Enabling OpenCV (and python) FFMPEG Video in Ubuntu 9.04

by admin

Introduction

The OpenCV is one of the greates and widely using image library for all developers and students. However, I am not a OpenCC and Graphics guy, but I choose OpenCV for Video Recording purpose. Since I mostly live and develop within Ubuntu, I tried writing and testing a little python-opencv program, but not working. It is mainly because the problem of new ffmpeg in ubuntu 9.04 Jaunty – see, https://bugs.launchpad.net/ubuntu/+source/opencv/+bug/311188. While searching the Internet, I found an article to use video streaming of opencv(here, http://gijs.pythonic.nl/blog/2009/may/3/getting-video-io-working-opencv-and-ubuntu-jaunty-/). I tired because I don’t want to reinvent the wheel of course, but not working like many comments on ‘cvCreateVideoWriter‘ function.

Prepare to compile

Prepare to build

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sudo apt-get build-dep python-opencv
sudo apt-get install libswscale-dev swig

Prepare to configure

Link avcodec.h, avformat.h, avio.h, avutil.h and swscale.h in the /usr/include/ffmpeg (you have to create) like below.

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ls /usr/include/ffmpeg
avcodec.h -> ../libavcodec/avcodec.h
avformat.h -> ../libavformat/avformat.h
avio.h -> ../libavformat/avio.h
avutil.h -> ../libavutil/avutil.h
swscale.h -> ../libswscale/swscale.h

Checkout OpenCV

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svn co https://opencvlibrary.svn.sourceforge.net/svnroot/opencvlibrary/tags/latest_tested_snapshot

Configure & Make

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cd latest_tested_snapshot/opencv
./configure --enable-shared --enable-swscale --enable-gpl --with-swig
  • –enabled-shared : as shared library
  • –enable-swscale : alternative work around for ffmpeg
  • –enable-gpl : opensource library
  • –with-swig : regenerate swig interfaces
...
    Video I/O ---------------------
    Use QuickTime / Mac OS X: no
    Use xine:                 no
    Use gstreamer:            no
    Use ffmpeg:               yes
    Use dc1394 & raw1394:     no
    Use v4l:                  yes
    Use v4l2:                 yes
    Use unicap:               no

Wrappers for other languages ========================

    SWIG                      /usr/bin/swig -c++
    Python                    yes
    Octave                    no
...

The highlighted configuration items are important, ffmpeg / swig / python. If everything is find, do make. The interface files in the checkout directory are not properly generated, so you have to generate yourself.

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make
sudo make install

Test and Correct OpenCV Python files

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$ cd /usr/local/lib/python2.6/site-packages/opencv
$ python
Python 2.6.2 (release26-maint, Apr 19 2009, 01:56:41)
[GCC 4.3.3] on linux2
Type "help", "copyright", "credits" or "license" for ...
>>> import cv.py
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "cv.py", line 8473, in <module>
    CV_SEQ_CONTOUR=CV_SEQ_POLYGON
NameError: name 'CV_SEQ_POLYGON' is not defined

Open cv.py and Edit

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CV_SEQ_CONTOUR=CV_SEQ_POLYGON

(line 8473) to

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CV_SEQ_CONTOUR=CV_SEQ_POLYGON_TREE

Everything is done.

Example of OpenCV and PyGame

Displaying two Video Cameras as one concatenated video and record it to a file.

screenshot_0551

screenshot_056

To make my program independent, I just copied the opencv python binding to the local directory.

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import sys
import pygame
import Image
import opencv

from PIL import Image
from pygame.locals import *

from opencv import highgui
from opencv import cv

def get_image( camera1, camera2 ) :
    im1 = highgui.cvQueryFrame( camera1 )
    im2 = highgui.cvQueryFrame( camera2 )
   
    pil1 = opencv.adaptors.Ipl2PIL( im1 )
    pil2 = opencv.adaptors.Ipl2PIL( im2 )

    img = Image.new( "RGB", (pil1.size[0] + pil2.size[0], pil1.size[1]) )
   
    img.paste( pil1, (0,0,pil1.size[0],pil1.size[1]) )
    img.paste( pil2, (pil1.size[0],0,pil1.size[0]+pil2.size[0], pil2.size[1] ) )

    return img

def CV_FOURCC( c1, c2, c3, c4 ) :
    return (((ord(c1))&255)             \
                + (((ord(c2))&255)<<8)  \
                + (((ord(c3))&255)<<16) \
                + (((ord(c4))&255)<<24))

if __name__ == "__main__" :

    camera1 = highgui.cvCreateCameraCapture( 0 )
    camera2 = highgui.cvCreateCameraCapture( 1 )

    ( width, height ) = ( 640, 480 )
    fps = 30.0
    pygame.init()
    window = pygame.display.set_mode( ( width * 2, height ) )
    pygame.display.set_caption( "WebCam Demo" )
    screen = pygame.display.get_surface()

    writer = highgui.cvCreateVideoWriter( "captured.avi",
                                          CV_FOURCC('M','J','P','G'),
                                          fps,  
                                          cv.cvSize(width * 2, height) )

    if not writer :
        print "Error on writer"
        exit(1)

    on_exit = False

    while not on_exit :
        events = pygame.event.get()
        for event in events:
            if event.type == QUIT or event.type == KEYDOWN:
                on_exit = True

        im = get_image( camera1, camera2 )

        highgui.cvWriteFrame( writer, opencv.adaptors.PIL2Ipl(im) )
       
        pg_img = pygame.image.frombuffer( im.tostring(), im.size, im.mode )
       
        screen.blit( pg_img, (0,0) )
        pygame.display.flip()
        pygame.time.delay( int( 1000 * 1.0 / fps ) )
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python webcam.py
Output #0, avi, to 'captured.avi':
Stream #0.0: Video: mjpeg, yuvj420p, 1280x480, q=2-31, 78643 kb/s, 90k tbn, 30 tbc

Reference

  1. https://bugs.launchpad.net/ubuntu/+source/opencv/+bug/311188\
  2. http://ubuntuforums.org/showthread.php?p=7315433
  3. http://code.google.com/p/ctypes-opencv/source/checkout
  4. http://gijs.pythonic.nl/blog/2009/may/3/getting-video-io-working-opencv-and-ubuntu-jaunty-/
  5. http://www.pythonware.com/products/pil/

Disclamer

I copied all of ideas from the Internet and just do it myself for my purpose. However, if you want, feel free to use above example under GPL v.2. Thanks.