#!/bin/sh

START=''
DURATION=''

usage()
{
 cat <<END

usage: `basename $0` -s start -d duration -- mencoder_options

the start and duration should be expressed in the form hh:mm:ss
if no start is given the recording begins immediatly
if the duration is empty mencoder should be stoped with a SIGINT
Examples:
# start recording at 6 AM and stop after 1 hour and 45 minutes
# using full size PAL and a video bitrate of 900 kbpm
`basename $0` -s 6:00:00 -d 1:45:00 -- -tv width=704:height=576 -lavcopts vbitrate=900
END
exit 1
}

while getopts :s:d: opt; do
 case $opt in
  s)
   START="$OPTARG"
  ;;
  d)
   DURATION="$OPTARG"
  ;;
  *)
   usage
  ;;
 esac
done
shift $(( $OPTIND - 1 ))

EXTRAOPTS=''
[ -n "$DURATION" ] && EXTRAOPTS="-endpos $DURATION"

if [ -z "$START" ]; then
 INTERVAL=0
else
 INTERVAL=$(( `date -d "$START" +%s` - `date +%s` )) # in seconds
 [ $INTERVAL -lt 0 ] && INTERVAL=$(( $INTERVAL + 3600 * 24 )) # add a day
fi
echo "waiting $INTERVAL seconds..."
sleep $INTERVAL

# capture the sound from the Auxiliary port
# (if it's the audio cable plugs into line-in use "Line", for CD-in use "CD")
amixer set Aux cap

# encode
mencoder -quiet -oac mp3lame -lameopts vbr=2:q=7:mode=3 -ovc lavc \
 -lavcopts vcodec=mpeg4:autoaspect:vlelim=-4:vcelim=7:lumi_mask=0.3:dark_mask=0.3:vbitrate=500 \
 -tv driver=v4l2:width=352:height=288 $EXTRAOPTS \
 -o /src/tv/tv_`date '+%Y-%m-%d_%H:%M:%S'`.avi "$@" tv://

# reset capture device to microphone
amixer set Mic cap