[mythtv] DVB Features (Subtitles & Interactive)

[David Matthews]

On Wednesday, Dec 8, 2004, at 12:00 Europe/London, 
mythtv-dev-request at mythtv.org wrote:
> Date: Wed, 8 Dec 2004 11:32:25 +0000
> From: Paul Wheeler <paulrwheeler at gmail.com>
> Subject: [mythtv] DVB Features (Subtitles & Interactive)
> To: mythtv-dev at mythtv.org
> Message-ID: <2bfaa54f041208033268c4227 at mail.gmail.com>
> Content-Type: text/plain; charset=US-ASCII
>
> Hello all,
>
> I have two questions about the state of DVB in Myth, I am based in the 
> UK.
>
> Interactive
> ======
>
> I dont know if this is a uk only thing as havent heard it mentioned at
> all on the mailing lists. Can  Myth handle 'going interactive' an
> example is the BBCi service. From what i can tell from scan etc this
> has its own PID with the information. Again what is the state with
> this, have people looked at it in the past and turned it away for some
> reason (what was that reason). In interactive you get a menu and can
> select different streams to watch. Does anyone know if this is a
> hardware issue?

It seemed to me that the lack of interactive and text services was the 
only drawback with Myth when compared with a set-top box.  Since no one 
else seems to be working on this I've been looking at it with a view to 
providing something which can be used in Myth as well as other 
applications.  In the UK interactive data is encoded in MHEG 5, a 
programming language sort of half way between HTML and Java.  Most 
other countries seem to be going for MHP which is Java based.  Both 
MHEG and MHP are transmitted using DSM-CC and there's a program called 
dvbdata which will record the streams.

I've got to the stage where I can display text and graphics and simple 
interactions work using object carousels recorded with dvbdata.  To get 
something working quickly I've been writing an application in Visual 
C++ on Windows.  It's been a long time since I wrote much X-Windows 
code so that was the best way to start.  The intention was always to 
port it Linux so there's very little that is specific to Windows.  I've 
more or less reached the point where it will need to be ported since I 
need to be able to control the tuner directly from the application.  
It's certainly not ready for release yet and any help with it would be 
appreciated.

David.