[Brian Theado] - 01Jan04 -
After writing the [babbleback machine] program, my daughter begged me daily for more than a month to play.  Her interest is finally starting to wan.  She still enjoys playing with it if I turn it on.  Along the way, I got the idea of making a video camera version of the same program.  I have a digital camera with Firewire (aka iLink, aka IEEE1394) connectivity.  I searched to no avail for a program or set of programs that would make doing this easy on Microsoft Windows.

I turned my search to Linux and hit the jackpot.  Linux has a command-line program called dvgrab that makes it simple to capture data from a digital video camera.  A program called kino will playback video files.  Both programs are available at http://kino.schirmacher.de.  Tcl is a great languange to glue the two applications together into a program that constantly records video and plays it back with a 2 second delay.

Here's the sourcecode for the script
 #!/usr/bin/tclsh
 proc queueFile dv {
    # Read the line of output from dvgrab and extract the filename
    set line [gets $dv]
    puts $line
    regexp {(.+):} $line -> file
        
    # Queue the file for playback using the existing xine session
    exec xine -S mrl=$file
        
    # Delete the file when it is done playing (hopefully it will be done)
    variable delay
    after [expr ($delay * 1000) + 100] [list file delete $file]
 }
 # Launch xine
    set xinePid [exec xine --hide-gui &]
 # Launch dvgrab.  Configure it to split off a new file every $delay seconds
    set delay 2
    set framesPerSecond 30 ;# NTSC format
    set framesToGrab [expr $delay *  $framesPerSecond]
    set dv [open "|dvgrab --frames $framesToGrab --format dv2  --autosplit cinemaback"]
            
 # dvgrab outputs a line with the file name each time it splits off a new file
    fileevent $dv readable [list queueFile $dv]
    vwait forever

If you don't have Linux installed and you want to try this script out, then check out Knoppix (http://www.knoppix.org).  It is a live CD distribution of Linux that will run directly from a CD with no installation necessary.  Just download the iso image and burn it to a CD.  It comes with firewire drivers, dvgrab, and kino all pre-installed.  

To activate the firewire drivers, just execute:
 sudo insmod ieee1394
 sudo insmod ohci1394
 sudo insmod raw1394

Camera idiosyncrasies: My camera is a Panasonic PV-DV202 and I found that if it has a tape in it and it isn't recording, then it shuts off after a few minutes.  It doesn't seem to recognize that data is being sent across the firewire cable.  I work around this by removing the tape.