install
cd ..
echo "downloading libvpx VP8/VP9 video encoder and decoder)"
# use git or tarball (not both)
git clone --depth 1 http://git.chromium.org/webm/libvpx.git
cd libvpx
# wget http://webm.googlecode.com/files/libvpx-v1.1.0.tar.bz2 (this seems not to be update, but can still be used if the fedoraproject link below is not available))
# wget http://pkgs.fedoraproject.org/repo/pkgs/libvpx/libvpx-v1.2.0.tar.bz2/400d7c940c5f9d394893d42ae5f463e6/libvpx-v1.2.0.tar.bz2
# tar xvjf libvpx-v1.2.0.tar.bz2
# cd libvpx-v1.2.0
echo "installing libvpx"
./configure --disable-examples
make
sudo make install
cd ..
sudo ldconfig
echo "downloading ffmpeg"
# git clone http://repo.or.cz/r/ffmpeg.git
git clone git://source.ffmpeg.org/ffmpeg.git
cd ffmpeg/
# wget http://ffmpeg.org/releases/ffmpeg-2.0.tar.bz2
# tar -xvjf ffmpeg-2.0.tar.bz2
# cd ffmpeg-2.0/
echo "installing ffmpeg"
if [ $flag -eq 0 ]; then
./configure --enable-gpl --enable-libass --enable-libfdk-aac --enable-libopus --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-nonfree --enable-postproc --enable-version3 --enable-x11grab --enable-libvpx
else
./configure --enable-gpl --enable-libass --enable-libfdk-aac --enable-libopus --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-nonfree --enable-postproc --enable-version3 --enable-x11grab --enable-libvpx --enable-shared
fi
make
sudo make install
hash -r
cd .. # move up one level to prepare folder
cd .. # move up one level to opencv folder
echo "Checking to see if you're using your new ffmpeg"
ffmpeg 2>&1 | head -n1
sudo ldconfigSTEP 2 (Install OpenCV and necessary packages)
echo "Installing Dependenices"
sudo apt-get install libtiff4-dev libjpeg-dev libjasper-dev
echo "installing Video I/O libraries, support for Firewire video cameras and video streaming libraries"
sudo apt-get install libav-tools libavcodec-dev libavformat-dev libswscale-dev libdc1394-22-dev libxine-dev libgstreamer0.10-dev libgstreamer-plugins-base0.10-dev libv4l-dev v4l-utils v4l-conf
echo "installing the Python development environment and the Python Numerical library"
sudo apt-get install python-dev python-numpy
echo "installing the parallel code processing library (the Intel tbb library)"
sudo apt-get install libtbb-dev
echo "installing the Qt dev library"
sudo apt-get install libqt4-dev libgtk2.0-dev
echo "installing other dependencies (if need be it would upgrade current version of the packages)"
sudo apt-get install patch subversion ruby librtmp0 librtmp-dev libfaac-dev libmp3lame-dev libopencore-amrnb-dev libopencore-amrwb-dev libvpx-dev libxvidcore-dev
echo installing optional packages"
sudo apt-get install libdc1394-utils libdc1394-22-dev libdc1394-22 libjpeg-dev libpng-dev libtiff-dev libjasper-devSTEP 3 (run ldconfig)
# Open a new terminal window
# Open /etc/ld.so.conf and check,
# if the paths "/usr/lib" and "/usr/local/lib" including the quote exist in the file. If not, add them manually or by
sudo echo "/usr/local/lib" >> /etc/ld.so.conf
sudo echo "/usr/lib" >> /etc/ld.so.conf
# execute the following
sudo ldconfigSTEP 4a (Build & Install for OS Usage)
# still ensure you haven't close the new terminal window open in STEP 3
# execute the following
mkdir os_build
cd os_build
cmake -DCMAKE_BUILD_TYPE=RELEASE -DCMAKE_INSTALL_PREFIX=/usr/local -DBUILD_NEW_PYTHON_SUPPORT=ON -DINSTALL_PYTHON_EXAMPLES=ON -DWITH_TBB=ON -DWITH_V4L=ON -DINSTALL_C_EXAMPLES=ON -DBUILD_EXAMPLES=ON -DWITH_QT=ON -DWITH_OPENGL=ON -DWITH_OPENCL=ON -DWITH_EIGEN=ON -DWITH_OPENEXR=ON ..
make
sudo make install
# add the following to user environment variable ~/.bashrc
export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:/usr/local/lib
export PKG_CONFIG_PATH=${PKG_CONFIG_PATH}:/usr/local/lib/pkgconfig
# execute the following
sudo ldconfig
# start to use and enjoy opencv, it should have been install into any of these locations
# /usr/local/include/opencv2, /usr/local/include/opencv, /usr/include/opencv, /usr/include/opencv2, /usr/local/share/opencv
# /usr/local/share/OpenCV, /usr/share/opencv, /usr/share/OpenCV, /usr/local/bin/opencv*, /usr/local/lib/libopencv*STEP 4b (Build for Java Usage) : OPTIONAL
# still ensure you haven't close the new terminal window open in STEP 4
# execute the following
cd ..
mkdir java_build
cd java_build
cmake -DCMAKE_BUILD_TYPE=RELEASE -DBUILD_SHARED_LIBS=OFF -DINSTALL_PYTHON_EXAMPLES=ON -DWITH_TBB=ON -DWITH_V4L=ON -DINSTALL_C_EXAMPLES=ON -DBUILD_EXAMPLES=ON -DWITH_QT=ON -DWITH_OPENGL=ON -DWITH_OPENCL=ON -DWITH_EIGEN=ON -DWITH_OPENEXR=ON ..
make
# You can check the "java_build/bin" directory to locate the jar and libopencv_java.so file for your development
# As stated in the docs, the Java bindings dynamic library is all-sufficient, i.e. doesn’t depend on other OpenCV libs, but includes all the OpenCV code insideSTEP 5 (install v4l : Note : installing v4l-utils after opencv installation works for Ubuntu 12.04.2 & OpenCV 2.4.6.1)
# still ensure you haven't close the new terminal window open in STEP 3
# goto http://www.linuxtv.org/downloads/v4l-utils
# download the latest v4l such as v4l-utils-0.9.5.tar.bz2
# copy the downloaded file to the current terminal dir (following previous step, this should be /prepare)
# execute the following
tar -xvjf v4l-utils-0.9.5.tar.bz2
cd v4l-utils-0.9.5/
./configure
make
sudo make install
cd ..
cd .. # (to go to )
sudo ldconfigWorth Noting
# To check the path where opencv & other lib files are stored, do:
pkg-config --cflags opencv
(output will come as)
-I/usr/include/opencv
pkg-config --libs opencv
(output will come as)
-lopencv_core -lopencv_imgproc -lopencv_highgui -lopencv_ --ml -lopencv_video -lopencv_features2d -lopencv_calib3d -lopencv_objdetect -lopencv_contrib -lopencv_legacy -lopencv_flann
# The above paths are needed to compile your opencv programs, as given in the next illustration.
# write a simple C program to test, by saving below program in a file named DisplayImage.c
#include
#include <opencv2></opencv2>highgui/highgui.hpp>
int main(int argc, char *argv[]) {
IplImage* img=0; /* pointer to an image */
printf("Hello\n");
if(argv[1] != 0)
img = cvLoadImage(argv[1], 0); // 1 for color
else
printf("Enter filename\n");
if(img != 0) {
cvNamedWindow("Display", CV_WINDOW_AUTOSIZE); // create a window
cvShowImage("Display", img); // show image in window
cvWaitKey(0); // wait until user hits a key
cvDestroyWindow("Display");
}
else
printf("File not found\n");
return 0;
}
# write a simple C++ program to test, by saving below program in a file named DisplayImage.cpp
#include
#include <opencv2></opencv2>opencv.hpp>
#include <opencv2></opencv2>highgui/highgui.hpp>
using namespace cv;
int main( int argc, char** argv )
{
Mat image;
image = imread( argv[1], 1 );
if( argc != 2 || !image.data )
{
printf( "No image data \n" );
return -1;
}
namedWindow( "Display Image", CV_WINDOW_AUTOSIZE );
imshow( "Display Image", image );
waitKey(0);
return 0;
}
# To compile & run :
g++ `pkg-config --cflags --libs opencv` && ./a.out img
or
g++ -I/usr/include/opencv -I/usr/local/include -lopencv_core -lopencv_highgui -lopencv_ml -lopencv_imgproc -lopencv_video -lopencv_features2d -lopencv_calib3d -lopencv_objdetect -lopencv_contrib -lopencv_legacy -lopencv_flann -lopencv_nonfree && ./a.out img
where “img” is the name of any image with extension within the same folder .
You should be able to see “Hello” and the image in a different window.
If this runs, Congrats! now you can run any C/C++ program with opencv lib.
# Now lets simplify the above big command by making a shortcut for it:
go to your local home directory(cd /home/) and open the .bashrc file using gedit(the file will be hidden). Append the following to the file:
alias gcv="g++ -I/usr/include/opencv -I/usr/local/include -lopencv_core -lopencv_highgui -lopencv_ml -lopencv_imgproc -lopencv_video -lopencv_features2d -lopencv_calib3d -lopencv_objdetect -lopencv_contrib -lopencv_legacy -lopencv_flann -lopencv_nonfree"
and save. Close the terminal and open it again.(as this process requires relogin of the terminal)
# Now, go to directory containing a sample program & do
gcv && ./a.out
or
gcv
./a.out input_img.jpgAs you can see the commands now become similar to $cc filename.c, $./a.out which are used normally for compiling and executing C/C++ programs.
Some ways to check whether all lib files are installed-
apt-cache search opencv
returns :
libcv-dev - Translation package for libcv-dev
libcv2.3 - computer vision library - libcv* translation package
libcvaux-dev - Translation package for libcvaux-dev
libcvaux2.3 - computer vision library - libcvaux translation package
libhighgui-dev - Translation package for libhighgui-dev
libhighgui2.3 - computer vision library - libhighgui translation package
libopencv-calib3d-dev - development files for libopencv-calib3d
libopencv-calib3d2.3 - computer vision Camera Calibration library
libopencv-contrib-dev - development files for libopencv-contrib
libopencv-contrib2.3 - computer vision contrib library
libopencv-core-dev - development files for libopencv-core
libopencv-core2.3 - computer vision core library
libopencv-dev - development files for opencv
libopencv-features2d-dev - development files for libopencv-features2d
libopencv-features2d2.3 - computer vision Feature Detection and Descriptor Extraction library
libopencv-flann-dev - development files for libopencv-flann
libopencv-flann2.3 - computer vision Clustering and Search in Multi-Dimensional spaces library
libopencv-gpu-dev - development files for libopencv-gpu
libopencv-gpu2.3 - computer vision GPU Processing library
libopencv-highgui-dev - development files for libopencv-highgui
libopencv-highgui2.3 - computer vision High-level GUI and Media I/O library
libopencv-imgproc-dev - development files for libopencv-imgproc
libopencv-imgproc2.3 - computer vision Image Processing library
libopencv-legacy-dev - development files for libopencv-legacy
libopencv-legacy2.3 - computer vision legacy library
libopencv-ml-dev - development files for libopencv-ml
libopencv-ml2.3 - computer vision Machine Learning library
libopencv-objdetect-dev - development files for libopencv-objdetect
libopencv-objdetect2.3 - computer vision Object Detection library
libopencv-video-dev - development files for libopencv-video
libopencv-video2.3 - computer vision Video analysis library
opencv-doc - OpenCV documentation and examples
python-opencv - Python bindings for the computer vision library -
Does the H.264 standard allow separate luma and chroma qp control in Baseline Profile ?
28 août 2013, par Bhaskar DeyAlthough the wikipedia article states that separate luma and chroma QP is only supported in High profiles, I didn't find any supporting reference. At least, Rec. ITU-T H.264 (04/2013) section A.2.1 does not mention any such limitation for the Baseline Profile.
Any comment in this regard would be of great help.
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More Cinepak Madness
20 octobre 2011, par Multimedia Mike — Codec TechnologyFellow digital archaeologist Clone2727 found a possible fifth variant of the Cinepak video codec. He asked me if I cared to investigate the sample. I assured him I wouldn’t be able to die a happy multimedia nerd unless I have cataloged all possible Cinepak variants known to exist in the wild. I’m sure there are chemistry nerds out there who are ecstatic when another element is added to the periodic table. Well, that’s me, except with weird multimedia formats.
Background
Cinepak is a video codec that saw widespread use in the early days of digital multimedia. To date, we have cataloged 4 variants of Cinepak in the wild. This distinction is useful when trying to write and maintain an all-in-one decoder. The variants are :- The standard type : Most Cinepak data falls into this category. It decodes to a modified/simplified YUV 4:2:0 planar colorspace and is often seen in AVI and QuickTime/MOV files.
- 8-bit greyscale : Essentially the same as the standard type but with only a Y plane. This has only been identified in AVI files and is distinguished by the file header’s video bits/pixel field being set to 8 instead of 24.
- 8-bit paletted : Again, this is identified by the video header specifying 8 bits/pixel for a Cinepak stream. There is essentially only a Y plane in the data, however, each 8-bit value is a palette index. The palette is transported along with the video header. To date, only one known sample of this format has even been spotted in the wild, and it’s classified as NSFW. It is also a QuickTime/MOV file.
- Sega/FILM CPK data : Sega Saturn games often used CPK files which stored a variant of Cinepak that, while very close the standard Cinepak, couldn’t be decoded with standard decoder components.
So, a flexible Cinepak decoder has to identify if the file’s video header specified 8 bits/pixel. How does it distinguish between greyscale and paletted ? If a file is paletted, a custom palette should have been included with the video header. Thus, if video bits/pixel is 8 and a palette is present, use paletted ; else, use greyscale. Beyond that, the Cinepak decoder has a heuristic to determine how to handle the standard type of data, which might deviate slightly if it comes from a Sega CPK file.
The Fifth Variant ?
Now, regarding this fifth variant– the reason this issue came up is because of that aforementioned heuristic. Basically, a Cinepak chunk is supposed to store the length of the entire chunk in its header. The data from a Sega CPK file plays fast and loose with this chunk size and the discrepancy makes it easy to determine if the data requires special handling. However, a handful of files discovered on a Macintosh game called “The Journeyman Project : Pegasus Prime” have chunk lengths which are sometimes in disagreement with the lengths reported in the containing QuickTime file’s stsz atom. This trips the heuristic and tries to apply the CPK rules against Cinepak data which, aside from the weird chunk length, is perfectly compliant.Here are the first few chunk sizes, as reported by the file header (stsz atom) and the chunk :
size from stsz = 7880 (0x1EC8) ; from header = 3940 (0xF64) size from stsz = 3940 (0xF64) ; from header = 3940 (0xF64) size from stsz = 15792 (0x3DB0) ; from header = 3948 (0xF6C) size from stsz = 11844 (0x2E44) ; from header = 3948 (0xF6C)
Hey, there’s a pattern here. If they don’t match, then the stsz size is an even multiple of the chunk size (2x, 3x, or 4x in my observation). I suppose I could revise the heuristic to state that if the stsz size is 2x, 3x, 4x, or equal to the chunk header, qualify it as compliant Cinepak data.
Of course it feels impure, but software engineering is rarely about programmatic purity. A decade of special cases in the FFmpeg / Libav codebases are a testament to that.
What’s A Variant ?
Suddenly, I find myself contemplating what truly constitutes a variant. Maybe this was just a broken encoder program making these files ? And for that, I assign it the designation of distinct variation, like some sort of special, unique showflake ?Then again, I documented Magic Carpet FLIC as being a distinct variant of the broader FLIC format (which has an enormous number of variants as well).