[linux-dvb] XML Channel file format

[<mocm@convergence.de>]

Dave Chapman writes:
 > 
 > On Saturday 24 November 2001 15:56, mocm@convergence.de wrote:
 > > The extra information is ok. I could write a program that just parses
 > > the relevant information for the libdvb and ignores the rest. We may
 > > need something for the LNB information, though. I don't want to use
 > > any extra libraries, because I want to keep libdvb simple.
 > 
 > I can understand you wanting to keep libdvb simple and independent, but it 
 > may be a lot of work for you to correctly incorporate an XML parser into 
 > libdvb.

Not a full XML parser, just the very strict format, we would require.

 > 
 > For example, empty elements can be written as either <element></element>, or 
 > <element />.  You also need to take account of things like
character

There should not be any empty elements.
 
 > encodings and entities (e.g. "&amp;"). If you use something like libxml, then 
 > you can just more or less forget about these things.
 > 
 > Also, if you use libxml, you can just call one function to read the entire 
 > XML file into a tree structure in memory.  The application can then 
 > manipulate the tree and write it back to an XML file with a single command.
 > 

Yes, I know, but this bloat everything and I am not convinced that
libxml ist the most efficient library. I will take a look at expat.

 > Regarding things like LNB information.  This has nothing to do with the 
 > channels - it should be stored in a separate setup file for the user.  This 
 > can also include Diseqc information and details on which card(s) can receive 
 > which satellites.
 > 

I don't know if those files should be separat. Without the LNB
information all the channel stuff is useless. I was even thinking of
getting rid of the favorite channel list and just marking the channels
in the resource file.

 > We should also not forget DVB-C and DVB-T when we are doing this.
 > 

Yes, of course.


 > I think the basic structure of the XML file should be as close to the DVB SI 
 > information as possible.  After all, the main purpose of a channels file is 
 > to store that information.
 > 

I think it is enough to stop at the PMT level. It is even enough to
stop at the program PID and get the rest during the tuning operation.
That's what they do in the Nokia format.

It should also be possible to just give a transponder list and let the
program search for the available channels.
That's why I suggested a simple parser that can ignore the irrelevant
data in the full XML document.
That is only for the tuning application. Other applications may use
different data. 

Marcus

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Dr. Marcus Metzler                             
mocm@netcologne.de                     http://www.metzlerbros.de
mocm@convergence.de                    http://www.convergence.de

Convergence Integrated Media GmbH          
Rosenthaler Str. 51                   
D-10178 Berlin                             
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