#!/usr/bin/perl
#
# tvrec.pl -c channel -t HH:MM:SS -o out.avi
#
$channel = "";
$endpos = "";
$file = "";

if ( @ARGV eq 0 ) {
    print "usage: tvrec.pl -c channel -t HH:MM:SS -o out.avi\n";
    exit -1;
}
while ( @ARGV ) {
    $_ = shift @ARGV;
    if ( /-c/ ) {
	$channel = shift @ARGV;
    } elsif ( /-t/ ) {
	$endpos = shift @ARGV;
    } elsif ( /-o/ ) {
	$file = shift @ARGV;
    } else {
	print "unknown option: " . $_ . "\n";
	exit -1;
    }
}
if ( $channel eq "" ) {
    print "channel is not specified\n";
    exit -1;
}
if ( $endpos eq "" ) {
    print "time is not specified\n";
    exit -1;
}
if ( $file eq "" ) {
    print "output file is not specified\n";
    exit -1;
}

$cmd1 = "v4lctl -c /dev/video0 setnorm NTSC";
# この設定だと，Celeron 2.4GHz で CPU 占有率は 70% 弱くらい．
$cmd2 = "mencoder " # nice -19 mencoder (優先度最高) だと映像と音がズレる．
. "-vop scale=640:480,crop=624:468:8:0,pp=lb "
. "-tv driver=v4l2:device=/dev/video0:input=1:amode=1 "
. "-tv norm=NTSC:width=640:height=480 "
. "-tv chanlist=japan-bcast:channel=$channel "
. "-ovc lavc "
. "-lavcopts vcodec=mpeg4:vbitrate=1025 "
# -lameopts に aq=0 (音質最高) を指定すると映像と音が完全にズレる．
. "-oac mp3lame -lameopts cbr:br=128 "
. "-endpos $endpos "
. "tv:// "
. "-o $file";

system($cmd1) eq 0 or die "system $cmd1 faild: $?\n";
system($cmd2) eq 0 or die "system $cmd2 faild: $?\n";