Have LinuxMCE automatically control the TV and Stereo
How to set it up
First add the TV's and stereos in LinuxMCE Admin on the Wizard, Devices, A/V Equipment page. Then go to Wizard, Devices, Media Directors. In the Pipes column click 'Edit' and create a specify for audio pipe the device you want the audio to go to, including the input to use on that device, and the same for the video device.
How to use it
It's all automatic. LinuxMCE will automatically manage the a/v equipment once you've specified the a/v pipe.
If the A/V equipment is controlled in some way that LinuxMCE can get feedback from it, such as RS232 or Ethernet, then you can also physically turn on or adjust any relevant device and set it's input to whatever the Media Director is connected to. LinuxMCE will then assume you want to watch TV with the PVR on that media director and set everything up automatically.
The message translation class is used within the infrared devices (like gc100), and within GSD (generic serial device) to translate commands and handle things like toggle vs discrete inputs. Devices which are controlled using GSD and a serial/ethernet interface will fire events AV_Input_Changed and Device_OnOff which Media_Plugin has interceptors for and will use the a/v pipes to figure out what device you're trying to use.