Documentation/media/dvb-drivers/avermedia.rst

   1 HOWTO: Get An Avermedia DVB-T working under Linux
   2 -------------------------------------------------
   3
   4 February 14th 2006
   5
   6 .. note::
   7
   8    This documentation is outdated. Please check at the DVB wiki
   9    at https://linuxtv.org/wiki for more updated info.
  10
  11    There's a section there specific for Avermedia boards at:
  12    https://linuxtv.org/wiki/index.php/AVerMedia
  13
  14
  15 Assumptions and Introduction
  16 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  17
  18 It  is assumed that the reader understands the basic structure
  19 of  the Linux Kernel DVB drivers and the general principles of
  20 Digital TV.
  21
  22 One  significant difference between Digital TV and Analogue TV
  23 that  the  unwary  (like  myself)  should  consider  is  that,
  24 although  the  component  structure  of budget DVB-T cards are
  25 substantially  similar  to Analogue TV cards, they function in
  26 substantially different ways.
  27
  28 The  purpose  of  an  Analogue TV is to receive and display an
  29 Analogue  Television  signal. An Analogue TV signal (otherwise
  30 known  as  composite  video)  is  an  analogue  encoding  of a
  31 sequence  of  image frames (25 per second) rasterised using an
  32 interlacing   technique.   Interlacing  takes  two  fields  to
  33 represent  one  frame.  Computers today are at their best when
  34 dealing  with  digital  signals,  not  analogue  signals and a
  35 composite  video signal is about as far removed from a digital
  36 data stream as you can get. Therefore, an Analogue TV card for
  37 a PC has the following purpose:
  38
  39 * Tune the receiver to receive a broadcast signal
  40 * demodulate the broadcast signal
  41 * demultiplex  the  analogue video signal and analogue audio
  42   signal. **NOTE:** some countries employ a digital audio signal
  43   embedded  within the modulated composite analogue signal -
  44   NICAM.)
  45 * digitize  the analogue video signal and make the resulting
  46   datastream available to the data bus.
  47
  48 The  digital  datastream from an Analogue TV card is generated
  49 by  circuitry on the card and is often presented uncompressed.
  50 For  a PAL TV signal encoded at a resolution of 768x576 24-bit
  51 color pixels over 25 frames per second - a fair amount of data
  52 is  generated and must be processed by the PC before it can be
  53 displayed  on the video monitor screen. Some Analogue TV cards
  54 for  PCs  have  onboard  MPEG2  encoders  which permit the raw
  55 digital  data  stream  to be presented to the PC in an encoded
  56 and  compressed  form  -  similar  to the form that is used in
  57 Digital TV.
  58
  59 The  purpose of a simple budget digital TV card (DVB-T,C or S)
  60 is to simply:
  61
  62 * Tune the received to receive a broadcast signal.
  63 * Extract  the encoded digital datastream from the broadcast
  64   signal.
  65 * Make  the  encoded digital datastream (MPEG2) available to
  66   the data bus.
  67
  68 The  significant  difference between the two is that the tuner
  69 on  the analogue TV card spits out an Analogue signal, whereas
  70 the  tuner  on  the  digital  TV  card  spits out a compressed
  71 encoded   digital   datastream.   As  the  signal  is  already
  72 digitised,  it  is  trivial  to pass this datastream to the PC
  73 databus  with  minimal  additional processing and then extract
  74 the  digital  video  and audio datastreams passing them to the
  75 appropriate software or hardware for decoding and viewing.
  76
  77 The Avermedia DVB-T
  78 ~~~~~~~~~~~~~~~~~~~
  79
  80 The Avermedia DVB-T is a budget PCI DVB card. It has 3 inputs:
  81
  82 * RF Tuner Input
  83 * Composite Video Input (RCA Jack)
  84 * SVIDEO Input (Mini-DIN)
  85
  86 The  RF  Tuner  Input  is the input to the tuner module of the
  87 card.  The  Tuner  is  otherwise known as the "Frontend" . The
  88 Frontend of the Avermedia DVB-T is a Microtune 7202D. A timely
  89 post  to  the  linux-dvb  mailing  list  ascertained  that the
  90 Microtune  7202D  is  supported  by the sp887x driver which is
  91 found in the dvb-hw CVS module.
  92
  93 The  DVB-T card is based around the BT878 chip which is a very
  94 common multimedia bridge and often found on Analogue TV cards.
  95 There is no on-board MPEG2 decoder, which means that all MPEG2
  96 decoding  must  be done in software, or if you have one, on an
  97 MPEG2 hardware decoding card or chipset.
  98
  99
 100 Getting the card going
 101 ~~~~~~~~~~~~~~~~~~~~~~
 102
 103 In order to fire up the card, it is necessary to load a number
 104 of modules from the DVB driver set. Prior to this it will have
 105 been  necessary to download these drivers from the linuxtv CVS
 106 server and compile them successfully.
 107
 108 Depending on the card's feature set, the Device Driver API for
 109 DVB under Linux will expose some of the following device files
 110 in the /dev tree:
 111
 112 * /dev/dvb/adapter0/audio0
 113 * /dev/dvb/adapter0/ca0
 114 * /dev/dvb/adapter0/demux0
 115 * /dev/dvb/adapter0/dvr0
 116 * /dev/dvb/adapter0/frontend0
 117 * /dev/dvb/adapter0/net0
 118 * /dev/dvb/adapter0/osd0
 119 * /dev/dvb/adapter0/video0
 120
 121 The  primary  device  nodes that we are interested in (at this
 122 stage) for the Avermedia DVB-T are:
 123
 124 * /dev/dvb/adapter0/dvr0
 125 * /dev/dvb/adapter0/frontend0
 126
 127 The dvr0 device node is used to read the MPEG2 Data Stream and
 128 the frontend0 node is used to tune the frontend tuner module.
 129
 130 At  this  stage,  it  has  not  been  able  to  ascertain  the
 131 functionality  of the remaining device nodes in respect of the
 132 Avermedia  DVBT.  However,  full  functionality  in respect of
 133 tuning,  receiving  and  supplying  the  MPEG2  data stream is
 134 possible  with the currently available versions of the driver.
 135 It  may be possible that additional functionality is available
 136 from  the  card  (i.e.  viewing the additional analogue inputs
 137 that  the card presents), but this has not been tested yet. If
 138 I get around to this, I'll update the document with whatever I
 139 find.
 140
 141 To  power  up  the  card,  load  the  following modules in the
 142 following order:
 143
 144 * modprobe bttv (normally loaded automatically)
 145 * modprobe dvb-bt8xx (or place dvb-bt8xx in /etc/modules)
 146
 147 Insertion  of  these  modules  into  the  running  kernel will
 148 activate the appropriate DVB device nodes. It is then possible
 149 to start accessing the card with utilities such as scan, tzap,
 150 dvbstream etc.
 151
 152 The frontend module sp887x.o, requires an external   firmware.
 153 Please use  the  command "get_dvb_firmware sp887x" to download
 154 it. Then copy it to /usr/lib/hotplug/firmware or /lib/firmware/
 155 (depending on configuration of firmware hotplug).
 156
 157 Receiving DVB-T in Australia
 158 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 159
 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
 163 card.
 164
 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
 168 Dandenong.
 169
 170 The frequencies broadcast by Mount Dandenong are:
 171
 172 Table 1. Transponder Frequencies Mount Dandenong, Vic, Aus.
 173 Broadcaster Channel Frequency
 174 ABC         VHF 12  226.5 MHz
 175 TEN         VHF 11  219.5 MHz
 176 NINE        VHF 8   191.625 MHz
 177 SEVEN       VHF 6   177.5 MHz
 178 SBS         UHF 29  536.5 MHz
 179
 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:
 185
 186 ::
 187
 188         # Data file for DVB scan program
 189         #
 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
 198
 199 The   defaults   for   the  transponder  frequency  and  other
 200 modulation parameters were obtained from www.dba.org.au.
 201
 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
 205 antenna).
 206
 207 Here's my channels.conf file for anyone who's interested:
 208
 209 ::
 210
 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
 241
 242 Known Limitations
 243 ~~~~~~~~~~~~~~~~~
 244
 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.
 250
 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.
 255
 256 Further Update
 257 ~~~~~~~~~~~~~~
 258
 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.
 265
 266 Many  thanks to Nigel Pearson for the updates to this document
 267 since the recent revision of the driver.