DVD Pictures
Many people get their new widescreen HDTV home and pop in their favorite DVD expecting to have a full screen picture, rid of those pesky black bars, only to find out that some DVDs will be full screen and other are not. What the heck is going on? I read the package and it says "Wide Screen," but there are still some bars top and bottom on the picture.
You try different menu settings and the only way to get rid of the bars is with the zoom control, but you think that is a bit of a harsh method and you must be doing something wrong. Trying some other DVDs yield full screen pictures and you are ready to pull your hair out over this. I bought a wide screen TV to watch wide screen movies, so what the hell is happening here?
The fault is not with you, your TV, or the DVD. The fault is terminology. Terminology by different products to describe their product as opposed to some common meaning of, in this case, "wide screen."
When you buy a wide screen HDTV the "wide screen" phrase means the aspect ratio of the TV screen to differentiate it from the, up to now, standard narrow screen TVs we have been looking at for decades. The narrow screen TVs have a 4:3 aspect ratio or a screen whose width is 1.333 times the height, 4 divided by 3. The new "wide screen" HDTVs have a 16:9 aspect ratio or a screen whose width is 1.78 times the height, 16 divided by 9. The numbers that will concern us as we go along are the decimal values like 1.33 and 1.78.
Now when you pick up a DVD and read the "wide screen" on its cover, that wide screen does not refer to the aspect ratio of the TV screen it is designed to be used with, Which is what you were probably thinking when you read it, but rather the aspect ratio of the projected image, regardless of the type TV you are going to vied the DVD on. Some DVDs have a wide screen side and a full screen side which seems to indicate what aspect ratio TV screen the version is to be used with, but actually the full screen side will be cropped, or pan scanned for a 4:3 TV screen. I know it only adds to the confusion. So the terminology used by DVD labels are wide screen to describe the image that will be projected and full screen to describe the TV screen the projected image is intended for.
Maybe some examples would be in order to further illustrate.
Here is a frame showing the full picture that is taken by the cameras. Notice it is very close to the 4:3 aspect ratio. The picture will be cropped to the particular aspect ratio that the film maker desires. The popular aspect ratios for movies are 1.85:1 (normal widescreen movies) to 2.76:1 (ultra Panavision) and I will use these two for our examples. Other aspect ratios are 2.35:1, 2.39:1 and 2.40:1. I'm using the extreme case of 2.76:1 because it graphically illustrates the issue better than a ratio that would be closer to the 1.78:1 HDTV aspect ratio.
Original film frame before cropping
If the film is to be cropped to 1.85:1 aspect ratio the resulting picture will look like this:
Notice the film is cropped to 1.85:1 aspect ratio by chopping off some of the top and bottom of the original picture. Also since I have displayed the picture on a black field that is sized with a 1.78:1 aspect ratio (HDTV) there are small black bars at the top and bottom of the screen. When DVDs are mastered they sometimes will stretch the image to fill the HDTV screen and either crop the sides slightly or just stretch the image vertically only. This results in an image like this:
As you can see a picture stretched vertically like the one above does not distort the image enough to where it is noticeable. If the image is zoomed and cropped on the sides, again the loss of image is very small:
Now let's look at the widest films shown these days in 2.76:1 Ultra Panivision. The same picture shown on a 1.78 HDTV screen would look like this if the original wide screen (as far as what the film maker considers wide screen) is merged into a black 1.78:1 aspect ratio screen:
Notice there is a lot more of the top and bottom cropped from the original picture. This is the film makers decision to show his/hers film in the 2.85:1 aspect ratio and when you see the finished film in the theater you don't really miss the parts that were cropped, because you really didn't know they were ever there. But now what to do with a DVD whose image must be shown on either a 1.33 SDTV screen or a 1.78:1 HDTV screen? If the DVD is full screen, then only a part of the image is shown and the 1.33:1 window is panned over the original 2.76:1 images to where the action is located. Generally in still shots like our example, the center of the original image will be shown. This cropping and pan-scan action can really detract from the film, so often on the other side of the DVD will be a wide screen version where the original aspect ratio version of the film is recorded. On Cinemascope and Panavision films supplied in widescreen they do not try to fill up your 1.78:1 HDTV screen. Why? Because the stretching would be too much and zooming would remove too much of the picture. Pan-scan is thought to be too distracting for the small benefit and finally many of the film makers refuse to license the films unless the DVD will show the film in its original aspect ratio.
But just to illustrate some of the problems trying to fill up the HDTV screen with these 2.76:1 movies, consider these:
The above photo is the resulting image zoomed so that the height fills the 1.78:1 HDTV screen. Notice there is a good bit of the picture missing on the left and the right of the screen. Now you might say looking at our example that you could live with the missing picture parts and it would be a fair exchange to allow your screen to be filled. Unfortunately for you, the film makers that control the film rights to be distributed on DVD, do not agree with you. Many DVD players have a zoom function that will accomplish the task of filling up the HDTV screen, but beware there is generally a loss of picture quality to go along with the zoom function.
Just for completeness I thought I would show a picture of what the image would look like if we just stretched the picture vertically. As can be seen everything gets very tall and skinny looking. If there were people in the picture, they would look very weird, so that is obviously not an option.
So as not to mislead, the 2.76:1 is not very popular on DVD with only one title available. The most popular aspect ratio for DVDs is 1.85:1 with 6,405 titles followed by 2.35:1 with 2,995 titles. Data was obtained from www.imbd.com, Aspect Ratio Table. Still the most DVDs are the 1.33 (4:3) with 11,387 titles, but most of these are TV shows rather than movies released in theaters.
I know it takes a bit of getting used to looking at the black bars on some DVDs, but rest assured the issue is not with your equipment or the way you are using it.
