A Discussion On Poor SD On HDTVs

mswoods1

I got a kick out out of how my Vizio instruction manual described why SD material looked so bad on an HD TV [which btw, is the way I'll be describing it to my friends and family, since I don't want to go into the details about digital transferring, compression, scaling, etc...] :

"Your new digital flat panel TV is so much better than your old TV, that it will show interference and deficiencies that you did not know you had."

Sembhi

I recently bought a Samsung TV. HDTV quality is great, SD...not so much. I looked over this thread to why this problem occurs but I needed suggestions on what I should do to fix it.

kmohr3

I, too, just bought a Samsung (LNT4042H) and am experiencing the poor SD quality.

One thing that I notice: when I disconnect the box and connect the cable back up to the RF connection on the back, SD looks pretty good.

In other words, I didn't notice the poor SD quality until the Insight tech brought the DVR box and installed it. I went to Insight and made them give me a new box, too - same problem with SD.

kmohr3

I hooked up S-Video cable from the DVR box to the TV tonight, and it did improve the picture quality with SD programs somewhat - still not perfect, but better.

Sonny300

Even on say, a 42" set, wouldn`t a 720P capable HDTV do a better job of displaying SD, than a 1080P set? I have read all the threads on this and hence the question.

bobcat68

A 3 year old thread that's still relevent... cool.

Anyway, I just switched from cable to DN. They hooked up my 2 TVs with a 322 tuner. The SD picture on my older 36" SD CRT TV via the RF input is tolerable. But the SD picture on my 51" Hitachi HD CRT rear projection TV leaves something to be desired. My main complaint is the lack of definition during motion. After reading this entire post, I understand why its happing.

My question is, if I was to upgrade to their new VIP222 HD receiver, would it improve the SD on my HD TV? Or is the SD output the same as the 322?

TIA

igorveltman@gm

I recently bought a Canon HV-20. Now I will shoot some scenes for one of my friends works. It will be played in SDTV sets. Is it better to record HDTV mode? There's any difference at all?

tither777

thanks for info... i have dish through yamaha rxv2600 then hdmi to samsung 50" and sd in fuzzy like you said to the tee, some time hd is a grainy. sometimes... is there something in my reciever that i can use to help. i think it has those filters and upscaling and that stuff im a novice and though the more stuff the better.

2nd. i have read in other posts of tuning my hdtv of the torch mode???? clueless??? how do i tune it to look better, thank you for your time phil

GekoBR

OTA results by system:

NTSC - Never Twice the Same Color

PAL - Pay for the Added Luxury

SECAM - System Essentially Contrary to the American Method

ATSC - Always The Same Color (BLACK)

DVB - Detector of Vehicles Beside (internal antena)

ISDB - Initially Secret Discovered by Brazil (the newest one)

dhfleming

An excellent discussion as to why OTA standard def pictures suck on a HDTV. Next question: Why do standard def signals fed directly into the monitor via AV cables also suck? These signals are not compressed for transmission. As someone who has 40 years worth of irreplacable home movies and video recorded on tape and disc, I expect my $3000 HDTV to reproduce these images at least as good as a $100 Wal-Mart Special! Did the hot shot engineers simply not realize people don't want to give up their priceless memories, did they engineer this purposely so standard TV would look bad in comparison (my theory), or were they just stupid (my second guess)?

I cannot believe it's not possible for a "superior" sytem to display the "inferior" signal in at least the same quality as the "inferior" system could.

Mike999

Bottom line: if you want to display a SD source at its maximum size on an HDTV, then the image will have to be rescaled, and rescaling an image will always lead to some degradation in PQ.

The analogy with *blowing up a photograph* is entirely correct, and while the loss in quality can be minimized with a good scaler or by sitting further back from the screen, SD sources - especially cable and satellite - are probably never going to look as good as they do on a high quality CRT.

riddlemay

I have a situation to report which goes to show that largish HD sets can display a good SD picture—and that therefore would seem to prove that there is not anything inherent in the conversion/rescaling process from 480 to 1080, or inherent in large screen size, that works against a good SD picture. And then I have a question.

The situation: We have two services coming into the house, and two receivers, hooked up to the same 1080p 40” Bravia. One is DirecTV HD, and the other is non-HD Comcast digital.

On DirecTV HD (which is hooked up via an HDMI cable), the HD picture varies from very good to awesome depending on the channel—but the SD picture varies from poor to just-acceptable.

Meanwhile, on the input that gets the plain old Comcast digital (non-HD) signal (which is hooked up via composite video cable—yellow/red/white), the SD picture is mostly quite good! Channel for channel, when you switch between inputs, the Comcast SD picture consistently beats the pants off the SD picture being delivered by the DirecTV HD receiver.

I don’t know why this should be, but it is.

Now, here’s my question. If we decide to upgrade to a Comcast HD receiver, will we lose the good SD quality we’re currently seeing from Comcast? Is there something about an SD-only receiver (like the Comcast receiver we currently have) that makes it better able to receive and pass on SD signals than an HD receiver?

(Alternatively, is there something in a composite video connection that does a better job with SD than an HDMI connection does?)

Or do you think that with a Comcast HD receiver hooked up via HDMI we will continue to get SD quality equal to what we currently have with Comcast, with the bonus of HD added on?

sbjunky

Wow, now thats what I call informed! I'm new to the forum. I've seen many great posts, but this one has helped me the most so far. Thanks Rbinck

rbinck

Thank you.

__________________
www.highdefinitionblog.com
www.BlogOfHawaii.com

dlleno

Hi all. new to the forum here but have been lurking for some time. I'm quite interested in this topic as well, and this is a most informative thread indeed, particularly around the various SD PQ contributions coming from electronics -- receivers, connections, compression artifacts, display settings, display technology, etc.

I thought it might be good to re-visit the viewing distance piece of the equation, particularly from the visual acuity point of view. In a nutshell, this means "sit far enough away from your display so that your eye cannot resolve the unwanted detail that is causing the PQ issue". I realize this has already been mentioned more than once in this thread; I'm out to show the theoretical basis behind it.

A great many web site calculators and advice columns have proposed maximum HDTV viewing distances, for the most part aimed a sitting you close enough to the screen so that your eye CAN resolve the detail inherant in the picture content and delivered by the display screen. Essentially, these rules are often based on the fact that 20/20 human vision can resolve information down to 1/60th of a degree. check out ndt-ed.org/EducationResources/CommunityCollege/PenetrantTest/Introduction/visualacuity.htm for more detail on that.

Thus, the maximum viewing angle is:

(horizontal resolution)/60.

For example, 1080p is 1920 pixels wide, which corresponds to 32 degrees viewing angle. Calculating the maximum viewing distance for various screen sizes is a matter of analyzing the geometry.

We can use this same rule of thumb to calculate the MINIMUM viewing distance which will PREVENT the eye from resolving the unwanted picture detail that is causing the PQ problem.

Consdider the best possible SD picture from a 480p 4x3 DVD player (640x480) reproduced perfectly on a 42" diagonal HDTV in 4x3 mode (bars on the side; no stretch). The maximum viewing angle is 640/60 = 10.7 degrees. The SD picture width is ~27 1/2" on the 40" HDTV and the the geometry says that a viewing distance of over 12 feet is required to acheive the maximum viewing angle for this content.

The same content on a 50" HDTV would require nearly 15 feet viewing distance in order to prevent the eye from distinguishing greater than best possible SD resolution.

Note that this is the best possible SD scenario. If you are viewing at this (minimum) distance and still have PQ problems, then you either have content that is less than 640x480 resolution, or you have one or more of the other contributing factors mentioned here. or both.

Striking the balance between tolerable SD quality and acheiving an immersive HD experience is of course a personal compromise.