Introduction to EVP
(Effective Image and Video Processing toolbox for scilab)


EVP is created as a sub-project of Scilab Aurora.
EVP intends to do image processing and video processing tasks.
EVP is meant to a effective toolbox for Scilab.
It uses OpenCV for image I/O, uses FFMPEG for video I/O. We implement a lot of filters and image transform by ourselves.


#1,How to use libvideo:

in = video_open( filename );
[frame_rate, frame_num] = video_info( in );
img = video_read_frame( in );
// do something with the image ...
// or: video_close_all();

out = video_open_w( filename, bit_rate, width, height, frame_rate );
// prepare img with size width*height ...
video_write_frame( img, out);
video_close_w( out);
// or :video_close_all_w();

Here is a example for converting video format:

in = video_open( 'ww.mpg');
out = video_open_w ('out.swf', 400000, 352, 288, 25);

[frame, num ] = video_info(in)

for i=1:num
im = video_read_frame(in);
video_write_frame( im, out );

video_close_w( out );

#2, How to use libimg:

img = imread( filename );
imwrite( img, filename );

#3, How to use libimdraw & libtimer

imdraw(img, 0, dst_x, dst_y, dst_w, dst_h );

t1 = time();
// do something

sleep( millonseconds );

Here is a example: a simple video player
(Following is Window Version. Look demos/player.sce for full code.)

in = video_open( 'ww.mpg');
[frame, num ] = video_info(in)
for i=1:num
im = video_read_frame(in);
imdraw(im, 0, 0,0,352, 288);

#4, Resize, rotate

im = imread("lena.png");

#5, add filter to image

Here is a example to add mosaic filter to a image:

// add filter: mosaic
img = Mosaic(im,8);
// show the effect


EVP refers some source code fo SIVP ( to SIVP team.

1, Support almost all video format under both Linux and Windows.
We use FFmpeg. FFmpeg is a complete solution to record, convert and stream audio and video. It includes libavcodec, the leading audio/video codec library. FFmpeg is a charming library. Now we can open almost all type of video file under both Linux and windows. For more information, go to

2, We provide a more efficient way to read and write video file. VFW is a out of date , and can not fulfill our requetment.

3, a more efficient way to show image:
We implement imdraw in a special way. The tradition methon is converting image to ppm format, passing it to TCL/TK to show it in a window. This methon is system independent, but it is not a efficient way, can not fulfill Scilab Aurora's requestment. So I have to use Win32 API (under Windows), and gdk-pixbuf (under Linux). It is proved that our effort makes sense.

4. We implement quite a lot of filters. Most of them is implemented by scilab script, which reduces the loss in image type converting. Resize and rotate is implemented for efficiency also;

5. It is much easier to use, we includes all the dependent libraries in our binary installer.

1, For some reasons, we uses OpenCV to read and write image. However it seems that Image Magic is a better library to processing images. While OpenCV is uesful for compute vision.

2, imshow is not well done, we will finish it in the future.


Thanks to Yang Kaigui who makes a GUI installer for both Windows & Linux Version.
We have test it under Windows, Ubuntu, Debian and FC5.
You can also install evp by hand:
(Windows) unpack the file to $SCILAB/contrib
(Linux) unpak the file to SCILAB/contrib, and mv libs/* $SCILAB/libs

If you can load libraries propery under FC5, run fllowing script:
chcon -t texrel_shlib_t $SCILAB/libs/*

If you can not install EVP propery in your system, it is better to compile the source by yourself.
EVP uses OpenCV for image I/O, and uses FFMPEG for video I/O.
The imdraw function is system dependency.On windows, it uses Win32 API.On Linux, it uses xlib and gdk-pixbuf-2.0.
So you have all the libraries installed before compile.
See note.txt under each src/ directories for more detail

After complie, copy they to $SCILAB/contribe/
Run scilab, and you will get EVP in toolbox>EVP.
Good Luck.


Scilab >= 4.0 (
Xlib & gdk-pixbuf-2.0 (Linux)
(We include these libraries in binary version. But if you want to install from source, install those libraries first.)
OpenCV >= 0.9.6 (
FFMPEG >= 0.4.9 (


Look man for detail.


Jonbo <>
- Wrote video I/O, image I/O, imdraw, libtimer

Yang Kaigui <>
- filters, and EVP Linux port and GUI installer

Zhou Xiyue <>
- resize and rotate

Scilab Aurora Team

Homepage :

1,Some error with FC5:
If you can't load libraries propery under FC5, run fllowing script:
chcon -t texrel_shlib_t $SCILAB/libs/*