Thanks for the reply,
So, just to make sure i get this. I'm in Canada, so I would need to get a set top box from our service provider. That receiver would be in the basement next to the core and connects to the core via sat cable (rg6) and a capture card. How does the HDMI matrix integrate? Will it allow the sat signal from one receiver to be sent over the network, or would i need to run hdmi from the matrix to the rest of the md's.
Well if the STB is SD then you could use an SD capture card to digitise the output of the STB. If the STB is HD then you can use a capture card such as the HD-PVR yo capture the HD picture out put and deliver it to MythTV for recording etc.
What we prefer to do is keep video from provider STB's or PVR's outside the system and just use an HDMI video matrix to distribute the HD video signal to whichever room you require it in. You would use LinuXMCE to control the PVR/STB's using IR (or IP or RS232 if that is supported by PVR/STB). You loose some flexibility in terms of where the recordings are stored - they are stored in the individual PVR's but you gain in picture quality.
The PVR/STB need to be connected to your Dish/LNB and there video output either needs to be captured into the Core or be distributed via the HDMI Video Matrix and CAT5/6 Baluns/extenders to the TV in any room. The TV itself can be controlled via RS232 or IR.
All the best