[GRASS5] Re: [GRASS-CVS] hamish: grass/html/html r.out.mpeg.html,1.4,1.5

[Hamish]

> > update broken Berkeley ftp link and add link to netpbm's ppmtompeg
> > which is the same thing as mpeg_encode

r.out.mpeg is now updated to use 'ppmtompeg' if it exists. This means
the module will work out of the box on any system with netpbm installed.
(ie most unix; Cygwin & OSX with a download)

Note this is MPEG-1, old and inefficient but Free Software.

Might add a flag in future to dump PPM frames somewhere to let the user
use a newer non-free encoder. (Xvid? Ogg Theora? the new BBC wavelet one?)
Maybe a script using g.mlist + r.out.ppm in a loop is a simpler solution.


> Just curious:
> Does it work better than the old Berkeley software (which gives
> terrible errors here)?

Which version of mpeg_encode? The latest is 1.5c (circa 1995?).

I'd very much expect the netpbm version to be better maintained and give
better results, but that's just a guess. I haven't tried mpeg_encode[*].

[*] someone who does have mpeg_encode: can you test the module please?
    Specifically to see if the exit-code test works.


> If so, what about using 'ppmtompeg' with -c flag and mpeg_encode
> without?

The -c flag makes the current region settings for columns and rows
become the size for the animation. This should probably have some sort
of error &/or override flag if you try to make a 2000x4000 pixel movie..

Without the -c flag, a 365 frame movie took about 200mb disk space in
$MAPSET/.tmp during runtime .. I'm not too worried about that these days.


No shock, but Mplayer does a much better job on playback than UCB
mpeg_play. But mpeg_play lets you step frame by frame which is handy.


Next: figure out how to get d.nviz to automatically generate MPEGs.
(but not by me right now)



Hamish