Creating Moviegrams

First get the width, length and framerate of the movie you want to create a moviegram of:

# mediainfo -f movie.avi | grep '\(Width\|Frame \(rate\|count\)\)'

Find out the ratio at which to play the movie:

# echo '3 k <fps> <number of frames> <movie width> / / p' | dc

This will probably result in a number smaller than 1.0.

Now cut the single frames out of the movie:

# avconv -i movie.avi -vsync 1 -r rate image-%04.pnm

Cut a single column from all those frames:

# for i in `seq 1 width`; do f="$(seq -f %04g $i $i)"; echo $f; pamcut -left "$(($i- 1))" -width 1 < "image-${f}.pnm" > "col-${f}.pnm"; done

Combine all the columns into a single image:

# pnmcat -lr col-0*.pnm > part-1.pnm # pnmcat can only open 1024 files at once so we have to process it in smaller batches
# pnmcat -lr col-1*.pnm > part-2.pnm
# pnmcat -lr part-*.pnm | pnmtopng > moviegram.png