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diff --git a/Documentation/dvb/faq.txt b/Documentation/dvb/faq.txt new file mode 100644 index 0000000..2511a33 --- /dev/null +++ b/Documentation/dvb/faq.txt @@ -0,0 +1,159 @@ +Some very frequently asked questions about linuxtv-dvb + +1. The signal seems to die a few seconds after tuning. + + It's not a bug, it's a feature. Because the frontends have + significant power requirements (and hence get very hot), they + are powered down if they are unused (i.e. if the frontend device + is closed). The dvb-core.o module parameter "dvb_shutdown_timeout" + allow you to change the timeout (default 5 seconds). Setting the + timeout to 0 disables the timeout feature. + +2. How can I watch TV? + + The driver distribution includes some simple utilities which + are mainly intended for testing and to demonstrate how the + DVB API works. + + Depending on whether you have a DVB-S, DVB-C or DVB-T card, use + apps/szap/szap, czap or tzap. You must supply a channel list + in ~/.[sct]zap/channels.conf. If you are lucky you can just copy + one of the supplied channel lists, or you can create a new one + by running apps/scan/scan. If you run scan on an unknown network + you might have to supply some start data in apps/scan/initial.h. + + If you have a card with a built-in hardware MPEG-decoder the + drivers create a video4linux device (/dev/v4l/video0) which + you can use to watch TV with any v4l application. xawtv is known + to work. Note that you cannot change channels with xawtv, you + have to zap using [sct]zap. If you want a nice application for + TV watching and record/playback, have a look at VDR. + + If your card does not have a hardware MPEG decoder you need + a software MPEG decoder. Mplayer or xine are known to work. + Newsflash: MythTV also has DVB support now. + Note: Only very recent versions of Mplayer and xine can decode. + MPEG2 transport streams (TS) directly. Then, run + '[sct]zap channelname -r' in one xterm, and keep it running, + and start 'mplayer - < /dev/dvb/adapter0/dvr0' or + 'xine stdin://mpeg2 < /dev/dvb/adapter0/dvr0' in a second xterm. + That's all far from perfect, but it seems no one has written + a nice DVB application which includes a builtin software MPEG + decoder yet. + + Newsflash: Newest xine directly supports DVB. Just copy your + channels.conf to ~/.xine and start 'xine dvb://', or select + the DVB button in the xine GUI. Channel switching works using the + numpad pgup/pgdown (NP9 / NP3) keys to scroll through the channel osd + menu and pressing numpad-enter to switch to the selected channel. + + Note: Older versions of xine and mplayer understand MPEG program + streams (PS) only, and can be used in conjunction with the + ts2ps tool from the Metzler Brother's dvb-mpegtools package. + +3. Which other DVB applications exist? + + http://www.cadsoft.de/people/kls/vdr/ + Klaus Schmidinger's Video Disk Recorder + + http://www.metzlerbros.org/dvb/ + Metzler Bros. DVB development; alternate drivers and + DVB utilities, include dvb-mpegtools and tuxzap. + + http://sourceforge.net/projects/dvbtools/ + Dave Chapman's dvbtools package, including + dvbstream and dvbtune + + http://www.linuxdvb.tv/ + Henning Holtschneider's site with many interesting + links and docs + + http://www.dbox2.info/ + LinuxDVB on the dBox2 + + http://www.tuxbox.org/ + http://cvs.tuxbox.org/ + the TuxBox CVS many interesting DVB applications and the dBox2 + DVB source + + http://sourceforge.net/projects/dvbsak/ + DVB Swiss Army Knife library and utilities + + http://www.nenie.org/misc/mpsys/ + MPSYS: a MPEG2 system library and tools + + http://mplayerhq.hu/ + mplayer + + http://xine.sourceforge.net/ + http://xinehq.de/ + xine + + http://www.mythtv.org/ + MythTV - analog TV PVR, but now with DVB support, too + (with software MPEG decode) + + http://dvbsnoop.sourceforge.net/ + DVB sniffer program to monitor, analyze, debug, dump + or view dvb/mpeg/dsm-cc/mhp stream information (TS, + PES, SECTION) + +4. Can't get a signal tuned correctly + + If you are using a Technotrend/Hauppauge DVB-C card *without* analog + module, you might have to use module parameter adac=-1 (dvb-ttpci.o). + +5. The dvb_net device doesn't give me any packets at all + + Run tcpdump on the dvb0_0 interface. This sets the interface + into promiscous mode so it accepts any packets from the PID + you have configured with the dvbnet utility. Check if there + are any packets with the IP addr and MAC addr you have + configured with ifconfig. + + If tcpdump doesn't give you any output, check the statistics + which ifconfig outputs. (Note: If the MAC address is wrong, + dvb_net won't get any input; thus you have to run tcpdump + before checking the statistics.) If there are no packets at + all then maybe the PID is wrong. If there are error packets, + then either the PID is wrong or the stream does not conform to + the MPE standard (EN 301 192, http://www.etsi.org/). You can + use e.g. dvbsnoop for debugging. + +6. The dvb_net device doesn't give me any multicast packets + + Check your routes if they include the multicast address range. + Additionally make sure that "source validation by reversed path + lookup" is disabled: + $ "echo 0 > /proc/sys/net/ipv4/conf/dvb0/rp_filter" + +7. What the hell are all those modules that need to be loaded? + + For a dvb-ttpci av7110 based full-featured card the following + modules are loaded: + + - videodev: Video4Linux core module. This is the base module that + gives you access to the "analog" tv picture of the av7110 mpeg2 + decoder. + + - v4l2-common: common functions for Video4Linux-2 drivers + + - v4l1-compat: backward compatibility layer for Video4Linux-1 legacy + applications + + - dvb-core: DVB core module. This provides you with the + /dev/dvb/adapter entries + + - saa7146: SAA7146 core driver. This is need to access any SAA7146 + based card in your system. + + - saa7146_vv: SAA7146 video and vbi functions. These are only needed + for full-featured cards. + + - videobuf-dma-sg: capture helper module for the saa7146_vv driver. This + one is responsible to handle capture buffers. + + - dvb-ttpci: The main driver for AV7110 based, full-featured + DVB-S/C/T cards + +eof |
