Digital Video

Erase MiniDV tapes via IEEE1394 interface

Many other guides suggested camcorder recording with the lens cap to erase a minidv on but this can capture environment activity on the tape. It is possible to create artificial video on the computer and send it to the camcorder to overwrite the media. One or more random passes followed by a zero pass is desirable. Some camcorders may not be able to erase the first half second of tape so a small lenscapping may be desirable.

We want dvcont from package libavc1394-tools and test-dv from libiec61883

test-dv was not incuded in the binary package by default, so edited examples/Makefile.am to include test-dv and debian/libiec61883-dev.install to change /usr/bin/plug* to /usr/bin/* followed by dpkg-buildpackage -rfakeroot

git clone git://git.kernel.org/pub/scm/libs/ieee1394/libiec61883.git 
/mirror/git/git.kernel.org/pub/scm/libs/ieee1394/libiec61883.git
/union/git/git.kernel.org/pub/scm/libs/ieee1394/libiec61883.git/configure
--prefix=/union/git/git.kernel.org/pub/scm/libs/ieee1394/libiec61883.bin

Write random data:

dvcont rewind
dvcont record
/union/git/source.ffmpeg.org/ffmpeg.git/ffmpeg -r 25 -s 720x576 -f rawvideo -i /dev/urandom \
-ar 48k -ac 2 -f s16le -i /dev/urandom -target dv -y /dev/stdout | \
/union/git/git.kernel.org/pub/scm/libs/ieee1394/libiec61883.git/examples/test-dv /dev/stdin

For a blanking pass try zeros

dvcont rewind
dvcont record
/union/git/source.ffmpeg.org/ffmpeg.git/ffmpeg -r 25 -s 720x576 -f rawvideo -i /dev/zero -ar 48k -ac 2 -f s16le -i /dev/zero -target dv -y /dev/stdout | \
/union/git/git.kernel.org/pub/scm/libs/ieee1394/libiec61883.git/examples/test-dv /dev/stdin

DVgrab uses

To get an Mpeg stream: dvgrab -format raw | ffmpeg -f dv -i - -target vcd - | vlc -

You can do this in xscreensaver-getimage-video to get frames from the IEEE1394 DV camera on your xscreensaver:

my @programs = (
  "dvgrab --format jpeg --jpeg-overwrite --every 25 $tmpdir/webcam < /dev/null " .
  "> /dev/null 2> /dev/null & C=\$! ; sleep 1; kill \$C; ".
  "mv $tmpdir/webcam.jpg $tmpfile", # IEEE1394 camera