Features to look for on a HDTV set continued...

Comb Filter

If you will be hooking up older video equipment (VCR, DVD or video camera), then a TV with a Comb Filter will be an important consideration. Comb Filters are not necessary with digital video, component or S-video connections, since they bypass a TV’s comb filter; but they are very necessary with composite video or RF connections, which are sometimes the only connection available on older equipment. A Comb Filter clears up any fuzziness or discoloration in fine picture detail that may be introduced by RF and composite video connections limited bandwidth capabilities.

With digital television Comb Filters come in 3 forms, the 2-Line, the 3-Line and the 3D Digital Comb Filter. The most basic variety is the 2-Line Digital, which separates the luminance (black and white and detail information) and the chrominance (the color information) while processing two consecutive horizontal scan lines to clean the picture quality. The 3-Line Digital is more advanced, and uses the information from 3 consecutive horizontal scan lines to perform the needed correction. The 3-D is the most advance version. It analyzes three consecutive scan lines as well as the previous and subsequent video fields to make the correct adjustments.

Reverse 3:2 Pulldown ("Inverse telecining")

If you watch a lot of DVDs and your DVD player is not a new progressive scan model (check your owners manual) then a television with Reverse 3:2 Pulldown may be of interest to you. Reverse 3:2 Pulldown or de-interlacing as it is sometimes called, will eliminate most, if not all of the apparent subtle jerking you see in smooth camera pans. This process allows DVDs to be displayed using progressive scan frames rather than interlaced frames.

The DVD format stores the original film information in its native frame rate, which is shot at 24 frames per second, and as interlaced frames, so that it will be compatible with the old analog TV format. DVD players then manipulate the play back speed from 24 frames per second to 30 frames per second, so that it will match the video frame rate standard. The original consumer VHS / Betamax standards displayed video in an interlaced manner, (with interlacing only half of the complete picture is drawn at a time, so the 30 frames per second needed for video is made up of 60 half frames).

This technique performed by the DVD is known as “3:2 Pulldown” or "telecining". DVD players manipulate the playback to go from 24 to 30 frames per second by periodically repeating the original film frames, so that scenes don’t end up running faster than intended. The manipulation performed by older DVDs combined with the interlaced playback is what causes the subtle jerking you would see in smooth pans.

Modern DVD players perform the de-interlacing and send a progressive scan frame to Digital TV, so if you already own a progressive scan DVD player or you will be purchasing a Blu-ray or HD DVD player, then having the Reverse 3:2 Pulldown feature on your TV is not a necessity.

Remote Control

The remote control is something that often doesn't get close scrutiny. The remote is after all the device that will control your new TV and all of the other equipment that hooks up to it. A superior remote will be able to control the TV, satellite receiver, set-top cable box, DVD player, VCR, CD player and an AV receiver from several different manufacturers. The remote should also have the capability to learn esoteric commands of the other equipment. Another helpful feature is built in macro-commands, so that you can push one button to turn on the TV, satellite receiver and AV receiver to watch TV; push another button to turn off the satellite receiver, turn on the HD DVD player and change the video source input on the HDTV or AV receiver to watch a video. The other nice feature is a backlit remote, so you can see the keys in the dark.

CEC

CEC (Consumer Electronic Control) is an optional specification that is part of HDMI version 1.3a. This specification allows components to discover, communicate and self configure other CEC components in your system, so that optimal configuration becomes plug and play. For example, a feature know as “One Touch Play” will allow a CEC enabled Blu-ray player to switch the active source input on a CEC enabled HDTV, to the HDMI connection the player is connected to, simply by pushing the “Play” button. Follow this link for more on the CEC specification.

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