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Re: Anamorphic and letterbox question

Posted: 06 Sep 2015, 12:10
by saltysam
i think the basic answer is letterbox you have to zoom the picture to fill the screen,losing resolution in the process.Anamorphic enhances the image automatically without the need for zooming, giving you 25% more resolution over letterbox non-anamorphic.

Re: Anamorphic and letterbox question

Posted: 06 Sep 2015, 14:41
by Markgway

Re: Anamorphic and letterbox question

Posted: 07 Sep 2015, 05:26
by HungFist
Mo wrote: One more question. Does letterbox mean widescreen? And does it mean it is a particular aspect ratio?
Yes, it means widescreen, but no, it doesn't refer to any particular widescreen aspect ratio.

The term was originally coined back when everyone had fullscreen televisions (4:3 = 1.33:). I guess that was in the 1980s. Letterbox basically meant that black bars will appear on top and bottom. It did not, however, explain how big the black borders would be. If the aspect ratio was around 1.78:1 or 1.85:1 we would have moderate black bars when viewed on fullscreen television. If the aspect ratio was around 2:35:1, we would have very big black borders.

Once we got widescreen televisions (16:9 = 1.78:1) we were able to get rid of the black border entirely if the aspect ratio was 1.78:1 or almost entirely if the aspect ratio was 1.85:1 by zooming in. However, if the aspect ratio was 2.35:1, we would still have moderate black borders left even after zooming in.

Non-anamorphic dvds with widescreen aspect ratio can always be called letterbox because in their basic form (that is, before zooming... remember, the term was coined before widescreen televisions existed) they feature black bars on top and bottom. The black bar is, in fact, coded into the image. With anamorphic dvds you can imagine that the comparison point is widescreen televisions with 1.78:1 aspect ratio! Anamorphic dvds with 1.78:1 aspect ratio need not code any black bar into the image because it's the same aspect ratio as the TV (*). Anamorphic dvds with 2.35:1 aspect ratio can be called 16:9 Letterbox (this is common at least in Japan, but I don't remember about other countries) because even on widescreen televisions they still feature black bars.

* My explanation is technically not entirely correct because the reality with anamorphic encoding is more complex and technical, but perhaps that's not so important here. And if I got something totally wrong, I'm sure Shing will let me know :lol:

Re: Anamorphic and letterbox question

Posted: 07 Sep 2015, 09:53
by HungFist
Mo wrote: Another question I have is- what is the difference between 1.78 and 1.85, and also 2.35 and 2.40?
Those are simply slightly different aspect ratios. 1.85:1 is often used in filming, but widescreen television is 1.78:1. That means that a tiny black bar still appears because 1.85:1 is a little wider (unless your TV has overscan, which means it automatically zooms in a little bit without asking you. I think modern TVs don't suffer from it, but older ones usually did. Criterion used to do some "windowboxed transfers" where small black borders were added to the image to prevent losing image due to overscan). It's also not so rare for 1.85:1 films to be cropped to 1.78:1 for DVD releases to fill the screen (you only lose a small amount of image).

2.35:1 is the standard for, ehm, 2.35:1 aspect ratio. 2.40:1 a slightly wider, less common variation. Even wider aspect ratios do exist, e.g. Tarantino filmed The Hateful Eight in 2.76:1

Re: Anamorphic and letterbox question

Posted: 07 Sep 2015, 11:03
by grim_tales
2.35:1 means the picture information is 2.35 units (?) wide to 1 unit high (I think) :?

Re: Anamorphic and letterbox question

Posted: 07 Sep 2015, 14:23
by Markgway
Mo wrote:I don't think that link answers my last 2 questions. I read through it, it's very confusing.
Sorry, I guess I didn't understand your question.

I see it's been answered by others though, so it's all good.

Re: Anamorphic and letterbox question

Posted: 07 Sep 2015, 22:06
by Masterofoneinchpunch
Mo wrote:No problem Mark. I've read a lot of info on aspect ratios and while most of it goes over my head, I think I'm starting to understand it.

Now I'm trying to figure out the ":1" in 2.35:1, 1.85:1... I think I've seen movies listed in 2.35:2? But I can't remember. Basically I'm wondering if the :1 is even necessary.

I appreciate the help Grim Tales but I'm not able to comprehend what you are saying.
I think you have got ratios down. The ":1" is simple it is just the height portion. Now it is not always ":1". Sometimes you see the ratio 16:9, 4:3 (really the same thing as 1:33 ratio) with the first number being the width and the second being the height. You usually see those ratios most of the time mentioned with TVs not with movie ratios.

Movies, for the most part (there are exceptions), started off with a 1.37:1 ratio. When TV became popular (at a 1.33:1 ratio), they thought of several ways to get/keep audiences in the theater. One was 3-D which was not that successful at the time and the more successful was having wider screens. You saw for several years experimenting with many different ratios (as you wrote some of them above) and you still see different ratios used today. At Disneyland they even had a few films which went around you completely so you could see "all around you".

Now many directors at the time in the 1950s did not like the idea of going to widescreen. But it became the norm.

Re: Anamorphic and letterbox question

Posted: 08 Sep 2015, 02:24
by grim_tales
Weird, I've never heard of or seen 1.85:2 or 2.35:2?

Re: Anamorphic and letterbox question

Posted: 08 Sep 2015, 04:51
by HungFist
Mo wrote:Ok so I must have been mistaken. There is no such thing as 2.35:2 and 1.85:2?
Nope. You've been dreaming.
grim_tales wrote:2.35:1 means the picture information is 2.35 units (?) wide to 1 unit high (I think) :?
Yep. Exactly like that. It means the image is 2.35 times as wide as it is high. It's relative of course... the height can be any number, but the width must be 2.35 times more. E.g. if the height was 10, then the width would be 23.5... if the hight was 20, the width would be 47

Here's an example of a film shot in 2.35:1


Let's see about it again

Image Image
Image Image Image Image

Re: Anamorphic and letterbox question

Posted: 08 Sep 2015, 05:53
by Shingster
EDIT: I wrote the following before the last few posts! :D

I'll take a stab at explaining why there is a difference between anamorphic and letterbox on DVDs:

Right Mo, you have to bear in mind that for decades TV displays were almost square, what we call the 4:3 (or 1.33:1) ratio. This means that if you multiple the height of the screen by 4 you get the same number as if you multply the width of the screen by 3. So the image is a little wider than it is tall.

- So TVs were 4:3 displays for decades, this means the broadcast standard had to be in 4:3. So every TV show was shown in 4:3 and that is what the NTSC standard is (in North America) and the PAL standard also (in Europe).

- When DVDs came around they adopted the broadcast standards of NTSC for america and PAL for europe. So the native resolution of DVD video is 4:3.

- Now, the problem here is that many films are in fact wider than 4:3. Many are 1.85:1 or even wider at 2.35:1 (for reasons oneinchpunch explained in his last post). This meant that films don't cleanly fit onto the NTSC/PAL 4:3 native resolution. So what to do?

- Well, you can crop the widescreen to 4:3, but with films composed for the wide 2.35:1 ratio you could end up with 2 actors talking to each other but not onscreen because they stand too far outside of the 4:3 image after you've cropped the sides! Pan & Scan solves this by altering where you crop to 4:3 so you try to centre on the action. So Pan & Scan basically means "smart" 4:3.

- Alternatively you can "letterbox" the widescreen film. That means placing black borders above and below the 1.85:1 or 2.35:1 image so combined the whole image is 4:3. This is what letterboxing is, simply adding black borders above and below an image. The problem with letterboxing is that when you view on a widescreen TV (which is a 16:9 display) you've now got the problem of the image being 4:3, so the TV has to "zoom in" which means zooming into the centre of the image so the black borders are offscreen. This loses resolution because you're zooming, so the image becomes softer.

- The final method of making widescreen 4:3 is called "anamorphic" with this method you take a 1.85:1 or 2.35:1 image and stretch it vertically so it becomes 4:3. This way a TV with an anamorphic mode can "squish" the image back down to its original widescreen ratio. This is what 4:3 TVs and widescreen 16:9 TVs do if they have an anamorphic mode. This way you never have to zoom into the image, even on a widescreen TV, so the image retains its original "sharpness" (resolution).

This is all there is to DVDs. Blu-rays or HD television is completely different though, because the broadcast or Blu-ray standard is actually 1920x1080p in hi-def. This is natively a wide ratio: 1.78:1 just like a widescreen TV. So what they do with Blu-rays is simply letterbox the image if it's 2.35:1, but because widescreen TVs can now accept 1.78:1 ratio as its native image, there's no zooming in involved, it simply displays the Blu-ray in its original "sharpness". if a film is 4:3 they "pillarbox" the image, which means adding black borders to the left and right of the image so it becomes 1.78:1.

Re: Anamorphic and letterbox question

Posted: 08 Sep 2015, 06:04
by Shingster
Mo wrote:There is no such thing as 2.35:2 and 1.85:2?
Because ratios are a mathematical term. You keep dividing the dimensions down until the smallest dimension is 1 and both dimensions are 1 or above. So 4:3 you divide by 3 to get it to 1 & hence 1.33:1.

1.85:2 you would divide it by 1.85 to get that to 1, hence it would be 1:1.08 or 0.92:1 if you divide by 2. The point of ratios in mathemetics is to show them like fractions, hence wanting to bring them down to 1 for their simplest form (but imo I prefer ratios in integer form, so 4:3 or 16:9 rather than 1.33:1 or 1.78:1)

Re: Anamorphic and letterbox question

Posted: 08 Sep 2015, 19:14
by Shingster
Think of them like fractions. 16:9 means 16/9 or 16 divided by 9, which equals 1.777777777777778 or 1.78 when you round it up.

2.35:1 is always listed this way because it's a very awkward fraction for people to visualise. It's 47:20.