[mythtv] Documentation of DVB DB parameters
Ben Bucksch
linux.news at bucksch.org
Thu May 1 03:42:11 EDT 2003
To be able to try out the DVB code, you need to fill your DB manually
with the configuration of your card and channels. Somebody write a
script/program to import a channels.conf? Anyways, here is the
documentation for it. I'll submit it for inclusion in CVS somewhere
(like keys.txt), but I may improve it before that. This email is
available in HTML and plaintext.
1. Purpose
This doc tries to describe Myth's database. For now, it is spotty.
2. Format of this document
Top-level headings (level 1) are table names (apart from the general
description. Headings of level 2 are column names. The body usually
starts with the data type. Integer means a round number.
3. Property Lists
These are several name/value pairs in a single column, to keep the DB
layout simpler.
The headings of level 3 define in which cases the properties apply (e.g.
a property makes only sense for DVB-S).
The headings of level 4 (e.g. "freq") define the name of the property,
including spaces, capitalization is ignored.
Values are technically strings, but the implementation will usually
complain and ignore the value, if they are not in the expected
format/data type. The expected format is noted directly following the
heading. Boolean (or in short bool) means "1" for yes/on and "0" for
no/false. For strings, capitalization may or may not matter, depending
on the property, spaces usually do matter.
Currently, property lists are stored in columns directly in the table,
in the format "name1=value1|name2=value2", e.g.
"freq=3563457|pol=v|symbol rate=22000".
------------------------------------------------------------------------
4. channel
4.1. channum
String. Used to be the phyiscal (on-the-air) channel, the sometimes
internal id for channels and also the way users change the channel. The
first usage is now moved to the tuning column.
4.2. tuning
Property list. Parameters needed to change the channel on a given card.
Typically, if one of these properties differs between 2 channels, these
2 channels cannot be tuned to at the same time using the same card.
4.2.1. Analog TV
4.2.1.1. channum
String (usually integer) The phyiscal (on-the-air) channel, in a
country-specific canonical format, e.g. "11" or "SE05".
4.2.1.2. finetune
Integer. To slighly tune a bit higher/lower than the channum, to get a
better receivement of the channel.
4.2.2. DVB all
4.2.2.1. freq
Integer. Frequency, in Hz (?)
4.2.3. DVB-S
4.2.3.1. pol
"H" or "V". Polarization - horiozontal or vertical
4.2.3.2. symbol rate
Integer
4.2.3.3. tone
Bool. No idea what this is.
4.2.3.4. diseqc
Integer. Controls motorized rotating sat dishes, you only need this, if
you have such a dish with a motor. You'll know, if you do.
4.2.4. DVB-C
4.2.4.1. inversion
bool or "auto"
4.2.4.2. bandwidth
6, 7, 8 or "auto"
in MHz.
4.2.4.3. hp code rate
"1_2", "2_3", "3_4", "4_5", "5_6", "6_7", "7_8", "8_9" or "auto"
FEC_1_2, FEC_2_3 and so on.
4.2.4.4. lp code rate
Format same as hp code rate. Only needed, if hierarchy is not none.
Noone needs this yet, to my knowledge.
4.2.4.5. modulation
"QPSK", "QAM_16", "QAM_32", "QAM_64", "QAM_128", "QAM_256" or "auto"
4.2.4.6. transmission mode
2, 8 or "auto"
in K.
4.2.4.7. guard interval
4, 8, 16, 32 or "auto"
in 1/n (?)
4.2.4.8. hierarchy
"none" = 0, 1, 2, 4 or "auto"
Noone needs this yet, to my knowledge.
4.3. subtuning
Property list.
Parameters needed to change the channel, but usually on the software level.
For DVB, if these properties differ between 2 channels, but all
properties in column "tuning" match, these 2 channels may still be
receiveable at the same time using the same card.
For other runing types, the meaning/usage is to be defined.
4.3.1. DVB
4.3.1.1. pid vid
Integer. Program ID for the video stream
4.3.1.2. pid aud
Integer. Program ID for the audio stream
5. capturecard
5.1. cardtype
"V4L", "MPEG, "DVB" or "Stream"
V4L: Analog TV cards without hardware encoding
MPEG: Analog TV cards with hardware encoding
DVB: DVB cards (getting MPEG directly from the feed). Experimental.
Stream: Getting MPEG (MPEG PS, ideally) from an external program via
stdout (pipe). Untested.
5.2. options
5.2.1. DVB
5.2.1.1. use ts
Bool. Get a full transport stream from the hardware/driver and filter
out the channel within MythTV.
Not sure yet what is best for each card type (full card or budget card),
depends on driver, userspace library, computing power etc., needs testing.
5.2.1.2. dvb type
"S", "C" or "T"
DVB-S (satellite), DVB-C (cable) or DVB-T (terrestrical = antenna)
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