• Room and screen size
• Screen technology: LED, LCD, OLED and Plasma
• Which screen technology to go for?
• HD source, FreeSAT, SKY, BBCHD, ITVHD,BluRay DVD
• The connections for HD
• Implementing 3D
• 3D glasses
• Viewing position for 3D
• Source of 3D films
• The many ways of delivering 3D
• Amateur production of 3D
• Parallax barrier technology
• Comments on early demonstrations

All the big name Consumer Electronics giants like Sony, Panasonic, Samsung, Philips, Toshiba, etc. have announced yet more Plasma and LCD 3D TVs to be released. These manufacturers are aggressively marketing 3D televisions and making a strong case for their introduction into the consumer's homes. But in the end when we are ready to buy we initially just want;-

(a) The best value for our money

(b) A good quality displayed picture

Then we might consider how the item will look in our living room.

Additionally, for us film makers, we ask can we connect our existing AV kit to it i.e. do the panels have the desired connections? We can't, however, look at any of these things in isolation without additionally having to choose between the various technologies of the screen as well as its size.

Room and screen size

Our first task is to look at the room size and see what size screen we need, however there are a couple of things we need to consider first. If you decide to splash out on a 3D TV, which are currently running at roughly double the price of non 3D screens as of the date of this article, the current smallest consumer 3D TV is 40 inch (measured diagonally), but also if you want to really enjoy the picture detail available in FULL HD 1920 by 1080 TV you need to be surprisingly close as the eye's 20/20 vision doesn't naturally perceive detail at a distance. For instance compare the detail you perceive on someone's facial skin at talking distance of about 3 feet in comparison to someone sitting in an arm chair the other side of the room.

From the chart a 42 incher its ideal viewing distance is only 5 feet 6 inches away for best detail, and a 55 incher is 7 feet 4 inches. Even the 101 incher only just gets to the other side of a small room at only 8 feet 5 inches. As a guide the viewing distance is suggested as 4 times the vertical height of the picture area. Not nearly as far as you thought is it? In the end there is usually a compromise on costs and what you can get away with, without imminent domestic strife and divorce.

Screen technology: LED, LCD, OLED and Plasma

Now we have looked at our screen size we now need to turn our attention to panel technology, LED, LCD, Plasma or OLED. Firstly LED and LCD are the same technology it uses a liquid crystal to turn off the light from a back lit source we are simply discussing the type of backlighting. LCD are simply made with liquid crystal light switches which work by applying an electrical charge to allow or prevent the light source from behind being seen by the viewer in front. Breaking this down to basics for LCD screens, it's nothing more than having a fluorescent tube at the back, which will age, change colour over time, and wear out just as does our domestic lighting. Sadly it has to be noted that it is not economical to change the tube after production, so you have to throw it away when its worn out, a sort of built in obsolescence. Early adopters of LCD screens will now be finding this happening and indeed some screens are now appearing on the local council recycling centres.

On the LED ones they are either edge lit or back lit by a bank of Light Emitting Diodes which is the preferred backlighting alternative to fluorescent tubes as they will last for in excess of 10 times as long or many years. The edge lit ones are less evenly lit than "Full LED" ones as they suffer from getting good light into the centre of the screen from the edge of the glass.

However LCD itself, regardless of the backlighting source suffers from a number of disadvantages. When making your evaluation, you first of all need to get past the impressiveness of the display brightness in the relatively high lighting level of the retail sales floor. The viewing angle is much poorer on the LCD screens than on the Plasma, so if you regularly have guests or family members sitting close to the left or right hand sides of the screen they will get a changed brightness and colour perception of the picture as they move further round towards the screen edges. A room corner position with the screen diagonally across the corner is kindest for LCD, giving most viewers the best unaltered picture.

The viewing angle however on a Plasma screen is 180 degrees so there is no such problem with those.

The OLED panels are probably going to be the best in 5 years time, which use organic LED panels where the light output is right on the front of the panel and one LED per pixel, but as yet screen sizes are only up 15 inch at around £2000 a piece, but like all new technologies as the production yield and consistency goes up, the risk of volumes of big rejected panels with a failed pixel reduces, and up goes the panel size. (The larger the panel the more OLED's are required - it's a numbers game). It's also a very low power technology and probably the nearest modern equivalent to the glowing phosphors on the front of the old style TV tube. But if you are ready to buy now this technology is not a consideration.

Which screen technology to go for?

If we look at picture quality and trueness of image we always have a difficult assessment job on our hands as we rarely have the original image to compare to. However there are some factors about Plasma screens natural performance that is better. The colour and greyscale linearity of a Plasma screen is much superior to LCD backlit, with whatever technology, but the Plasma is not as impressively bright as LCD. Also LCD panels are becoming sleekishly thin and tend to look more sexy than the thicker Plasma screens, but we should buy on performance not look.

Personally I prefer the truer reproduction of the Plasma. Plasma is cheaper to produce which is reflected in the lower price. Plasma has one non green credentials snag however in that a 63 incher will cost 0.357KW hour to run and keep you warm in the winter! (Samsung P63C7000 quoted, costing £2,218 @ Amazon).

Plasma has a major advantage over LCD which is that it's inherently faster at turning off the light than LCD at some 2 milliseconds whereas LCD it even depends what the last colour displayed was as to how long it can take to turn the cell off, and that may be up to 10 milliseconds, giving more blurring and "drag" on fast motion shots.

Manufacturers will try and sell you on superb blacks and high contrast ratios. What you really want to look at however is the amount of detail in the black which they don't want you to look at.

So in conclusion I would recommend Plasma technology at present providing you can afford to run it, as it gives the widest viewing angle, and trueness of image, and the fastest response time on action movies. Do check first though how good the TV is at reproducing standard definition and that it handles 4 by 3 sources such as film club footage on the inputs you want to use, as we are going to be stuck with needing to display Standard Definition (SD) for years to come yet.

HD source, FreeSAT, SKY, BBCHD, ITVHD,BluRay DVD

So assuming you have bought in to some technology, where are you going to get your HD material from for your new TV? There is of course your own camcorder which I am sure you will already have verified you can connect to your new screen. So let's look at our externally provided material.

Looking at broadcast TV you have Freeview, FreeSAT and SKY. The line up for the free services is not currently very impressive offering only BBCHD, ITV1HD and Channel 4 HD, as channel spacing is currently an issue with the analogue channels still on air this may well be the restriction until 2012. A number of TV's have now either Freeview or FreeSAT built in, but do make sure its the FreeSAT-HD or Freeview HD versions to avoid disappointment.

Sky of course charge HD customers a £10 per month extra for HD on top of the subscription package charges, but has a most impressive array of HD channels including films, drama, documentary and natural history.

The other source is a BluRay DVD player which can not only upscale standard DVD's to pseudo HD but also provide Full HD and 3D content as well.

The connections for HD

Ok so now we have chosen our screen technology and size we now need to look at connections and inputs. Warning! Some TV's lose the S-Video connection completely others embody it in a SCART connector, so if you want one, just make sure its there.

The typical inputs are:

PC 15 pin for your laptop

HDMI up to 4 of those

Component video

Composite video

SCART only one or maybe 2 (one maybe S-Video and RGB)

The newer HDMI connection is a digital connection and allows a conversation between the connected device and the TV to ascertain how each will talk to the other. It also carries the HDCP - HD Copy Protection code between the DVD player and the TV, the DVD player asking if its a TV display on the end before it will display full resolution content. This was insisted on by Hollywood to help prevent bootlegging of HD DVD's (very good quality source) onto the car boot sale markets.

Implementing 3D

Now we move onto 3D, which really best is left in the cinema, but it's not to say that an immersive experience can't be had at home. The cinema technology is to use two projectors each fed with individual footage, left and right eye film. This is passed through a polarising filter one eye material being clockwise polarised light the other being anticlockwise light. A special reflective screen is needed to maintain light polarisation such that the viewer uses polarised lens glasses to view the material being shown reflected from the screen. This is probably the most comfortable 3D viewing experience of all technologies currently available.

So now we move on to something more practical in the home environment, as 2 projectors and a special screen are not acceptable in the home. So what we need is our nice new Full-HD screen to be able to play 3D movies. But we have a problem; we have 1 screen and the need for a different video for each eye , so we need a simple way to do this.

The first sort of 3D was Anaglyph which meant using magenta and cyan filtered glasses, but these gave poor colour rendition and caused user discomfort for long periods. YouTube has video examples of this method being used to display 3D material over standard computer monitors, and that is its main advantage, no special display is required.

The home method promoted at present is to tell the TV to alternately switch the image between left and right eye frames, but at double the normal frame rate to avoid flicker. So if you look at a 3D TV and say the rugby posts are on the screen, there will appear to be 4 verticals instead of two as you are being presented with the view for both eyes at the same time as the speed response of the eye is too slow to see the separate images.

3D glasses

So we need to have these images separated for us somehow. This is done with glasses which contain an active LCD shutter, which synchronises to an infra red beam coming out from the TV. By this method one eye is blanked whilst the other is active, thus the presented double image is divided out for us. The glasses have active electronics which need a battery, and the rechargeable ones should be bought. There are both clip on glasses for those that already wear glasses and full glasses with side frames. The main snag with this system in the home is that every viewer needs glasses and it is totally immersive, so you can't look down at your knitting. The glasses are around £60 a pair and some TV sets include one two or even no pairs, so check these are thrown in or beat up the sales assistant as 2.4 children and parents gets expensive!

I suggest that 3D TV's are currently overpriced as in fact all that changes in the TV is the addition of the infra red synchronising LED on the front, and an electronic switch to alternate the pictures and some software to detect the incoming picture stream. Ok that's oversimplified but I don't believe it justifies nearly twice the price.

There is a user manual warning that the 3D effect may be experienced differently depending on the viewer. You may not notice the 3D effect at all if you have a 'prescription for one eye that is very different from the other eye'. Also low energy fluorescent lamps are not recommended in the viewing room as they can appear to make the glasses have flicker which is clearly going to be annoying.

Samsung have got a pseudo 3D mode on their TV's which is supposed to make 2D material look like 3D which has solicited a number of positive user comments.

Viewing position for 3D

All 3D viewing though has rather stricter rules to obey than standard 2D viewing as regards seating position within the room. If we take the Panasonic Viera TV manual as an example;-

A number of cautions are proposed in the Panasonic manual for using the glasses and watching 3D content, a sample of which are below;-

• Be careful not to strike the TV screen or other people unintentionally. When using the 3D Eyewear the distance between the user and screen can be misjudged.
  
  
• Remove the 3D Eyewear before moving around to avoid falling or accidental injury.
  
  
• If having eyestrain or discomfort, etc. Stop using the 3D Eyewear immediately, if you feel tired, are not feeling well or experience any discomfort.
  
  
• Stop using the 3D Eyewear if you can clearly see double images when viewing 3D content.After viewing 3D contents or playing 3D games, take a short break to readjust your senses.
  
  
• Stopping the usage of the 3D Eyewear
  
• Stop using the 3D Eyewear immediately if a malfunction or fault occurs, or if you experience any redness, pain, or skin irritation around the nose or temples.
  

Samsung warn that 3D content may shock or surprise so users with a heart condition should not watch it!

Source of 3D films

Delivery of 3D content is either from a 3D ready BluRay DVD player or from a broadcaster. Sky are planning to lead with a channel starting October 2010 and I don't expect any moves on Freeview until 2012 when more channel space is available. The DVD player is capable of delivering twice the normal frame rate to the TV and to be a little fairer on the TV pricing it also has to be able to receive twice the frame rate. This sort of methology is called sequential frame.

The many ways of delivering 3D

Now you guessed it there couldn't possibly be one 3D delivery standard could there? Of course not. So lets look again at an extract from the Panasonic Viera TV manual.

 

At the top it talks about how the DVD player will deliver its content to the screen which is in Full HD resolution.

The table at the bottom shows how the broadcasters are going to be forced to deliver 3D content to you, which is principally driven by the avoidance of having to supply consumers with new receiver hardware.

Now clearly if we are using the same picture space to display two pictures at the same time, as in the side by side example below this is only going to be at half the resolution of the original image;-

The TV's job here is to crop the images alternately and stretch it full screen. So at this point you could feel somewhat cheated as your nice new FULL HD TV is going to be fed a half FULL HD picture resolution in 3D mode. Unless different transmission standards are established with new transmitters, and consumers are disposed to change their receivers (and that includes all the cable and BT Vision viewers) this is 3D broadcasting for the foreseeable future.

Amateur production of 3D

Material such as this in the above picture is extremely simple for amateur film makers to produce in an edit given a 3D camera, which records both eye films as separate files. However in the Grass Valley Edius 3D application note there are some cautions for us all:-

Can you place graphics and text in the video?

Ans: It is not advisable to do so. Even if you place the exact same graphic or text in each of the clips, it will look as if it is placed very far away, and can cause viewer discomfort.

However, this problem may be avoided by carefully moving the text or graphic from one clip, and adjusting the depth (this, along with colour correction of the video, can only be done manually).

 

PC monitors support not only Side-by-Side, but also individual Left-eye and Right-eye video channels, so you can play back the video once the correct format has been chosen.

Parallax barrier technology

There are lots of comments for glasses-less 3D TV viewing, and indeed the TV set manufacturers are working on this, using for example parallax barrier technology.

 

The diagram above shows what glasses-less technology Sharp are currently working on. But the current problems are display quality or resolution and the seating position is even more restricted than for viewing with the glasses described earlier. This technology has a way to go yet and is probably 3 to 5 years away according to articles on the web.

Comments on early demonstrations

Then we come to content which of course it's all in the end going to be relying on and driven by. I was very unimpressed with the Sky demonstration last year at the Production show at Earl's Court, due to the perfect focus of all the players on the football pitch regardless of depth/distance away. Of course when you look at a scene only what your eyes are concentrating on is in focus unless it's all a long way off. That was where the natural world perceived by the eyes appeared to be departing from what I was being shown.

The tennis had some peculiarities about it too in that the court end linesmen almost seemed to be sitting on the bottom of the screen and the electronic score display seemed to be strangely floating above the action. It will be interesting to see what 2011 brings us at Earls Court in terms of improvements.

Amazon are currently only sporting 18 BluRay DVD titles on their list for 3D viewing at home so I guess it really is early days yet to make the whole thing worth while.

by Mike Sanders September 2010