1 .. SPDX-License-Identifier: GPL-2.0
3 HOWTO: Get An Avermedia DVB-T working under Linux
4 -------------------------------------------------
10 This documentation is outdated. Please check at the DVB wiki
11 at https://linuxtv.org/wiki for more updated info.
13 There's a section there specific for Avermedia boards at:
14 https://linuxtv.org/wiki/index.php/AVerMedia
17 Assumptions and Introduction
18 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
20 It is assumed that the reader understands the basic structure
21 of the Linux Kernel DVB drivers and the general principles of
24 One significant difference between Digital TV and Analogue TV
25 that the unwary (like myself) should consider is that,
26 although the component structure of budget DVB-T cards are
27 substantially similar to Analogue TV cards, they function in
28 substantially different ways.
30 The purpose of an Analogue TV is to receive and display an
31 Analogue Television signal. An Analogue TV signal (otherwise
32 known as composite video) is an analogue encoding of a
33 sequence of image frames (25 per second) rasterised using an
34 interlacing technique. Interlacing takes two fields to
35 represent one frame. Computers today are at their best when
36 dealing with digital signals, not analogue signals and a
37 composite video signal is about as far removed from a digital
38 data stream as you can get. Therefore, an Analogue TV card for
39 a PC has the following purpose:
41 * Tune the receiver to receive a broadcast signal
42 * demodulate the broadcast signal
43 * demultiplex the analogue video signal and analogue audio
44 signal. **NOTE:** some countries employ a digital audio signal
45 embedded within the modulated composite analogue signal -
47 * digitize the analogue video signal and make the resulting
48 datastream available to the data bus.
50 The digital datastream from an Analogue TV card is generated
51 by circuitry on the card and is often presented uncompressed.
52 For a PAL TV signal encoded at a resolution of 768x576 24-bit
53 color pixels over 25 frames per second - a fair amount of data
54 is generated and must be processed by the PC before it can be
55 displayed on the video monitor screen. Some Analogue TV cards
56 for PCs have onboard MPEG2 encoders which permit the raw
57 digital data stream to be presented to the PC in an encoded
58 and compressed form - similar to the form that is used in
61 The purpose of a simple budget digital TV card (DVB-T,C or S)
64 * Tune the received to receive a broadcast signal.
65 * Extract the encoded digital datastream from the broadcast
67 * Make the encoded digital datastream (MPEG2) available to
70 The significant difference between the two is that the tuner
71 on the analogue TV card spits out an Analogue signal, whereas
72 the tuner on the digital TV card spits out a compressed
73 encoded digital datastream. As the signal is already
74 digitised, it is trivial to pass this datastream to the PC
75 databus with minimal additional processing and then extract
76 the digital video and audio datastreams passing them to the
77 appropriate software or hardware for decoding and viewing.
82 The Avermedia DVB-T is a budget PCI DVB card. It has 3 inputs:
85 * Composite Video Input (RCA Jack)
86 * SVIDEO Input (Mini-DIN)
88 The RF Tuner Input is the input to the tuner module of the
89 card. The Tuner is otherwise known as the "Frontend" . The
90 Frontend of the Avermedia DVB-T is a Microtune 7202D. A timely
91 post to the linux-dvb mailing list ascertained that the
92 Microtune 7202D is supported by the sp887x driver which is
93 found in the dvb-hw CVS module.
95 The DVB-T card is based around the BT878 chip which is a very
96 common multimedia bridge and often found on Analogue TV cards.
97 There is no on-board MPEG2 decoder, which means that all MPEG2
98 decoding must be done in software, or if you have one, on an
99 MPEG2 hardware decoding card or chipset.
102 Getting the card going
103 ~~~~~~~~~~~~~~~~~~~~~~
105 In order to fire up the card, it is necessary to load a number
106 of modules from the DVB driver set. Prior to this it will have
107 been necessary to download these drivers from the linuxtv CVS
108 server and compile them successfully.
110 Depending on the card's feature set, the Device Driver API for
111 DVB under Linux will expose some of the following device files
114 * /dev/dvb/adapter0/audio0
115 * /dev/dvb/adapter0/ca0
116 * /dev/dvb/adapter0/demux0
117 * /dev/dvb/adapter0/dvr0
118 * /dev/dvb/adapter0/frontend0
119 * /dev/dvb/adapter0/net0
120 * /dev/dvb/adapter0/osd0
121 * /dev/dvb/adapter0/video0
123 The primary device nodes that we are interested in (at this
124 stage) for the Avermedia DVB-T are:
126 * /dev/dvb/adapter0/dvr0
127 * /dev/dvb/adapter0/frontend0
129 The dvr0 device node is used to read the MPEG2 Data Stream and
130 the frontend0 node is used to tune the frontend tuner module.
132 At this stage, it has not been able to ascertain the
133 functionality of the remaining device nodes in respect of the
134 Avermedia DVBT. However, full functionality in respect of
135 tuning, receiving and supplying the MPEG2 data stream is
136 possible with the currently available versions of the driver.
137 It may be possible that additional functionality is available
138 from the card (i.e. viewing the additional analogue inputs
139 that the card presents), but this has not been tested yet. If
140 I get around to this, I'll update the document with whatever I
143 To power up the card, load the following modules in the
146 * modprobe bttv (normally loaded automatically)
147 * modprobe dvb-bt8xx (or place dvb-bt8xx in /etc/modules)
149 Insertion of these modules into the running kernel will
150 activate the appropriate DVB device nodes. It is then possible
151 to start accessing the card with utilities such as scan, tzap,
154 The frontend module sp887x.o, requires an external firmware.
157 Receiving DVB-T in Australia
158 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
160 I have no experience of DVB-T in other countries other than
161 Australia, so I will attempt to explain how it works here in
162 Melbourne and how this affects the configuration of the DVB-T
165 The Digital Broadcasting Australia website has a Reception
166 locatortool which provides information on transponder channels
167 and frequencies. My local transmitter happens to be Mount
170 The frequencies broadcast by Mount Dandenong are:
172 Table 1. Transponder Frequencies Mount Dandenong, Vic, Aus.
173 Broadcaster Channel Frequency
176 NINE VHF 8 191.625 MHz
177 SEVEN VHF 6 177.5 MHz
180 The Scan utility has a set of compiled-in defaults for various
181 countries and regions, but if they do not suit, or if you have
182 a pre-compiled scan binary, you can specify a data file on the
183 command line which contains the transponder frequencies. Here
184 is a sample file for the above channel transponders:
188 # Data file for DVB scan program
190 # C Frequency SymbolRate FEC QAM
191 # S Frequency Polarisation SymbolRate FEC
192 # T Frequency Bandwidth FEC FEC2 QAM Mode Guard Hier
193 T 226500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
194 T 191625000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
195 T 219500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
196 T 177500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
197 T 536500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
199 The defaults for the transponder frequency and other
200 modulation parameters were obtained from www.dba.org.au.
202 When Scan runs, it will output channels.conf information for
203 any channel's transponders which the card's frontend can lock
204 onto. (i.e. any whose signal is strong enough at your
207 Here's my channels.conf file for anyone who's interested:
211 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
212 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
213 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
214 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
215 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
216 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
217 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
218 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
219 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
220 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
221 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
222 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
223 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
224 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
225 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
226 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
227 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
228 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
229 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
230 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
231 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
232 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
233 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
234 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
235 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
236 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
237 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
238 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
239 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
240 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
245 At present I can say with confidence that the frontend tunes
246 via /dev/dvb/adapter{x}/frontend0 and supplies an MPEG2 stream
247 via /dev/dvb/adapter{x}/dvr0. I have not tested the
248 functionality of any other part of the card yet. I will do so
249 over time and update this document.
251 There are some limitations in the i2c layer due to a returned
252 error message inconsistency. Although this generates errors in
253 dmesg and the system logs, it does not appear to affect the
254 ability of the frontend to function correctly.
259 dvbstream and VideoLAN Client on windows works a treat with
260 DVB, in fact this is currently serving as my main way of
261 viewing DVB-T at the moment. Additionally, VLC is happily
262 decoding HDTV signals, although the PC is dropping the odd
263 frame here and there - I assume due to processing capability -
264 as all the decoding is being done under windows in software.
266 Many thanks to Nigel Pearson for the updates to this document
267 since the recent revision of the driver.