Matrix Elements VB-800 Bedienungsanleitung PDF herunterladen (Seite 49)

Chapter 9. Stream a DVB channel (satellite or digital terrestial TV)

Stream with VLC

Note: VLC has many more features than VLS. First you can use the advanced stream output options such as

transcoding and all kinds of output supports. Second VLC can take advantage of the Common Interface supported by

some DVB adapters to descramble one or several services. Currently released versions of VLC only support the

low-level API so some adapters won’t work (budget-ci cards work, twinhan doesn’t). Some CAM modules aren’t

compatible with some DVB cards, check the linux-dvb documentation for more information. So-called "professional"

CAM modules are able to descramble up to twelve services, whereas customer-oriented modules are often limited to

one or two services unless otherwise speciﬁed.

VLC must be compiled with --enable-dvb and you need the linux-dvb headers installed in your system. An example

command-line is as follows :

vlc -vvv --color --ttl 12 --ts-es-id-pid --programs=8508,8505 dvb: \

--dvb-frequency=11739000 --dvb-srate=27500000 --dvb-voltage=13 \

--sout-standard-access=udp --sout-standard-mux=ts --sout \

’#duplicate{dst=rtp{dst=address1,mux=ts},select="program=8508",dst=rtp{dst=address2,mux=ts},select="program=8505"}’

The example above shows the minimum set of options needed to stream out two services. Here is a list of frontend options,

depending on the frontend type:

• common options

• dvb-adapter : speciﬁes the adapter to use in case you have several adapters in your machine (by default use adapter 0)

• dvb-device : speciﬁes the name of the DVB device to use (should not be needed with a standard linux-dvb installation)

• dvb-srate : speciﬁes the symbol rate of the modulated signal, in symbols/s

• dvb-inversion : speciﬁes whether the signal is inverted or not (default is automatic detection)

• dvb-budget-mode : enters a special mode where all PIDs are retrieved by the driver; it should no longer be necessary

as VLC should ﬁlter wanted PIDs

• satellite frontend (QPSK)

• dvb-frequency : speciﬁes the frequency to tune to in kHz; according to the frequency range, VLC auto-detects the

band to use: S (2.5-2.7 GHz), C-lower (3.4-4.2 GHz), C-higher (4.5-4.8 GHz), Ku (10.7-13.25 GHz) or direct BIS

frequency (0.95-2.15 GHz); it is mandatory to supply the dvb-srate option to satellite frontends

• dvb-voltage : speciﬁes the voltage to apply on the IF; most LNBs behave differently when supplied with 13 V or 18 V;

universal LNBs select vertical polarity with 13 V and horizontal with 18 V; you can also select 0 V if your LNB has

another power supply (default is 13 V)

• dvb-tone : speciﬁes whether to send a 22 kHz pulse tone to the LNB; universal LNBs switch to high-band when this

pulse is sent; by default VLC automatically adopts the correct behaviour if the frequency supplied is in the Ku band

(other bands do not need this)

• dvb-fec : speciﬁes the code-rate to use for Forward Error Correction; type in the ﬁrst number of the code-rate, for 2/3

use --dvb-rate=2, etc. (default is 9, meaning automatic detection)

• dvb-high-voltage : enables a special mode of the DVB adapter to compensate for the voltage loss in very long cables

(AFAIK it is present in the API, but no DVB adapter actually implements it)

• dvb-lnb-lof1, dvb-lnb-lof2, dvb-lnb-slof : speciﬁes the frequencies of the ﬁrst and second local oscillators, and the

frequency at which the 22 kHz pulse should be activated to enable the second oscillator; by default VLC uses the

values for universal LNBs if the frequency supplied is in the Ku band (other bands do not need this)

1 2 ... 44 45 46 47 48 49 50 51 52 53 54 ... 64 65

Keine Kommentare

Matrix Elements VB-800 Bedienungsanleitung Seite 49