16:9 TV -- but widescreen DVD image is within 4:3 area? - AVS Forum
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Old 07-21-2002, 09:53 PM - Thread Starter
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Dr Joe wrote this in this thread:

http://www.avsforum.com/avs-vb/showt...hreadid=155276

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This isn't a problem for anamorphic DVD's as they are mostly expanded properly by the player, but for letterboxed DVD's it is -- if your DVD player doesn't do scaling then the letterboxed video will be stuck in the 4:3 window.
I'm really confused about this. Under what circumstances would the DVD play within the 4:3 area of a direct view 16:9 TV? I would guess there would be black bars on all four sides?

Is this a problem associated with certain TVs, or is it a DVD problem?

This never happens with HD feeds, right? But what about HBO and Showtime, since they have HD in 4:3 sometimes, right?

I try to buy only wide screen DVDs, but my wife gets some deals on DVDs, and they are 4:3 sometimes.

Please enlighten me.

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Old 07-21-2002, 11:25 PM
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he speaks cryptically, though i know he is only intending on conveying the truth. here's how it breaks down.

in terms of aspect ratio, there are three major kinds of DVDs:

1.widescreen dvds that are encoded anamorphically. on your 4:3 set, they are widescreen letterboxed. if you have a 16:9 set, they will expand properly to fit the wide screen, thus either eliminating the bars or making them smaller (this is the essence of anamorphic encoding).

2.there are non-anamorphic dvds with a fullscreen image-- these are generally TV shows that originally aired in 4:3, or pan and scan versions of movies. these discs have a full 4:3 image and are encoded for 4:3 tvs. thus, if you play it on your 4:3 tv at home, it fills the screen. if you play it on your 16:9 tv, it will either appear windowboxed (with only the 4:3 portion of the screen active) or stretched (if your tv locks into "full" mode with all 480p and up signals, and you're using a prog-scan dvd player)

3. letterboxed non-anamorphic discs. these tend to be older transfers of movies, but in widescreen nonetheless (an example that leaps to mind is fox's Strange Days, which really needs a new dvd with a transfer that will do the film justice...). on your 4:3 tv, it will appear letterboxed (the same way a letterboxed anamorphic dvd will look on your 4:3 tv). on your 16:9 tv, however, it will appear to be boxed inside a box-- that is, a letterboxed image inside only the 4:3 ("windowboxed") area of your widescreen tv. now you can see why people are so adamant about wanting all widescreen dvds to be anamorphically encoded. thankfully, if you are not using a prog-scan dvd player, or if your tv DOES allow you to use its scaling modes on 480p and greater material, then you can zoom in on the image to cut off the letteboxes. unfortunately, this does cost you resolution, especially if your tv has a crappy scaler.

this will never happen with hd material. all hd needs to be broadcast in the 16:9 ratio to meet the specs for the signal. when you see 4:3 on hbo-hd, it's an upconverted (line doubled) standard def image on a 16:9 background (in short, hbo is "seinding" you the windowbox bars on the sides of the picture)

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Old 07-21-2002, 11:41 PM - Thread Starter
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Mr. Gonk ---

thanks for the reply.

If I understand you, then saying something is "anamorphically encoded" means that the widescreen movie has the right flags (is that the right term?) to tell the 16:9 TV to not put the image within a 4:3 box?

I always thought widescreen was widescreen. But apparently it is not when it comes to direct view TVs. I don't think this is a problem at all on my CRT front PJ.

I'm still confused about what you said about HBO and Showtime. I've seen some posts about their pan-and-scan of movies on their HD feeds... and I thought someone complained about Showtime showing HD movies in 4:3.

I'm not really clear on this. Does Showtime send their HD feed in 4:3, or is it 16:9, but pan and scanned? How about HBO?

I'm guessing that the HDNET and the Dish Demo HD feed are all 16:9, all of the time?

This wouldn't be an issue for me, but I am going to sell some PJs (some day) in order to buy a direct-view HD tv.

Thanks.

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Old 07-22-2002, 12:02 AM
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I explained why clearly in the context of the post (at least, I thought so!).

I will expand upon the topic, although this REALLY belongs in the DVD hardware forum.


1) What format is DVD video?

DVD video is inherently 4:3. Say it, slowly -- this is the number one most misunderstood characteristic of DVD video. DVD video is inherently 4:3.

Video is stored in three ways:

A) 4:3 full screen. In this format, motion pictures are cropped to fit the 4:3 window, then saved to the disc.

B) Letterboxed or matted. In this format, motion pictures are saved in the 4:3 frame so that they fit in the 4:3 window with their original aspect ratio (OAR) intact. There are black bars at the top and bottom of the 4:3 window; resolution is lost because the picture is smaller than the available scan lines.

C) Anamorphic or enhanced. In this format, the motion pictures are saved at the proper verticle height to fill the 4:3 window; instead of cropping the edges like you would for 4:3 fullscreen, the image is squeezed sideways, squished to fit the 4:3 window.

2) How does an interlaced player present these formats?

An interlaced player sends the video in the 4:3 frame to the TV. The TV can be set for three modes.

A) 4:3 Fullscreen. This is propper for cropped movies, or for video that was full screen to begin with (like many TV show season collections). In this mode, with the F38310, there are grey sidebars added to fill the 16:9 screen.

B) "Full". This is a zoom mode for letterboxed movies. In this mode the TV expands the 4:3 frame presented by the DVD player in both the horizontal and vertical dimensions to fill the 16:9 screen.

C)"Fill". This is a stretch mode for anamorphic movies. In this mode the TV stretches the 4:3 frame sideways to fill the 16:9 screen.

Please note 1, for the letterboxed and anamorphic modes, if the video is in an OAR of 2.35:1, there will be small black bars at the top and bottom of the video. An OAR of 1.85:1 or 1.77:1 will effectively fill the 16:9 window.

Please note 2, it is the television, not the player, which is doing the scaling in interlaced mode.

3) OK, well, how does progressive video change things?

Well, not all televisions which can accept a 480p input can scale the video internally. It is a case of too much video information, I guess. Specifically, the F38310 can't scale 480p or 1080i. The set treats all 480p and HDTV as inherently 16:9. Most progressive players perform internal stretching of anamorphic/enhanced DVD. This video will properly fill the 16:9 window of the F38310 and other HDTV's like it which don't scale progressive/high definition video. However, most progressive DVD players will send 4:3 fullscreen video and letterboxed video as 4:3 -- and because the F38310 locks in 16:9, you then can't scale the video to fill the screen. Some players, specifically those with a genesis video processor, CAN perform scaling before the image is presented to the TV player. 4:3 fullscreen and letterboxed material can be forced to several zoom modes with this type of DVD player.

For example, the Panasonic RP91 is highly thought of (go over to the DVD Hardware forum and do a search). It has 4 modes for 4:3 video: Normal, the image is stretched horizontally to fill the screen; Auto, properly flagged letterboxed DVD's are zoomed; 4:3 fullscreen video is presented in "fullscreen" 4:3 mode (non-zoomed); Shrink, all 4:3 video is presented in 4:3 fullscreen (non-zoomed) mode; Zoom, all video is presented horizontally and vertically zoomed for letterboxed material to fill the 16:9 screen. There are a few players (not the RP91) with "free zoom" modes which can zoom a 2.35:1 movie to fit in the 16:9 screen without any black bars at the top and bottom, however, you lose a little bit on the right and left edges.

There is a tradeoff for the ability to zoom 4:3 progressive video: generally, people consider other video chips, such as the Faruodja/Sage video chip, to handle deinterlacing better than the Genesis chip.

4) So what are my choices if I have a TV like the F38310?

Well, you can buy a cheaper player like the Panasonic RP56, with the sage/faroudja chip, which everybody speaks very highly of, and, when there is letterboxed material you want to zoom, switch off the progressive output, and view the material in interlaced mode. The F38310 will be able to zoom the image for you, and will internally upconvert the 480i to 540p.

Or, you can go with a player that zooms progressive video for you. generally this will be a player with a genesis video chip, and there are several good ones out there. Cheap ones won't handle deinterlacing as well as those with the sage/faroudja chipset, however a few of the more expensive players like the Panasonic RP91 do a very good job.


As to HBO-HD, Showtime-HD, and digital OTA television, if they are broadcasting in 480p or above, you can't zoom it. High-definition prgramming is 16:9, so it fills the TV window. unfortunately, most programming on OTA netork digital feeds,and quite a bit on Showtime and HBO-HD, isn't really high definition. This other programming is "upconverted" NTSC 480i 4:3 video. Being originally 4:3, when your TV gets it in 480p, 720p, or 1080i, it can't zoom it. This is a pain for shows like "ER" on NBC -- my wife can't zoom the digital feed, so she watches the analog, using the TV set's zoom mode to fill the TV window. Digital OTA stations do have a choice -- they can send the 4:3 in the OAR or they can play with the aspect ratio. The best results are when they zoom the video as you would the letterbox format, and then squeeze the video a little bit vertifcally -- cropping it at the very top and bottom of the screen. This fills the screen without distorting the video quite as much as stretching it sideways to fill does.


Hope this helps,


Joe

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