Basic High Definition Questions

Stan Welks · 06-16-2007, 04:00 PM

1.) How is the quality of HD DVD or Blu Ray DVD compared to film shown in a theater? Does it come close to the resolution and quality of film?

2.) How are older films that were not shot in HD now being made available in HD on HD DVD or Blu Ray? Is film so much higher resolution than HD that they are just remastering the film and downconverting it to HD DVD or Blu Ray? Or are they actually adding resolution to it somehow to make it look better?

Thanks.

David Norman · 06-16-2007, 04:13 PM

1) Different animal I guess. The best HD transfers are very nice but are quite different than what you see in a non Digital Cinema. I'd say the contrast of any HD Disc is significantly less than a Film based presentation, but the sharpness/detail can actually be better without having to worry about projector issues/frame judder- gate weave/Theater limitations/print wear and multi generation prints, etc. There's also the difference just in sheer size and energy that a GOOD theater screen/sound system can provide.

2) Old films can look just as good (or pretty close) as newer films IF the original elements are in good shape. If the films were shot with good camera equipment on good film stock and have been preserved properly, most 35mm and particularly70mm films have mudh more information than even the best HD disc can encode. Casablanca and The Searchers are superb looking and Adventures of Robin Hood from the 30's likely look as good as they ever have maybe including anything other than first run prints. The end result is still limited to quality of the elements and competance to the individual doing the transfer or the effort that a studio goes in restoring the elements.

Jari K · 06-16-2007, 04:41 PM

I guess it´s safe to say that 1080p HD can´t match for a proper 35mm film. 35mm film has more resolution and also other factors, that will make film still somewhat "superior".

Douglas Monce · 06-16-2007, 05:36 PM

The HD format ie 1920 x 1080 is referred to as 1k resolution. The resolving power of 35mm film today is a little bit over 4k resolution. Most films today that are being scanned for restoration are scanned in at 4k resolution.

Digital projection is the theater is now going to 4k resolution projectors, but so far there are no practical 4k cameras.

35mm has a much wider latitude from blacks to whites than digital has at this point, but that will probably change.

One big advantage that digital has in a theater is there is no loss of image quality in the delivery end. The prints you see in a theater in 35mm are actually 3 or 4 times removed from the original camera negative. Every time the film is copied it loses some of its sharpness and becomes more grainy. So in reality 35mm doesn't resolve at 4k in most first run theaters. With digital you see what the filmmakers saw in the editing room

One other thing that can have an effect on what you see in the theater is gate weave. A 35mm print running through a projector will move from side to side ever so slightly. That can have the effect of reducing apparent sharpness of the image. Digital has no gate weave and can there for appear sharper.

Doug

Adam Gregorich · 06-16-2007, 07:12 PM

Great info!

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Robert George · 06-16-2007, 08:34 PM

Actually, HD DVD and Blu-ray are very close to 2K resolution. The terms "2K" and "4K" refer to horizontal resolution of the display device. 2K D-Cinema uses a TI DMD with a native resolution of 1080 X 2048. 4K has a resolution of 2160 X 4096. Only Sony's commercial SXRD technology has achieved 4K resolution in commercial application. There are only a literal handful of 4K venues at this time. 2K D-Cinema was somewhere around 600 screens last I read (could be more now).

As an aside, Rave Motion Pictures theater chain opened their first "all digital" multiplex, The Bayou 15, in Pensacola a few months ago. 15 screens using Christie 2K DLP projectors. It's about 3 miles from my house

.

On the topic of 35mm film and how it compares, it is true that 35mm film is capable of up to about 4K resolution. In practical terms, however, the average high-speed theatrical print comes nowhere close to that. 2K captures pretty much what a decent commercial print can, but with much greater brightness, contrast, and color capability. I've now seen several movies at the local Rave, and believe me, taken as a whole, the Christie's and D-Cinema stomp the film prints Rave is showing on the other side of town.

Although HD DVD and Blu-ray are very close to D-Cinema in resolution, D-Cinema has much greater color depth and a helluva lot less compression. D-Cinema specs allow a maximum bit rate of 250 mb/s and compression is a very mild 5:1 at most (JPEG-2000). Also, D-Cinema uses all available pixels and aspect ratios are achieved using optics.

Douglas Monce · 06-16-2007, 10:15 PM

Quote:

Originally Posted by Robert George

Actually, HD DVD and Blu-ray are very close to 2K resolution. The terms "2K" and "4K" refer to horizontal resolution of the display device. 2K D-Cinema uses a TI DMD with a native resolution of 1080 X 2048. 4K has a resolution of 2160 X 4096. Only Sony's commercial SXRD technology has achieved 4K resolution in commercial application. There are only a literal handful of 4K venues at this time. 2K D-Cinema was somewhere around 600 screens last I read (could be more now).

As an aside, Rave Motion Pictures theater chain opened their first "all digital" multiplex, The Bayou 15, in Pensacola a few months ago. 15 screens using Christie 2K DLP projectors. It's about 3 miles from my house

.

On the topic of 35mm film and how it compares, it is true that 35mm film is capable of up to about 4K resolution. In practical terms, however, the average high-speed theatrical print comes nowhere close to that. 2K captures pretty much what a decent commercial print can, but with much greater brightness, contrast, and color capability. I've now seen several movies at the local Rave, and believe me, taken as a whole, the Christie's and D-Cinema stomp the film prints Rave is showing on the other side of town.

Although HD DVD and Blu-ray are very close to D-Cinema in resolution, D-Cinema has much greater color depth and a helluva lot less compression. D-Cinema specs allow a maximum bit rate of 250 mb/s and compression is a very mild 5:1 at most (JPEG-2000). Also, D-Cinema uses all available pixels and aspect ratios are achieved using optics.

2k D Cinema is actually 1998 × 1080. However this is a 1.85:1 aspect ratio format. The 1920 × 1080 HDTV format is often referred to as 1k because of its 16:9 ratio and it's lower color depth.

D-Cinema does NOT use all of its pixals for all aspect ratios.
2k D-Cinema is 2048 × 858 at 2.39:1 and 1998 × 1080 for 1.85:1.

4k D-Cinema is 4096 × 1714 for 2.39:1 and 3996 × 2160 for 1.85:1.

The different aspect ratios are created on the chip not through optics.

Doug

Robert George · 06-17-2007, 12:33 PM

Quote:

The different aspect ratios are created on the chip not through optics.

The Christie CP2000 has an optional 1.26:1 anamorphic lens for venues using side masking screens. All the digital screens I personally have seen use side masking.

Douglas Monce · 06-17-2007, 02:26 PM

Quote:

Originally Posted by Robert George

The Christie CP2000 has an optional 1.26:1 anamorphic lens for venues using side masking screens. All the digital screens I personally have seen use side masking.

The screen would use side masking if you used an anamorphic lens or not. The standard lens on the Christie is a zoom so it can fill the screen with a non anamorphic 2.39:1 image. I'm not sure how many films have actually been released in an anamorphic format in d-cinema yet.

Doug