The Perl and Raku Conference 2025: Greenville, South Carolina - June 27-29 Learn more

 / 
Linux-DVB-1.03
River stage zero No dependents
/ Linux::DVB

NAME

Linux::DVB - interface to (some parts of) the Linux DVB API

SYNOPSIS


            

              
              
use Linux::DVB;

DESCRIPTION

This module provides an interface to the Linux DVB API. It is a straightforward translation of the C API. You should read the Linux DVB API description to make any sense of this module. It can be found here:


            

              
              
http://www.linuxtv.org/docs/dvbapi/dvbapi.html

All constants from frontend.h and demux.h are exported by their C name and by default.

Noteworthy differences to the C API: unions and sub-structs are usually translated into flat perl hashes, i.e struct.u.qam.symbol_rate becomes $struct->{symbol_rate}.

Noteworthy limitations of this module include: No interface to the video, audio and net devices. If you need this functionality bug the author.

Linux::DVB::Frontend CLASS

SYNOPSIS


            

              
              
my $fe = new Linux::DVB::Frontend $path, $writable;
my $fe = new Linux::DVB::Frontend
            "/dev/dvb/adapter0/frontend0", 1;
$fe->fh; # filehandle
$fe->fd; # fileno
$fe->blocking (0); # or 1
$fe->{name}
$fe->{type}
$fe->frontend_info->{name}
$fe->status & FE_HAS_LOCK
print $fe->ber, $fe->snr, $fe->signal_strength, $fe->uncorrected;
my $tune = $fe->parameters;
$tune->{frequency};
$tune->{symbol_rate};
$fe->set (parameter => value, ...)

Sets frontend parameters. All values are stuffed into the dvb_frontend_parameters structure without conversion and passed to FE_SET_FRONTEND.

Returns true on success.

All modes:


            

              
              
frequency         =>
inversion         =>

QPSK frontends:


            

              
              
symbol_rate       =>
fec_inner         =>

QAM frontends:


            

              
              
symbol_rate       =>
modulation        =>

QFDM frontends:


            

              
              
bandwidth         =>
code_rate_HP      =>
code_rate_LP      =>
constellation     =>
transmission_mode =>
$fe->parameters

Calls FE_GET_FRONTEND and returns a hash reference that contains the same keys as given to the set method.

Example:


            

              
              
Data::Dumper::Dumper $fe->get
{
  frequency   => 426000000, # 426 Mhz
  inversion   => 0,         # INVERSION_OFF
  symbol_rate => 6900000,   # 6.9 MB/s
  modulation  => 3,         # QAM_64
}
$ok = $fe->diseqc_reset_overload

If the bus has been automatically powered off due to power overload, this call restores the power to the bus. The call requires read/write access to the device. This call has no effect if the device is manually powered off. Not all DVB adapters support this call.

$ok = $fe->diseqc_voltage (13|18)

Set the DiSEqC voltage to either 13 or 18 volts.

$ok = $fe->diseqc_tone (1|0)

Enables (1) or disables (0) the DiSEqC continuous 22khz tone generation.

$ok = $fe->diseqc_send_burst (0|1)

Sends a 22KHz tone burst of type SEC_MINI_A (0) or SEC_MINI_B (1).

$ok = $fe->diseqc_cmd ($command)

Sends a DiSEqC command ($command is 3 to 6 bytes of binary data).

$reply = $fe->diseqc_reply ($timeout)

Receives a reply to a DiSEqC 2.0 command and returns it as a binary octet string 0..4 bytes in length (or undef in the error case).

Linux::DVB::Demux CLASS

SYNOPSIS


            

              
              
my $dmx = new Linux::DVB::Demux
            "/dev/dvb/adapter0/demux0";
$fe->fh; # filehandle
$fe->fd; # fileno
$fe->blocking (1); # non-blocking is default
$dmx->buffer (16384);
$dmx->sct_filter ($pid, "filter", "mask", $timeout=0, $flags=DMX_CHECK_CRC);
$dmx->pes_filter ($pid, $input, $output, $type, $flags=0);
$dmx->start; 
$dmx->stop;

Linux::DVB::Decode CLASS

SYNOPSIS


            

              
              
$si_decoded_hashref = Linux::DVB::Decode::si $section_data;
$hashref = Linux::DVB::Decode::si $section_data

Tries to parse the string inside $section_data as an SI table and return it as a hash reference. Only the first SI table will be returned as hash reference, and the $section_data will be modified in-place by removing the table data.

The way to use this function is to append new data to your $section_data and then call Linux::DVB::Decode::si in a loop until it returns undef. Please ntoe, however, that the Linux DVB API will return only one table at a time from sysread, so you can safely assume that every sysread will return exactly one (or zero in case of errors) SI table.

Here is an example of what to expect:


            

              
              
{
  'segment_last_section_number' => 112,
  'table_id' => 81,
  'service_id' => 28129,
  'original_network_id' => 1,
  'section_syntax_indicator' => 1,
  'current_next_indicator' => 1,
  'events' => [
                {
                  'running_status' => 0,
                  'start_time_hms' => 2097152,
                  'event_id' => 39505,
                  'free_CA_mode' => 0,
                  'start_time_mjd' => 53470,
                  'descriptors' => [
                                     {
                                       'event_name' => 'Nachrichten',
                                       'text' => '',
                                       'ISO_639_language_code' => 'deu',
                                       'type' => 77
                                     },
                                     {
                                       'programme_identification_label' => 337280,
                                       'type' => 105
                                     },
                                     {
                                       'raw_data' => '22:0010.04#00',
                                       'type' => 130
                                     }
                                   ],
                  'duration' => 1280
                },
                {
                  'running_status' => 0,
                  'start_time_hms' => 2098432,
                  'event_id' => 39506,
                  'free_CA_mode' => 0,
                  'start_time_mjd' => 53470,
                  'descriptors' => [
                                     {
                                       'event_name' => 'SR 1 - Nachtwerk',
                                       'text' => '',
                                       'ISO_639_language_code' => 'deu',
                                       'type' => 77
                                     },
                                     {
                                       'programme_identification_label' => 337285,
                                       'type' => 105
                                     },
                                     {
                                       'raw_data' => '22:0510.04#00',
                                       'type' => 130
                                     }
                                   ],
                  'duration' => 87296
                }
              ],
  'last_table_id' => 81,
  'section_number' => 112,
  'last_section_number' => 176,
  'version_number' => 31,
  'transport_stream_id' => 1101
}
$text = Linux::DVB::Decode::text $data

Converts text found in DVB si tables into perl text. Only iso-8859-1..-11 and UTF-16 is supported, other encodings (big5 etc. is not. Bug me if you need this).

%Linux::DVB::Decode::nibble_to_genre

A two-level hash mapping genre nibbles to genres, e.g.


            

              
              
$Linux::DVB::Decode::nibble_to_genre{7}{6}
=> 'film/cinema'
($sec,$min,$hour) = Linux::DVB::Decode::time $hms
($mday,$mon,$year) = Linux::DVB::Decode::date $mjd
($sec,$min,$hour,$mday,$mon,$year) = Linux::DVB::Decode::datetime $mjd, $hms
$sec = Linux::DVB::Decode::time_linear $hms
$sec = Linux::DVB::Decode::datetime_linear $mjd, $hms

Break down a "DVB time" (modified julian date + bcd encoded seconds) into it's components (non-_linear) or into a seconds count (_linear variants) since the epoch (datetime_linear) or the start of the day (time_linear).

The format of the returns value of the date and datetime functions is not compatible with Time::Local. Use the _linear functions instead.

Example:


            

              
              
my $time = Linux::DVB::Decode::datetime_linear $mjd, $hms
printf "Starts at %s\n",
   POSIX::strftime "%Y-%m-%d %H:%M:%S",
      localtime $time;

AUTHORS


            

              
              
Marc Lehmann <schmorp@schmorp.de>, http://home.schmorp.de/
Magnus Schmidt, eMail at http://www.27b-6.de/email.php