[OctDev] AVI encoding toolbox

[Stefan v. d. W. <st...@su...>]

Hi all

The attached code allows octave to generate AVI (video) files.  I used
ffmpeg's libavcodec -- one of the few available GPL/LGPL packages around.

To compile this you'll need a recent version of ffmpeg.  Under Debian,
install the 'ffmpeg', 'libavformat-dev' and 'libavcodec-dev' packages.
Under RPM-based systems 'ffmpeg' and 'libffmpeg0-devel' should suffice.

The following code demonstrates avifile's usage:

#----------------------------

# create the avifile object
m = avifile("test.avi", "msmpegv4")

# make a hundred frames
for i = 1:100
  I = zeros(100,100,3);

  # draw something in the frame -- in this case, a sine-wave  
  # with changing phase
  for x = 1:100
      I(round(50+10*sin((x+i)/100*4*pi)), x, 1) = 40;  # red
      I(round(50+10*sin((x+i)/100*4*pi)), x, 2) = 40;  # green
      I(round(50+10*sin((x+i)/100*4*pi)), x, 3) = 180; # blue
  endfor
  
  # add the frame to the movie
  addframe(m, I)

  printf(".")
endfor

# close the file and write headers
clear m

#----------------------------

To get a list of codecs, do

avifile("codecs")

The code is still beta.  Especially, when generating two videos in one
octave session, the second video seems to be broken.  At the moment,
only write support is implemented.  Any feedback/fixes appreciated.

Regards
Stefan