High Definition vs. DVD

[authorpilot]

Question:

I've read a lot of posts from individuals stating that one can enjoy High Definition quality on their HD compatiable TV's just by watching a DVD movie (assuming they are not yet set-up for receiving/watching HD signals).

Correct me if I am wrong.....It would seem to me that DVD would be LESS quality then HD signals. DVD is recorded in digital format, however, you still see the imperfections in the 35mm film from which it was copied from.....correct??? Unless of course, the DVD was not recorded from a 35mm movie, but recorded purely digital from the recording site, then it would be comparable to HD.

Whereas, HD signals transmit a purely digital signal, recorded DIRECTLY as digital (not from 35mm), and sent to my TV which displays a pure digital signal. Right?

I just want to know if I am correct by telling my "visitors" at home that the DVD's quality that I am showing them will be the same as the HD signal that I receive over the air, when I decide to get a receiver box.

I'd like to hear some theory on this, or someone point me to a link where this has been discussed already.

Thank you. Good day.

Pete :D

[57U]

I'm going to have to throw a few numbers at you. I hope it's not too confusing.

High Definition TV is programming that has a certain amount of definition (scan lines), hence the term High Definition. High Definition signals are those that are 720P (720 lines in progressive scan) or 1080i (1080 lines, interlaced).

DVD is either 480i (480 lines interlaced) or 480P (480 lines progressive scan), depending on whether you have a progressive scan DVD player or not.

HDNBC, HDCBS, HDPBS transmit in 1080i (high definition)
HDABC transmits in 720P (also high definition).
Fox transmits in 480P (some call this EDTV (E for Enhanced definition, but it's not High Def)).
Standard Definition TV is 480i.

Progressive scan is "superior" to interlaced, so a 480P signal is better than a 480i signal. Some would even argue that the ABC 720P signal is superior to a 1080i signal. 480P is obviously inferior to 720P and 1080i.

Since DVDs are "only" 480i, or 480p, they are not considered High Definition. They are of very good quality and many sets "upconvert" these signals, so there is little to differentiate the final DVD result from "true HDTV", but there is a difference that you can see between DVDs and HDTV.

Here's a useful link.

TV Resolution History (http://www.msnbc.com/news/TECH_Front.asp?launch=/modules/hdtv/)

The original source of the material is inconsequential, provided it is of high enough quality. For example a good 35 mm movie will have more definition than an HDTV can show, so an HDTV signal can be made from a good analogue move. There are plenty of 35 and 70 mm movies that are being shown as HD programming.

A poor digital image can have less resolution than an HDTV, so therefore a purely digital source of poor quality is not HDTV. (for example a 1 megapixel digital camera has about half the resolution required for HDTV). Mr George Lucas' digital cameras and equipment do however, have enough resolution - Star Wars 1 & 2 for example.

[JoeInBH]

The hierarchy basically goes:

Regular TV or DVD (480i)
Progressive Scan DVD/Fox (480p)
Filmed HD material (virtually all prime time HDTV) (720p or 1080i)
Video HD material (Jay Leno, HD sporting events) (720p or 1080i)

Although filmed and video HD material has the same resolution, I think (and most would agree) that HD material shot on video is significantly sharper/crisper than HD material shot on film. The vast majority of HD programming has been transferred from film. The quality of this HD material is better than progressive scan DVD, but it's not as significant a jump (in my opinion) as either (i) the jump from 480i to 480p or (ii) the jump from HD film to HD video.

I definitely don't mean to disparage filmed HD - I love it, and in the case of movies (Lucas notwithstanding) it's the best you're going to get. But when I really want to show off the HD to friends, I invite them over to see HD sporting events. This weekend, CBS does the US Open in HD, and next weekend, CBS is doing both the US Open and a college football game in HD. The amount of HD programming has grown enough that I would recommend that anyone buying an HDTV go all the way and make sure they can receive HD signals (via cable, antenna, or satellite, depending on your circumstances).

Joe

[woodman]

Pete:
There's a lot of confusion and misunderstanding about these issues. I'll try to help you wade through it and come out the other side with a bit better understanding of just what's going on.


[QUOTE]Originally posted by authorpilot
Question:

I've read a lot of posts from individuals stating that one can enjoy High Definition quality on their HD compatiable TV's just by watching a DVD movie (assuming they are not yet set-up for receiving/watching HD signals).

Correct me if I am wrong.....It would seem to me that DVD would be LESS quality then HD signals. DVD is recorded in digital format, however, you still see the imperfections in the 35mm film from which it was copied from.....correct??? Unless of course, the DVD was not recorded from a 35mm movie, but recorded purely digital from the recording site, then it would be comparable to HD.
[QUOTE]

A little correction is needed here. First off, the difference between DVDs (as they exist today) and true HDTV are the inherent differences in the two formats in terms of scanning formats and "resolution". True HDTV uses scanning formats that are either 150% (720p) or 225% (1080i) greater than the DVD format uses. Furthermore (and even of greater importance) is the fact that HDTV is capable of more than double the amount of fine detail (otherwise known as "resolution") of DVDs! You are quite right about DVDs being of less quality than HDTV, but it's not a matter of imperfections in the original film from which the DVD was made, but rather from the lesser capabilities of the DVD medium.

[QUOTE]
Whereas, HD signals transmit a purely digital signal, recorded DIRECTLY as digital (not from 35mm), and sent to my TV which displays a pure digital signal. Right? [QUOTE]

Not exactly. HDTV signals are a purely digital signal, but it may (in fact, very often IS) originate as 35mm or 70mm film. Plus, just before it enters your TV set, it's converted from digital into analog, which is what nearly all of today's TV sets require.

[QUOTE]
I just want to know if I am correct by telling my "visitors" at home that the DVD's quality that I am showing them will be the same as the HD signal that I receive over the air, when I decide to get a receiver box. [QUOTE]

No, the HDTV pictures will be considerably more detailed than the images from the DVDs - if everything works as it should.

Hope this helps your understanding

[drjohnc]

Don't forget that many of the newer studio masters are on 1080p video tape ... yep, video tape! They "down-convert" to produce a 480i DVD. I own a DVHS recorder (JVC), the 1080i D-Theater material that's available really blows their DVD counterparts away. (This most likely leads to another thread). Even the newer "Superbit" DVD's can't hold a candle to HD. HD-DVDs are still a mote in some lonely technician's eye. When the copy protection aspects are worked out, then we can have true HD from a DVD player.

[pwdw]

A friend and I just compared switching between the U571 DVD and U571 D-Theater. The D-Theater tape is 1080i High Definition. Both signals were component into a Sony RP. The difference was staggering. My friend had thought that his DVD looked great until he saw the comparison. Now he thinks the DVD is crappy. BTW film has a much higher resolution than any HDTV recording medium(including the cameras used by George Lucas). A pristine film transfer to HDTV is the BEST picture available at home. "Live" cameras such as the ones used on Leno and sports look good, but film has a much higher contrast ratio. D-Theater movies are the highest quality HDTV available for consumer use--right now.

[HokieD]

Standard TV is 480i? I'm confused...cable and satellite aren't even close to the picture quality of a DVD at 480i on my tv. Standard TV may be 480i, but the signal I'm getting isn't. I know about compression, but something else is going on.

When you have houseguests, it's safe to show DVD and tell them that HD is more than twice as clear and it is, believe me. Even better, find a good deal on an OTA tuner and show them Leno or a football game and let the picture do all the talking.

BTW, are there any new product besides 1080i tape? Are there any plans for new DVD players that can play "super" DVD's at 1080i? Sidebar: tape, yuck! - I lived through the tape age of the 80's and never want to go there again.

[57U]

1. If you have a really good NTSC (480i) station (like a movie channel), you'd be amazed at how clear it looks. Most signals have a lot of compression or artifacts, that's why there's such a difference between NTSC and DVD.

2. HDTV is theoretically 2X as sharp as DVDs, but with upconversion, actual HDTV resolution limits, etc. You should probably say that HDTV is noticably better than DVDs, instead of 2X

3. Yes - HD PVRs are on the way very shortly,

HD DVDs are further away - Blu-Ray, etc. There are some "battles" in the HD DVD arena that you can read about on the web.

Also HD VOD (Video on Demand) is also in the works (We have some basic SD VOD in Toronto already) All the equipment is at the suppliers end. You just need a STB to receive. No additional equipment at your end, which is nice.

[woodman]

Originally posted by HokieD
Standard TV is 480i? I'm confused...cable and satellite aren't even close to the picture quality of a DVD at 480i on my tv. Standard TV may be 480i, but the signal I'm getting isn't. I know about compression, but something else is going on. [QUOTE]

Yes, you are confused (as are scads of other people) about "resolution" and "scanning formats". The 480i, 480p, 540p, 720p, 1080i,etc. are SCANNING FORMATS used to display images on a TV set or other video 'monitor'. They are NOT resolution, which is a totally different entity inherent in the video
format in use. Standard NTSC television images use the 480i scanning format, but are limited to 330 "lines of resolution". Translated into plain English, this "spec" refers to how many times the electron beam(s) can turn on and off as they sweep across the screen, forming the image that you see. In other words, it's the capability to reproduce fine detail in an image. DVDs, being a "digital" medium are capable of much more "resolution" (540 'lines') although they use the same scanning format as OTA television. Finally, contrary to what many believe, "compression" used by satellite TV systems, is NOT responsible for limiting "resolution" per se. In fact, if the source signal had more than a 330 line rez, DBS satellite is capable of rendering it. Most sat TV programming doesn't fall into this category however.

[QUOTE]
BTW, are there any new product besides 1080i tape? Are there any plans for new DVD players that can play "super" DVD's at 1080i? Sidebar: tape, yuck! - I lived through the tape age of the 80's and never want to go there again.

Plans? Sure. Actual products? No. Research is well under way to produce HiDef DVDs, but the inane paranoia of the movie studios will very likely delay their appearance far beyond when the products are actually ready for the marketplace!

[57U]

Yes, you are confused (as are scads of other people) about "resolution" and "scanning formats". Thanks, I'll change this in my FAQs.

Standard NTSC television images use the 480i scanning format, but are limited to 330 "lines of resolution".Since 1941 there have been 525 active lines, with broadcasters currently being able to use 480 of these lines, with 340 pixels per line.

[woodman]

Originally posted by 57U


Since 1941 there have been 525 active lines, with broadcasters currently being able to use 480 of these lines, with 340 pixels per line.

Not quite, Mr.U ... or shall I get familiar and just call you "57" ?

Anyway, the NTSC standard calls for a 525 line "frame" of video, with 30 frames per second (or 60 "fields") which translates to a 15,750hZ scanning frquency. There are 25-30 of these scan lines which are blacked out (since they occur during the "vertical blanking interval" or VBI as it's known in the technical sectors. This is the time that the electron beam(s) move from the bottom of the screen back up to the top to begin another video "field" (in an interlaced format such as 480i). That leaves roughly about 500 lines which could be called "active" since they contain video information. But "overscan" in the display device eats up about 20 or so lines, leaving the 480 which is now being referred to as a "standard".

Keep up your good efforts, Agent57

[drjohnc]

I completely agree with members Woodman and 57U. Its apples talking about oranges to pears when it comes to the differences between 480i, 500 scan lines, overscanning, line doubling, etc.

I run all of the TIVO, Laserdisc, and regular SVHS (what's left of it) through a iScan line doubler for 480p into the back of my set. The picture is much better (subjective) than when I omit the iScan and run straight SVHS or component.

For HDTV, I run component output (from DVHS, OTA HD, or RCA DTC-100) through a switch into the component input of the set. The picture is fabulous (when receiving 1080i). The DTC-100's RGB is put through an Audio Authority converter to component. For those of us who have seen DTheater tapes, or Leno, Jag, etc., in true HD there is no comparison to DVD, or "ordinary" programs. Will HD-DVD surpass DTheater. Yes, sometime in the future. You can look up the copyright wars raging among the millionaire Hollywood producers and directors right now. The only way to view recorded HD content at home (barring machines which can play studio masters -- at a $30,000 price tag) are the DVHS machines. And the only way to get 5.1 sound with the HD picture is through DTheater tapes. I am very, very anxious to see the first HD-DVD players on the market.

[HokieD]

Great, this helps explain why my DVD looks incredibly better than satellite or cable. So DVD can do 500 lines, how about HD? And you're right...the scan 480-1080 is misunderstood by many.

Also, can anyone tell the difference between progressive scan and interlaced DVD? My parents just bought a Sony progressive scan DVD player for their 61" 4:3 television after my urging that they get the best. There's a switch on the back that lets you toggle progressive and interlaced. I watched Fargo in both modes and could not tell a difference. I expected a noticeably clearer picture.

I was thinking about getting rid of my interlaced DVD and upgrading to progressive scan, but after this experience decided it would be a waste of money. Thoughts?

[57U]

Hokie: See the following thread on

"Resolution" (http://www.hdtvoice.com/voice/showthread.php?s=&threadid=1048)

Progressive scan "draws" the image on your TV in one "stroke". Interlaced does it in "two strokes" (oversimplification, but let's leave it that way for now).

The progressive should be "better", "smoother" picture, however, different sets do different things with the various signals.

I have heard many times that people will notice no difference between a 480i and 480P signal from a DVD. Perhaps the set does such a good job at "upconverting" the 480i that there is basically no visual difference. Depends on the set and the DVD player. A good 480i DVD player will beat out a "cheapo" 480P player any time.

Upgrading your DVD player is probably a waste of money. Wait until you need a new one, then upgrade, or perhaps by then there will be HD-DVD player/recorders.

[HokieD]

Thanks. I would like to be able to listen to burned MP3's, but I think I'll wait for the next generation of DVD players.