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1Some very frequently asked questions about linuxtv-dvb
2
31. 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 paramter "dvb_shutdown_timeout"
9 allow you to change the timeout (default 5 seconds). Setting the
10 timeout to 0 disables the timeout feature.
11
122. 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
543. 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://www.linuxstb.org/
64 http://sourceforge.net/projects/dvbtools/
65 Dave Chapman's dvbtools package, including
66 dvbstream and dvbtune
67
68 http://www.linuxdvb.tv/
69 Henning Holtschneider's site with many interesting
70 links and docs
71
72 http://www.dbox2.info/
73 LinuxDVB on the dBox2
74
75 http://www.tuxbox.org/
76 http://cvs.tuxbox.org/
77 the TuxBox CVS many interesting DVB applications and the dBox2
78 DVB source
79
80 http://sourceforge.net/projects/dvbsak/
81 DVB Swiss Army Knife library and utilities
82
83 http://www.nenie.org/misc/mpsys/
84 MPSYS: a MPEG2 system library and tools
85
86 http://mplayerhq.hu/
87 mplayer
88
89 http://xine.sourceforge.net/
90 http://xinehq.de/
91 xine
92
93 http://www.mythtv.org/
94 MythTV - analog TV PVR, but now with DVB support, too
95 (with software MPEG decode)
96
97 http://dvbsnoop.sourceforge.net/
98 DVB sniffer program to monitor, analyze, debug, dump
99 or view dvb/mpeg/dsm-cc/mhp stream information (TS,
100 PES, SECTION)
101
1024. Can't get a signal tuned correctly
103
104 If you are using a Technotrend/Hauppauge DVB-C card *without* analog
105 module, you might have to use module parameter adac=-1 (dvb-ttpci.o).
106
1075. The dvb_net device doesn't give me any packets at all
108
109 Run tcpdump on the dvb0_0 interface. This sets the interface
110 into promiscous mode so it accepts any packets from the PID
111 you have configured with the dvbnet utility. Check if there
112 are any packets with the IP addr and MAC addr you have
113 configured with ifconfig.
114
115 If tcpdump doesn't give you any output, check the statistics
116 which ifconfig outputs. (Note: If the MAC address is wrong,
117 dvb_net won't get any input; thus you have to run tcpdump
118 before checking the statistics.) If there are no packets at
119 all then maybe the PID is wrong. If there are error packets,
120 then either the PID is wrong or the stream does not conform to
121 the MPE standard (EN 301 192, http://www.etsi.org/). You can
122 use e.g. dvbsnoop for debugging.
123
1246. The dvb_net device doesn't give me any multicast packets
125
126 Check your routes if they include the multicast address range.
127 Additionally make sure that "source validation by reversed path
128 lookup" is disabled:
129 $ "echo 0 > /proc/sys/net/ipv4/conf/dvb0/rp_filter"
130
1317. What the hell are all those modules that need to be loaded?
132
133 For a dvb-ttpci av7110 based full-featured card the following
134 modules are loaded:
135
136 - videodev: Video4Linux core module. This is the base module that
137 gives you access to the "analog" tv picture of the av7110 mpeg2
138 decoder.
139
140 - v4l2-common: common functions for Video4Linux-2 drivers
141
142 - v4l1-compat: backward compatiblity layer for Video4Linux-1 legacy
143 applications
144
145 - dvb-core: DVB core module. This provides you with the
146 /dev/dvb/adapter entries
147
148 - saa7146: SAA7146 core driver. This is need to access any SAA7146
149 based card in your system.
150
151 - saa7146_vv: SAA7146 video and vbi functions. These are only needed
152 for full-featured cards.
153
154 - video-buf: capture helper module for the saa7146_vv driver. This
155 one is responsible to handle capture buffers.
156
157 - dvb-ttpci: The main driver for AV7110 based, full-featued
158 DVB-S/C/T cards
159
160eof