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Aspect Ratios
I have a question that pertains to making a widescreen DVD.
I have noticed that even if a film is widescreen, and the DVD presents the film in widescreen, there seem to be three different aspect ratio formats prevalent on the DVDs commercially produced.
In many, the DVD’s video is indeed in widescreen.
But also in many, the DVD’s video is 1.33, and the film is letterboxed. Now, among these 1.33 letterboxed DVDs, for some reason, only about half actually automatically fill up the widescreen LCD monitor on my computer, when played back with Nero, and the other half of these 1.33 DVDs display the widescreen inside a 1.33 frame, such that there is black space on all sides of the movie.
I’d assume that the safest way to guarantee that a widescreen film indeed fills up an entire widescreen monitor is to encode the DVD video file in widescreen (16X9, for example).
But I am curious why DVD playback software sometimes interprets 1.33 in correct widescreen display, and sometimes doesn’t, even when there is widescreen letterboxed video in both?
I hope my question makes sense.
Jaxon
Jaxon
Vegas 7 Pro
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1 Reply
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I know how it’s supposed to work:
(1) All DVD-video is 720×480 with a screen aspect of 4:3 or 16:9.
(2) Same pixel resolution, different pixel aspect ratios: 4:3 uses 0.9:1 PAR, 16:9 uses 1.2:1 PAR.
(3) The encoded video has a software flag/bit somewhere up front in the header that tells the DVD player (software or hardware) which one of those two screen aspects it is. I guess because of the great variety in encoding/authoring apps and great variety of players, this doesn’t always come out right.
(4) Many movie-theater movies actually have a 2.4:1 aspect. Converting 4:3 and 16:9 for comparison gives you 1.33:1, 1.78:1 and 2.4:1 screen aspects.
(5) So the 2.4:1 screen aspect still needs to be mashed into one of the two standard DVD-Video formats in #1, which necessarily means black bars top and bottom. 720×480, 16:9, PAR 1.2:1 with 56-60 pixel bars top and bottom, for example. But it could be anything and plenty of movies have been made at other screen aspects (see also, Ben Hur, Lawrence of Arabia, etc.).When you are seeing a movie with black bars all around, it’s probably a 2.4:1 cinematic movie on a 16:9 DVD-Video that is being played back at 4:3. Ugh. Usually, you can see the encoded video black bars top and bottom (with a little noise in them) and see that it’s different from the side black bars that will be perfect computer-generated black from the background of the player. Again, plenty of reasons this can happen, especially when ripping clips off of discs (possible to rip a scene and miss the 16:9 bit flag in the header of the file? Just wild speculation).
Anyhow, more info on screen/pixel aspect ratios here and in my book, of course.
__________
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and being on television is the difference between
conceiving a child and having a baby made in a test tube.
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