This is complicated to explain and (once all the “other” bugs are worked out) will likely be the biggest complain of people moving to HDTV. SDTV broadcasts are 4:3 (nearly square). HDTV broadcasts are 16:9 (widescreen). If you watch a 4:3 SDTV program on a 16:9 TV, you have several options.
One option is called “pillar box”, where the 4:3 program fills the screen top to bottom, but not side-to-side, and thus there will be empty (usually black or gray) bars or “pillars” added to the sides of the image. Another option is called “stretch” or “fill” which stretches the image wider so it fills the fill 16:9 screen. You get no annoying black bars on the sides, but the picture is distorted with objects and people appearing “short and wide”. Some equipment has a fill mode that stretches the outer left and right edges of the image more than the middle which helps to minimize the “wide” appearance of objects in the center of the screen, but can give the image a “fishbowl” effect when the camera pans. Another way to view 4:3 content on a 16:9 set is in “zoom” or “crop” mode. This literally zooms-in on the image so it fills the width of the screen, but at the expense of cutting or “cropping” of some of the top and bottom of the picture.
In addition to these basic three choices for adapting 4:3 content to a 16:9 screen, some equipment may have options to adjust how much zooming and stretching is done. For example, some zoom adjusts can reach a happy medium where the “pillar” bars are much more narrow and less of the top and bottom are cut-off. Other may have adjustments for the stretch mode that allow the image to be stretch slightly in height at the expense of cutting-off some fo the top and bottom, but reducing the “wide” distortion.
Your HR2x has the ability to show SDTV channels in pillar box, stretch, or zoom mode, although with no “fine” adjustments. The HR2x will *not* allow you to make any of these adjustments to HDTV content on a 16:9 TV. Your TV may have some of these adjustments and it may or may not allow them to be selected when it is receiving an HDTV signal. For example, I have an older Panasonic 42” plasma that will allow aspect adjustments on SDTV signals (480i or 480p), but it will not allow them on HDTV signals (720p or 1080i). My newer 50” Panasonic plasma allows the adjustments on any signal, from 480i up to 1080p.
My guess is that you have your HR2x set to either “crop” or “stretch” mode for SDTV channels. When you tune to an SDTV channel, the HR2x automatically adjusts the 4:3 picture so it fills your 16:9 TV. However, when you tune to an HDTV channel, the HR2x simply passes the image as it is broadcast by the station. And there’s the “rub” – even though you are watching an HDTV channel, the actual program content they are showing may have originally been recorded in a 4:3 aspect ration and not 16:9. In this case, the broadcast station has to choose how they want to fit that into their 16:9 HDTV broadcast. They may choose to zoom it, stretch it, or just put in the pillar bars. Regardless of what they do, your HR2x has no control – it can only send that image to your TV as broadcast.
By the way, different HDTV stations do different things. Most of the newer programs on the major networks (NBC, ABC, CBS, FOX) are being filmed in 16:9 HDTV. Examples include American Idol, Law & Order, CSI, etc. Some programs, like Deal or No Deal and local news segments, are still in SDTV and thus have the pillar bars added. Some of the “cable” networks like TLC and Discovery take their older 4:3 content and do a decent job with a combination of zoom and stretch that results in very narrow pillar bars, very little loss of top and bottom edges due to cropping, and very little distortion from stretching. Some stations like TNT-HD do a horrible job of putting 4:3 content into a 16:9 broadcast by stretching it and using the “fishbowl” effect. It’s especially aggravating when they do this on the “pan and scan: 4:3 version of a theatrical movie that was originally filmed in 16:9 widescreen mode.
I hope this helps explain why you see what you do! I know I rambled on, but I hear enough people talking about this that it seemed like it needed the explanation.