BBC Widescreen Broadcast Policy

[paulsherwin]

Originally Posted by YC-156

A word regarding stretchyvision: You get used to it after a while and your brain automagically compensates. The only stumbling block is that you have to allow this to happen by ignoring the odd aspect ratio distortions in the beginning.

I wonder if there are real differences in the way different people process images which makes them more or less sensitive to stretchyvision? It's a well known fact that some people are very sensitive to audio digital compression degradation which other people simply can't hear. Similarly people with perfect pitch can get very irritated by music played slightly too fast or too slowly, while others can't hear anything wrong.

I don't have functioning stereoscopic vision so my brain uses relative changes in image size to estimate distance and motion (that's why I can drive a car but can't play tennis ) Maybe this is why I find stretchyvision so disturbing?

Paul

[Nickthedentist]

Originally Posted by paulsherwin

I don't have functioning stereoscopic vision so my brain uses relative changes in image size to estimate distance and motion (that's why I can drive a car but can't play tennis ) Maybe this is why I find stretchyvision so disturbing?

No, I have "normal" vision but find stretchyvision very irritating, just like a mistuned radio, wow & flutter etc.

[YC-156]

Originally Posted by paulsherwin

I wonder if there are real differences in the way different people process images which makes them more or less sensitive to stretchyvision?

Could be, yet pretty much all of us demonstratedly do have the ability to apply 'automatic' image adjustments to our visual field: The lenses in our eyes shows us the world upside down, yet to the consciousness the world has been 'flipped' for us. Very handy me thinks.

For the record, then I don't particularly enjoy the distortions as found on DAB radio and in many MP3 files.

While there probably are exceptions like yourself Paul, I suspect this is mainly a question of learning to compensate. (Sorry Nick. ). I cannot recall ever hearing about a child complaining about objects on the telly being out of round.

I have experienced another case of having to apply optical post processing to the visual input: When I was a teenager the technology behind glasses didn't allow for making lenses to my prescription (-13 diopters nearsightedness) without severe chromatic distortion. Bright lightsources outside the central vield of view turned into rainbows, white surfaces had coloured edges etc. Looked very strange.

Yet after a while of being forced to wear the glasses every waking hour I no longer noticed, except when it really mattered: The starfields of the night sky. The rest of the time I unconsciously knew the colour of light sources near the edge of my vision etc.

Since I buy the latest and the greatest in glasses, I replace them regularly. That usually requires some measure of getting used to the new 'distortion frame', so that may account for my ability to ignore stretchyvision. Today my vision with glasses is more perfect than that of the average adult. Had it checked quite recently in connection with my driver's license.

Originally Posted by paulsherwin

I don't have functioning stereoscopic vision so my brain uses relative changes in image size to estimate distance and motion (that's why I can drive a car but can't play tennis ) Maybe this is why I find stretchyvision so disturbing?

Well, the lack of stereoscopic vision, no matter the cause, does hint to a flaw in your ability to 'post process' what you see, so it might be part of the problem.

OT: If you don't mind me asking Paul, then how do you loose stereoscopic vision? Assuming you weren't born that way, of course.

Frank N.

[paulsherwin]

Originally Posted by YC-156

OT: If you don't mind me asking Paul, then how do you loose stereoscopic vision? Assuming you weren't born that way, of course.

I had a measles infection when I was 2 which caused some brain damage. A serious divergent squint developed and I imagine I lost stereoscopic vision at that time. The squint was corrected surgically when I was 5 but the eyes work independently and I can consciously choose which eye to use (right eye is dominant though). The optical prescriptions are completely different - the right eye is short sighted and the left long sighted.

This means I need to judge distance and movement by changes in the relative dimensions of things. In most cases this works very well but there seems to be more 'computational overhead' which means I'm poor at ball games, catching thrown objects etc.

Anybody with a significant squint or a blind eye needs to compensate in this way, so there are quite a few of us around.

I didn't mean to suggest that a tolerance of stretchyvision and audio compression distortion are related. They were just examples of things where people's perception and sensitivity varies for no obvious reason.

Paul

[Aerodyne]

A bit off topic, but I can sympathise - or at least empathise - with Paul's vision problem, as I too have long sight in one eye, short sight in the other and astigmatism problems with both. This is why, to my disgust, a visit to IMAX to watch stereo films is doomed to failure, as were the visits in the 1950s to see films such as 'House of Wax' in stereo. All I get for my pains in double vision and a headache. Even now, on occasion, double vision takes over and I simply have to wait until my tired brain decides to resume processing, usually about 5-6 minutes! With regard to the topic subject, however... I find the one annoying thing about widescreen transmissions is the fact that, upon switching channels - say, from Freeview to Sky - you are left to manually adjust to compensate, even though you might have your receiver set to 'automatic' selection - yet the moment adverts come on (too often, of course) the screen reverts to a correct ratio. It is as though the adverts are transmitted in widescreen but the programs may or may not be, at least that's the only answer I can find. Perhaps the ads are more important? Perish the thought.
-Tony

[ppppenguin]

In theory there is a signal carried somewhere (ISTR line 23 in analogue, heaven knows where in digital) which indicates to the receiver how it should set the aspect ratio. The broadcasters often get this signal wrong.

http://www.intersil.com/data/an/an97...de%20screen%22

[paulsherwin]

Originally Posted by Aerodyne

I find the one annoying thing about widescreen transmissions is the fact that, upon switching channels - say, from Freeview to Sky - you are left to manually adjust to compensate, even though you might have your receiver set to 'automatic' selection - yet the moment adverts come on (too often, of course) the screen reverts to a correct ratio. It is as though the adverts are transmitted in widescreen but the programs may or may not be, at least that's the only answer I can find. Perhaps the ads are more important? Perish the thought.
-Tony

Adverts *are* transmitted in widescreen on all channels which have any widescreen output. If the programme content is 4:3 the digibox will switch aspect ratios at the start and end of the ad break. The 4:3 content will be displayed in whatever way you've told the TV to do it.

Some WS TVs (including mine) seem to forget which 4:3 option you've selected and revert to the default stretchyvision at times. I've never managed to work out what triggers this and I don't know if it's a fault or a misfeature.

Some WS TVs (usually expensive ones) have a setting whereby they'll try to guess what to do with 4:3 pictures depending on the programme content. These can get seriously confused

Paul

[Kat Manton]

Hi,

My problem with 'stretchyvision' is that it's just plain wrong - a 4:3 picture is a 4:3 picture - displayed correctly on a widescreen set there are supposed to be black bars left and right. Only a 4:3 picture will fill the screen on a 4:3 set, and only a 16:9 picture will fill the screen on a 16:9 set. So I don't understand why some feel a need to watch a distorted picture, just so the screen is filled, when it's not supposed to be filled.

It really does annoy the hell out of me if I'm visiting someone and the aspect ratio's been set incorrectly; I can get into arguments and once ended up confiscating the remote having set the picture correctly.

The inverse is also true, we tend to watch Freeview in 16:9 on our 4:3 set - there are black bars top and bottom - but the picture is the right shape, the bars top and bottom are correct and are meant to be there. If I do stretch the picture (watching Freeview on 405-line sets), I zoom it, so the centre 4:3 section of the 16:9 picture is displayed 4:3 full-screen without distortion.

Television is supposed to look vaguely realistic; wheels on cars are round and people are, well, people-shaped. On every set I work on I'll spend time adjusting height, width, linearity, colour balance etc to get colour rendition looking natural, and get the circle on a test card circular, the squares square.

A set displaying a 'stretchyvision' picture is as annoying to me as one where the height or width are massively out of adjustment. It's distortion and must be corrected...

Regards, Kat

[Tazman1966]

Well said Kat!

Stretchyvision. GRRRR!

Incidentally, both my wife and my brother in law suffer from "astigmatism" in their sight and neither of them can tell whether the aspect ratio is correct or not.

Tas

[dave walsh]

I've wondered about this for along time as two particular individuals I know always express preference for 4x3 and it's irritating when you like widesceen and have a set you are rather pleased with. [Although I know that a well set up b/w 405 4x3 image can be excellent]. Most people don't seem to find a "stretched" picture a problem with the broader image-especially on an outdoor panorama shot! The discussion here re BBC Policy [on thread moderators] seems to confirm my suspicion that it's an interesting aspect [ratio] of visual perception that could be usefully researched. Why just some people in the population? This might have implications for a tv screen formats or other aspects of the psychology of sight that we don't know abou! Dave