1.. SPDX-License-Identifier: GPL-2.0 2 3FAQ 4=== 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 note:: 7 8 This documentation is outdated.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 11Some very frequently asked questions about linuxtv-dvb 12 131. The signal seems to die a few seconds after tuning. 14 15 It's not a bug, it's a feature. Because the frontends have 16 significant power requirements (and hence get very hot), they 17 are powered down if they are unused (i.e. if the frontend device 18 is closed). The dvb-core.o module parameter "dvb_shutdown_timeout" 19 allow you to change the timeout (default 5 seconds). Setting the 20 timeout to 0 disables the timeout feature. 21 222. How can I watch TV? 23 24 The driver distribution includes some simple utilities which 25 are mainly intended for testing and to demonstrate how the 26 DVB API works. 27 28 Depending on whether you have a DVB-S, DVB-C or DVB-T card, use 29 apps/szap/szap, czap or tzap. You must supply a channel list 30 in ~/.[sct]zap/channels.conf. If you are lucky you can just copy 31 one of the supplied channel lists, or you can create a new one 32 by running apps/scan/scan. If you run scan on an unknown network 33 you might have to supply some start data in apps/scan/initial.h. 34 35 If you have a card with a built-in hardware MPEG-decoder the 36 drivers create a video4linux device (/dev/v4l/video0) which 37 you can use to watch TV with any v4l application. xawtv is known 38 to work. Note that you cannot change channels with xawtv, you 39 have to zap using [sct]zap. If you want a nice application for 40 TV watching and record/playback, have a look at VDR. 41 42 If your card does not have a hardware MPEG decoder you need 43 a software MPEG decoder. Mplayer or xine are known to work. 44 Newsflash: MythTV also has DVB support now. 45 Note: Only very recent versions of Mplayer and xine can decode. 46 MPEG2 transport streams (TS) directly. Then, run 47 '[sct]zap channelname -r' in one xterm, and keep it running, 48 and start 'mplayer - < /dev/dvb/adapter0/dvr0' or 49 'xine stdin://mpeg2 < /dev/dvb/adapter0/dvr0' in a second xterm. 50 That's all far from perfect, but it seems no one has written 51 a nice DVB application which includes a builtin software MPEG 52 decoder yet. 53 54 Newsflash: Newest xine directly supports DVB. Just copy your 55 channels.conf to ~/.xine and start 'xine dvb://', or select 56 the DVB button in the xine GUI. Channel switching works using the 57 numpad pgup/pgdown (NP9 / NP3) keys to scroll through the channel osd 58 menu and pressing numpad-enter to switch to the selected channel. 59 60 Note: Older versions of xine and mplayer understand MPEG program 61 streams (PS) only, and can be used in conjunction with the 62 ts2ps tool from the Metzler Brother's dvb-mpegtools package. 63 643. Which other DVB applications exist? 65 66 http://www.cadsoft.de/people/kls/vdr/ 67 Klaus Schmidinger's Video Disk Recorder 68 69 http://www.metzlerbros.org/dvb/ 70 Metzler Bros. DVB development; alternate drivers and 71 DVB utilities, include dvb-mpegtools and tuxzap. 72 73 http://sourceforge.net/projects/dvbtools/ 74 Dave Chapman's dvbtools package, including 75 dvbstream and dvbtune 76 77 http://www.linuxdvb.tv/ 78 Henning Holtschneider's site with many interesting 79 links and docs 80 81 http://www.dbox2.info/ 82 LinuxDVB on the dBox2 83 84 http://www.tuxbox.org/ and http://cvs.tuxbox.org/ 85 the TuxBox CVS many interesting DVB applications and the dBox2 86 DVB source 87 88 https://linuxtv.org/downloads 89 DVB Swiss Army Knife library and utilities 90 91 http://www.nenie.org/misc/mpsys/ 92 MPSYS: a MPEG2 system library and tools 93 94 http://mplayerhq.hu/ 95 mplayer 96 97 http://xine.sourceforge.net/ and http://xinehq.de/ 98 xine 99 100 http://www.mythtv.org/ 101 MythTV - analog TV PVR, but now with DVB support, too 102 (with software MPEG decode) 103 104 http://dvbsnoop.sourceforge.net/ 105 DVB sniffer program to monitor, analyze, debug, dump 106 or view dvb/mpeg/dsm-cc/mhp stream information (TS, 107 PES, SECTION) 108 1094. Can't get a signal tuned correctly 110 111 If you are using a Technotrend/Hauppauge DVB-C card *without* analog 112 module, you might have to use module parameter adac=-1 (dvb-ttpci.o). 113 1145. The dvb_net device doesn't give me any packets at all 115 116 Run tcpdump on the dvb0_0 interface. This sets the interface 117 into promiscuous mode so it accepts any packets from the PID 118 you have configured with the dvbnet utility. Check if there 119 are any packets with the IP addr and MAC addr you have 120 configured with ifconfig. 121 122 If tcpdump doesn't give you any output, check the statistics 123 which ifconfig outputs. (Note: If the MAC address is wrong, 124 dvb_net won't get any input; thus you have to run tcpdump 125 before checking the statistics.) If there are no packets at 126 all then maybe the PID is wrong. If there are error packets, 127 then either the PID is wrong or the stream does not conform to 128 the MPE standard (EN 301 192, http://www.etsi.org/). You can 129 use e.g. dvbsnoop for debugging. 130 1316. The dvb_net device doesn't give me any multicast packets 132 133 Check your routes if they include the multicast address range. 134 Additionally make sure that "source validation by reversed path 135 lookup" is disabled: 136 137.. code-block:: none 138 139 $ "echo 0 > /proc/sys/net/ipv4/conf/dvb0/rp_filter" 140 1417. What the hell are all those modules that need to be loaded? 142 143 For a dvb-ttpci av7110 based full-featured card the following 144 modules are loaded: 145 146 - videodev: Video4Linux core module. This is the base module that 147 gives you access to the "analog" tv picture of the av7110 mpeg2 148 decoder. 149 150 - v4l2-common: common functions for Video4Linux-2 drivers 151 152 - v4l1-compat: backward compatibility layer for Video4Linux-1 legacy 153 applications 154 155 - dvb-core: DVB core module. This provides you with the 156 /dev/dvb/adapter entries 157 158 - saa7146: SAA7146 core driver. This is need to access any SAA7146 159 based card in your system. 160 161 - saa7146_vv: SAA7146 video and vbi functions. These are only needed 162 for full-featured cards. 163 164 - videobuf-dma-sg: capture helper module for the saa7146_vv driver. This 165 one is responsible to handle capture buffers. 166 167 - dvb-ttpci: The main driver for AV7110 based, full-featured 168 DVB-S/C/T cards 169 170