Film-Tech Forum ARCHIVE: What is HDMI?

my profile | my password | search | faq & rules | forum home

»	Film-Tech Forum ARCHIVE » Community » The Afterlife » What is HDMI? (Page 2)

This topic comprises 2 pages: 1 2

Author

Topic: What is HDMI?

David Stambaugh
Film God

Posts: 4021
From: Eugene, Oregon
Registered: Jan 2002

posted 02-06-2006 09:45 PM

I think you're right. I remember reading that somewhere.

| IP: Logged

Evans A Criswell
Phenomenal Film Handler

Posts: 1579
From: Huntsville, AL, USA
Registered: Mar 2000

posted 02-06-2006 09:54 PM

I beleive the Sony CRT-based HDTVs (at least the rear-projection ones) only operate at 540p or 1080i, based on the mode, but do the "native 480p" by operating at 540p and adjusting the vertical height to throw the unused area off the screen. The 960i is done the same way, by operating in 1080i and shoving some of it off the screen.

| IP: Logged

Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 02-07-2006 12:01 AM

Evidence, por favor.

| IP: Logged

Evans A Criswell
Phenomenal Film Handler

Posts: 1579
From: Huntsville, AL, USA
Registered: Mar 2000

posted 02-07-2006 09:51 AM

I had one of those rear projection Sony 57-inch HDTVs.

Here's a forum site with a typical thread about the Sonys. (Forum thread)

Here's one quote from it. The problem is that people even "in the know" about the Sonys dont' always agree on this, but many people stated that the CRTs run in 540p/1080i (their design frequency) and they do 480i/960i and the 360i/720p in zoom mode by adjusting the vertical height to move the unused lines out of the picture area. I believe this because when I had that set, when I used the "zoom" mode (as you would to watch a non-anamporhic DVD), the scan lines were visibly farther apart and the picture was noticeably dimmer. I beleive it, but it's hard to prove. Examining a circuit diagram for these sets would be the only way to verify it. My Hitachi set handles 480i/480p by converting it to either 1080i or 540p, and its zoom mode for non-anamorphic widescreen material converts to 1080i or 540p as well without the brightness change due to fewer scan lines hitting the CRTs.

Here's a typical quote from the thread about the Sony sets, although in any thread, you'll see countering posts:

quote:

CRT-based displays are quite different from the newer technologies. They must choose some sort of “middle ground” since it is quite expensive to change the scan frequency without elaborate compensation circuits. Therefore, 1080i was chosen for the fixed scan frequency. This way they were able to natively scan the 1808i resolution of the second highest format specified by the ATSC. It was assumed that this would be most popular format since it did not use up all of the allocated bandwidth.

A CRT-based display reproduces 1080i flawlessly since it operates at the same resolution. 480i signals are line-doubled to 960i. Since the TV is natively running at 1080i, 120 scan lines are not being used. The television increases the vertical size to move the unused scan lines into the non-viewable area of the screen. 480p (same as 960i) are handled in the same way.

| IP: Logged

Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99

posted 02-07-2006 09:59 AM

I also notice that the ZOOM mode is dimmer and the scan lines are further apart. But to me it doesn't seem that 480p on my Sony direct view set (when viewed directly) is any or much dimmer in 480p than it is when in 1080i.

Also, that stuff about it being "expensive" to have different scan frequencies seems like BS to me since every CRT computer monitor does it on a much more versatile scale and quite cheaply.

| IP: Logged

Evans A Criswell
Phenomenal Film Handler

Posts: 1579
From: Huntsville, AL, USA
Registered: Mar 2000

posted 02-07-2006 10:07 AM

Well, there's not enough difference in 1080 and 960 to notice the drop in brightness by zooming so tht 120 scan lines are lost, but in the zoom mode, there is a more drastic difference in 960 and 720.

| IP: Logged

All times are Central (GMT -6:00)

This topic comprises 2 pages: 1 2

Printer-friendly view of this topic

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.