faq.txt 5.7 KB

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  1. Some very frequently asked questions about linuxtv-dvb
  2. 1. The signal seems to die a few seconds after tuning.
  3. It's not a bug, it's a feature. Because the frontends have
  4. significant power requirements (and hence get very hot), they
  5. are powered down if they are unused (i.e. if the frontend device
  6. is closed). The dvb-core.o module parameter "dvb_shutdown_timeout"
  7. allow you to change the timeout (default 5 seconds). Setting the
  8. timeout to 0 disables the timeout feature.
  9. 2. How can I watch TV?
  10. The driver distribution includes some simple utilities which
  11. are mainly intended for testing and to demonstrate how the
  12. DVB API works.
  13. Depending on whether you have a DVB-S, DVB-C or DVB-T card, use
  14. apps/szap/szap, czap or tzap. You must supply a channel list
  15. in ~/.[sct]zap/channels.conf. If you are lucky you can just copy
  16. one of the supplied channel lists, or you can create a new one
  17. by running apps/scan/scan. If you run scan on an unknown network
  18. you might have to supply some start data in apps/scan/initial.h.
  19. If you have a card with a built-in hardware MPEG-decoder the
  20. drivers create a video4linux device (/dev/v4l/video0) which
  21. you can use to watch TV with any v4l application. xawtv is known
  22. to work. Note that you cannot change channels with xawtv, you
  23. have to zap using [sct]zap. If you want a nice application for
  24. TV watching and record/playback, have a look at VDR.
  25. If your card does not have a hardware MPEG decoder you need
  26. a software MPEG decoder. Mplayer or xine are known to work.
  27. Newsflash: MythTV also has DVB support now.
  28. Note: Only very recent versions of Mplayer and xine can decode.
  29. MPEG2 transport streams (TS) directly. Then, run
  30. '[sct]zap channelname -r' in one xterm, and keep it running,
  31. and start 'mplayer - < /dev/dvb/adapter0/dvr0' or
  32. 'xine stdin://mpeg2 < /dev/dvb/adapter0/dvr0' in a second xterm.
  33. That's all far from perfect, but it seems no one has written
  34. a nice DVB application which includes a builtin software MPEG
  35. decoder yet.
  36. Newsflash: Newest xine directly supports DVB. Just copy your
  37. channels.conf to ~/.xine and start 'xine dvb://', or select
  38. the DVB button in the xine GUI. Channel switching works using the
  39. numpad pgup/pgdown (NP9 / NP3) keys to scroll through the channel osd
  40. menu and pressing numpad-enter to switch to the selected channel.
  41. Note: Older versions of xine and mplayer understand MPEG program
  42. streams (PS) only, and can be used in conjunction with the
  43. ts2ps tool from the Metzler Brother's dvb-mpegtools package.
  44. 3. Which other DVB applications exist?
  45. http://www.cadsoft.de/people/kls/vdr/
  46. Klaus Schmidinger's Video Disk Recorder
  47. http://www.metzlerbros.org/dvb/
  48. Metzler Bros. DVB development; alternate drivers and
  49. DVB utilities, include dvb-mpegtools and tuxzap.
  50. http://sourceforge.net/projects/dvbtools/
  51. Dave Chapman's dvbtools package, including
  52. dvbstream and dvbtune
  53. http://www.linuxdvb.tv/
  54. Henning Holtschneider's site with many interesting
  55. links and docs
  56. http://www.dbox2.info/
  57. LinuxDVB on the dBox2
  58. http://www.tuxbox.org/
  59. http://cvs.tuxbox.org/
  60. the TuxBox CVS many interesting DVB applications and the dBox2
  61. DVB source
  62. http://sourceforge.net/projects/dvbsak/
  63. DVB Swiss Army Knife library and utilities
  64. http://www.nenie.org/misc/mpsys/
  65. MPSYS: a MPEG2 system library and tools
  66. http://mplayerhq.hu/
  67. mplayer
  68. http://xine.sourceforge.net/
  69. http://xinehq.de/
  70. xine
  71. http://www.mythtv.org/
  72. MythTV - analog TV PVR, but now with DVB support, too
  73. (with software MPEG decode)
  74. http://dvbsnoop.sourceforge.net/
  75. DVB sniffer program to monitor, analyze, debug, dump
  76. or view dvb/mpeg/dsm-cc/mhp stream information (TS,
  77. PES, SECTION)
  78. 4. Can't get a signal tuned correctly
  79. If you are using a Technotrend/Hauppauge DVB-C card *without* analog
  80. module, you might have to use module parameter adac=-1 (dvb-ttpci.o).
  81. 5. The dvb_net device doesn't give me any packets at all
  82. Run tcpdump on the dvb0_0 interface. This sets the interface
  83. into promiscous mode so it accepts any packets from the PID
  84. you have configured with the dvbnet utility. Check if there
  85. are any packets with the IP addr and MAC addr you have
  86. configured with ifconfig.
  87. If tcpdump doesn't give you any output, check the statistics
  88. which ifconfig outputs. (Note: If the MAC address is wrong,
  89. dvb_net won't get any input; thus you have to run tcpdump
  90. before checking the statistics.) If there are no packets at
  91. all then maybe the PID is wrong. If there are error packets,
  92. then either the PID is wrong or the stream does not conform to
  93. the MPE standard (EN 301 192, http://www.etsi.org/). You can
  94. use e.g. dvbsnoop for debugging.
  95. 6. The dvb_net device doesn't give me any multicast packets
  96. Check your routes if they include the multicast address range.
  97. Additionally make sure that "source validation by reversed path
  98. lookup" is disabled:
  99. $ "echo 0 > /proc/sys/net/ipv4/conf/dvb0/rp_filter"
  100. 7. What the hell are all those modules that need to be loaded?
  101. For a dvb-ttpci av7110 based full-featured card the following
  102. modules are loaded:
  103. - videodev: Video4Linux core module. This is the base module that
  104. gives you access to the "analog" tv picture of the av7110 mpeg2
  105. decoder.
  106. - v4l2-common: common functions for Video4Linux-2 drivers
  107. - v4l1-compat: backward compatibility layer for Video4Linux-1 legacy
  108. applications
  109. - dvb-core: DVB core module. This provides you with the
  110. /dev/dvb/adapter entries
  111. - saa7146: SAA7146 core driver. This is need to access any SAA7146
  112. based card in your system.
  113. - saa7146_vv: SAA7146 video and vbi functions. These are only needed
  114. for full-featured cards.
  115. - video-buf: capture helper module for the saa7146_vv driver. This
  116. one is responsible to handle capture buffers.
  117. - dvb-ttpci: The main driver for AV7110 based, full-featured
  118. DVB-S/C/T cards
  119. eof