Kamaelia.Device.DVB.Tuner

• component Tuner

• DVB-T (Digital Terrestrial TV) Tuner
  • Example Usage
  • How does it work?
    • Tuning parameters

DVB-T (Digital Terrestrial TV) Tuner

Tunes to the specified frequency, using the specified parameters, using a DVB tuner device; then outputs packets from the received MPEG transport stream as requested.

Example Usage

Record entire received MPEG transport stream, from a particular frequency and set of tuning parameters to file:

feparams = {
    "inversion" : dvb3.frontend.INVERSION_AUTO,
    "constellation" : dvb3.frontend.QAM_16,
    "code_rate_HP" : dvb3.frontend.FEC_3_4,
    "code_rate_LP" : dvb3.frontend.FEC_3_4,
}

Pipeline( OneShot( msg=["ADD", [0x2000] ] ),    # send the msg ["ADD", [0x2000]]
          Tuner(537.833330, feparams),
          SimpleFileWriter("dump.ts"),
        ).run()

Record just packets with packet ID (PID) 0 and 18:

Pipeline( OneShot( msg=["ADD", [0, 18] ] ),
          Tuner(537833330.0, feparams),
          SimpleFileWriter("dump.ts"),
        ).run()

How does it work?

Tuner tunes, using the specified tuning parameters to a DVB-T transmitted multiplex. You can also specify which DVB tuner card (device) to use if there is more than one in your system.

To start with it outputs nothing. To start or stop outputting packets, send messages to the "inbox" inbox of the form:

[ "ADD",    [pid, pid, ...] ]
[ "REMOVE", [pid, pid, ...] ]

These instruct Tuner to output packets from the received multiplex with the specified packet IDs (PIDs).

Most DVB tuner devices understand a special packet ID of 0x2000 to request the entire transport stream of all packets with all IDs.

This component will terminate if a shutdownMicroprocess or producerFinished message is sent to the "control" inbox. The message will be forwarded on out of the "signal" outbox just before termination.

Tuning parameters

The tuning parameters come from the dvb3.frontend library. Specify them as a dictionary:

{
     "bandwidth"             : dvb3.frontend.BANDWIDTH_?_MHZ where ? is 6, 7 or 8
     "constellation"         : dvb3.frontend.QPSK, QAM_16 or QAM_64
     "hierarchy_information" : dvb3.frontend.HIERARCHY_? where ? is NONE, 1, 2 or 4
     "code_rate_HP"          : dvb3.frontend.FEC_X_Y where X/Y = 1/2, 2/3, 3/4, 5/6, 7/8
     "code_rate_LP"          : dvb3.frontend.FEC_X_Y where X/Y = 1/2, 2/3, 3/4, 5/6, 7/8
     "guard_interval"        : dvb3.frontend.GUARD_INTERVAL_1_? where ? is 32, 16, 8 or 4
     "transmission_mode"     : dvb3.frontend.TRANSMISSION_MODE_?K where ? is 2 or 8
     "inversion"             : dvb3.frontend.INVERSION_AUTO
}

---

Kamaelia.Device.DVB.Tuner.Tuner

class Tuner(Axon.ThreadedComponent.threadedcomponent)

Tuner(freq[,feparams][,card]) -> new Tuner component.

Tunes the DVB-T card to the given frequency with the given parameters. Send (ADD, [PID list]) or (REMOVE, [PID list]) messages to its "inbox" inbox to cuase it to output MPEG transport stream packets (with the specified PIDs) from its "outbox" outbox.

Keyword arguments:

• freq -- Frequency to tune to in MHz
• feparams -- Dictionary of parameters for the tuner front end (default={})
• card -- Which DVB device to use (default=0)

Inboxes

Outboxes

Methods defined here

__init__(self, freq[, feparams][, card])

x.__init__(...) initializes x; see x.__class__.__doc__ for signature

addPID(self, pid)

Adds the given PID to the transport stream that will be available in "/dev/dvb/adapter0/dvr0"

handleCommand(self, cmd, demuxers)

main(self)

notLocked(self)

Returns True if the frontend is not yet locked. Returns False if it is locked.

shutdown(self)

tune_DVB(self, frequency[, feparams])