Based on kernel version 4.1. Page generated on 2015-06-28 12:12 EST.
1 Some very frequently asked questions about linuxtv-dvb 2 3 1. The signal seems to die a few seconds after tuning. 4 5 It's not a bug, it's a feature. Because the frontends have 6 significant power requirements (and hence get very hot), they 7 are powered down if they are unused (i.e. if the frontend device 8 is closed). The dvb-core.o module parameter "dvb_shutdown_timeout" 9 allow you to change the timeout (default 5 seconds). Setting the 10 timeout to 0 disables the timeout feature. 11 12 2. How can I watch TV? 13 14 The driver distribution includes some simple utilities which 15 are mainly intended for testing and to demonstrate how the 16 DVB API works. 17 18 Depending on whether you have a DVB-S, DVB-C or DVB-T card, use 19 apps/szap/szap, czap or tzap. You must supply a channel list 20 in ~/.[sct]zap/channels.conf. If you are lucky you can just copy 21 one of the supplied channel lists, or you can create a new one 22 by running apps/scan/scan. If you run scan on an unknown network 23 you might have to supply some start data in apps/scan/initial.h. 24 25 If you have a card with a built-in hardware MPEG-decoder the 26 drivers create a video4linux device (/dev/v4l/video0) which 27 you can use to watch TV with any v4l application. xawtv is known 28 to work. Note that you cannot change channels with xawtv, you 29 have to zap using [sct]zap. If you want a nice application for 30 TV watching and record/playback, have a look at VDR. 31 32 If your card does not have a hardware MPEG decoder you need 33 a software MPEG decoder. Mplayer or xine are known to work. 34 Newsflash: MythTV also has DVB support now. 35 Note: Only very recent versions of Mplayer and xine can decode. 36 MPEG2 transport streams (TS) directly. Then, run 37 '[sct]zap channelname -r' in one xterm, and keep it running, 38 and start 'mplayer - < /dev/dvb/adapter0/dvr0' or 39 'xine stdin://mpeg2 < /dev/dvb/adapter0/dvr0' in a second xterm. 40 That's all far from perfect, but it seems no one has written 41 a nice DVB application which includes a builtin software MPEG 42 decoder yet. 43 44 Newsflash: Newest xine directly supports DVB. Just copy your 45 channels.conf to ~/.xine and start 'xine dvb://', or select 46 the DVB button in the xine GUI. Channel switching works using the 47 numpad pgup/pgdown (NP9 / NP3) keys to scroll through the channel osd 48 menu and pressing numpad-enter to switch to the selected channel. 49 50 Note: Older versions of xine and mplayer understand MPEG program 51 streams (PS) only, and can be used in conjunction with the 52 ts2ps tool from the Metzler Brother's dvb-mpegtools package. 53 54 3. Which other DVB applications exist? 55 56 http://www.cadsoft.de/people/kls/vdr/ 57 Klaus Schmidinger's Video Disk Recorder 58 59 http://www.metzlerbros.org/dvb/ 60 Metzler Bros. DVB development; alternate drivers and 61 DVB utilities, include dvb-mpegtools and tuxzap. 62 63 http://sourceforge.net/projects/dvbtools/ 64 Dave Chapman's dvbtools package, including 65 dvbstream and dvbtune 66 67 http://www.linuxdvb.tv/ 68 Henning Holtschneider's site with many interesting 69 links and docs 70 71 http://www.dbox2.info/ 72 LinuxDVB on the dBox2 73 74 http://www.tuxbox.org/ 75 http://cvs.tuxbox.org/ 76 the TuxBox CVS many interesting DVB applications and the dBox2 77 DVB source 78 79 http://www.linuxtv.org/downloads/ 80 DVB Swiss Army Knife library and utilities 81 82 http://www.nenie.org/misc/mpsys/ 83 MPSYS: a MPEG2 system library and tools 84 85 http://mplayerhq.hu/ 86 mplayer 87 88 http://xine.sourceforge.net/ 89 http://xinehq.de/ 90 xine 91 92 http://www.mythtv.org/ 93 MythTV - analog TV PVR, but now with DVB support, too 94 (with software MPEG decode) 95 96 http://dvbsnoop.sourceforge.net/ 97 DVB sniffer program to monitor, analyze, debug, dump 98 or view dvb/mpeg/dsm-cc/mhp stream information (TS, 99 PES, SECTION) 100 101 4. Can't get a signal tuned correctly 102 103 If you are using a Technotrend/Hauppauge DVB-C card *without* analog 104 module, you might have to use module parameter adac=-1 (dvb-ttpci.o). 105 106 5. The dvb_net device doesn't give me any packets at all 107 108 Run tcpdump on the dvb0_0 interface. This sets the interface 109 into promiscuous mode so it accepts any packets from the PID 110 you have configured with the dvbnet utility. Check if there 111 are any packets with the IP addr and MAC addr you have 112 configured with ifconfig. 113 114 If tcpdump doesn't give you any output, check the statistics 115 which ifconfig outputs. (Note: If the MAC address is wrong, 116 dvb_net won't get any input; thus you have to run tcpdump 117 before checking the statistics.) If there are no packets at 118 all then maybe the PID is wrong. If there are error packets, 119 then either the PID is wrong or the stream does not conform to 120 the MPE standard (EN 301 192, http://www.etsi.org/). You can 121 use e.g. dvbsnoop for debugging. 122 123 6. The dvb_net device doesn't give me any multicast packets 124 125 Check your routes if they include the multicast address range. 126 Additionally make sure that "source validation by reversed path 127 lookup" is disabled: 128 $ "echo 0 > /proc/sys/net/ipv4/conf/dvb0/rp_filter" 129 130 7. What the hell are all those modules that need to be loaded? 131 132 For a dvb-ttpci av7110 based full-featured card the following 133 modules are loaded: 134 135 - videodev: Video4Linux core module. This is the base module that 136 gives you access to the "analog" tv picture of the av7110 mpeg2 137 decoder. 138 139 - v4l2-common: common functions for Video4Linux-2 drivers 140 141 - v4l1-compat: backward compatibility layer for Video4Linux-1 legacy 142 applications 143 144 - dvb-core: DVB core module. This provides you with the 145 /dev/dvb/adapter entries 146 147 - saa7146: SAA7146 core driver. This is need to access any SAA7146 148 based card in your system. 149 150 - saa7146_vv: SAA7146 video and vbi functions. These are only needed 151 for full-featured cards. 152 153 - videobuf-dma-sg: capture helper module for the saa7146_vv driver. This 154 one is responsible to handle capture buffers. 155 156 - dvb-ttpci: The main driver for AV7110 based, full-featured 157 DVB-S/C/T cards 158 159 eof