[mythtv-users] Why cant we make a STB?

mythtv.t.wuuza at xoxy.net mythtv.t.wuuza at xoxy.net
Fri Feb 6 16:03:47 UTC 2009

>> It's pretty much just the Sigma chip (as expected, the sigmas chip is
>> meant to be a "total package.") Obviously some RAM, an HDMI
>> controller, etc., but the only real "meat" to the system is the Sigma
>> chip, which makes it unsatisfactory for any (non-uPnP) myth purpose.
> You keep saying that a Sigma chip is unsuitable for any non-uPnP myth
> purpose. Why? Because of a legal hurdle, like Sigma won't give out
> documentation to port MythTV's front end without a restrictive NDA
> which would prevent source distribution? Or because of some technical
> hurdle, like insufficient RAM, no way to draw the GUI/OSD etc?

Currently it's not suitable, but it could be.  I'm not exactly sure,  
but I'm pretty sure the Sage software and HD box work together like  
GB-PVR and the PopcornHour do.  GB-PVR (and Sage) originally worked  
with MediaMVPs by taking advantage of the RFB/VNC protocol they used  
to get the UI from the backend.  Thus, you got a full GB-PVR UI on any  
TV by using the MediaMVP.  mvpmc incorporated this "emulation mode"  
into the code base, and so an MVP using mvpmc could connect to a  
GB-PVR server.  The PopcornHour is now the default HD extender for  
GB-PVR because mvpmc has been ported to it.  Most of the other mvpmc  
functionality isn't finished, but the emulation mode works well.  So  
GB-PVR users have a full HD frontend just by buying the PopcornHour.

The way it works is that all the GUI is rendered on the server and  
sent to the extender.  (It's fast - I believe it only sends changes.   
I used GB-PVR for 2 years with an MVP.)  When media is played somehow  
it hands it off to the hardware, but keypresses are still sent to the  
server, so things like commercial skipping still work.  GB-PVR even  
handled fast-forward so it worked faster than the 2x hardware speed on  
the MVP.

mvpmc on the MVP works well enough with Myth, and I don't miss Windows  
at all, but I do miss the full GUI sometimes and have been stalling  
with HD because I really don't know what will replace my MVPs  
(recorded TV with comskip at a minimum, easy and low power desired).   
I think taking advantage of something like the PopcornHour would be  
great - the hardware is ready to go and efficient (ION's the only  
thing close).  I doubt getting the UI running through the emulation  
mode would be all that tough (there's already some info and code here  
http://www.rst38.org.uk/vdr/mediamvp/), but I don't know about the  
media stuff.  Unfortunately GB-PVR is closed source, and I know he  
spent a lot of time on that integration is isn't likely to tell all  
the secrets.  Anyway, with this method, the extender really doesn't  
have to have much general purpose grunt, and the hard stuff can be  
written in whatever language using whatever tools, since it runs on  
the backend.  Porting mvpmc to other hardware is easier than porting a  

The PopcornHour seems more open than some others.  The forums have  
info/source, and here's some apps for it:


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