RPTVs & Enhanced For Widescreen DVDs
Dear Gary: As the new owner of a Philips/Marantz 55-inch HD-ready RPTV, I am newly excited about my (100 plus title) DVD collection. I am curious about a subject which I’m sure you’ve covered in detail many times, but as a new reader I have not seen explained. I understand anamorphic, although I don’t follow the why or when of how a DVD player (or TV set) would “unsqueeze” such a disc. But more importantly, having viewed the majority of my “catalog” on the new set, I see that there is a vast swing between the awesome image quality on some (mostly recent) discs and the compressed (anamorphic?) image on others. Yes, I can alter the screen format (panoramic, theater 1 & 2, 16:9 , etc.) but in doing so, the image resolution goes down the tubes. I assume that I am doing nothing more than “blowing up” the image, and therefore, the quality is taking a proportionate dive. Many of the more recent discs that default to the correct, full screen image indicate that they are “enhanced for widescreen televisions.” Discs like Mask Of Zorro, Gladiator, The Patriot and The Perfect Storm are truly impressive to view, but many of my older titles like Clear And Present Danger, True Lies and Ghost And The Darkness have to be “converted” and thus lose the impressive clarity of the previous titles mentioned. Interestingly, one of my oldest discs, The Fifth Element is every bit as impressive as the newer titles. What is really occurring here, and what can I look for or how can I determine whether a future purchase will yield the native full image or require me to alter the format and sacrifice image quality? As a final add-on, I should mention that I am running my DVD player through a DVDO iScan line doubler, so if the “native” image isn’t correct, I am forced to bypass the unit and use the television’s internal doubler in order to alter screen format.
Landon Hollander
Video Technical Editor Greg Rogers Comments:
DVDs store video data as a series of numbers that represent the content of video frames. Unlike film, there are no physical images on the DVD, so there is nothing to squeeze or unsqueeze. DVD video data represents the content of either a 4:3 aspect ratio frame or a 16:9 aspect ratio frame. (In fact, it could be any aspect ratio, but those are the only two included in the DVD standard.) In both cases, a full frame consists of a 720 x 480 pixel array. When the video frame on a DVD represents a 16:9 frame the DVD is usually labeled “Enhanced For 16:9,” “Enhanced For Widescreen TVs,” or “anamorphic.” I dislike the latter term since it is confusing as well as misleading. It is confusing because it has nothing to do with anamorphic films—Panavision or “scope” movies shot with an anamorphic lens. Those movies can be letterboxed on a DVD using 4:3 frames or 16:9 frames. The advantage of using a 16:9 frame on the DVD is that the vertical resolution is increased by 33 percent for any picture put inside a 16:9 frame compared to a 4:3 frame. Since both frames have the same 480 pixel height, a 16:9 picture in a 4:3 frame has only 360 pixels in the vertical direction. The same picture in a 16:9 frame uses all 480 pixels...an improvement of 33 percent in vertical resolution. Of course, you must have a TV with a 16:9 screen to display the additional resolution. Otherwise, the DVD player will scale the 480 pixel height back into 360 pixels to produce a letterboxed image inside a 4:3 frame. As long as the TV screen has the same aspect ratio as the DVD video frame, it will be displayed without geometrical distortion. But to display a widescreen movie letterboxed inside a DVD 4:3 frame on a 16:9 TV, the TV must expand the image vertically until the screen represents the center 16:9 portion of a larger “virtual” 4:3 screen. In this case, you will see only 360 pixels of information from top to bottom of the screen instead of 480 pixels with 16:9 DVDs. This is the degradation in vertical resolution and image quality that you see with non-16:9 (non-anamorphic) DVDs. Fortunately most DVD content providers have seen the light and are producing 16:9 DVDs now. I hope that they will go back and remaster some of the titles that were already released in 4:3. Until then, I just don’t buy those titles.
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