[BB_Mike]

I tried some searching, and some FAQs, but the question is kind of vauge for both of those. I couldn't really find a better forum either.


How is it that the movie channels can show various aspect ratio movies in High Definition? For instance, any of the Matrix movies, with their large letter box ratio.


How does this compare to when I "expand" the movie while watching it on DVD? (which still leaves some of the letterbox... more of a vertical stretching, if you will.)


How does this compare to the advertised "HD-DVD players"? Which are said to just upconvert to 1080i.


-sidenote: Is there some online literature about HD, that is factual and not just reporter based conjecture? Something like an "HD for Idiots" book!

 

[bgall]

Most movies that are on HD channels are actually down converted from film, which has a higher resolution then HD.


Now as to why does it fill a 16x9 screen, there are two things that are done.


One is taking a film that was filmed on Super 35 (which is filmed with a square sized ratio then the tops and bottom are covered over for the theater, leaving off extra footage) On some transfers, they open up part of the matte so that it fills the 16x9 screen.


The other way is re-formatting a 2.35 film to fit the 1.78 size of HD, which is what they also do for standard VHS tapes.


I hope this helps a little bit, and that I wont getting attack for having some incorrect info in my response

 

[BB_Mike]

Ahhh, I think I'm catching on. So the original filming is some kind of SUPER definition. It gets played on a "1:1" level at the theaters, but it is downgraded a good deal for DVD, or even VHS. However, with the upcoming "High Definition DVD" concept, we are getting even closer to the SUPER definition of original filming?


So, some day I may get to watch "A street car named desire" in actual HD? Or is there a a period in time which used less than 1080i in resoltion?

 

[HDHTPC]

Go back much more than 10 years and everything was either low def video tape or film. Go back before the 1970s and *everything* was film. Thankfully good filmstock has plenty of resolution... So you can take lots of old films and "telecine" them to modern digital HD and they look great. Almost as good as they didn't in the theaters originally.


Most films shot on 35mm film have possibly 3000x2000 effective resolution, but you lost a bunch of that scanning that into a digital 1920x1080 signal.

The signal is further degraded as it is digitally compressed for broadcast.


Since films are done with various aspect ratios they need to get converted for 16x9 HD playback. Some channels (such as Showtime or HDnet movies) does OAR with letterboxing (black bars above and below) to show the film as indended. Some other stations (like HBO) do pan-and-scan where they zoom in on a 16x9 portion of the film and crop off the edges.

 

[HDHTPC]

And yes, "A streetcar named desire" could likely be telecined and shown in great HD glory... As long as a good quality film print is still available in an archive somewhere. Some great movies have been lost due to neglect, fire, floods, etc...

 

[BB_Mike]

WOW!

Thanks for the input guys.

It's like a vinyl album versus a CD, you can't get better than Analog, unless you get just good enough to fool the human perseption of quality.


So, is it is not safe to assume that a broadcast showing (from a movie channel) of any movie in HD, to include it's original theatrical aspect ratio, would be better than my DVD. Based on the possibility that they have to compress the HD quality? Which means D*TV's broadcast might be a better PQ than my local Comcast feed. However, it is likely, that since their source data (on whatever media that should be), is a true 1080i, it may indeed be better than my DVD version?


Does OAR = Original Aspect Ratio?


Carlos, you have on your homepage an "HD library". How is this achieaved? Is it just a digtal recording of a broadcasted signal? The printed movie covers have me interested. Far as I can tell, the whole "HD-DVD" thing wont happen until next year, and even then it will be too expensive for me.

 

[Joxer]

HD channels like HDnet-movies and InHD have been broadcasting a lot of classic movies from the 50s,60s,70s in full HD recently - very high quality for old films! Its like seeing them for the first time since most theaters back then were poor quality conditions.

 

[chroma601]

The aspect ratio of films before widescreen was generally 1.33, or 4:3. To preserve OAR on these older films, they would have to be shown "pillarboxed", with black bars along the sides, on a 16:9 monitor. The alternative would be "tilt and scan", in which the top and bottom of the image would be selectively cropped out for the 16:9 screen to be filled.


An interesting variation of the letterbox controversy!

 

[HDHTPC]

HDnet shows old Hogan's Heroes episodes slightly pillarboxed.


> So, is it is not safe to assume that a broadcast showing

> (from a movie channel) of any movie in HD, to include it's

> original theatrical aspect ratio, would be better than my DVD.


Generally speaking, yes, HD broadcasts are better than DVDs.

 

[Morris Jones]

Yes, an HD broadcast should be better picture quality than a DVD, and equivalent audio quality.


Keep in mind that all of these formats are compressed using lossy compression (MPEG-2) -- all of them, including DVD, 1080i to 480p, and every standard definition channel you get from DirecTV or digital cable.


So whoever controls the MPEG-2 encoder has by far the greatest impact on the picture quality.


Film is certainly the highest resolution storage available, but comes with other quirks of the analog world. Like a cantankerous uncle in the family. You have to treat it with care, and understand how to compensate chemically for weirdnesses in color, gamma, dynamic range, and just plain age.


Mojo

 

[Karyk]

Quote:

Originally posted by Morris Jones Film is certainly the highest resolution storage available, but comes with other quirks of the analog world.

I've never been to one, but I believe there are now digital theaters (I think the Cinerama in Seattle owned by Paul Allen is one such theater). Any idea what the resolution is on that type of system?


I think what people don't realize is the importance of resolution as size increases. If you projected a DVD or HD image onto a theater screen, everyone would probably walk out, unless maybe they were sitting way in the back (and/or had poor eyesight) and couldn't see the image problems.


BTW, one old film converted to DVD, that was seemingly done well, is The Wizard of Oz.

 

[Morris Jones]

I found a good article on Digital Distribution in the Editor's Guild newsletter.

Quote:

Compression: Digital cinema masters are currently produced at an HD resolution of 1,920 pixels wide by 1,080 high, at an uncompressed bit rate of 1.5 gigabytes per second. In order to make distribution and transmission cost-effective, the master must be compressed using one of several algorithms. The major studios are initially using both wavelet and MPEG-2-based systems.

So essentially it's 1080p with higher quality compression. The article has a lot more cool information.


Mojo

 

[Rick_R]

When I went to a digital theater for a digital presentation of Star Wars Episode I they told us it was a 1080 projector.


Also note that movies made on film are copied for distribution. The copy you see in a theater is a fourth generation. There is reduction is resolution in each copy. I believe the copies are:

Origional Negative-> editing positive-> distribution negative-> theater copy


Digitally made movies are copied with no loss in resolution. As a result the 1080 HD copy can be almost as good a film based theater copy. The film theater copy also degrades as it is shown over and over again.


Rick R

 

[Ken H]

Quote:

Originally posted by chroma601 The aspect ratio of films before widescreen was generally 1.33, or 4:3. To preserve OAR on these older films, they would have to be shown "pillarboxed", with black bars along the sides, on a 16:9 monitor.

Which is the vastly preferred method, IMO.


For fodder like Hogans Hero's, I really don't care what is done with the AR, but when you start thinking about Gone With The Wind, The Wizard Of Oz, and the hundreds of Academy aspect ratio films worth viewing in HD, it's very clear to me the only way they should be transfered is to maintain OAR. Let the STB / HDTV manipulate the image (zoom, stretch, etc.) to fill the screen. Period.