Documentation/dvb/avermedia.txt

   1
   2 HOWTO: Get An Avermedia DVB-T working under Linux
   3            ______________________________________________
   4
   5    Table of Contents
   6    Assumptions and Introduction
   7    The Avermedia DVB-T
   8    Getting the card going
   9    Receiving DVB-T in Australia
  10    Known Limitations
  11    Further Update
  12
  13 Assumptions and Introduction
  14
  15    It  is assumed that the reader understands the basic structure
  16    of  the Linux Kernel DVB drivers and the general principles of
  17    Digital TV.
  18
  19    One  significant difference between Digital TV and Analogue TV
  20    that  the  unwary  (like  myself)  should  consider  is  that,
  21    although  the  component  structure  of budget DVB-T cards are
  22    substantially  similar  to Analogue TV cards, they function in
  23    substantially different ways.
  24
  25    The  purpose  of  an  Analogue TV is to receive and display an
  26    Analogue  Television  signal. An Analogue TV signal (otherwise
  27    known  as  composite  video)  is  an  analogue  encoding  of a
  28    sequence  of  image frames (25 per second) rasterised using an
  29    interlacing   technique.   Interlacing  takes  two  fields  to
  30    represent  one  frame.  Computers today are at their best when
  31    dealing  with  digital  signals,  not  analogue  signals and a
  32    composite  video signal is about as far removed from a digital
  33    data stream as you can get. Therefore, an Analogue TV card for
  34    a PC has the following purpose:
  35
  36      * Tune the receiver to receive a broadcast signal
  37      * demodulate the broadcast signal
  38      * demultiplex  the  analogue video signal and analogue audio
  39        signal  (note some countries employ a digital audio signal
  40        embedded  within the modulated composite analogue signal -
  41        NICAM.)
  42      * digitize  the analogue video signal and make the resulting
  43        datastream available to the data bus.
  44
  45    The  digital  datastream from an Analogue TV card is generated
  46    by  circuitry on the card and is often presented uncompressed.
  47    For  a PAL TV signal encoded at a resolution of 768x576 24-bit
  48    color pixels over 25 frames per second - a fair amount of data
  49    is  generated and must be proceesed by the PC before it can be
  50    displayed  on the video monitor screen. Some Analogue TV cards
  51    for  PC's  have  onboard  MPEG2  encoders which permit the raw
  52    digital  data  stream  to be presented to the PC in an encoded
  53    and  compressed  form  -  similar  to the form that is used in
  54    Digital TV.
  55
  56    The  purpose of a simple budget digital TV card (DVB-T,C or S)
  57    is to simply:
  58
  59      * Tune the received to receive a broadcast signal.
  60      * Extract  the encoded digital datastream from the broadcast
  61        signal.
  62      * Make  the  encoded digital datastream (MPEG2) available to
  63        the data bus.
  64
  65    The  significant  difference between the two is that the tuner
  66    on  the analogue TV card spits out an Analogue signal, whereas
  67    the  tuner  on  the  digital  TV  card  spits out a compressed
  68    encoded   digital   datastream.   As  the  signal  is  already
  69    digitised,  it  is  trivial  to pass this datastream to the PC
  70    databus  with  minimal  additional processing and then extract
  71    the  digital  video  and audio datastreams passing them to the
  72    appropriate software or hardware for decoding and viewing.
  73      _________________________________________________________
  74
  75 The Avermedia DVB-T
  76
  77    The Avermedia DVB-T is a budget PCI DVB card. It has 3 inputs:
  78
  79      * RF Tuner Input
  80      * Composite Video Input (RCA Jack)
  81      * SVIDEO Input (Mini-DIN)
  82
  83    The  RF  Tuner  Input  is the input to the tuner module of the
  84    card.  The  Tuner  is  otherwise known as the "Frontend" . The
  85    Frontend of the Avermedia DVB-T is a Microtune 7202D. A timely
  86    post  to  the  linux-dvb  mailing  list  ascertained  that the
  87    Microtune  7202D  is  supported  by the sp887x driver which is
  88    found in the dvb-hw CVS module.
  89
  90    The  DVB-T card is based around the BT878 chip which is a very
  91    common multimedia bridge and often found on Analogue TV cards.
  92    There is no on-board MPEG2 decoder, which means that all MPEG2
  93    decoding  must  be done in software, or if you have one, on an
  94    MPEG2 hardware decoding card or chipset.
  95      _________________________________________________________
  96
  97 Getting the card going
  98
  99    In order to fire up the card, it is necessary to load a number
 100    of modules from the DVB driver set. Prior to this it will have
 101    been  necessary to download these drivers from the linuxtv CVS
 102    server and compile them successfully.
 103
 104    Depending on the card's feature set, the Device Driver API for
 105    DVB under Linux will expose some of the following device files
 106    in the /dev tree:
 107
 108      * /dev/dvb/adapter0/audio0
 109      * /dev/dvb/adapter0/ca0
 110      * /dev/dvb/adapter0/demux0
 111      * /dev/dvb/adapter0/dvr0
 112      * /dev/dvb/adapter0/frontend0
 113      * /dev/dvb/adapter0/net0
 114      * /dev/dvb/adapter0/osd0
 115      * /dev/dvb/adapter0/video0
 116
 117    The  primary  device  nodes that we are interested in (at this
 118    stage) for the Avermedia DVB-T are:
 119
 120      * /dev/dvb/adapter0/dvr0
 121      * /dev/dvb/adapter0/frontend0
 122
 123    The dvr0 device node is used to read the MPEG2 Data Stream and
 124    the frontend0 node is used to tune the frontend tuner module.
 125
 126    At  this  stage,  it  has  not  been  able  to  ascertain  the
 127    functionality  of the remaining device nodes in respect of the
 128    Avermedia  DVBT.  However,  full  functionality  in respect of
 129    tuning,  receiving  and  supplying  the  MPEG2  data stream is
 130    possible  with the currently available versions of the driver.
 131    It  may be possible that additional functionality is available
 132    from  the  card  (i.e.  viewing the additional analogue inputs
 133    that  the card presents), but this has not been tested yet. If
 134    I get around to this, I'll update the document with whatever I
 135    find.
 136
 137    To  power  up  the  card,  load  the  following modules in the
 138    following order:
 139
 140      * insmod dvb-core.o
 141      * modprobe bttv.o
 142      * insmod bt878.o
 143      * insmod dvb-bt8xx.o
 144      * insmod sp887x.o
 145
 146    Insertion  of  these  modules  into  the  running  kernel will
 147    activate the appropriate DVB device nodes. It is then possible
 148    to start accessing the card with utilities such as scan, tzap,
 149    dvbstream etc.
 150
 151    The frontend module sp887x.o, requires an external   firmware.
 152    Please use  the  command "get_dvb_firmware sp887x" to download
 153    it. Then copy it to /usr/lib/hotplug/firmware.
 154
 155 Receiving DVB-T in Australia
 156
 157    I  have  no  experience of DVB-T in other countries other than
 158    Australia,  so  I will attempt to explain how it works here in
 159    Melbourne  and how this affects the configuration of the DVB-T
 160    card.
 161
 162    The  Digital  Broadcasting  Australia  website has a Reception
 163    locatortool which provides information on transponder channels
 164    and  frequencies.  My  local  transmitter  happens to be Mount
 165    Dandenong.
 166
 167    The frequencies broadcast by Mount Dandenong are:
 168
 169    Table 1. Transponder Frequencies Mount Dandenong, Vic, Aus.
 170    Broadcaster Channel Frequency
 171    ABC         VHF 12  226.5 MHz
 172    TEN         VHF 11  219.5 MHz
 173    NINE        VHF 8   191.625 MHz
 174    SEVEN       VHF 6   177.5 MHz
 175    SBS         UHF 29  536.5 MHz
 176
 177    The Scan utility has a set of compiled-in defaults for various
 178    countries and regions, but if they do not suit, or if you have
 179    a pre-compiled scan binary, you can specify a data file on the
 180    command  line which contains the transponder frequencies. Here
 181    is a sample file for the above channel transponders:
 182 # Data file for DVB scan program
 183 #
 184 # C Frequency SymbolRate FEC QAM
 185 # S Frequency Polarisation SymbolRate FEC
 186 # T Frequency Bandwidth FEC FEC2 QAM Mode Guard Hier
 187 T 226500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
 188 T 191625000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
 189 T 219500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
 190 T 177500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
 191 T 536500000 7MHz 2/3 NONE QAM64 8k 1/8 NONE
 192
 193    The   defaults   for   the  transponder  frequency  and  other
 194    modulation parameters were obtained from www.dba.org.au.
 195
 196    When  Scan  runs, it will output channels.conf information for
 197    any  channel's transponders which the card's frontend can lock
 198    onto.  (i.e.  any  whose  signal  is  strong  enough  at  your
 199    antenna).
 200
 201    Here's my channels.conf file for anyone who's interested:
 202 ABC HDTV:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64
 203 :TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:2307:0:560
 204 ABC TV Melbourne:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_
 205 4:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:65
 206 0:561
 207 ABC TV 2:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64
 208 :TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:562
 209 ABC TV 3:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64
 210 :TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:563
 211 ABC TV 4:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:QAM_64
 212 :TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:564
 213 ABC DiG Radio:226500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_3_4:Q
 214 AM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:0:2311:56
 215 6
 216 TEN Digital:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM
 217 _64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:158
 218 5
 219 TEN Digital 1:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:Q
 220 AM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1
 221 586
 222 TEN Digital 2:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:Q
 223 AM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1
 224 587
 225 TEN Digital 3:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:Q
 226 AM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1
 227 588
 228 TEN Digital:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM
 229 _64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:158
 230 9
 231 TEN Digital 4:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:Q
 232 AM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:1
 233 590
 234 TEN Digital:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM
 235 _64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:159
 236 1
 237 TEN HD:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_64:T
 238 RANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:514:0:1592
 239 TEN Digital:219500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM
 240 _64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:650:159
 241 3
 242 Nine Digital:191625000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QA
 243 M_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:513:660:10
 244 72
 245 Nine Digital HD:191625000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2
 246 :QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:512:0:1
 247 073
 248 Nine Guide:191625000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_3_4:FEC_1_2:QAM_
 249 64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_16:HIERARCHY_NONE:514:670:1074
 250 7 Digital:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_6
 251 4:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:769:770:1328
 252 7 Digital 1:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM
 253 _64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:769:770:1329
 254 7 Digital 2:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM
 255 _64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:769:770:1330
 256 7 Digital 3:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM
 257 _64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:769:770:1331
 258 7 HD Digital:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QA
 259 M_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:833:834:133
 260 2
 261 7 Program Guide:177500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3
 262 :QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:865:866:
 263 1334
 264 SBS HD:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:T
 265 RANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:102:103:784
 266 SBS DIGITAL 1:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:Q
 267 AM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:161:81:785
 268 SBS DIGITAL 2:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:Q
 269 AM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:162:83:786
 270 SBS EPG:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM_64:
 271 TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:163:85:787
 272 SBS RADIO 1:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM
 273 _64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:0:201:798
 274 SBS RADIO 2:536500000:INVERSION_OFF:BANDWIDTH_7_MHZ:FEC_2_3:FEC_2_3:QAM
 275 _64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:0:202:799
 276      _________________________________________________________
 277
 278 Known Limitations
 279
 280    At  present  I can say with confidence that the frontend tunes
 281    via /dev/dvb/adapter{x}/frontend0 and supplies an MPEG2 stream
 282    via   /dev/dvb/adapter{x}/dvr0.   I   have   not   tested  the
 283    functionality  of any other part of the card yet. I will do so
 284    over time and update this document.
 285
 286    There  are some limitations in the i2c layer due to a returned
 287    error message inconsistency. Although this generates errors in
 288    dmesg  and  the  system logs, it does not appear to affect the
 289    ability of the frontend to function correctly.
 290      _________________________________________________________
 291
 292 Further Update
 293
 294    dvbstream  and  VideoLAN  Client on windows works a treat with
 295    DVB,  in  fact  this  is  currently  serving as my main way of
 296    viewing  DVB-T  at  the  moment.  Additionally, VLC is happily
 297    decoding  HDTV  signals,  although  the PC is dropping the odd
 298    frame here and there - I assume due to processing capability -
 299    as all the decoding is being done under windows in software.
 300
 301    Many  thanks to Nigel Pearson for the updates to this document
 302    since the recent revision of the driver.
 303
 304    January 29th 2004