Playing with this new Hitachi 42" plasma today...
One of the 4:3 aspect ratio settings completely fills the screen, no black bars, and no zoom. (I can zoom in for a couple additional settings)
When switching back and forth between the full-screen 4:3 setting and the 16:9 setting, I don't see a lot of difference in the vertical squashing effect. What am I missing?
Also, I haven't really seen any HDTV images yet, partially I suppose because of my cable box. When plugging in my Stevie Ray Vaughan Austin City Limits concert DVD, I don't see an appreciable difference in picture resolution.
So that begs the question, are all DVDs recorded in higher resolution, or is there some marking that lets me know I'm in for a treat or not?
Like zahc said, DVD's are not high def. The only true high-def images are from the Blu-Ray and HD-DVD units playing HD-DVD or Blu-Ray discs. Your cable signal isn't high-def either, that is unless you have the high-def programming package. If I recall, DVD's are 525 lines of horizontal resolutoin (old TV images were 400, again, if memory serves). Standard def DVDs will be noticeably better on high-def sets, but over an old-style TV that could only display 400 lines.
Some TV's, and I think HItachi is one, have a resolution upconverter that will take a standard-def signal and upconvert it to high-def for use by the TV. It doesn't increase the picture to an actual high-def quality, but it does ensure that you are seeing the most pristine image possible from your standard-def source. The latest generation of DVDs, especially those digitally filmed or encoded directly from a digital source (like Pixar's stuff), will benefit the most from this upconversion.
If one of the 4:3 settings fills the screen with no zoom then the TV is morphing the 4:3 signal to fill your 16:9 screen (stretching it). At that setting you should see some distortion of the picture (everone looks strangly bloated or "wide"). If you see no difference between the two settings in terms of distorted picture, then the TV is zooming enough to fill the screen but the effect may just not be as noticeable on that particular program.
The real key is to have your cable box, DVD, and any other video sources set to properly encode the signal to your 16:9 television (and these are actually pretty critical). Once those settings are correct, any other adjustments that need to be made can be accomplished by thumbing through the aspect ratio settings on the TV.
Also, make sure you are using the best possible connection between the video sources and the TV. At the very least you should be using the base band outputs (video, audio right, audio left). If your sources have the capabilty of going comonent (I think they are labeled Y, Pa, and Pb), by all means use them. If your DVD player is labeled "Progressive Scan" it will have these type outputs. Just be sure to use cables shielded for video. Cables shielded for audio can allow signal interference from other RF sources and cause some image issues. Audio signals tend to be less prone to interference so they may not be fully shielded (cost savings). The cables don't have to be high-zoot mega-dollar stuff, just make sure it says "video" and appears to be a decent build quality with heavy insulating jacket and metal ends with good strain reliefs. Count on paying at least $10-$12 per cable for something decent, or $25 or so for a combo Y/Pa/Pb cable (where all three conductors are video shielded).
Brad