February 3rd, 2012 | 6 Comments
In the first post regarding animations we have created a bunch of png files and combined them to a single gif animation. Now we want to generate again a bunch of png files, but combine them to a movie.
We create the png files in analogy to the gif example, hence we will discuss only the generation of the movie here. In order to compose a avi file from the png files we are using Mencoder. Gnuplot is able to directly start Mencoder by its
# Create movie with mencoder ENCODER = system('which mencoder'); if (strlen(ENCODER)==0) print '=== mencoder not found ==='; exit CMD = 'mencoder mf://animation/*.png -mf fps=25:type=png -ovc lavc -lavcopts vcodec=mpeg4:mbd=2:trell -oac copy -o huygen.avi' system(CMD)
The first two lines check if Mencoder is available and quit gnuplot if not. The Mencoder command itselfs gets the directory containing the png files
mf://animation/*.png, frames per second and input type
-mf fps=25:type=png, video
-ovc and audio
-oac options, and finally of course the output file
In order to generate a webm video file for a web site, ffmpeg can be used to convert the video.
$ ffmpeg -i huygen.avi huygen.webm