[mythtv] Freesat (UK)

[Simon Kenyon]

David Matthews wrote:
> Stuart Auchterlonie wrote:
>   
>> James Buckley wrote:
>>     
>>> Although not exactly on topic, is there any chance that patches to
>>>  get Freesat's EPG would make it into 0.21-fixes. 0.22 could be a 
>>> while, and the new EPG will make a lot of people's lives easier. I
>>>  know it's not directly a fix for a bug, but neither was Schedule 
>>> Direct (although I can see that the new EPG is not quite as 
>>> critical as SD was).
>>>
>>>       
>> Well lets just get them working in head first....
>>
>>     
>
> This is the situation as I understand it. I did ask on the BBC
> backstage mailing list about whether the technical details for Freesat
> were available but the reply was that currently the manufacturers of
> set-top boxes had agreed exclusive access to them. That means that the
> details are limited to what can be worked out from the on-air information.
>
> The Freesat information seems to be transmitted on non-standard PIDs
> presumably to avoid conflicts with existing Sky boxes.
>
> There is an SDT transmitted on a non-standard PID of 3841.  I've only
> looked at this with dvbsnoop but presumably it would be possible to get
> MythTV to scan it and I guess it would require a patch that allowed the
> user to set a non-standard PID in mythtv-setup. It might be useful since
> it seems to contain the "default authority" for the CRIDs and may also
> contain the channel numbers. It seems to have "Channel 4" in there where
> the default tables contain something like "8350".  For the moment,
> though, it's possible to insert the data manually into the database.
>
> The EPG is transmitted as EIT on PID 3842.  It contains CRIDs that are
> similar to those on Freeview and, for BBC, identical. The text is
> compressed and I've largely worked out the compression by comparing the
> Freesat and Freeview data. It seems to be based on the ATSC compression
> scheme but uses non-standard compression tables. There are two tables,
> one for programme titles and the other for the description. They are
> Huffman encoded with the encoding for each character depending on the
> preceding character. That means that it's very difficult or impossible
> to get a complete table because it's not just a matter of seeing every
> character but seeing every combination of characters.  Nevertheless I've
> got most of the titles and text to decompress correctly now so it is
> possible to use this as an EPG but with some of the titles and text
> truncated.
>
> What is the attitude towards having a patch that would be known to be
> incomplete and would have to be updated periodically?  Should I create a
> ticket anyway so that people can try it out? It's definitely going to be
> work-in-progress and just at the moment I don't have much time to do any
> more on it.
>   

i applied your patch from a couple of days ago and it get the program 
durations and genres and (here is the strange bit), some occasional 
program titles.
i will test any patches and report results back. i could also provide 
access to a box with two dvb-s cards pointed at astra-28.2e.
--
simon