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back to article How to choose the right screen size

How big is big enough? It’s a question many of us have asked, as we cruise the aisles of Currys or John Lewis, looking for a new TV. It’s all too easy to be seduced by a special offer, or by extra features like net connectivity, and end up with a TV that’s larger than you anticipated. And while you might make space for a jumbo …

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square pixels all round

Most broadcasters use 1440x1080 for transmission which is an anamorphic version of 1920x1080. That means it is 16x9 squashed to roughly 4:3 and then expanded again(similar to what they do to films on DVD). The scalers in settop boxes will do the conversion back to 1920 so the viewer never actually sees 1440. They do this because the slight drop in horizontal resolution (almost invisible to viewers on all but the largest displays at sensible viewing distances), saves some bitrate which in turn makes the MPEG compression easier (hence less coding artefacts). This is not a BBC only thing, almost everyone does it because it makes the pictures at broadcast bitrates look better!

As for overscan, the 16x9 picture, which is now 1920 scaled from 1440, is completely overscanned on most TVs which means that even broadcasting 1920 and receiving on a 1920 display doesn't always give you pixel mapping, and you never see pixel mapped 1440 as that would be the wrong aspect ratio so everyone would look short and fat!

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My so-called HD camcorder does this

I was shocked! shocked! when I examined the video files with ffmpeg

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MJI
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Overscanning - not here

I switched all HDMI connections to pixel mapping, Humax HDR rescales BBC HD, but I think the Humax overscans.

Lot better picture

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MJI
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Don't worry

The best domestic ones are 1440x1080 on tape (HDV) rather than 1920x1080 on HDD or card.

Resolution isn't everything.

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Anonymous Coward

Re Don't worry & My so callled HD camcorder does this

"The best domestic ones are 1440x1080 on tape (HDV) rather than 1920x1080 on HDD or card."

There is an alternative, below the cost of professional movie cameras.

A good reason for buying a DSLR or hybrid bridge camera is that some can shoot full 1080p at 30fps that's 1920x1080 pixels, generally with wider aperture lens and higher quality sensors.

A Fuji HS10 can be bought for about £250 - mine produces stunning video even at the 720p setting

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I recently "downgraded"

From a cheap 1920x1080 37" LCD to a nice quality 1024x768 42" plasma and can't tell the difference in terms of resolution. Picture quality is through the roof though.

I'm buggered if I can figure out why the apparently square pixels on the plasma manage to have a 16:9 aspect at that resolution though.

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MJI
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I went straight to top end LCD

Not the poncy chassised ones, just where the money went on panel and drive electronics.

Definate difference in picture between different LCD models

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Anonymous Coward

re: I recently "downgraded"

@johnnytruant

XGA 1024x768 was a standard IBM computer display, particularly with built in hardware processing to offload video processing from the CPU. Using that hardware processing, could be a cheap option for plasma displays, that appear to have been mainly made for the US market.

Plasma displays may not to be made with square pixels. So most non-square pixel plasma displays need to use additional processing as well as the 4:3 'scaler' that has been built into all digital receivers.

Divide 1024x768 by 256 and you get 4x3, obviously not a 16:9 display if the pixels are square.

The "apparently square pixels" cannot be square they must be rectangular - wider than their height in the ratio 4:3, to produce an actual 16:9 display

For a non-square pixel display, a full 1920x1080 video being received would generally be transformed from 1920 by 4:3 into 1440 in each line, to change square pixels to display on the rectangular pixel display.

Except that the UK transmissions on DVB-T/S are now generally compressed by the 4:3 scaler to reduce 1920x1080 to 1440x1080 etc - so such a compressed picture displays without processing if the pixels are displayed 4:3 shape rather than square.

So generally the 1024x768 plasma display does not have to rescale the pixel dimensions, for UK HDTV.

That leaves the built in processing to resize the picture, from 1440x1080 to 1024x768 - which is the same reduction in each dimension: (1024/1440)*1080=768 Rather than being done by a CPU this could be done by the cheap old hardware that was made for the IBM XGA displays.

Compared to very early plasma displays that sometimes had to process broadcasts with three picture transforms, this 1024x768 plasma display is generally performing one resizing transformation, in order to reduce definition by about 30%, which should be noticeable. Depends what you are watching, at what distance, and all the other qualifications. You would probably notice a difference between your old 1920x1080 LCD-TV and the new 1024x768 plasma-TV if watching a Blu-ray 1080p video.

However the better colour of new plasma display, compared to an old LCD display, is probably more satisfying for the moment, until the plasma display deteriorates with age.

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Pint

Dr Who

Still getting used to our new 40" HD set, upgraded from 26" CRT.

Trying to get the right contrast and brightness right. Even films that got Oscars for the lighting look like bad 70s Dr Who...

some things only time and beer will cure.

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MJI
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Worth playing with

Also try getting a setup DVD or BluRay - they work wonders.

I set up my old CRT and the sharpness adjustment was a laugh - as it was 50Hz and RGB it was fully sharp with no edge enhancement - best for CRT by far, it only worked on non RGB and who uses that!.

Sorted out brightness and contrast anyway on the LCD panel, Rest were fiddle with until it looked right

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Boffin

Setup DVD

An alternative is to use a DVD or I believe BluRay disk produced with THX (like any recent Star Wars disk). This contains a setup tool called THX Optimizer

On the menu screen, move the highlighted area to the THX logo, and press enter or play. You should find several setup tests for resolution, contrast, colour balance, sound and a couple of other things. To get the colour right, you really need a blue filter of a particular pantone colour, but you can get an idea without it.

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You may not need a special disc

Quite a few Sony BD releases have test patterns, accessible by pressing S-O-N-Y when the main menu is on screen (that's 7669 if you don't have letters on your remote)

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Unhappy

Scary thing is...

They are working on newer resolutions that are even denser.

http://www.bbc.co.uk/news/technology-11436939

256" TV in your future???

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If you have the living room on the pic - why not

You will need to apply a bulldozer to your average 20th century build British house and rebuild it so it has the living room from the cute picture attached to the article. 90% of those have the sitting room with obstructions on 3 out of 4 walls preventing the sane positioning of anything bigger than 32 in. In order to fit anything bigger you either have to put it above the fireplace (wrong viewing angle) or remodel the ground floor in a more "modernistic" style as per the picture.

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get a sledgehammer out...

I removed the gas fire & token fireplace, just to get one flat wall for my Panasonic 37" lcd. Gained floor space too.

The installers re-routed the Freesat cable through the wall. Painted the wall licquorice brown, so the tv frame is camouflaged.

Sources are Virgin hd & ps3.

We sit 2.5 - 3 m away. Looks great.

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Pint

Simple but effective. Top Tips (not Viz).

Don't laugh but I do have a solution for people when choosing a screen size. Simply get some large pieces of cardboard with 16:9 ratios of a number of common screen sizes. Then plonk them in the corner of your room or above the mantlepiece, sit back and see if they're the right size for the room.

It may seem silly but it has stopped people I know from buying behemoths that would swallow their living rooms or postage stamps that would give them eye strain.

No, no need to pay me but you could buy me a pint.

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Why above the mantlepiece?

I never have understood situating the telly over the mantlepiece- it always seems uncomfortably high to me when sitting on a typical sofa - like sitting in the front row of a cinema.

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MJI
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We have no fireplace

So wins all round

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You're lucky.

I have a rented place where they've done a Lawrence-Llewowen-Bellend and papered one 'feature' wall, then put in one of those B&Q electric fires with fake wooden fireplace surrounds.

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Go

Right Size

Mostly agree, and I know lots of people who have done this. But one extra piece of advice to consider:

Once you figure out which size you (or more likely, the wife) think is the right size, go for one size larger (2"-3"), especially if moving from CRT to flat.

Almost everyone I know has come to that conclusion a couple of weeks into their new TV. (Caveated with "this only applies to aethetics, and obviously not to physical limitations")

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Gold badge

Fireplace

They're freeing up floorspace by not having a TV cabinet but don't wish to get rid of their fireplace.

I got rid of the fireplace, mounted the TV just above the gap and put three shelves in the gap where the fire was. Perfect height IMHO, although I do worry about the TV being so low that the dogs will damage it when playing (they're quite tall dogs).

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MJI
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Pint

Bellend

Sorry that earned an upvote.

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Been saying this since HD came out.

Not that I'm some luddite who doesn't like it. Just that most people don't sit with their nose touching the screen. From the other end of a living room, unless you have a super-sized screen (above, say, 25-28 inches), are you really going to tell much difference between HD and even a normal DVD? And no, I don't have crappy eyesight. It's good enough to see the "invisible" pixels on an iPhone4, at least.

The biggest benefit I can see with HD, is that finally broadcasters have upped the bandwidth of their digital channels to approximate a level of quality achieved by standard analogue PAL several decades ago.

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MJI
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Sit the other way

Put TV on the long wall and sit opposite it.

I hate watching TV diagonally.

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Paris Hilton

"super-sized"

"From the other end of a living room, unless you have a super-sized screen (above, say, 25-28 inches)"

You've got an odd idea of super-sized if you think 28+ is massive? 25-28 barely counts as a PC monitor these days...

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Boffin

Simpler maths

Isn't it possible to simplify those formulas a bit?

d = 0.7277 * sqrt(D * D / 337)

= 0.7277 * sqrt(D * D) / sqrt(337)

= 0.7277 * D / sqrt(337)

= (0.7277 / sqrt(337)) * D

= 0.03964 * D

Removing excess precision, you get d = 0.04 * D.

Or to put it another way, take your TV size in inches, and multiply by 4. You need to sit that many centimeters from the screen (or closer) to see all the details in a full HD picture.

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Bronze badge

Yes

You're right, we could probably simplify but a) don't all those fancy symbols look impressive and scientific? and b) how would you know we hadn't just made up a number?

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Dead Vulture

Simple maths!

Really, this is supposed to be connected to the technical Internet! The equations are all wrong.

sqrt(D*D) != D

sqrt(D*D) = abs(D)

(This makes a different if I'm watching your TV from the flat next door. I wouldn't want you to waste your money on a -60" TV, that's too small).

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FAIL

Re: Nigel

a) Yes. And if you show your working as you simplify it then you get to write even more fancy symbols!

b) If you show your working then it can be checked.

While TV shopping, I can do "multiply by 4" in my head. I can't do a square root in my head.

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Boffin

@Nigel (b)

But since the article states that you're working off a figure from a BBC survey, we KNOW that you're working with made-up numbers!

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Boffin

re: Simple maths!

sqrt (D * D) != abs(D)

sqrt (D * D) = +/- D. Or I think you were probably aiming for abs(sqrt (D * D)) = D

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Headmaster

Re: Simple maths pedants

Annihilator: The sqrt() function is normally defined to return the positive square root of a number. So sqrt(D * D) = abs(D), it's not +/-D.

Anon: D is the distance from the screen. Having a negative distance doesn't make sense (you can only see the picture from one side of the TV!). So we know that D > 0. So sqrt(D * D) = abs(D) = D.

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Broadcast dimensions

For years I put up with an old screen and listened to conversations where, if I was lucky, I could see the tips of the noses of the people talking (lost the remote so couldn't put the screen into "letter box mode").

Finally gave up and bought a "widescreen" 22" telly and now I regularly see the last couple of letters of the various BBC on screen logos with the rest off screen.

The screen is set to auto detect broadcast dimensions and change accordingly.

I don't understand.

Mostly I don't care as Virgin's TV quality is appalling and the picture regularly breaks up into pixels and there's so little on that mostly we use it for Radio 4.

But I'm still curious as to why.

Are there two sorts of widescreen? Or is this down to incompetence by VM?

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Go

Re: Broadcast dimensions

Check your Virgin box is set up for a 16:9 TV. If the Virgin box is configured for a 4:3 TV, then it will be converting everything to 4:3.

Try pressing the Wide button on your TV

If that doesn't work... are you using a CRT? CRTs have a thing called "overscan" - they deliberately make the picture slightly larger than the screen, so you lose a little bit at the edges. There are boring technical reasons for this, to do with how CRTs work. Better CRTs have less overscan. Flatscreens don't have (as much) overscan.

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RE Broadcast Dimensions

My old Toppy was doing that for a while, turned out a firmware update + factory reset had set its scart output back to 4:3. Have you checked your Virgin box is set to the right aspect?

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Widescreen switching can be a nightmare

I was mildly annoyed that after an update to the firmware on my Panasonic TV, it wasn't responding correctly to some of the WSS signalling from my Toppy, and 4:3 material was being stretched to fill the screen ("VulgarVision")

It's been resolved in the end by replacing some of my other AV gear, so the Toppy is now running through a Yahama AV amp which upscales everything, and has control over black bars, so 4:3 material is correctly pillarboxed once more.

Acutally getting the Toppy to respond correctly to all the various AFD formats was one of the most tedious and long winded updates we went through a few years back.

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Virgin Box Settings

Awesome bit of advice.

The VM box was indeed set for 4:3 - now sorted.

Many thanks for that.

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Anonymous Coward

(Assuming we're talking digital sources here)

Resolution is nothing. Quantisation artefacts are everything.

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Give me...

...an HDTV that is as dumb as a dumb thing with maybe just a couple of HDMI/component connectors. That's all I need. I'll plug low-power PC into that and it can do all the network/fancy stuff. This also means I can control what content gets shown, how it gets shown and what codecs will work; not have to suffer some broken, OEM-only content restricted bull-crap. The orther connectors would just be for consoles.

Hmm...I could probably route them through the PC...

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Stop

Content is king, not TV

I have a cheap 'n' dirty LCD TV (not big, about 28 or 32") Bought before the whole HD hype. My Virgin cable TV gives me some HD channels for free.

The picture quality on the HD channels is miles better than on the standard def channels - even though I'm viewing both on the same cheap standard def TV via a boring SCART connection.

I think this shows that it's not really the TV resolution that's the killer (althought that does help) but it's the bandwidth of the source material. If the material is compressed as far as it can go, then it'll look crap on any TV. Add a bit more bandwidth, and we can all get more quality without spending a penny on a new TV.

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42" EDTV here

Yes, you know, the 480p sort. It was a hand-me-down gift. I probably sit about 3 or 4m away and can see the pixels on any high contrast objects. But I don't really care.

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Alert

HD TV and Xbox Kinect...

What's the distance recommendation for using a Kinect?

So, now how big does your TV need to be?

Answers on a postcard.

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Alert

kinect = 6ft or 1.8 metres

Therefore you need at least a 45" TV and that's for one person

Apparently for 2 people to be playing you want to be 2.5 meters away means you need a 62"

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Happy

you need a 62"

Ta. that's enough justification for me.

Let's go shopping...

(what do you mean that's not what the article intended..)

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Thumb Up

58" 1080p TV, 3.5m

That is just right for me and yes, 1080p makes a difference.

It is a good Samsung plasma, if you have a poor TV that can take away the benefits of resolution.

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Stop

All those questions...

What about the last one; how big do YOU want your TV to be ? Because your questions will all be worthless each time the bradcasters change resolution. Should we buy a bigger TV each time ? Or a bigger house ? Now for math, you could have put the effort to set a small table with all standard values. I'll begin for you;

32", 720p, pixel size: 0,558mm, distance for 1' angle/pixel: 1.92m

32", 1080p, pixel size: 0,372mm, distance for 1' angle/pixel: 1,27m.

Cheers.

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Happy

size matters...

how big do YOU want your TV to be ? I think you mean:

How big does your WIFE want your TV to be ?

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Megaphone

Oh, now we know

All this argument , claim and counterclaim is why when my telly died last week, I went and bought a second hand CRT from the charity shop for £30.

Call me when they've sorted it out and there's one thing to buy at a reasonable cost which isn't going to be superceded by something else in 6 months time...kinda like my old telly.

And if dvd producers would stop putting the subtitles in the black border on the bottom of the picture, that'd be nice, then when I'm watching something I can tell what the frenchman/american/alien said.

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FAIL

Welcome to the 21st Century

If you're waiting for a time when TVs won't be superseded by the next generation in six months, you will never buy a TV again. Just buy one you think is really good and use it for three years or more, like everyone who doesn't feel the urge to condemn rapid technological development as a bad thing.

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Re: subtitles

You've probably got your DVD player or Freeview player or Sky+ box or whatever set to output a 4:3 picture, so it's letterboxing the 16:9 then putting subtitles on at the bottom. Probably things would improve if you set the box to 16:9, adjusting your TV's picture stretching setting accordingly.

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