1 .. SPDX-License-Identifier: GPL-2.0 1 .. SPDX-License-Identifier: GPL-2.0
2 2
3 FAQ 3 FAQ
4 === 4 ===
5 5
6 .. note:: 6 .. note::
7 7
8 1. With Digital TV, a single physical cha 8 1. With Digital TV, a single physical channel may have different
9 contents inside it. The specs call eac 9 contents inside it. The specs call each one as a *service*.
10 This is what a TV user would call "cha 10 This is what a TV user would call "channel". So, in order to
11 avoid confusion, we're calling *transp 11 avoid confusion, we're calling *transponders* as the physical
12 channel on this FAQ, and *services* fo 12 channel on this FAQ, and *services* for the logical channel.
13 2. The LinuxTV community maintains some W 13 2. The LinuxTV community maintains some Wiki pages with contain
14 a lot of information related to the me 14 a lot of information related to the media subsystem. If you
15 don't find an answer for your needs he 15 don't find an answer for your needs here, it is likely that
16 you'll be able to get something useful 16 you'll be able to get something useful there. It is hosted
17 at: 17 at:
18 18
19 https://www.linuxtv.org/wiki/ 19 https://www.linuxtv.org/wiki/
20 20
21 Some very frequently asked questions about Lin 21 Some very frequently asked questions about Linux Digital TV support
22 22
23 1. The signal seems to die a few seconds after 23 1. The signal seems to die a few seconds after tuning.
24 24
25 It's not a bug, it's a feature. Becaus 25 It's not a bug, it's a feature. Because the frontends have
26 significant power requirements (and he 26 significant power requirements (and hence get very hot), they
27 are powered down if they are unused (i 27 are powered down if they are unused (i.e. if the frontend device
28 is closed). The ``dvb-core`` module pa 28 is closed). The ``dvb-core`` module parameter ``dvb_shutdown_timeout``
29 allow you to change the timeout (defau 29 allow you to change the timeout (default 5 seconds). Setting the
30 timeout to 0 disables the timeout feat 30 timeout to 0 disables the timeout feature.
31 31
32 2. How can I watch TV? 32 2. How can I watch TV?
33 33
34 Together with the Linux Kernel, the Di 34 Together with the Linux Kernel, the Digital TV developers support
35 some simple utilities which are mainly 35 some simple utilities which are mainly intended for testing
36 and to demonstrate how the DVB API wor 36 and to demonstrate how the DVB API works. This is called DVB v5
37 tools and are grouped together with th 37 tools and are grouped together with the ``v4l-utils`` git repository:
38 38
39 https://git.linuxtv.org/v4l-utils. 39 https://git.linuxtv.org/v4l-utils.git/
40 40
41 You can find more information at the L 41 You can find more information at the LinuxTV wiki:
42 42
43 https://www.linuxtv.org/wiki/index 43 https://www.linuxtv.org/wiki/index.php/DVBv5_Tools
44 44
45 The first step is to get a list of ser 45 The first step is to get a list of services that are transmitted.
46 46
47 This is done by using several existing 47 This is done by using several existing tools. You can use
48 for example the ``dvbv5-scan`` tool. Y 48 for example the ``dvbv5-scan`` tool. You can find more information
49 about it at: 49 about it at:
50 50
51 https://www.linuxtv.org/wiki/index 51 https://www.linuxtv.org/wiki/index.php/Dvbv5-scan
52 52
53 There are some other applications like 53 There are some other applications like ``w_scan`` [#]_ that do a
54 blind scan, trying hard to find all po 54 blind scan, trying hard to find all possible channels, but
55 those consumes a large amount of time 55 those consumes a large amount of time to run.
56 56
57 .. [#] https://www.linuxtv.org/wiki/in 57 .. [#] https://www.linuxtv.org/wiki/index.php/W_scan
58 58
59 Also, some applications like ``kaffein 59 Also, some applications like ``kaffeine`` have their own code
60 to scan for services. So, you don't ne 60 to scan for services. So, you don't need to use an external
61 application to obtain such list. 61 application to obtain such list.
62 62
63 Most of such tools need a file contain 63 Most of such tools need a file containing a list of channel
64 transponders available on your area. S 64 transponders available on your area. So, LinuxTV developers
65 maintain tables of Digital TV channel 65 maintain tables of Digital TV channel transponders, receiving
66 patches from the community to keep the 66 patches from the community to keep them updated.
67 67
68 This list is hosted at: 68 This list is hosted at:
69 69
70 https://git.linuxtv.org/dtv-scan-t 70 https://git.linuxtv.org/dtv-scan-tables.git
71 71
72 And packaged on several distributions. 72 And packaged on several distributions.
73 73
74 Kaffeine has some blind scan support f 74 Kaffeine has some blind scan support for some terrestrial standards.
75 It also relies on DTV scan tables, alt 75 It also relies on DTV scan tables, although it contains a copy
76 of it internally (and, if requested by 76 of it internally (and, if requested by the user, it will download
77 newer versions of it). 77 newer versions of it).
78 78
79 If you are lucky you can just use one 79 If you are lucky you can just use one of the supplied channel
80 transponders. If not, you may need to 80 transponders. If not, you may need to seek for such info at
81 the Internet and create a new file. Th 81 the Internet and create a new file. There are several sites with
82 contains physical channel lists. For c 82 contains physical channel lists. For cable and satellite, usually
83 knowing how to tune into a single chan 83 knowing how to tune into a single channel is enough for the
84 scanning tool to identify the other ch 84 scanning tool to identify the other channels. On some places,
85 this could also work for terrestrial t 85 this could also work for terrestrial transmissions.
86 86
87 Once you have a transponders list, you 87 Once you have a transponders list, you need to generate a services
88 list with a tool like ``dvbv5-scan``. 88 list with a tool like ``dvbv5-scan``.
89 89
90 Almost all modern Digital TV cards don 90 Almost all modern Digital TV cards don't have built-in hardware
91 MPEG-decoders. So, it is up to the app 91 MPEG-decoders. So, it is up to the application to get a MPEG-TS
92 stream provided by the board, split it 92 stream provided by the board, split it into audio, video and other
93 data and decode. 93 data and decode.
94 94
95 3. Which Digital TV applications exist? 95 3. Which Digital TV applications exist?
96 96
97 Several media player applications are 97 Several media player applications are capable of tuning into
98 digital TV channels, including Kaffein 98 digital TV channels, including Kaffeine, Vlc, mplayer and MythTV.
99 99
100 Kaffeine aims to be very user-friendly 100 Kaffeine aims to be very user-friendly, and it is maintained
101 by one of the Kernel driver developers 101 by one of the Kernel driver developers.
102 102
103 A comprehensive list of those and othe 103 A comprehensive list of those and other apps can be found at:
104 104
105 https://www.linuxtv.org/wiki/index 105 https://www.linuxtv.org/wiki/index.php/TV_Related_Software
106 106
107 Some of the most popular ones are link 107 Some of the most popular ones are linked below:
108 108
109 https://kde.org/applications/multimedi 109 https://kde.org/applications/multimedia/org.kde.kaffeine
110 KDE media player, focused on D 110 KDE media player, focused on Digital TV support
111 111
112 https://www.linuxtv.org/vdrwiki/index. 112 https://www.linuxtv.org/vdrwiki/index.php/Main_Page
113 Klaus Schmidinger's Video Disk 113 Klaus Schmidinger's Video Disk Recorder
114 114
115 https://linuxtv.org/downloads and http 115 https://linuxtv.org/downloads and https://git.linuxtv.org/
116 Digital TV and other media-rel 116 Digital TV and other media-related applications and
117 Kernel drivers. The ``v4l-util 117 Kernel drivers. The ``v4l-utils`` package there contains
118 several swiss knife tools for 118 several swiss knife tools for using with Digital TV.
119 119
120 http://sourceforge.net/projects/dvbtoo 120 http://sourceforge.net/projects/dvbtools/
121 Dave Chapman's dvbtools packag 121 Dave Chapman's dvbtools package, including
122 dvbstream and dvbtune 122 dvbstream and dvbtune
123 123
124 http://www.dbox2.info/ 124 http://www.dbox2.info/
125 LinuxDVB on the dBox2 125 LinuxDVB on the dBox2
126 126
127 http://www.tuxbox.org/ 127 http://www.tuxbox.org/
128 the TuxBox CVS many interestin 128 the TuxBox CVS many interesting DVB applications and the dBox2
129 DVB source 129 DVB source
130 130
131 http://www.nenie.org/misc/mpsys/ 131 http://www.nenie.org/misc/mpsys/
132 MPSYS: a MPEG2 system library 132 MPSYS: a MPEG2 system library and tools
133 133
134 https://www.videolan.org/vlc/index.pt. 134 https://www.videolan.org/vlc/index.pt.html
135 Vlc 135 Vlc
136 136
137 http://mplayerhq.hu/ 137 http://mplayerhq.hu/
138 MPlayer 138 MPlayer
139 139
140 http://xine.sourceforge.net/ and http: 140 http://xine.sourceforge.net/ and http://xinehq.de/
141 Xine 141 Xine
142 142
143 http://www.mythtv.org/ 143 http://www.mythtv.org/
144 MythTV - analog TV and digital 144 MythTV - analog TV and digital TV PVR
145 145
146 http://dvbsnoop.sourceforge.net/ 146 http://dvbsnoop.sourceforge.net/
147 DVB sniffer program to monitor 147 DVB sniffer program to monitor, analyze, debug, dump
148 or view dvb/mpeg/dsm-cc/mhp st 148 or view dvb/mpeg/dsm-cc/mhp stream information (TS,
149 PES, SECTION) 149 PES, SECTION)
150 150
151 4. Can't get a signal tuned correctly 151 4. Can't get a signal tuned correctly
152 152
153 That could be due to a lot of problems 153 That could be due to a lot of problems. On my personal experience,
154 usually TV cards need stronger signals 154 usually TV cards need stronger signals than TV sets, and are more
155 sensitive to noise. So, perhaps you ju 155 sensitive to noise. So, perhaps you just need a better antenna or
156 cabling. Yet, it could also be some ha 156 cabling. Yet, it could also be some hardware or driver issue.
157 157
158 For example, if you are using a Techno 158 For example, if you are using a Technotrend/Hauppauge DVB-C card
159 *without* analog module, you might hav 159 *without* analog module, you might have to use module parameter
160 adac=-1 (dvb-ttpci.o). 160 adac=-1 (dvb-ttpci.o).
161 161
162 Please see the FAQ page at linuxtv.org 162 Please see the FAQ page at linuxtv.org, as it could contain some
163 valuable information: 163 valuable information:
164 164
165 https://www.linuxtv.org/wiki/index 165 https://www.linuxtv.org/wiki/index.php/FAQ_%26_Troubleshooting
166 166
167 If that doesn't work, check at the lin 167 If that doesn't work, check at the linux-media ML archives, to
168 see if someone else had a similar prob 168 see if someone else had a similar problem with your hardware
169 and/or digital TV service provider: 169 and/or digital TV service provider:
170 170
171 https://lore.kernel.org/linux-medi 171 https://lore.kernel.org/linux-media/
172 172
173 If none of this works, you can try sen 173 If none of this works, you can try sending an e-mail to the
174 linux-media ML and see if someone else 174 linux-media ML and see if someone else could shed some light.
175 The e-mail is linux-media AT vger.kern 175 The e-mail is linux-media AT vger.kernel.org.
176 176
177 5. The dvb_net device doesn't give me any pack 177 5. The dvb_net device doesn't give me any packets at all
178 178
179 Run ``tcpdump`` on the ``dvb0_0`` inte 179 Run ``tcpdump`` on the ``dvb0_0`` interface. This sets the interface
180 into promiscuous mode so it accepts an 180 into promiscuous mode so it accepts any packets from the PID
181 you have configured with the ``dvbnet` 181 you have configured with the ``dvbnet`` utility. Check if there
182 are any packets with the IP addr and M 182 are any packets with the IP addr and MAC addr you have
183 configured with ``ifconfig`` or with ` 183 configured with ``ifconfig`` or with ``ip addr``.
184 184
185 If ``tcpdump`` doesn't give you any ou 185 If ``tcpdump`` doesn't give you any output, check the statistics
186 which ``ifconfig`` or ``netstat -ni`` 186 which ``ifconfig`` or ``netstat -ni`` outputs. (Note: If the MAC
187 address is wrong, ``dvb_net`` won't ge 187 address is wrong, ``dvb_net`` won't get any input; thus you have to
188 run ``tcpdump`` before checking the st 188 run ``tcpdump`` before checking the statistics.) If there are no
189 packets at all then maybe the PID is w 189 packets at all then maybe the PID is wrong. If there are error packets,
190 then either the PID is wrong or the st 190 then either the PID is wrong or the stream does not conform to
191 the MPE standard (EN 301 192, http://w 191 the MPE standard (EN 301 192, http://www.etsi.org/). You can
192 use e.g. ``dvbsnoop`` for debugging. 192 use e.g. ``dvbsnoop`` for debugging.
193 193
194 6. The ``dvb_net`` device doesn't give me any 194 6. The ``dvb_net`` device doesn't give me any multicast packets
195 195
196 Check your routes if they include the 196 Check your routes if they include the multicast address range.
197 Additionally make sure that "source va 197 Additionally make sure that "source validation by reversed path
198 lookup" is disabled:: 198 lookup" is disabled::
199 199
200 $ "echo 0 > /proc/sys/net/ipv4/conf/ 200 $ "echo 0 > /proc/sys/net/ipv4/conf/dvb0/rp_filter"
201 201
202 7. What are all those modules that need to be 202 7. What are all those modules that need to be loaded?
203 203
204 In order to make it more flexible and 204 In order to make it more flexible and support different hardware
205 combinations, the media subsystem is w 205 combinations, the media subsystem is written on a modular way.
206 206
207 So, besides the Digital TV hardware mo 207 So, besides the Digital TV hardware module for the main chipset,
208 it also needs to load a frontend drive 208 it also needs to load a frontend driver, plus the Digital TV
209 core. If the board also has remote con 209 core. If the board also has remote controller, it will also
210 need the remote controller core and th 210 need the remote controller core and the remote controller tables.
211 The same happens if the board has supp 211 The same happens if the board has support for analog TV: the
212 core support for video4linux need to b 212 core support for video4linux need to be loaded.
213 213
214 The actual module names are Linux-kern 214 The actual module names are Linux-kernel version specific, as,
215 from time to time, things change, in o 215 from time to time, things change, in order to make the media
216 support more flexible. 216 support more flexible.
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