• animations from picture sequences

• splitting a movie into frames

There is a nice tool out there called motion that generates single picture snapshots from a video4linux device. We will use this tools as an example to generate the pictures and convert the pictures to a movie. Assuming we have a webcam on /dev/video1, try

motion -d /dev/video1 -Q

for a couple of seconds to generate snapshots in a directory try, that is based on time formats. The current year 2002/ is assumed to be the top level directory.
The import module -x imlist simply takes a list of frames that will make the final movie. One picture/frame per row. Generate the list with

find 2002/ ! -type d | sort > list

and start transcode to convert the sequence to a XviD codec movie with. But wait a second. There is no auto-probing for this mode. Use tcprobe on a single image and write down the frame parameter. We find

andromeda:transcode>tcprobe -i 2002/04/24/23/04/39-03.jpg
[tcprobe] JPEG image
[tcprobe] summary for 2002/04/24/23/04/39-03.jpg, (*) = not default, 0 = not detected
import frame size: -g 352x288 [720x576] (*)
frame rate: -f 1.000 [25.000] frc=0 (*)
no audio track: use "null" import module for audio


which provides the required information to start

transcode -i list -x imlist,null -g 352x288 -y xvid,null -f 1 -o movie.avi -H 0

We choose a frame rate of one frame per second and switch auto-probing and audio (import/export) completely off. This will generate our fancy surveillance movie.

Native support for writing to uncompressed PPM pictures is provided by the "-y ppm" module.

transcode [...] -y ppm

will extract all video frames to frame-00000.ppm, frame-00001.ppm, ... but will quickly fill up your hard disk. Audio is discarded unless you provide a filename with option "-m". Other native support is available for PGM "rawbits" image data with option "-K" and file extension "png", which requires less space.

-y im

For writing compressed frames for a file format supported by ImageMagick and export module -y im we must provide an identifier with option "-F".

transcode [...] -y im -F tiff -c 0-20

writes 20 video frames as TIFF image format pictures to the files

frame.000000.tiff, frame.000001.tiff, ..., frame.000019.tiff.

Other possible and useful image formats are "jpg" and "png". Please see the ImageMagick documentation for supported image formats. It is possible to change the prefix with option "-o".