[mythtv] MHEG-5 support for New Zealand Profile

David Matthews dm at prolingua.co.uk
Tue Feb 13 09:55:57 UTC 2007

Steven Ellis wrote:
> Ok I've now got some MHEG streams showing up and some sample data.
> Problem is I can't get it to display anything.
> Have a look at http://www.mythtv.co.nz/mythtv/?p=33 for details on my
> attempts so far and debug output from mythfrontend.
> I also tried using rb-download to try and suck the MHEG data out of the
> stream but it didn't get very far as shown below.
> Dave - what tools did you use to debug the mheg and dsmcc data?

I've looked at your log and it seems that it was loading and running the
MHEG.  The difficulty was when it got to here:
{:Scene  ( '/s.m' 0 )
     :Items (
         {:Link ( '/s.m' 1 )
             :EventSource  ( '/s.m' 0 )
             :EventType UserInput
             :EventData 300
             :LinkEffect (
                 :Launch ( ( '/epg/a' 0 ) )
     :InputEventReg 13
     :SceneCS 720 576
This is waiting for user input.  It is setting the input event register
(i.e. the set of buttons to recognise) to 13 and waiting for a user
event number 300.  Until that event arrives nothing will happen.  The
mapping of buttons to EventData codes and the input event register
values are defined by the profile.  For the UK the red button generates
100, green 101 etc.  The input register values used are 3, 4 or 5.  You
can find this in the UK profile at
http://www.dtg.org.uk/publications/books/mheg_profile_106.pdf under

You need to find out or guess the key and input register values for the
NZ profile and then modify MHIContext::OfferKey in mhi.cpp to generate
the appropriate input values.


More information about the mythtv-dev mailing list