270 lines
13 KiB
ReStructuredText
270 lines
13 KiB
ReStructuredText
|
.. SPDX-License-Identifier: GPL-2.0
|
||
|
|
|
||
|
|
HOWTO: Get An Avermedia DVB-T working under Linux
|
||
|
|
-------------------------------------------------
|
||
|
|
|
||
|
|
February 14th 2006
|
||
|
|
|
||
|
|
.. note::
|
||
|
|
|
||
|
|
This documentation is outdated. Please check at the DVB wiki
|
||
|
|
at https://linuxtv.org/wiki for more updated info.
|
||
|
|
|
||
|
|
There's a section there specific for Avermedia boards at:
|
||
|
|
https://linuxtv.org/wiki/index.php/AVerMedia
|
||
|
|
|
||
|
|
|
||
|
|
Assumptions and Introduction
|
||
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
||
|
|
|
||
|
|
It is assumed that the reader understands the basic structure
|
||
|
|
of the Linux Kernel DVB drivers and the general principles of
|
||
|
|
Digital TV.
|
||
|
|
|
||
|
|
One significant difference between Digital TV and Analogue TV
|
||
|
|
that the unwary (like myself) should consider is that,
|
||
|
|
although the component structure of budget DVB-T cards are
|
||
|
|
substantially similar to Analogue TV cards, they function in
|
||
|
|
substantially different ways.
|
||
|
|
|
||
|
|
The purpose of an Analogue TV is to receive and display an
|
||
|
|
Analogue Television signal. An Analogue TV signal (otherwise
|
||
|
|
known as composite video) is an analogue encoding of a
|
||
|
|
sequence of image frames (25 per second) rasterised using an
|
||
|
|
interlacing technique. Interlacing takes two fields to
|
||
|
|
represent one frame. Computers today are at their best when
|
||
|
|
dealing with digital signals, not analogue signals and a
|
||
|
|
composite video signal is about as far removed from a digital
|
||
|
|
data stream as you can get. Therefore, an Analogue TV card for
|
||
|
|
a PC has the following purpose:
|
||
|
|
|
||
|
|
* Tune the receiver to receive a broadcast signal
|
||
|
|
* demodulate the broadcast signal
|
||
|
|
* demultiplex the analogue video signal and analogue audio
|
||
|
|
signal. **NOTE:** some countries employ a digital audio signal
|
||
|
|
embedded within the modulated composite analogue signal -
|
||
|
|
NICAM.)
|
||
|
|
* digitize the analogue video signal and make the resulting
|
||
|
|
datastream available to the data bus.
|
||
|
|
|
||
|
|
The digital datastream from an Analogue TV card is generated
|
||
|
|
by circuitry on the card and is often presented uncompressed.
|
||
|
|
For a PAL TV signal encoded at a resolution of 768x576 24-bit
|
||
|
|
color pixels over 25 frames per second - a fair amount of data
|
||
|
|
is generated and must be processed by the PC before it can be
|
||
|
|
displayed on the video monitor screen. Some Analogue TV cards
|
||
|
|
for PCs have onboard MPEG2 encoders which permit the raw
|
||
|
|
digital data stream to be presented to the PC in an encoded
|
||
|
|
and compressed form - similar to the form that is used in
|
||
|
|
Digital TV.
|
||
|
|
|
||
|
|
The purpose of a simple budget digital TV card (DVB-T,C or S)
|
||
|
|
is to simply:
|
||
|
|
|
||
|
|
* Tune the received to receive a broadcast signal.
|
||
|
|
* Extract the encoded digital datastream from the broadcast
|
||
|
|
signal.
|
||
|
|
* Make the encoded digital datastream (MPEG2) available to
|
||
|
|
the data bus.
|
||
|
|
|
||
|
|
The significant difference between the two is that the tuner
|
||
|
|
on the analogue TV card spits out an Analogue signal, whereas
|
||
|
|
the tuner on the digital TV card spits out a compressed
|
||
|
|
encoded digital datastream. As the signal is already
|
||
|
|
digitised, it is trivial to pass this datastream to the PC
|
||
|
|
databus with minimal additional processing and then extract
|
||
|
|
the digital video and audio datastreams passing them to the
|
||
|
|
appropriate software or hardware for decoding and viewing.
|
||
|
|
|
||
|
|
The Avermedia DVB-T
|
||
|
|
~~~~~~~~~~~~~~~~~~~
|
||
|
|
|
||
|
|
The Avermedia DVB-T is a budget PCI DVB card. It has 3 inputs:
|
||
|
|
|
||
|
|
* RF Tuner Input
|
||
|
|
* Composite Video Input (RCA Jack)
|
||
|
|
* SVIDEO Input (Mini-DIN)
|
||
|
|
|
||
|
|
The RF Tuner Input is the input to the tuner module of the
|
||
|
|
card. The Tuner is otherwise known as the "Frontend" . The
|
||
|
|
Frontend of the Avermedia DVB-T is a Microtune 7202D. A timely
|
||
|
|
post to the linux-dvb mailing list ascertained that the
|
||
|
|
Microtune 7202D is supported by the sp887x driver which is
|
||
|
|
found in the dvb-hw CVS module.
|
||
|
|
|
||
|
|
The DVB-T card is based around the BT878 chip which is a very
|
||
|
|
common multimedia bridge and often found on Analogue TV cards.
|
||
|
|
There is no on-board MPEG2 decoder, which means that all MPEG2
|
||
|
|
decoding must be done in software, or if you have one, on an
|
||
|
|
MPEG2 hardware decoding card or chipset.
|
||
|
|
|
||
|
|
|
||
|
|
Getting the card going
|
||
|
|
~~~~~~~~~~~~~~~~~~~~~~
|
||
|
|
|
||
|
|
In order to fire up the card, it is necessary to load a number
|
||
|
|
of modules from the DVB driver set. Prior to this it will have
|
||
|
|
been necessary to download these drivers from the linuxtv CVS
|
||
|
|
server and compile them successfully.
|
||
|
|
|
||
|
|
Depending on the card's feature set, the Device Driver API for
|
||
|
|
DVB under Linux will expose some of the following device files
|
||
|
|
in the /dev tree:
|
||
|
|
|
||
|
|
* /dev/dvb/adapter0/audio0
|
||
|
|
* /dev/dvb/adapter0/ca0
|
||
|
|
* /dev/dvb/adapter0/demux0
|
||
|
|
* /dev/dvb/adapter0/dvr0
|
||
|
|
* /dev/dvb/adapter0/frontend0
|
||
|
|
* /dev/dvb/adapter0/net0
|
||
|
|
* /dev/dvb/adapter0/osd0
|
||
|
|
* /dev/dvb/adapter0/video0
|
||
|
|
|
||
|
|
The primary device nodes that we are interested in (at this
|
||
|
|
stage) for the Avermedia DVB-T are:
|
||
|
|
|
||
|
|
* /dev/dvb/adapter0/dvr0
|
||
|
|
* /dev/dvb/adapter0/frontend0
|
||
|
|
|
||
|
|
The dvr0 device node is used to read the MPEG2 Data Stream and
|
||
|
|
the frontend0 node is used to tune the frontend tuner module.
|
||
|
|
|
||
|
|
At this stage, it has not been able to ascertain the
|
||
|
|
functionality of the remaining device nodes in respect of the
|
||
|
|
Avermedia DVBT. However, full functionality in respect of
|
||
|
|
tuning, receiving and supplying the MPEG2 data stream is
|
||
|
|
possible with the currently available versions of the driver.
|
||
|
|
It may be possible that additional functionality is available
|
||
|
|
from the card (i.e. viewing the additional analogue inputs
|
||
|
|
that the card presents), but this has not been tested yet. If
|
||
|
|
I get around to this, I'll update the document with whatever I
|
||
|
|
find.
|
||
|
|
|
||
|
|
To power up the card, load the following modules in the
|
||
|
|
following order:
|
||
|
|
|
||
|
|
* modprobe bttv (normally loaded automatically)
|
||
|
|
* modprobe dvb-bt8xx (or place dvb-bt8xx in /etc/modules)
|
||
|
|
|
||
|
|
Insertion of these modules into the running kernel will
|
||
|
|
activate the appropriate DVB device nodes. It is then possible
|
||
|
|
to start accessing the card with utilities such as scan, tzap,
|
||
|
|
dvbstream etc.
|
||
|
|
|
||
|
|
The frontend module sp887x.o, requires an external firmware.
|
||
|
|
Please use the command "get_dvb_firmware sp887x" to download
|
||
|
|
it. Then copy it to /usr/lib/hotplug/firmware or /lib/firmware/
|
||
|
|
(depending on configuration of firmware hotplug).
|
||
|
|
|
||
|
|
Receiving DVB-T in Australia
|
||
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
||
|
|
|
||
|
|
I have no experience of DVB-T in other countries other than
|
||
|
|
Australia, so I will attempt to explain how it works here in
|
||
|
|
Melbourne and how this affects the configuration of the DVB-T
|
||
|
|
card.
|
||
|
|
|
||
|
|
The Digital Broadcasting Australia website has a Reception
|
||
|
|
locatortool which provides information on transponder channels
|
||
|
|
and frequencies. My local transmitter happens to be Mount
|
||
|
|
Dandenong.
|
||
|
|
|
||
|
|
The frequencies broadcast by Mount Dandenong are:
|
||
|
|
|
||
|
|
Table 1. Transponder Frequencies Mount Dandenong, Vic, Aus.
|
||
|
|
Broadcaster Channel Frequency
|
||
|
|
ABC VHF 12 226.5 MHz
|
||
|
|
TEN VHF 11 219.5 MHz
|
||
|
|
NINE VHF 8 191.625 MHz
|
||
|
|
SEVEN VHF 6 177.5 MHz
|
||
|
|
SBS UHF 29 536.5 MHz
|
||
|
|
|
||
|
|
The Scan utility has a set of compiled-in defaults for various
|
||
|
|
countries and regions, but if they do not suit, or if you have
|
||
|
|
a pre-compiled scan binary, you can specify a data file on the
|
||
|
|
command line which contains the transponder frequencies. Here
|
||
|
|
is a sample file for the above channel transponders:
|
||
|
|
|
||
|
|
::
|
||
|
|
|
||
|
|
# Data file for DVB scan program
|
||
|
|
#
|
||
|
|
# C Frequency SymbolRate FEC QAM
|
||
|
|
# S Frequency Polarisation SymbolRate FEC
|
||
|
|
# T Frequency Bandwidth FEC FEC2 QAM Mode Guard Hier
|
||
|
|
T 226500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
|
||
|
|
T 191625000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
|
||
|
|
T 219500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
|
||
|
|
T 177500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
|
||
|
|
T 536500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
|
||
|
|
|
||
|
|
The defaults for the transponder frequency and other
|
||
|
|
modulation parameters were obtained from www.dba.org.au.
|
||
|
|
|
||
|
|
When Scan runs, it will output channels.conf information for
|
||
|
|
any channel's transponders which the card's frontend can lock
|
||
|
|
onto. (i.e. any whose signal is strong enough at your
|
||
|
|
antenna).
|
||
|
|
|
||
|
|
Here's my channels.conf file for anyone who's interested:
|
||
|
|
|
||
|
|
::
|
||
|
|
|
||
|
|
ABC HDTV:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:2307:0:560
|
||
|
|
ABC TV Melbourne:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:561
|
||
|
|
ABC TV 2:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:562
|
||
|
|
ABC TV 3:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:563
|
||
|
|
ABC TV 4:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:564
|
||
|
|
ABC DiG Radio:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:0:2311:566
|
||
|
|
TEN Digital:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1585
|
||
|
|
TEN Digital 1:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1586
|
||
|
|
TEN Digital 2:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1587
|
||
|
|
TEN Digital 3:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1588
|
||
|
|
TEN Digital:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1589
|
||
|
|
TEN Digital 4:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1590
|
||
|
|
TEN Digital:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1591
|
||
|
|
TEN HD:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:514:0:1592
|
||
|
|
TEN Digital:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1593
|
||
|
|
Nine Digital:191625000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:513:660:1072
|
||
|
|
Nine Digital HD:191625000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:0:1073
|
||
|
|
Nine Guide:191625000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:514:670:1074
|
||
|
|
7 Digital:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:769:770:1328
|
||
|
|
7 Digital 1:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:769:770:1329
|
||
|
|
7 Digital 2:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:769:770:1330
|
||
|
|
7 Digital 3:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:769:770:1331
|
||
|
|
7 HD Digital:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:833:834:1332
|
||
|
|
7 Program Guide:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:865:866:1334
|
||
|
|
SBS HD:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:102:103:784
|
||
|
|
SBS DIGITAL 1:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:161:81:785
|
||
|
|
SBS DIGITAL 2:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:162:83:786
|
||
|
|
SBS EPG:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:163:85:787
|
||
|
|
SBS RADIO 1:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:0:201:798
|
||
|
|
SBS RADIO 2:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:0:202:799
|
||
|
|
|
||
|
|
Known Limitations
|
||
|
|
~~~~~~~~~~~~~~~~~
|
||
|
|
|
||
|
|
At present I can say with confidence that the frontend tunes
|
||
|
|
via /dev/dvb/adapter{x}/frontend0 and supplies an MPEG2 stream
|
||
|
|
via /dev/dvb/adapter{x}/dvr0. I have not tested the
|
||
|
|
functionality of any other part of the card yet. I will do so
|
||
|
|
over time and update this document.
|
||
|
|
|
||
|
|
There are some limitations in the i2c layer due to a returned
|
||
|
|
error message inconsistency. Although this generates errors in
|
||
|
|
dmesg and the system logs, it does not appear to affect the
|
||
|
|
ability of the frontend to function correctly.
|
||
|
|
|
||
|
|
Further Update
|
||
|
|
~~~~~~~~~~~~~~
|
||
|
|
|
||
|
|
dvbstream and VideoLAN Client on windows works a treat with
|
||
|
|
DVB, in fact this is currently serving as my main way of
|
||
|
|
viewing DVB-T at the moment. Additionally, VLC is happily
|
||
|
|
decoding HDTV signals, although the PC is dropping the odd
|
||
|
|
frame here and there - I assume due to processing capability -
|
||
|
|
as all the decoding is being done under windows in software.
|
||
|
|
|
||
|
|
Many thanks to Nigel Pearson for the updates to this document
|
||
|
|
since the recent revision of the driver.
|