Do I need to buy a new TV to enjoy the HDTV programs?	What does "down-convert" mean?	What does "up-convert" mean?
If your current TV is not “HD Ready” and only able to receive analog signals, you will need to buy a HDTV set top box (receiver) in order to continue to receive the digital signals. However, due to the display limitation of analog TV, you will not able to enjoy the full benefit that digital broadcast can bring you.	Down-convert takes place when a digital broadcast signal exceeds the display capabilities of the your television and the broadcast signal is reduced to match the television's limited display capabilities. For example, if a channel broadcasts a digital program using 1080 lines (1080i format) while the your television is only able to display 576 lines, the 1080i signal is reduced or down-converted to only 576 lines, resulting in inferior picture quality.	Up-convert takes place when a digital television's display capabilities exceed the digital broadcast signal and the broadcast signal is increased to match the TV's display program using 576 lines (576i or 576p) and the digital television is able to display 1080 lines, the signal is increased or up-converted to match the TV, resulting in hazy picture quality.

Why Digital TV is better than Analog TV?

MPEG 2

The MPEG2 content is created from various resources such as moving video, graphic, text, it is then composited into a plane of pixels, these are encoded as if they all were moving video pixels.
At the consume side, decoding is a straightforward operation.
MPEG2 is a static presentation engine: if one broadcaster is retransmitting another broadcaster coverage of an event, the latter logo cannot be removed. You can add graphic and textual elements to the final presentation, but your cannot delete them.

MPEG 4

The MPEG4 is dynamic
Suited for interactive multi-media delivery systems at any bandwidth.
(from DMB-TH to HDTV)
MPEG4 is object-based, construct mul.
User can interact with objects in the scene: to change color of a car to see how it look, to tag a player on the field and watch all their moves, or personalize enhancements to an enhanced video program.
MPEG4 opens up new revenue otimedia scenes whick revolutionize the possibilities of interactive mediapportunities through the intergration of back office systems including transaction / e-commerce systems.