analog reception on hdtv

warhammer · 11-05-2005, 08:47 PM

I have been looking to buy a hdtv. In all the stores that i have looked at them the picture is allways outstanding. I have been told that the signal that generates the picture is a high definition loop that keeps repeating. My question to all of you who have hdtv is what does the picture look like when you are watching tv programs that are not being brodcast in hd on a HDTV. I have been told that the pictures are not nearly as good as what we are used to seeing on any 27 inch picture tube tv . Are there any hdtv 42 inch and above out there that can duplicate the quality of my 27 inch Sony picture tube when watching a program not in HD.

CatManDoo · 11-05-2005, 11:50 PM

Quote:

Originally Posted by warhammer

I have been looking to buy a hdtv. In all the stores that i have looked at them the picture is allways outstanding. I have been told that the signal that generates the picture is a high definition loop that keeps repeating. My question to all of you who have hdtv is what does the picture look like when you are watching tv programs that are not being brodcast in hd on a HDTV. I have been told that the pictures are not nearly as good as what we are used to seeing on any 27 inch picture tube tv . Are there any hdtv 42 inch and above out there that can duplicate the quality of my 27 inch Sony picture tube when watching a program not in HD.

#1. Crappy at best.
#2. No.

Nevertheless, the shows that you do get in HD on an HD set make it all worthwhile. The % of HD is continually increasing, albeit somewhat slower than most of us would like to see. But now is a great time to jump in. If you love sports and do most of your tv viewing during primetime, it is definitely worth it. Go for it!

doggie · 11-06-2005, 01:24 AM

I don't know what they mean by loop, but the picture displays more than twice the of lines of a standard TV and at the same time (progressive) versus a standard TV which alternates the line display (interlaced). About standard TV on an HDTV set, you should see a better non-HDTV picture (especially if you're getting digital satellite/cable), but of course, it'll look crappy compared to your HD programs. It just looks worse because most HDTV sets are bigger than 27" so everything is magnified. True HD has to be filmed with HD equipment, which is why HD on Discovery and PBS looks so far superior to anything you get on network primetime with TV shows and old movies just displayed in a 16:9 format. I really like the picture quality of the CRT, but if you want home theatre, you should go for a bigger screen (non-CRT).

**rbinck** · 11-06-2005, 10:00 AM

It somewhat depends on the equipment you use and the source of the SD. SD that is broadcast OTA that has been upconverted by expensive and very high quality video processors will be very good. Digital cable and satellite SD that has been overcompressed and output via low quality boxes will be horrible. I have found that you can not rely on reports for cable SD as they vary from cable system to cable system. Some are good others are not.

My SD using a SD TiVo is not watchable on my 50" HDTV, but is ok on my 40" HDTV. I usually watch SD on a 27" tube TV.

The best SD over satellite I've seen was on a 60" Zenith plasma using a SAT-520 receiver.

For more info see: Poor SD On HDTVs

rich2741 · 11-08-2005, 03:06 PM

Hi guys and gals. I just joined, so "Hello".

Just to give out a little background on myself... I'm a retired Electromagnetic Spectrum Authority, have 17 TV's (4 of which are large, full-blown HTS'), 17 DVD players (of one sort or another), over 1,200 DVD's, use DirecTv and twin OTA antennas for digital station pick-up, blah, blah, blah.

Quite a few of you probably already know most of what follows, so excuse me if I've repeated anything that is already on this site (I haven't had a chance to look around yet).

Just to clear the air on our viewing experiences, please remember that there is a difference between LCD/Plasma displays (fixed address displays) & direct trace/RPTV's (displays that use actual light beams [CRT's]). The former will always come up short unless the signal matrix delivered to it matches that of the display exactly, in addition to the fact that the present fixed address displays can not DISPLAY 1080i, but rather must downconvert it to the 720 matrix (native resolution) of the display. So, just because a 16X9 display/TV says "HDTV" does not automatically mean it will DISPLAY 1080i, as the 720i and 720p matrixes are -legally- allowed to be called "HDTV" signals (because they are). So be cautioned.

Anyway...

There are a plethora of variables that can and do come into play for this threads question, as is briefly outlined above and in RB's "Poor SD on HDTV's" (but not 100% accurate).

-All things being equal-, (which they're are not unless you're in a lab [but regardless])

The shortest, first stage reply would be to -

(A) Always purchase a display/TV on SPECIFICATIONS, not on what you see in a showroom. -ALL- TV's are overdriven (from one degree to another) right out of the factory... because they know most people buy TV's in a brightly lit showroom, where they sit side-by-side with other TV's. So they crank up the brightness, contrast, color saturation, etc, (even though the adjustment controls will read right in the middle on the menu) to make their TV the most VIBRANT in the pack. Except it doesn't work, because everybody (unless they are special 'repackaged' TV's) does it, and if they (or anyone else) backs down, they will look like the weak TV.

(B) Technically, the size of the display has nothing to do with the viewing quality (unless the pixel matrix is changed). What most people are refering to in this aspect is called "Perception of Clarity"; meaning the eye/brain will pick the image apart if viewed too closely (having nothing to do with actual resolution), and the ability to see the pixel matrix instead of enjoying the image itself is driving the visual experience. To negate that, always make sure the surface of your eyeballs are behind the 'minimum viewing distance' line. With average eyesight, and speaking only of a 16X9 aspect ratio screen, that distance would be twice the horizontal measurement of the screen itself. As an example: If you had a 64" WS TV it would horizontally measure 55.5" across. That would set the minimum viewing limit at 111" (9.25'), regardless if you are watching a 16X9 image or a 4X3 image within the 16X9 display area. No closer, or you will shoot yourself in the foot on perceived clarity. The aspect ratio of 16X9 was not pulled out of thin air; foremost it is based upon the ideal aspect ratio for human stereoscopic vision (I think this was ascertained at the Stevens Institute of Technology in New Jersey?), but also factored in was the pixel count coming up in the agreed upon ATSC Standard.

(C) Calibrate the display [I'd recommend DVE]. After 90 days, do it again. After that, once a year.

(D) Understand that the signal QUALITY is what it is; molested, unmolested, downconverted, upconverted, hacked up by various parties along the way, etc. YOU can only deal with what you have at the point of entry (sat dish, cable headend, OTA antenna) to your system, the quality of your components and information on how to extract the best viewing experience. Remember "garbage in (poor video) = garbage out" (poor image).

...which is the endpoint to the question of viewing SDTV transmissions on a HDTV display, and would be the first tier answer on this subject. Most everything that would follow in tier 2 would be variable dependent or component specific.

P.S.: I would not trade a day of butchered SDTV viewing on a large screen TV to watch a minute of analog TV on a 2" screen TV. I know what is POSSIBLE to see on my HDTV.

rich2741 · 11-08-2005, 03:32 PM

doggie wrote: "I don't know what they mean by loop, but the picture displays more than twice the of lines of a standard TV and at the same time (progressive) versus a standard TV which alternates the line display (interlaced)."

You will CONSCIOUSLY see -no- difference between a progressively displayed image and a interlaced image. They are the same EXACT resolution [480i versus 480p], there is no 'line doubling' going on between the 2 modes (that is something completely different). The viewing difference between them will only show up after a certain amount of time has passed (people have different sensitivity levels to this). The result is that interlaced viewing will cause visual fatigue of the eyes and mind long before a progressive image will. That is why you will no longer find interlaced monitors for computers, as people would get locked in front of them for 8 hours a day at work, resulting in excessive fatigue and even headaches.

pnanth · 11-08-2005, 08:20 PM

Your reply was very informative. One question: what do you mean to recalibrate?--and what is DVE?

I may not be as critical, but I have not been concious of any deterioation of SD, and contrary to that have often mistaken SD thinking it was HD. The analogy is when 78rpms went to LP and then CD. Enjoy them for what they are, and be pleased with the latest.

The Sony HDTV 40" Bravia brags about upconverting , but I really have no idea nor care to what this means in a technical sense, but I do believe some SD is better than it should be.

rich2741 · 11-09-2005, 07:24 AM

Calibration of your display (monitor/TV) is critical to getting the proper picture from it (Hey, you paid big bucks for that puppy!). That can amount to a multitude of things from having the right amount of overscan to tweaking convergence to dealing with red push to... well, you get the idea that quite a few adjustments need to be made to get great performance from the display. You, I, and the next guy, with next to no additional equipment can do this to about 95% of perfection (to get 100% you'd have to hire a ISF [Imaging Science Foundation] certified technician) within about 2 hours just by using a calibration disk (provided your TV manufacturer allows you to access certain controls); a special DVD that instructs you how to bring your display into proper alignment. Long gone are the days of 'adjust it until it looks good'; phhhh, you could be color blind for all they know.

I highly recommend the calibration disk titled "Digital Video Essentials" by Joe Kane (commonly known as "DVE"). DVE costs about $18 to $25, depending on where you buy it. Money very well spent, and you can use it on a bunch of TV's (as long as there is a DVD player hooked up to it). Heck, lend it out to friends after you're done and have them buy you a round of drinks. Additionally, it will even show you how to set up your audio system to a limited degree.

Recalibration is something you should do once a year as maintenance, because electronics (specifically the color guns) slowly age over time and can fall out of calibration (drift a bit). It's kind of futile to calibrate a display immediately when you get it home because it's so new and needs about 300 hours (about 3 months) to fully settle in to the point that it doesn't drift much, BUT, 3 months is a long time to wait so do it anyway.

It's not that "SD" has been degraded (it's a matrix, a formula, instructions, a Standard of delivery), but rather that the video transported via SD has been screwed with, or was not it's original format, or was junk to begin with. Kind of like your LP analogy... you can have a nice clean LP and stylus, or... there can be dust and grim all over it (generating pops and clicks). Don't blame the LP, or LP format, blame the caretaker. Now, on the other side of the coin, if there is all sorts of noise generated in the background of the track that was introduced while cutting the track at the studio... once again that would be the caretakers (in this case the studio engineer) fault. The LP / LP format is what it is. If it's worse than expected (according to specifications), we know something has gone askew somewhere along the line, anything from gross mishandling to simply turning up the amp to the point it starts to clip.

Upconversion (scaling, not to be confused with line doubling) can be OK as long as it takes place at your end, and the equipment (component processer) is truly up to the task. Upconversion will not make anything 'better'. The resolution has simply been rematrixed onto a larger number of pixels, but the resolution base still remains the same as the data has not been refined, but simply multiplied to fit a larger matrix (like 1 pixel now occupying the place of 4 pixels). You can not create something out of nothing by simple multiplication (versus line doubling [$$$] which actually extrapolates new data points from 2 opposing line sets).

Down conversion sucks. No if's, and's or but's... you lose resolution data as it is crunched down to fit the matrix (like going from the subtle differences spread across 4 pixels down to craming it onto 1 pixel).

Thinking SD might ever be confused for HD is a problem. There are big differences between the two.

The 5 ATSC (Advanced Television Standards Committee) Standard sub-groups are:

HDTV:

1080i - 1080 X 1920 = 2,073,600 pixels
720p - 720 X 1280 = 921,600 pixels
720i - 720 X 1280 = 921,600 pixels (no change in resolution, just delivery)

SDTV:

480i - 480 X 640 = 307,200 pixels
480p - 480 X 640 = 307,200 pixels (no change in resolution, just delivery)

So, the difference count in the pixels between HD and SD resolution is 300% to 670%. But that would be comparing 'apples to oranges' (1:1.78 [WS] vs 1:1.33 [FS]). To compare 'apples to apples' (same aspect ratios based on SD; pixel count within a fixed grid size of the same screen height), the "relative" pixel difference would be from 200.25% to 506.25%.

So the bottom line is, if you are comparing SD to HD (in a fair fashion; equal screen portions), HD will be 2 (720) to 5 (1080) times 'clearer' (higher rez) than SD (480). I marked "clearer" because, again, it all depends on the image data being proccessed. Garbage in will result in garbage out. If you watch a old "Honeymooner's" episode on SD (or even via HD) it will still visually suck because it visually sucked originally. The only improvement is that it is now a stable image (simply because it's digital).

You should drop by a high-end HTS retailer (like Sound Advice or something) and ask for a demonstration of GENUINE 1080i. Ask him to rack up a genuine 1080i clip (shot with a 1080i camera, not upconverted) shown on a genuine 1080i CRT driven display (not downconverted to 720). It will make your jaw drop open, and once you've seen it, you will recognize immediately and forever the difference between SD and real (top dog) HDTV.

If you experience better 'normal' (NTSC - analog) TV shows when watching them in SD, (ATSC - digital) it would be because the image is more stable in every way.

ja2935 · 11-09-2005, 09:54 AM

rich2741 - your posts are extremely interesting and for me just serves to illustrate that although 720x1280 is considered an HD standard, it is like looking at a 1MP digital photo as against the 2MP of a 1080x1920 display. Despite the higher refresh rate of the former I would be reluctant to ever buy a 720x1280 set!

pnanth · 11-09-2005, 02:24 PM

Thanks again. I've ordered the DVE. Some adverse comments regarding it--- to the effect they couldn't understand how to use it. Whatever, I'll have some fun with it.

Mistaking SD for HD---sometimes I receive SD material that is so good I momentarily blink, but in an instant it becomes very obvious that it is not. I made this comment for those who are inordinately worried about the quality of SD on the new HDTV's. It's like watching a "silent movie" on any TV. You discount the early technology and concentrate on the content.

.

RSawdey · 11-09-2005, 09:11 PM

You've got a couple errors, and an incomplete understanding Rich...

First, CRTs do NOT 'use actual light beams'... they emit an ELECTRON beam that causes chemical phosphors on the inside of the screen to emit light.

Your list of HD formats is incorrect, and omits framerates. ATSC HD formats are 1080p/24,30, 1080i/24,30, 720p/24,30,60. There is no 720i format.

Note that the commonly used formats are 1080i/30 and 720p/60. Although each frame of 1080i has twice the pixels, 720p has twice the frames per second... making both formats deliver about the same amount of pixels per second.

Usually recommended rule-of-thumb for size is twice the DIAGONAL... this is a compromise between the closer position optimal for HDTV, and further position for SDTV.

It's not too difficult to discriminate an interlaced image from a progressive one... the interlaced display show artifacts of combing and twitter with motion.

ja2935 · 11-09-2005, 10:43 PM

Sorry but I don't see how twice the frame rate makes up for half the definition except perhaps in very fast moving scenes to reduce blurr. The puck or tennis ball or whatever is still going to have fewer pixels with a 720p display than with a 1080i but presumably the edge when moving will be more clearly defined. For drama 1080 has to be better.

rich2741 · 11-10-2005, 06:01 AM

Sorry Mr. Wizard, but you are mistaken. You have drawn your information from a inferior source, a common mistake. But first...

You ARE technically correct in the use of the term "electron beam", but I want to relay that if I hit people 'right out of the gate' with terms like "Mebibyte" (read the word please), which is 1,048,576 bytes (what people really mean when they say "Megabyte" which is decimal [base 10], instead of binary [base 2]), I might tend to whack their world a bit too hard, instead of relaying information they can understand. So yes, once in a while I will make the decision to back off of the strict technical nomenclature just a bit if I feel it will help.

Second: If they've dropped 720i, then I am unaware of it. If it is fact, then it is simply a matter of an agreement to use the better (but not higher rez, or faster frame rate) format of 720p. But if that is the case, then why would 1080i not be dropped altogether in favor of 1080p? I respond to this in the form of a question ONLY because I have not had a chance to reconfirm my facts, but I doubt the Grand Alliance (you know who that is, right?) has changed anything (1080i, 720p, 720i, 480p, 480i). It is easily possible (through faster processors) to convert interlaced into progressive scan; you combine each field as it comes in and double up on the refresh rate.

So, with that said, let's get technical.

Each FRAME of 1080i has 2,073,600 pixels. Each FRAME of 720p (or i) has 921,600 pixels. 1080i has exactly 2.25 times the -resolution- of 720p (or i).

Here's where you went wrong... a FRAME is the complete and total utilization of the image area within the aspect ratio in 'one shot', versus a --FIELD-- is half the frame drawn in 2 succesive passes; odd lines descending 1st, then even lines descending 2nd, ergo, -2- FIELDS make 1 FRAME. The -resolution- does not change under any circumstances. If you believed that FIELDS are generated at 60 Hz, then FRAMES would appear at 120 Hz. Not so.

Frame rates are basically inconsequential once you meet the -minimum- criteria of passing the 'flicker point', which is roughly 60 FRAMES per second (but 75+ Hz is much better), based on the bottleneck of FIELDS showing at 30. Beyond that rate the mind can not discern much differance in the instance of moving (that's why we invented high speed cameras [ie: 10,000 fps] to slow down stuff we need to see in more detail). But I digress. To be technical, the FRAME rate is exactly 59.940059940059940059940059 Hertz (cycles per second) if you are referencing progressive scan, but if you are referencing the FIELD rate of interlaced scan, that would be 29.97002997 Hertz. This is because there are -2- FIELDS that make up -1- FRAME. Again, 2 fields equal 1 frame (interlacing). Double the field rate (which you must) and you get the frame rate (59.94 fps).

Additionally, frame rates are so inconsequential TO OUR MINDS (not in a synchronous sense of video delivery) that we mess with them all the time. Take the 3:2 pull down. If you are technically astute this will hit you like a ton of bricks.

Furthermore, to make things clear, the 24, 30, 60 'frame' rates you spoke of are...

24: This is a FILM (celluloid) frame rate. Cinematic high def digital cameras can shoot in this so they can be easily transfered to FILM for movie theater showing, no other reason.

30: This is not a -frame- rate, this is the US field rate of cinematic/broadcast video. It is also the frame rate of quasi-video streams (yuk!), like internet cameras, which can also be reduced to 15 fps (double yuk!).

60: This is the US frame rate of US cinematic/broadcast video. It is based on 2 facts. (A) our electrical system operates at 60 Hz, which mandates our electronic devices operate at 60 Hz (or a multiple thereof), and (B) it meets the normal 'flicker' test for normal viewing.

If you view PAL video (and all it variants), you are watching 25 Hz fields, 50 Hz frames, and even 100 Hz frames (a double of 50 Hz to make it an easy transition, and for purposes of reducing artifacts in high speed lateral movement, which pushes it past that sweet 75 Hz rate.)

So just to be crystal clear...

1080i is delivered at 60 frames per second (2 fields at a rate of 30 Hz)
720p is delivered at 60 frames per second (single frames at a rate of 60 Hz)
720i is delivered at 60 frames per second (2 fields at a rate of 30 Hz)
480p is delivered at 60 frames per second (single frames at a rate of 60 Hz)
480i is delivered at 60 frames per second (2 fields at a rate of 30 Hz)

Sorry, but you are mistaken again Mr. Wizard. The minimum viewing distance I spoke of in my former post was clearly marked as being for ** 16X9 ** aspect ration displays. Furthermore, the distance would be based upon defined pixel visability for average human vision acuity and the scope of vision (which is "perceived clarity"), not on upon a digital deliver format (you mentioned HD vs SD). The diagonal measurement you mentioned is meant for 4X3 displays (digital or analog displays) and has been presented as 1.5 to 2 times the diagonal. And lastly, if you are watching a 4X3 AR inside a 16X9 display, would you think people will move their chair about each time? (I'm being rhetorical; of course the chair/couch is going to be set in one place for the sake of a few inches)

Again, incorrect Mr. Wizard. You (or I) can not CONSCIOUSLY see the difference between progressive scan or interlaced scan. Comb filters are only required on COMPOSITE analog video signals, and has nothing to do with interlaced vs progressive scan. A comb filter effectively takes composite and breaks it out into S-video (separating chroma and luminance). The delivery format of ATSC is digital.

* Opps! Almost forgot-

ja2935,

You are correct in every way. See my comment above on PAL 100 as an example.

rich2741 · 11-10-2005, 06:38 AM

To answer the 2 posts from the last page-

Ja2935,

Yes, you are essentially correct (1 vs 2.25). This is why I try to warn people of the limitation of fixed address displays; not that they are bad, but simply inform them they can not ACTUALLY view 1080i in the display the just paid a fortune for. Just to expand on these displays, they absolutly shine in their own world because they are the ones that easily fit into a jet, limo, yacht, and if you are restricted in the amount of space you have in a condo. They definatly have their place. AND... once they figure out how to cram 2,073,600 pixels in the manufacturing process (that's the problem they have... it's a big failure rate at the plant), I'd buy 1 (or 2, or 3, or 4)!

PANATH,

Now I know what you meant.

DVE is not really that complicated. Some people just want to be able to see some magic words, push 1 or 2 buttons and have it done. It's not like that, it is a -process- (you'll see). That's why it takes a little time. Even if you find it a bit confusing at first, you can always go back to it later, or pause and backtrack the segment. Make sure your DVD player is hooked up to your display with COMPONENT cables (3 RCA plugs just for the video stream) -if- your system (TV and DVD player) can use them; if not, use S-video.

...while I'm mentioning this, I might as well relay the quality differences of the different video connections:

On a scale of zero to 100, this is roughly how it pans out-

Component video connection - rates 100 (perfect)
This uses 3 RCA plugs/sockets which are commonly color coded red, green, and blue. This type of video connection keeps all 3 signal streams separate. (1+1+1)

S-video connection - rates 85 (very good)
This connection uses a 4 pin, Mini-DIN plug/socket (a German standard). It separates the chromance and the luminance, which makes a world of difference. (2+1)

Composite connection - rates about 40 (bad)
This is a single yellow RCA plug/socket which combines all 3 video streams onto one line - yuk! This is the same connection a VCR uses. (3)

RF connection - Don't ever even think about using this! It is garbage! It not only crams all 3 streams, but also audio in one signal stream, then on top of that it sends it via analog RF to the TV on a coaxial cable. (don't confuse this comment with other coax distribution; sat/cable/TV. I'm talking about "re-distribution" here.)

rich2741 · 11-10-2005, 08:49 AM

Hmmmmm. I just noticed a few minor typos (misspellings) scattered throughout the last 2 posts. Since it is too late to modifiy them, please excuse me.

11-06-2005, 10:00 AM	#4
rbinck Administrator Join Date: Apr 2004 Location: Katy, Texas Posts: 12,335	It somewhat depends on the equipment you use and the source of the SD. SD that is broadcast OTA that has been upconverted by expensive and very high quality video processors will be very good. Digital cable and satellite SD that has been overcompressed and output via low quality boxes will be horrible. I have found that you can not rely on reports for cable SD as they vary from cable system to cable system. Some are good others are not. My SD using a SD TiVo is not watchable on my 50" HDTV, but is ok on my 40" HDTV. I usually watch SD on a 27" tube TV. The best SD over satellite I've seen was on a 60" Zenith plasma using a SAT-520 receiver. For more info see: Poor SD On HDTVs __________________ www.highdefinitionblog.com www.BlogOfHawaii.com

11-08-2005, 03:32 PM	#6
rich2741 Spectrum Authority Join Date: Nov 2005 Location: on the Intracoastal Waterway in Fort Lauderdale, Florida, USA Age: 53 Posts: 16	doggie wrote: "I don't know what they mean by loop, but the picture displays more than twice the of lines of a standard TV and at the same time (progressive) versus a standard TV which alternates the line display (interlaced)." You will CONSCIOUSLY see -no- difference between a progressively displayed image and a interlaced image. They are the same EXACT resolution [480i versus 480p], there is no 'line doubling' going on between the 2 modes (that is something completely different). The viewing difference between them will only show up after a certain amount of time has passed (people have different sensitivity levels to this). The result is that interlaced viewing will cause visual fatigue of the eyes and mind long before a progressive image will. That is why you will no longer find interlaced monitors for computers, as people would get locked in front of them for 8 hours a day at work, resulting in excessive fatigue and even headaches. Last edited by rich2741; 11-08-2005 at 03:35 PM.

11-08-2005, 08:20 PM	#7
pnanth A couch and an HDTV to go please. Join Date: Oct 2005 Posts: 11	Thanks to Rich 2741 Your reply was very informative. One question: what do you mean to recalibrate?--and what is DVE? I may not be as critical, but I have not been concious of any deterioation of SD, and contrary to that have often mistaken SD thinking it was HD. The analogy is when 78rpms went to LP and then CD. Enjoy them for what they are, and be pleased with the latest. The Sony HDTV 40" Bravia brags about upconverting , but I really have no idea nor care to what this means in a technical sense, but I do believe some SD is better than it should be.

11-09-2005, 07:24 AM	#8
rich2741 Spectrum Authority Join Date: Nov 2005 Location: on the Intracoastal Waterway in Fort Lauderdale, Florida, USA Age: 53 Posts: 16	Calibration of your display (monitor/TV) is critical to getting the proper picture from it (Hey, you paid big bucks for that puppy!). That can amount to a multitude of things from having the right amount of overscan to tweaking convergence to dealing with red push to... well, you get the idea that quite a few adjustments need to be made to get great performance from the display. You, I, and the next guy, with next to no additional equipment can do this to about 95% of perfection (to get 100% you'd have to hire a ISF [Imaging Science Foundation] certified technician) within about 2 hours just by using a calibration disk (provided your TV manufacturer allows you to access certain controls); a special DVD that instructs you how to bring your display into proper alignment. Long gone are the days of 'adjust it until it looks good'; phhhh, you could be color blind for all they know. I highly recommend the calibration disk titled "Digital Video Essentials" by Joe Kane (commonly known as "DVE"). DVE costs about $18 to $25, depending on where you buy it. Money very well spent, and you can use it on a bunch of TV's (as long as there is a DVD player hooked up to it). Heck, lend it out to friends after you're done and have them buy you a round of drinks. Additionally, it will even show you how to set up your audio system to a limited degree. Recalibration is something you should do once a year as maintenance, because electronics (specifically the color guns) slowly age over time and can fall out of calibration (drift a bit). It's kind of futile to calibrate a display immediately when you get it home because it's so new and needs about 300 hours (about 3 months) to fully settle in to the point that it doesn't drift much, BUT, 3 months is a long time to wait so do it anyway. It's not that "SD" has been degraded (it's a matrix, a formula, instructions, a Standard of delivery), but rather that the video transported via SD has been screwed with, or was not it's original format, or was junk to begin with. Kind of like your LP analogy... you can have a nice clean LP and stylus, or... there can be dust and grim all over it (generating pops and clicks). Don't blame the LP, or LP format, blame the caretaker. Now, on the other side of the coin, if there is all sorts of noise generated in the background of the track that was introduced while cutting the track at the studio... once again that would be the caretakers (in this case the studio engineer) fault. The LP / LP format is what it is. If it's worse than expected (according to specifications), we know something has gone askew somewhere along the line, anything from gross mishandling to simply turning up the amp to the point it starts to clip. Upconversion (scaling, not to be confused with line doubling) can be OK as long as it takes place at your end, and the equipment (component processer) is truly up to the task. Upconversion will not make anything 'better'. The resolution has simply been rematrixed onto a larger number of pixels, but the resolution base still remains the same as the data has not been refined, but simply multiplied to fit a larger matrix (like 1 pixel now occupying the place of 4 pixels). You can not create something out of nothing by simple multiplication (versus line doubling [$$$] which actually extrapolates new data points from 2 opposing line sets). Down conversion sucks. No if's, and's or but's... you lose resolution data as it is crunched down to fit the matrix (like going from the subtle differences spread across 4 pixels down to craming it onto 1 pixel). Thinking SD might ever be confused for HD is a problem. There are big differences between the two. The 5 ATSC (Advanced Television Standards Committee) Standard sub-groups are: HDTV: 1080i - 1080 X 1920 = 2,073,600 pixels 720p - 720 X 1280 = 921,600 pixels 720i - 720 X 1280 = 921,600 pixels (no change in resolution, just delivery) SDTV: 480i - 480 X 640 = 307,200 pixels 480p - 480 X 640 = 307,200 pixels (no change in resolution, just delivery) So, the difference count in the pixels between HD and SD resolution is 300% to 670%. But that would be comparing 'apples to oranges' (1:1.78 [WS] vs 1:1.33 [FS]). To compare 'apples to apples' (same aspect ratios based on SD; pixel count within a fixed grid size of the same screen height), the "relative" pixel difference would be from 200.25% to 506.25%. So the bottom line is, if you are comparing SD to HD (in a fair fashion; equal screen portions), HD will be 2 (720) to 5 (1080) times 'clearer' (higher rez) than SD (480). I marked "clearer" because, again, it all depends on the image data being proccessed. Garbage in will result in garbage out. If you watch a old "Honeymooner's" episode on SD (or even via HD) it will still visually suck because it visually sucked originally. The only improvement is that it is now a stable image (simply because it's digital). You should drop by a high-end HTS retailer (like Sound Advice or something) and ask for a demonstration of GENUINE 1080i. Ask him to rack up a genuine 1080i clip (shot with a 1080i camera, not upconverted) shown on a genuine 1080i CRT driven display (not downconverted to 720). It will make your jaw drop open, and once you've seen it, you will recognize immediately and forever the difference between SD and real (top dog) HDTV. If you experience better 'normal' (NTSC - analog) TV shows when watching them in SD, (ATSC - digital) it would be because the image is more stable in every way. Last edited by rich2741; 11-09-2005 at 07:28 AM.

11-09-2005, 09:54 AM	#9
ja2935 High Definition is the definition of life. Join Date: Jul 2004 Location: Atlanta, GA Posts: 1,034	rich2741 - your posts are extremely interesting and for me just serves to illustrate that although 720x1280 is considered an HD standard, it is like looking at a 1MP digital photo as against the 2MP of a 1080x1920 display. Despite the higher refresh rate of the former I would be reluctant to ever buy a 720x1280 set! __________________ Toshiba 34HF84 Comcast Motorola DCT 3416 (all digital), Component/Fiber Optic Toshiba SD4900 (Region Free), Component/Digital Coax Toshiba HD-A2, HDMI/Fiber Optic Yamaha YHT-160 Home Theater System

11-05-2005, 08:47 PM	#1
warhammer What is HD? Join Date: Sep 2004 Posts: 3	analog reception on hdtv I have been looking to buy a hdtv. In all the stores that i have looked at them the picture is allways outstanding. I have been told that the signal that generates the picture is a high definition loop that keeps repeating. My question to all of you who have hdtv is what does the picture look like when you are watching tv programs that are not being brodcast in hd on a HDTV. I have been told that the pictures are not nearly as good as what we are used to seeing on any 27 inch picture tube tv . Are there any hdtv 42 inch and above out there that can duplicate the quality of my 27 inch Sony picture tube when watching a program not in HD. Last edited by warhammer; 11-05-2005 at 08:50 PM. Reason: spelling

11-06-2005, 01:24 AM	#3
doggie TimeWarnerStinks Join Date: Oct 2005 Location: NYC Posts: 210	I don't know what they mean by loop, but the picture displays more than twice the of lines of a standard TV and at the same time (progressive) versus a standard TV which alternates the line display (interlaced). About standard TV on an HDTV set, you should see a better non-HDTV picture (especially if you're getting digital satellite/cable), but of course, it'll look crappy compared to your HD programs. It just looks worse because most HDTV sets are bigger than 27" so everything is magnified. True HD has to be filmed with HD equipment, which is why HD on Discovery and PBS looks so far superior to anything you get on network primetime with TV shows and old movies just displayed in a 16:9 format. I really like the picture quality of the CRT, but if you want home theatre, you should go for a bigger screen (non-CRT).

11-08-2005, 03:06 PM	#5
rich2741 Spectrum Authority Join Date: Nov 2005 Location: on the Intracoastal Waterway in Fort Lauderdale, Florida, USA Age: 53 Posts: 16	Hi guys and gals. I just joined, so "Hello". Just to give out a little background on myself... I'm a retired Electromagnetic Spectrum Authority, have 17 TV's (4 of which are large, full-blown HTS'), 17 DVD players (of one sort or another), over 1,200 DVD's, use DirecTv and twin OTA antennas for digital station pick-up, blah, blah, blah. Quite a few of you probably already know most of what follows, so excuse me if I've repeated anything that is already on this site (I haven't had a chance to look around yet). Just to clear the air on our viewing experiences, please remember that there is a difference between LCD/Plasma displays (fixed address displays) & direct trace/RPTV's (displays that use actual light beams [CRT's]). The former will always come up short unless the signal matrix delivered to it matches that of the display exactly, in addition to the fact that the present fixed address displays can not DISPLAY 1080i, but rather must downconvert it to the 720 matrix (native resolution) of the display. So, just because a 16X9 display/TV says "HDTV" does not automatically mean it will DISPLAY 1080i, as the 720i and 720p matrixes are -legally- allowed to be called "HDTV" signals (because they are). So be cautioned. Anyway... There are a plethora of variables that can and do come into play for this threads question, as is briefly outlined above and in RB's "Poor SD on HDTV's" (but not 100% accurate). -All things being equal-, (which they're are not unless you're in a lab [but regardless]) The shortest, first stage reply would be to - (A) Always purchase a display/TV on SPECIFICATIONS, not on what you see in a showroom. -ALL- TV's are overdriven (from one degree to another) right out of the factory... because they know most people buy TV's in a brightly lit showroom, where they sit side-by-side with other TV's. So they crank up the brightness, contrast, color saturation, etc, (even though the adjustment controls will read right in the middle on the menu) to make their TV the most VIBRANT in the pack. Except it doesn't work, because everybody (unless they are special 'repackaged' TV's) does it, and if they (or anyone else) backs down, they will look like the weak TV. (B) Technically, the size of the display has nothing to do with the viewing quality (unless the pixel matrix is changed). What most people are refering to in this aspect is called "Perception of Clarity"; meaning the eye/brain will pick the image apart if viewed too closely (having nothing to do with actual resolution), and the ability to see the pixel matrix instead of enjoying the image itself is driving the visual experience. To negate that, always make sure the surface of your eyeballs are behind the 'minimum viewing distance' line. With average eyesight, and speaking only of a 16X9 aspect ratio screen, that distance would be twice the horizontal measurement of the screen itself. As an example: If you had a 64" WS TV it would horizontally measure 55.5" across. That would set the minimum viewing limit at 111" (9.25'), regardless if you are watching a 16X9 image or a 4X3 image within the 16X9 display area. No closer, or you will shoot yourself in the foot on perceived clarity. The aspect ratio of 16X9 was not pulled out of thin air; foremost it is based upon the ideal aspect ratio for human stereoscopic vision (I think this was ascertained at the Stevens Institute of Technology in New Jersey?), but also factored in was the pixel count coming up in the agreed upon ATSC Standard. (C) Calibrate the display [I'd recommend DVE]. After 90 days, do it again. After that, once a year. (D) Understand that the signal QUALITY is what it is; molested, unmolested, downconverted, upconverted, hacked up by various parties along the way, etc. YOU can only deal with what you have at the point of entry (sat dish, cable headend, OTA antenna) to your system, the quality of your components and information on how to extract the best viewing experience. Remember "garbage in (poor video) = garbage out" (poor image). ...which is the endpoint to the question of viewing SDTV transmissions on a HDTV display, and would be the first tier answer on this subject. Most everything that would follow in tier 2 would be variable dependent or component specific. P.S.: I would not trade a day of butchered SDTV viewing on a large screen TV to watch a minute of analog TV on a 2" screen TV. I know what is POSSIBLE to see on my HDTV.

11-09-2005, 02:24 PM	#10
pnanth A couch and an HDTV to go please. Join Date: Oct 2005 Posts: 11	DVE/Rich2741 Thanks again. I've ordered the DVE. Some adverse comments regarding it--- to the effect they couldn't understand how to use it. Whatever, I'll have some fun with it. Mistaking SD for HD---sometimes I receive SD material that is so good I momentarily blink, but in an instant it becomes very obvious that it is not. I made this comment for those who are inordinately worried about the quality of SD on the new HDTV's. It's like watching a "silent movie" on any TV. You discount the early technology and concentrate on the content. .

11-09-2005, 09:11 PM	#11
RSawdey Mr. Wizard Join Date: Feb 2005 Location: Ferndale, Michigan Age: 61 Posts: 5,981	You've got a couple errors, and an incomplete understanding Rich... First, CRTs do NOT 'use actual light beams'... they emit an ELECTRON beam that causes chemical phosphors on the inside of the screen to emit light. Your list of HD formats is incorrect, and omits framerates. ATSC HD formats are 1080p/24,30, 1080i/24,30, 720p/24,30,60. There is no 720i format. Note that the commonly used formats are 1080i/30 and 720p/60. Although each frame of 1080i has twice the pixels, 720p has twice the frames per second... making both formats deliver about the same amount of pixels per second. Usually recommended rule-of-thumb for size is twice the DIAGONAL... this is a compromise between the closer position optimal for HDTV, and further position for SDTV. It's not too difficult to discriminate an interlaced image from a progressive one... the interlaced display show artifacts of combing and twitter with motion.

11-09-2005, 10:43 PM	#12
ja2935 High Definition is the definition of life. Join Date: Jul 2004 Location: Atlanta, GA Posts: 1,034	Sorry but I don't see how twice the frame rate makes up for half the definition except perhaps in very fast moving scenes to reduce blurr. The puck or tennis ball or whatever is still going to have fewer pixels with a 720p display than with a 1080i but presumably the edge when moving will be more clearly defined. For drama 1080 has to be better. __________________ Toshiba 34HF84 Comcast Motorola DCT 3416 (all digital), Component/Fiber Optic Toshiba SD4900 (Region Free), Component/Digital Coax Toshiba HD-A2, HDMI/Fiber Optic Yamaha YHT-160 Home Theater System

11-10-2005, 06:01 AM	#13
rich2741 Spectrum Authority Join Date: Nov 2005 Location: on the Intracoastal Waterway in Fort Lauderdale, Florida, USA Age: 53 Posts: 16	Sorry Mr. Wizard, but you are mistaken. You have drawn your information from a inferior source, a common mistake. But first... You ARE technically correct in the use of the term "electron beam", but I want to relay that if I hit people 'right out of the gate' with terms like "Mebibyte" (read the word please), which is 1,048,576 bytes (what people really mean when they say "Megabyte" which is decimal [base 10], instead of binary [base 2]), I might tend to whack their world a bit too hard, instead of relaying information they can understand. So yes, once in a while I will make the decision to back off of the strict technical nomenclature just a bit if I feel it will help. Second: If they've dropped 720i, then I am unaware of it. If it is fact, then it is simply a matter of an agreement to use the better (but not higher rez, or faster frame rate) format of 720p. But if that is the case, then why would 1080i not be dropped altogether in favor of 1080p? I respond to this in the form of a question ONLY because I have not had a chance to reconfirm my facts, but I doubt the Grand Alliance (you know who that is, right?) has changed anything (1080i, 720p, 720i, 480p, 480i). It is easily possible (through faster processors) to convert interlaced into progressive scan; you combine each field as it comes in and double up on the refresh rate. So, with that said, let's get technical. Each FRAME of 1080i has 2,073,600 pixels. Each FRAME of 720p (or i) has 921,600 pixels. 1080i has exactly 2.25 times the -resolution- of 720p (or i). Here's where you went wrong... a FRAME is the complete and total utilization of the image area within the aspect ratio in 'one shot', versus a --FIELD-- is half the frame drawn in 2 succesive passes; odd lines descending 1st, then even lines descending 2nd, ergo, -2- FIELDS make 1 FRAME. The -resolution- does not change under any circumstances. If you believed that FIELDS are generated at 60 Hz, then FRAMES would appear at 120 Hz. Not so. Frame rates are basically inconsequential once you meet the -minimum- criteria of passing the 'flicker point', which is roughly 60 FRAMES per second (but 75+ Hz is much better), based on the bottleneck of FIELDS showing at 30. Beyond that rate the mind can not discern much differance in the instance of moving (that's why we invented high speed cameras [ie: 10,000 fps] to slow down stuff we need to see in more detail). But I digress. To be technical, the FRAME rate is exactly 59.940059940059940059940059 Hertz (cycles per second) if you are referencing progressive scan, but if you are referencing the FIELD rate of interlaced scan, that would be 29.97002997 Hertz. This is because there are -2- FIELDS that make up -1- FRAME. Again, 2 fields equal 1 frame (interlacing). Double the field rate (which you must) and you get the frame rate (59.94 fps). Additionally, frame rates are so inconsequential TO OUR MINDS (not in a synchronous sense of video delivery) that we mess with them all the time. Take the 3:2 pull down. If you are technically astute this will hit you like a ton of bricks. Furthermore, to make things clear, the 24, 30, 60 'frame' rates you spoke of are... 24: This is a FILM (celluloid) frame rate. Cinematic high def digital cameras can shoot in this so they can be easily transfered to FILM for movie theater showing, no other reason. 30: This is not a -frame- rate, this is the US field rate of cinematic/broadcast video. It is also the frame rate of quasi-video streams (yuk!), like internet cameras, which can also be reduced to 15 fps (double yuk!). 60: This is the US frame rate of US cinematic/broadcast video. It is based on 2 facts. (A) our electrical system operates at 60 Hz, which mandates our electronic devices operate at 60 Hz (or a multiple thereof), and (B) it meets the normal 'flicker' test for normal viewing. If you view PAL video (and all it variants), you are watching 25 Hz fields, 50 Hz frames, and even 100 Hz frames (a double of 50 Hz to make it an easy transition, and for purposes of reducing artifacts in high speed lateral movement, which pushes it past that sweet 75 Hz rate.) So just to be crystal clear... 1080i is delivered at 60 frames per second (2 fields at a rate of 30 Hz) 720p is delivered at 60 frames per second (single frames at a rate of 60 Hz) 720i is delivered at 60 frames per second (2 fields at a rate of 30 Hz) 480p is delivered at 60 frames per second (single frames at a rate of 60 Hz) 480i is delivered at 60 frames per second (2 fields at a rate of 30 Hz) Sorry, but you are mistaken again Mr. Wizard. The minimum viewing distance I spoke of in my former post was clearly marked as being for 16X9 aspect ration displays. Furthermore, the distance would be based upon defined pixel visability for average human vision acuity and the scope of vision (which is "perceived clarity"), not on upon a digital deliver format (you mentioned HD vs SD). The diagonal measurement you mentioned is meant for 4X3 displays (digital or analog displays) and has been presented as 1.5 to 2 times the diagonal. And lastly, if you are watching a 4X3 AR inside a 16X9 display, would you think people will move their chair about each time? (I'm being rhetorical; of course the chair/couch is going to be set in one place for the sake of a few inches) Again, incorrect Mr. Wizard. You (or I) can not CONSCIOUSLY see the difference between progressive scan or interlaced scan. Comb filters are only required on COMPOSITE analog video signals, and has nothing to do with interlaced vs progressive scan. A comb filter effectively takes composite and breaks it out into S-video (separating chroma and luminance). The delivery format of ATSC is digital. * Opps! Almost forgot- ja2935, You are correct in every way. See my comment above on PAL 100 as an example. Last edited by rich2741; 11-10-2005 at 06:22 AM.

11-10-2005, 06:38 AM	#14
rich2741 Spectrum Authority Join Date: Nov 2005 Location: on the Intracoastal Waterway in Fort Lauderdale, Florida, USA Age: 53 Posts: 16	To answer the 2 posts from the last page- Ja2935, Yes, you are essentially correct (1 vs 2.25). This is why I try to warn people of the limitation of fixed address displays; not that they are bad, but simply inform them they can not ACTUALLY view 1080i in the display the just paid a fortune for. Just to expand on these displays, they absolutly shine in their own world because they are the ones that easily fit into a jet, limo, yacht, and if you are restricted in the amount of space you have in a condo. They definatly have their place. AND... once they figure out how to cram 2,073,600 pixels in the manufacturing process (that's the problem they have... it's a big failure rate at the plant), I'd buy 1 (or 2, or 3, or 4)! PANATH, Now I know what you meant. DVE is not really that complicated. Some people just want to be able to see some magic words, push 1 or 2 buttons and have it done. It's not like that, it is a -process- (you'll see). That's why it takes a little time. Even if you find it a bit confusing at first, you can always go back to it later, or pause and backtrack the segment. Make sure your DVD player is hooked up to your display with COMPONENT cables (3 RCA plugs just for the video stream) -if- your system (TV and DVD player) can use them; if not, use S-video. ...while I'm mentioning this, I might as well relay the quality differences of the different video connections: On a scale of zero to 100, this is roughly how it pans out- Component video connection - rates 100 (perfect) This uses 3 RCA plugs/sockets which are commonly color coded red, green, and blue. This type of video connection keeps all 3 signal streams separate. (1+1+1) S-video connection - rates 85 (very good) This connection uses a 4 pin, Mini-DIN plug/socket (a German standard). It separates the chromance and the luminance, which makes a world of difference. (2+1) Composite connection - rates about 40 (bad) This is a single yellow RCA plug/socket which combines all 3 video streams onto one line - yuk! This is the same connection a VCR uses. (3) RF connection - Don't ever even think about using this! It is garbage! It not only crams all 3 streams, but also audio in one signal stream, then on top of that it sends it via analog RF to the TV on a coaxial cable. (don't confuse this comment with other coax distribution; sat/cable/TV. I'm talking about "re-distribution" here.) Last edited by rich2741; 11-10-2005 at 07:05 AM.

11-10-2005, 08:49 AM	#15
rich2741 Spectrum Authority Join Date: Nov 2005 Location: on the Intracoastal Waterway in Fort Lauderdale, Florida, USA Age: 53 Posts: 16	Hmmmmm. I just noticed a few minor typos (misspellings) scattered throughout the last 2 posts. Since it is too late to modifiy them, please excuse me.

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