From my reading and trying to implement things in Linux and XP,
On the Linux side, there is a way to change the channels on the 620x via the 1394 cable, but I am not able to find software to record. On the XP side, it is easy to record, but no way to change the channel via the 1394 connection.
Is there a plug-in for Myth that will capture the TS stream from firewire and use the 6200ch plug-in to change the channel?
I don't think there is a way to do the channel changes from Windows (via 1394), and none of the front ends will capture the 1394 TS stream.