Dvb grabber.pl
From MythTV Official Wiki
| Author | Bob |
| Description | Perl script to grab 5 seconds from unencrypted DVB channels |
| Supports |
dvb_grabber.pl
Given a configuration file that matches the 'scan' program from linux-dvb, this script will output a file for each channel it can successfully capture.
Command line usage
perl dvb_grabber.pl -a 0 -f scan.conf
where the -a option is the DVB tuner ID and the -f option is the configuration file. This script will create a file name CXXX-YY.ts for each stream captured.
Dependencies
This program requires azap (from linux-dvb) and mplayer. It could be re-written to use ffmpeg instead of mplayer.
The Code
fix_scan_chan.pl
#!/usr/bin/perl
# Version 1.0 - Jul 7, 2010
use Getopt::Std;
use strict;
my($cf, $adapter, $fn, @fields, $chan, $azap_pid, $cat_pid, $pkt, $i, $pid,
$name, $height, $width, %opts);
$cf = $ENV{'HOME'} . "/.azap/channels.conf";
$adapter = 1;
getopts('a:f:', \%opts);
foreach (keys %opts) {
$adapter = int($opts{$_}) if($_ =~ m/a/);
$cf = $opts{$_} if($_ =~ m/f/);
}
open F, $cf || die "failed to open $cf: $!";
while(<F>) {
@fields = split /:/, $_;
$name = $fields[0];
$fn = $name . ".ts";
unlink "$fn" if(-e "$fn");
print "capturing $name ...";
# Start azap to tune desired channel
$azap_pid = fork();
if(! defined $azap_pid ) {
die "fork() failed: $!";
} elsif($azap_pid == 0) {
# Child process, exec azap
close(STDERR);
close(STDOUT);
exec("azap -c $cf -a $adapter -r $name");
exit(0);
}
# Wait for azap to tune
select undef, undef, undef, 1.0;
# Azap running, fork and cat device to get transport stream
$cat_pid = fork();
if(! defined $cat_pid ) {
die "fork() failed: $!";
} elsif($cat_pid == 0) {
close(STDERR);
close(STDOUT);
# Child process, copy from device file to output file
$i = 20;
while($i > 0) {
last if(open FHI, "< /dev/dvb/adapter${adapter}/dvr0");
$i--;
select undef, undef, undef, 0.25;
}
open FHO, "> $fn";
while(1) {
sysread FHI, $pkt, 188;
syswrite FHO, $pkt;
}
exit(0);
}
# Wait for enough data to be captured
sleep 5;
kill 1, $cat_pid;
kill 1, $azap_pid;
# Reap children
$i = 10;
while($i > 0) {
$pid = wait();
last if($pid == -1);
$i--;
}
if($i < 1) {
print "too many wait() attempts ";
}
if(! -e "$fn") {
print "no file, channel gone?\n";
next;
}
if(-s $fn < 1) {
unlink $fn;
print "0 bytes\n";
next;
}
undef $height;
undef $width;
if(open P, "mplayer -really-quiet -identify $fn -ao null -vo null -frames 0 2>/dev/null |") {
while(<P>) {
if($_ =~ m/ID_VIDEO_WIDTH=(.+)/) {
$width = $1;
}
if($_ =~ m/ID_VIDEO_HEIGHT=(.+)/) {
$height = $1;
}
next;
}
close(P);
}
if(! defined $width || ! defined $height) {
print " encrypted\n";
unlink $fn;
next;
}
print $width . "x" . $height . "\n";
}
