CEA-775-C defines mechanisms to allow a source of MPEG service, such as a cable or terrestrial set-top box, digital VCR, or DTV to utilize the MPEG decoding and display capabilities in a DTV. A method is included to allow the OSD Producer to supply bitmap graphic overlays for blending and composition in the DTV over decoded video. CEA-775-C supports an optional baseband analog audio/video connection between an audio/video source device and the DTV. Mechanisms are provided to allow the source device to control the selection of the audio/video source for display in the DTV between an MPEG service decoded in the DTV and incoming analog audio/video supplied to it via an external input. Nothing in CEA-775-C is intended to constrain the use of other 1394-based protocols.