wireless audio and video

[Wireless Audio and Video]

Account TomyMaggie.com

#24 Wireless Audio and Video solutions
In the previous columns I have discussed how to stream the Audio and video wirelessly. In this edition we will see how to make the end to end connection without wires both for Audio and Video. It is not very difficult to find a gorgeous looking high quality Amp and matching speaker sets (5.1/7.1/9.1 systems ) which goes with your room décor at a reasonable cost. But the wires crisscrossing the room interconnecting all these equipment will be an eye sore and invite the wrath of your better half. Let us see how to connect the speakers and TV without those ugly looking cables. Moreover a wireless connection gives you lot of flexibility in the placement of your equipment and speakers.
Wireless speakers come in different size and shape, employs different technologies to deliver reasonable good sound output. Apart from the Bluetooth speakers the most common one is wireless rear speakers employed in 5.1 systems. Wireless 5.1 rear speakers are common offer from most of the Consumer electronics companies as part of their all in one Home Theater solutions. But these suffer from poor quality and no wireless system can match the performance of connecting the same set of speakers with wires. Do not forget that the powered speakers / RF transmitters need power so you cannot do away with the power chord for a good sounding wireless system 
Wireless speakers can be broadly classified into the following 4 categories
Wireless PC Speakers
Wireless Surround Speakers
Wireless Outdoor Speakers
Bluetooth Speakers
In terms of technologies employed it can be any of the following.
Bluetooth speakers
Wi-Fi speakers which can be directly plugged into your Wi-Fi networks (This is coupled with media streaming)
Works in 2.4GHz but employs proprietary technology which is most common and better sounding
KEF Universal Wireless System
KEF’s Universal wireless system is an add-on to any existing surround sound speaker system from any manufacturer. It promises CD quality high fidelity sound and works in 2.4GHz using HFADPCM (Hi-Fidelity Adaptive Differential Pulse Code Modulation) wireless link that ensures real time audio delivery with no mutes, audio dropouts or loss of bonding.

It uses advanced features like AAFHSS (Advanced Frequency Hopping Spread Spectrum) with advanced forward error correction and Unique Pre-emptive frequency hopping and adaptive channel diversity to ensure that it always deliver high quality audio signal that remains interference-free from devices such as wireless LAN routers, digital cordless telephones, mobile phones and microwave ovens. The transmitter has 2X50W built-in amp and the receivers can be placed upto 70 feet away.



It cost you around $500/-
This is a good solution for quality conscious. For more information please visit the following link.
http://www.kef.com/us/SurroundSound/Wireless/Wireless

http://reviews.cnet.com/home-entertainment/kef-universal-wireless-system/4505-6449_7-32471312.html?tag=lia;rcol

Cue Acoustics SP1 Wireless Speakers (www.cue.com)
Cue Acoustics’ wireless PS1 speakers is single box solution with amplifier is also built into it. It aspire to be high quality speakers which can stream from audio devices and won’t cost you as much as a pair of tower speakers. PS1 speakers consists of a 3/4-inch tweeter, 3.5-inch midrange speaker and a 5-inch, down-firing sub-woofer built into the underside of the speaker. The PS1 system is powered by a D2 Audio amplifier (300 watts RMS total power) and functions as a DLNA media renderer. That means all you need is a device capable of pushing an audio signal to the speakers and you’re good to go. The one thing you need the wire for at all is for power. You can also connect wired sources, like TVs to the speakers using an optical cable or analog cables.
The PS1 speakers stand roughly 45 cms tall, 20cms wide , 25 cms thick and weighs around 8Kgs. It is made of fiber composite material and aluminum; they’re something you don’t necessarily want to hide. These can be used as bookshelf speakers producing great sound. This costs you around $2500/- but most reviewers agreed on its high quality sound.

Photograph by F. Martin Ramin for The Wall Street Journal

Philips SoundBar (HTS5131) (http://www.philips.co.in/c/soundbars/21453/cat/)
From the discussions so far, it is easy to make out that all the wireless solutions outlined here is a compromise, either in quality or cost or in its application. There is no really cost effective way to have wireless 5.1 or 7.1 professional speaker systems with all the 7 speakers in place. The wireless solution is limited to rear speakers; otherwise it will come at a prohibitive cost.
In this scenario where space is also at premium, Sound bars offer good quality solutions where high quality Amp and speakers are integrated. Subwoofers come separately which is wireless or wired depending on the model. As the inventors of SoundBars, Philips is still regarded very high for its soundBar solutions. SoundBars provides a virtual surround sound sonic experience from an integrated unit which can be placed under the TV either wall mounted or placed on the TV stand itself.

Philips SoundBar HTS5131 has a built in BluRay Player, integrated surround sound speakers and a separate subwoofer. It comes with both Dolby True HD and DTS Master Audio decoders and capable of connecting to internet and stream YouTube videos and online photos. It doubles up as a media player which plays most of the formats. It can connect to your iPhone using iLink technology to stream high quality music.

Bose SL2 Wireless Link
Those who are into Bose Audio systems can think of getting a pair of Bose SL2 wireless Link to make your rear speakers wireless and perform almost at the same level as wired speakers.

Wireless HD Video
There a many products available in the market to get your HD video to your monitor wirelessly. But none of them matches the performance and cost of a wired system. So remember that for convenience we are compromising quality.
There are many wireless video standards available in the market
Wireless HDMI (WHDMI)
WHDI (www.whdi.org)
Wireless HD
Ultra Wide-Band

Briteview Wireless HDMI (http://www.brite-view.com/)

BriteView wireless for HDMI 60 GHz Extender system uses a pair of Sender and Receiver units. The HDMI source is attached to the HDMI input on the Sender unit. The Receiver unit is attached to an HDMI-compliant display in the desired viewing area. The Sender and Receiver are arranged in a line-of-sight orientation with respect to each other and without obstructions in the way of the radio signal path. This Air- bridge your HDMI-ready device and HDTV in uncompressed 1080p HD quality Hybrid Transmission (Loop-through Connection): transmit HD signals through wired and wireless connections synchronously or separately It uses Brite-View’s Exclusive Transmission Enhancement Technology and can be viewed up to 100 feet (1080i) / 66 feet (1080p),

Gefen Wireless HDMI

http://www.gefen.com/kvm/dproduct.jsp?prod_id=8255
Netgear Push2TV and Push2TV HD(http://www.netgear.com/ptv)

Netgear Push2 TV is an easy to use TV adopter for Laptops using Intel Wireless Display technology (WiDi). It can receive video signals transmitted by Laptops powered by Intel Wireless Video Display technology. It can connect your TV using HDMI or AV cables and cost you around $120/-. It is available in Tata Croma stores.

Currently PTV 2000 available from Netgear and supports Full HD resolution.

To know more about Intel WiDi technology visit http://www.intel.com/content/www/us/en/architecture-and-technology/intel-wireless-display.html

In future some time I will discuss about Home Automation and Smart Homes. In the next edition we will come back to iPad applications. Meanwhile please send me your feedback

LCD TV Series 3: IS 3D TV for you?

You may not be aware that the 3D TV technology in the current form won’t cover the entire population. 4% to 10% of the population will not see any 3D effect while watching 3D TV. Current 3DTV technology is based on the fact that while looking at any object your right eye and left eye give a little different image (at different angle) and this difference (binocular vision) is interpreted by brain for perceiving the depth of the object. It is also known as stereopsis.  Is it true? Then what happens when you shut one of your eye and look at the same object. Do you see a 2D or 3Dimage? Most of you still perceive the depth which indicates that it is not just two images formed by right or left eye but your brain is trained to see it as a 3D object.  Somebody born with vision in one eye only may not visualize depth at all, I think so. Moreover 4 to 10% of the population won’t see 3D with the two slightly different images formed by left and right eyes. Their eyeball curvature changes to arrive at a focal point where they are able to visualize the depth (crap!) /  some similar phenomena.  They are called “3D blind”.   Current 3D TV technology will not help “3D blind” people since it is based on theory of binocular vision/ stereopsis.

So there three types of people as far as 3D Technology is concerned..

1. You area able to view 3D effect:  Lucky Guys 🙂

2. You are able to see the 3D effect but it has unacceptable side-effects such as headaches and nausea. 

3. You are unable to see 3D effect.   Unlucky guys 😦

If you are able to see the 3D effect but it causes you discomfort, you may have a mild binocular disorder. See a good Ophthalmologist.  

NVIDIA has given a 3D Blind test in their site.  There is a very simple test to find out .  http://www.mediacollege.com/3d/depth-perception/test.html

If you belong to the first category read on. If you happens to be in the other two category, wait for 3D TV technology to mature.   Meanwhile you can visit http://www.fixingmygaze.com

There are basically 3 type of 3D TV technology.

1. Polarization 3D Using Passive glasses  (Using Polarized glasses, like the way you watched Avatar Movie in theatre)

2. Alternate frame sequencing:   Active Shutter Glasses: This is the most common 3D TV technology currently used by Samsung and Sony

3. Lenticular viewing: (Autostreoscopy)  This does not need a glass, currently marketed by Philips but suffers narrow viewing angle. This is mainly targeted for professional market and is costly.

We will discuss in detail the Active glass technology which is employed in both Samsung (7000 and 8000 series) and Sony (HX900/ LX900) TVs.

These TVs use high frame rates, minimum 120Hz, 240Hz is the norm. In this right and left image is shown alternatively in a sequence and your shutter glass is synchronized with TV to block and allow the respective images meant for right and left eyes.  IR or Bluetooth wireless is used between the TV set and the glass for synchronization. There is an issue here where each frame is holding more than 16ms in LCD (unlike in CRT where it fades away fast). So your brain start seeing left and right frame leaking to other frame / eye (L) which in turn confuse it and manifest it as headache after prolonged view. So Samsung tries to solve this leakage by introducing blank frames in between , so 240/2 = 120 Hz for a complete frame (both left and right frame)  and 120/2 = 60Hz  effectively because of these blank framesL Now you start thinking 240Hz is not enough J.   Sony does not insert blank frames for their HX900 series and  a set of people start complaining about headaches L So it is better to watch some 3D movies for long time in these a 3DTV before deciding to put money on that.  Sony LX900 3DTV is available for demo from tomorrow onwards at Forum mall.  Active 3D glasses are costly too! How do you see 2D movies in 3D? More later………

Lenticular viewing: This technology has been pioneered by Philips, and is available as of today. TV sets that use this technology can be watched without those funny glasses that audiences used in theaters. These televisions use a lens that can send different images to each eye. That is, your left eye will see a completely different image from your right eye, which will emulate your two eyes’ use of stereopsis (the process by which your eyes discern depth). The one weakness of lenticular viewing, however, is that a viewer must sit in a very specific spot in front of the TV. This means that only a couple people would be able to comfortably watch the TV at once due to its small viewing angle.

240Hz LCD TV Do you really need them? 720P vs 1080i

Do you really need 240Hz LCD TV?

Spoiler Warning:  If you really want to enjoy watching movies in a TV it is better not to read this series.  You know very well how boring it is to watch a magic if you know the secrets behind it! If you know more and more about this LCD TV technology you start seeing a series of frames (not so perfect) instead of the video itself L It is like a drinking a soup with a fly in it. If you happen to notice the fly you will see only the fly and unable to experience the tasty soup! In other words it is like an itch you can’t scratch!.  This is my real life experience. If you still wants to go ahead, do not blame me for any after effects!

In olden days when we started with CRT based TVs, life was very simple with 30 (NTSC)/25 (PAL) frames per second  and interlaced scanning to conserve the transmission bandwidth. This continued with the initial days of LCD TVs too but LCD display is inherently progressive in nature so de-interlacing was necessary. LCD is a sample and hold (SnH) device unlike CRT tubes where you need to refresh continuously.  So for a DVD instead of 576i (576i/ 50 for PAL and 480i/ 60 for NTSC) in old TVs we have 576P/25 in LCD TVs which is perceived as a better picture.  In the following years we had seen the introduction of HD ready and Full HD (1080P) TVs but was inherently using 50/60Hz frame rates..  People started comparing LCD TVs with Plamsa TVs and find fault with its poor contrast level,  and slower response time.  So they invented dynamic contrast ratio and started specifying insane numbers instead of specifying static contrast ratio.  It is like specifying PMPO (Peak Music Power Output) in audio systems instead of RMS power.  Audio engineers relearned from Marketing guys that music is rich in harmonics and it is better to take upto  the nth harmonics while specifying power output. Once they successfully removed the reference level anybody can quote any numbers L Same story for dynamic contrast ratio.. now contrast ratio of LCD TV runs into millions ….

Since TV  is very competitive market each one wants to outsmart the other. One fine day one of them introduced 100Hz(PAL) / 120Hz(NTSC) LCD TVs saying that motion is not smooth in conventional LCD TVs. (blame its poor response time of 8ms on those days!).  So we need to have double the frame rate for not to miss any action sequence in sports.   Then another has come up with 200/240Hz TV. Everybody followed.  All of us forgot to do the maths . To have 240 Hz frames LCD response time should be within 2ms.  IF we can have LCDs with response time within 2ms why can’t we go back to the old 50/60Hz TV? To understand this further let me explain how they cook up 240 frames when the original source have only 24/50/60 Hz frames (24Hz for movies and 50/60Hz for videos).

There are fundamentally 3 approaches to the 200/ 240Hz. 

1. Repeat the 50/60 (full frames) 4 times to arrive at 200/240Hz – Simple but worst implementation.

2. MEMC: Motion Estimation Motion Compensation- Add 3 interpolated frames between two successive “real” frames. LCD response time should be within 2ms.

3. Scanning Backlight 240Hz – Use MEMC to achieve 120Hz and simply strobe the backlight  LED on and off!

3^rd one of strobing the LED backlight is introduced by LG  and Toshiba who  were in a hurry to get into 240Hz bandwagon.  2^nd one is the best among this  and Sony, Samsung etc are using this from beginning. Now others too,  including LG.  

Each LCD manufactures call  240Hz technology by different names,  Motion flow, Smooth Motion. True Motion, Auto Motion Plus etc..

LG has gone one step ahead of announcing 480Hz TVs. Use MEMC to 240Hz and use Scanning Backlight to extend this to 480Hz L

Again for to display 24Hz movies conventional LCD TVs  use  a feature called “2:3 pulldown”  which means to make up the difference between 24Hz Movies  and 30Hz TVs for every 5 frames they repeat two frames from the 3 “True” frames.  Remember that 240Hz is multiple of both 24 (movies) and 30.  So no pull down is needed.  You would have seen recent TVs support 1080P/24Hz for movies so that movies can be shown in its original sequence of frames.

So back to the old question do you really need 240Hz. Many are able to see the difference.    But Video Industry expert Dr. Raymond says that there is no perceivable difference.

http://www.displaymate.com/LCD_Response_Time_ShootOut.htm   Since I bought a costly 240 Hz Sony KDL-52NX800 TV recently I am trying my best to imagine some difference. I cannot say I am very successful  but I am blaming it on my fading eye sight J

Which is better 720P or 1080i?

You must be aware that some of broadcasting channels use 720P (mainly sports channels in US) whereas most of the DTH providers use 1080i.  Which is better? This was a big debate in a couple of years back.

To save bandwidth,  DTH providers use either 1080i or 720P  instead of 1080P.  Each field in 1080i has only 540 lines and two fields are necessary to show one frame. Sports enthusiast argued that they are affected by the motion blur and their heroes can even score a goal during this interval of scanning two lines in their TV J  So sports channels in US  introduced 720P where the scanning is progressive. To save storage space and to reduce processing power games (PS3/ Xbox) use mainly comes in 720P instead of 1080P.  

Going back to the basic question which is better (720P or 1080i) people forget that LCD screens are inherently progressive in nature unlike CRTs  (which uses 2 interlaced fields to come up with a frame) so the answer almost tilt in favour of 720P in the case of CRTs.   but it is very tough to arrive at a conclusion in LCDs.  Why?

LCD uses de-interlacing and all kinds of picture enhancement processing before painting the picture on to the screen.  As you know 1080i DTH transmits 1080P frame information in two fields of 540 lines. So in a way no information is lost and the current set of LCDs de-interlaces this and shows it as a 1080P picture with some milli seconds delay.  So in a way there is  no compromise on resolution but anything happens between the two fields are lost.

In short 1080i does not compromise on resolution but compromise on some very fast action sequence and 720P does compromise on resolution but capture some fast action. It is upto you to decide on which one is better.  For me 1080i is better any day since it does not compromise on resolution and I can live with what action is lost in between two frames. 

LCD TV Series

Last week I wrote about  Full HD / HD ready and got lots of response. So thought of writing about LED TVs

Most of you must be aware that the so called LED TVs are really not LED TVs. This is just a marketing gimmick to push their LED backlit LCD TVs. The real LED TVs are yet to come in large screens or at  affordable prices and is known as OLED TVs.  As of now the max size of commercially affordable OLED TVs is less than 30”.

What is the main difference between these? LCDs will not emit light unlike CRTs and it needs some other light source to illuminate the scene, LCD just act as a filter. The backlight can be CCFL (ex: an array of tube lights behind the screen!) or LED can be used for the same purpose. But LEDs are used as a (back) light source for LCD TVs in different ways which will be explained below. So all LED-LCD TVs are not created equal so there is lot of different in price too.  LCD screen is acting as filter for the backlighting cannot filter out completely the light for a dark scene, some light will escape through the LCD filter so the dark will not be completely black so the contrast ratio suffers.  This explains why the contrast ratio of a Typical LCD TV is less than a CRT or Plasma TVs. This is one of the reason why Pioneer Kuro Series is the king of TVs. 

Normal LCD TV with CCFL Backlighting

CCFL gives the source of light and the diffuser will make it evenly bright.  This consumes lot of power, A typical 40” TV will consume around 230W and with its mercury content it perceived not very eco friendly.

LED Backlit TVs

The LED back lit comes in different ways and manufactures use their own jargons to confuse the customer.

1. Edge lit LEDs (White LEDs), most common and cheapest.

2. Dynamic RGB LED Backlit (Sony)

3. Dynamic RGB LED Backlit with dimming (Sony)

4. Full  Array LED with local dimming (White LEDs)

5. Edge Lit LEDs with local dimming (This is a new avatar to confuse the consumers more )

6. Precision Dimming by Samsung (It is same as 4)

7. Dolby  vision (May the best, Implementation will be very costly)

Edge lit TVs

White LEDs are placed at the edge of the screen and the diffuser will make the screen evenly lit.  This has the advantage of 40% reduction in power consumption compared to CCFL lighting.  Screen is thinner compared to all other technologies and more eco friendly.  It gives better brightness and contrast  levels compared to CCFL backlighting. So picture quality is noticeably better for HD video. All LED TVs available in India belong to this category.

 

Full Array Backlit

Here there will be an array of LEDs in the back of the LCD screen.  This Full Array LEDs acts as the souce of light resulting in even lighting.  So this gives a better picture with a thicker TV compared to edge it Nobody wants to offer Full array with out local dimming now.

 

Backlit LED TVs

Full Array Backlit with Local dimming

With Full Array Backlit we have the advantage of putting LEDs  ON and OFF depending on what is happening in the video (the brightness of the scene).  . In other words, you can dim certain areas of the screen, while keeping other areas bright. In the simplest form, picture a split screen with black on one side and white on the other. Local dimming would allow the LEDs on the black side to be off and the LEDs on the white side to be lit.  This has the advantage of better contrast ratio since LEDs are put off locally (selectively) when the scene is dark. So no amount of light will filter through LCD screen.   Now how many LEDs you want to use to cover the backlighting.  More and more LEDs used in the Full array results in finer control of the scene as explained in Dolby Vision below. This will reduce the power consumption further.

Backlit Full array LEDs

Dolby Vision (Full Array LED Backlight with local dimming)

Dolby vision is from Dolby Laboratories.  After the initial video processing (de-interlacing, interpolation / inserting and dropping frames to fill the gap, scaling)  Dolby vision takes over.  It apparently analyze each frame and add another 8 bit for luminance (brightness) to the  24bit used for deep color (ex: 8 bit going to LED array and 24  bit to LCD screen) and create an low resolution image in backlit LED array and corresponding high resolution color image in LCD screen thus recreating the scene.  Since LCD screen is super imposed on the LED image you get much better contrast ratio to rival Pioneer Kuro Series Plasma TVs.

Figure showing LED image with super imposed LCD image.

The number of bits and LEDs used in LED array varies to give finer control and different pricing. All the TV manufactures offering Local dimming is using this technology using different number of LEDs resulting in variation of finer controls and thus pricing.  So customer life is not going to be easy to select  a LED TV L

EDGE LED with local dimming 

Apparently Full Array LED with local dimming is a costly affair as seen in Samsung 8500 series and yet to release Sonly HX900 series. So they have come up with another version of local dimming by putting ON and OFF the EDGE LED depending on the Video. There is no fine control here and the effect is almost column wise and the application is for very limited scenes.  This is another marketing gimmick to use the term “Local Dimming” and charge more from the customer.  LG 9000 series and Sony LX series tend to go this way……

Hope this clarifies the myth of LED TV.

If people are interested I will continue with 3D TVs…..

Regards,

Tomy

From: tomy_thomas
Posted At: Wednesday, May 26, 2010 1:52 PM
Posted To: KEC General
Conversation: Full HD or HD Ready or HD Ready 1080P
Subject: Full HD or HD Ready or HD Ready 1080P

I could see lot of debate on LCD TVs and its resolution recently. So I thought of sharing my firsthand experience.

You may think Full HD is (1080P) 1920X 1080 pixels resolution and the so called HD ready TV can show 720P and 1080i.  But it is a loosely defined and one of the most abused term. The definition is not same in US and Europe.  So look at the specification which will reveal more.  For ex: Sony markets their HD camcorders as Full HD but it can shoot video at 1080i only not 1080P. In some parts of the World HD ready means it is capable of accepting HD material but no built in HD tuner.   

But for discussion we will stick to these definition ( Resolution of HD Ready TVs is 1366 H x 768 V = 1 million pixels= 720P,  Resolution of Full HD TVs is 1920 H x 1080 V = 2 million pixel= 1080P.)

Do you need a full HD TV?

Short answer:  NO.   You need a Full HD TV if you satisfy one of the following conditions.

1. You use your TV as a computer monitor and the graphics card supports 1080P or more.

2. You are ready to spend plenty of money (more than the cost of your TV) on source material. Bluray movies (nothing else,  comes in 1080P as of now). All the so called HD DTH gives only 1080i not 1080P ex: Sun HD or any other DTH provider who are planning to give HD in future. I need to add SUN HD gives 7 channels in HD out of which 5 are true HD and two are upscaled  mostly nwith 4:3 aspect ratio.

3. You are investing on a TV for next 5+ years or more

80% (90%?) of the PS3 games comes in 720P not 1080P.  Normal human eye cannot distinguish between 720P or 1080P at a distance of 12’ for a 40inches TV. You need to sit closer 6’ to really appreciate the difference. The distance calculation is totally different for SD and HD TVs.  You need to sit much more closer to HD TV showing HD material to appreciate the difference.

Do not get fooled by the clarity of demo videos showed in the shop. It is shot with much higher resolution digital movie cameras (ex: RED, 4K resolution) and converted to 1080P, so you will never see such clarity even in Bluray movies. You can download these demo videos of any manufacturers at home from the site  www.demo-world.eu under trailers  Full 1080P section.  If you need I have plenty of them with me, at least 5GB.

Resolution for the commonly used video material.

DVD: 576P

DTH SD: 576i most cases Sun gives 576P but it is not better than Tata Sky+

SUN HD: 1080i

Digital 8 / Mini SD Camcorder : < 330 lines

HD Camcorder: 1080i

Most downloaded stuff (read torrent) can be 720P or 1080P but during due to poor conversion it loses most of its clarity and a good DVD picture is better an 720P downloaded .MKV movies.. You may tend to argue with me if you use a smaller 32 /40” TV, but nobody can miss the difference in my 52”  TV, Sony KDL-52NX800. 

But now most of the TV manufactures are offering 1080P at very low prices. So please go ahead and buy it but do not expect any great video unless you start investing on HD videos (Blurays).   DTH video is pathetic in many of these TVs (directly proportionate to the size of your TV) even if you do upscale this to HD.  Infact most of the systems upscaled DTH video is worse than the original.  Again you need to live with the aspect ratio issue. Most of the current DTH material is in 4:3 so you need to stretch the video to fill your 16:9 LCD TV. After some time you may get used to it J

There is a myth that Sony TVs are the best. It is not at all true.  All AV gurus / gadget freaks knows that Pioneer Kuro Series  Plasma TVs are widely considered as the benchmark / reference TV. Every other TV out there is aspiring to become a Kuro.  I am not denying the fact that there are challengers like Mitsubhishi Laser TV, but not yet got wide acceptance…

Even Samsung is ahead of Sony in LCD TV technology as on today. Latest hot TV technology is LCD TV using Scattered LED with local dimming (not edgelit LED or CCFL) as backlight and 3D.  Philips, Samsung and LG have TVs using LED with local dimming.  Samsung 8500 series is supposed to be next to Kuro for clarity in video. Unfortunately it is not marketed in India. Samsung wants to be low cost player here.  Philips 3D TV does not need glasses but the drawback of narrow viewing angle.    Sony has an answer with their latest Signature series HX900 (not LX900) which is planned to be launched in US in this June ’10.

I have invested a lot in Sony, Apple and Philips gadgets  thinking that they are very reliable products. Sony is anyway not known for features. I still have very high opinion about Apple and relatively good experience with Apple. But I had issues with these too, One 29CRT Philips TV model had a design defect which they refused to acknowledge.  Sony’s latest product 52” TV KDL-52NX800 TV had showed  a panel defect  within two days of delivery. They are kind enough to replace it within one week.  But I have very good experience (read reliability, not features) with most of their other products including their signature series (X) 40”TV  ..

Last week Sony surprised me with a killer product at  a killer price.  Sony BDP-S370 an excellent Bluray player for Rs 9900/-  So many things good about it ……..

Regards,

Tomy

LCD TV Series 2

LCD / LED-LCD / OLED TVs..

Last week I wrote about Full HD / HD ready and got lots of response. So thought of writing about LED TVs

Most of you must be aware that the so called LED TVs are really not LED TVs. This is just a marketing gimmick to push their LED backlit LCD TVs. The real LED TVs are yet to come in large screens or at affordable prices and is known as OLED TVs. As of now the max size of commercially affordable OLED TVs is less than 30”.

What is the main difference between these? LCDs will not emit light unlike CRTs and it needs some other light source to illuminate the scene, LCD just act as a filter. The backlight can be CCFL (ex: an array of tube lights behind the screen!) or LED can be used for the same purpose. But LEDs are used as a (back) light source for LCD TVs in different ways which will be explained below. So all LED-LCD TVs are not created equal so there is lot of different in price too. LCD screen is acting as filter for the backlighting cannot filter out completely the light for a dark scene, some light will escape through the LCD filter so the dark will not be completely black so the contrast ratio suffers. This explains why the contrast ratio of a Typical LCD TV is less than a CRT or Plasma TVs. This is one of the reason why Pioneer Kuro Series is the king of TVs.

Normal LCD TV with CCFL Backlighting

CCFL gives the source of light and the diffuser will make it evenly bright. This consumes lot of power, A typical 40” TV will consume around 230W and with its mercury content it perceived not very eco friendly.

LED Backlit TVs

The LED back lit comes in different ways and manufactures use their own jargons to confuse the customer.

1. Edge lit LEDs (White LEDs), most common and cheapest.

2. Dynamic RGB LED Backlit (Sony)

3. Dynamic RGB LED Backlit with dimming (Sony)

4. Full Array LED with local dimming (White LEDs)

5. Edge Lit LEDs with local dimming (This is a new avatar to confuse the consumers more )

6. Precision Dimming by Samsung (It is same as 4)

7. Dolby vision (May the best, Implementation will be very costly)

Edge lit TVs

White LEDs are placed at the edge of the screen and the diffuser will make the screen evenly lit. This has the advantage of 40% reduction in power consumption compared to CCFL lighting. Screen is thinner compared to all other technologies and more eco friendly. It gives better brightness and contrast levels compared to CCFL backlighting. So picture quality is noticeably better for HD video. All LED TVs available in India belong to this category.

Full Array Bcklit

Here there will be an array of LEDs in the back of the LCD screen. This Full Array LEDs acts as the souce of light resulting in even lighting. So this gives a better picture with a thicker TV compared to edge it Nobody wants to offer Full array with out local dimming now.

Backlit LED TVs

Full Array Backlit with Local dimming

With Full Array Backlit we have the advantage of putting LEDs ON and OFF depending on what is happening in the video (the brightness of the scene). . In other words, you can dim certain areas of the screen, while keeping other areas bright. In the simplest form, picture a split screen with black on one side and white on the other. Local dimming would allow the LEDs on the black side to be off and the LEDs on the white side to be lit. This has the advantage of better contrast ratio since LEDs are put off locally (selectively) when the scene is dark. So no amount of light will filter through LCD screen. Now how many LEDs you want to use to cover the backlighting. More and more LEDs used in the Full array results in finer control of the scene as explained in Dolby Vision below. This will reduce the power consumption further.

Backlit Full array LEDs

Dolby Vision (Full Array LED Backlight with local dimming)

Dolby vision is from Dolby Laboratories. After the initial video processing (de-interlacing, interpolation / inserting and dropping frames to fill the gap, scaling) Dolby vision takes over. It apparently analyze each frame and add another 8 bit for luminance (brightness) to the 24bit used for deep color (ex: 8 bit going to LED array and 24 bit to LCD screen) and create an low resolution image in backlit LED array and corresponding high resolution color image in LCD screen thus recreating the scene. Since LCD screen is super imposed on the LED image you get much better contrast ratio to rival Pioneer Kuro Series Plasma TVs.

Figure showing LED image with super imposed LCD image.

The number of bits and LEDs used in LED array varies to give finer control and different pricing. All the TV manufactures offering Local dimming is using this technology using different number of LEDs resulting in variation of finer controls and thus pricing. So customer life is not going to be easy to select a LED TV L

EDGE LED with local dimming

Apparently Full Array LED with local dimming is a costly affair as seen in Samsung 8500 series and yet to release Sonly HX900 series. So they have come up with another version of local dimming by putting ON and OFF the EDGE LED depending on the Video. There is no fine control here and the effect is almost column wise and the application is for very limited scenes. This is another marketing gimmick to use the term “Local Dimming” and charge more from the customer. LG 9000 series and Sony LX series tend to go this way……

Hope this clarifies the myth of LED TV. Read more in http://blogs.ad.infosys.com/users/tomy_thomas/

Subject: Full HD or HD Ready or HD Ready 1080P

I could see lot of debate on LCD TVs and its resolution recently. So I thought of sharing my firsthand experience.

You may think Full HD is (1080P) 1920X 1080 pixels resolution and the so called HD ready TV can show 720P and 1080i. But it is a loosely defined and one of the most abused term. The definition is not same in US and Europe. So look at the specification which will reveal more. For ex: Sony markets their HD camcorders as Full HD but it can shoot video at 1080i only not 1080P. In some parts of the World HD ready means it is capable of accepting HD material but no built in HD tuner.

But for discussion we will stick to these definition ( Resolution of HD Ready TVs is 1366 H x 768 V = 1 million pixels= 720P, Resolution of Full HD TVs is 1920 H x 1080 V = 2 million pixel= 1080P.)

Do you need a full HD TV?

Short answer: NO. You need a Full HD TV if you satisfy one of the following conditions.

1. You use your TV as a computer monitor and the graphics card supports 1080P or more.

2. You are ready to spend plenty of money (more than the cost of your TV) on source material. Bluray movies (nothing else, comes in 1080P as of now). All the so called HD DTH gives only 1080i not 1080P ex: Sun HD or any other DTH provider who are planning to give HD in future. I need to add SUN HD gives 7 channels in HD out of which 5 are true HD and two are upscaled mostly nwith 4:3 aspect ratio.

3. You are investing on a TV for next 5+ years or more

80% (90%?) of the PS3 games comes in 720P not 1080P. Normal human eye cannot distinguish between 720P or 1080P at a distance of 12’ for a 40inches TV. You need to sit closer 6’ to really appreciate the difference. The distance calculation is totally different for SD and HD TVs. You need to sit much more closer to HD TV showing HD material to appreciate the difference.

Do not get fooled by the clarity of demo videos showed in the shop. It is shot with much higher resolution digital movie cameras (ex: RED, 4K resolution) and converted to 1080P, so you will never see such clarity even in Bluray movies. You can download these demo videos of any manufacturers at home from the site http://www.demo-world.eu under trailers Full 1080P section. If you need I have plenty of them with me, at least 5GB.

Resolution for the commonly used video material.

DVD: 576P

DTH SD: 576i most cases Sun gives 576P but it is not better than Tata Sky+

SUN HD: 1080i

Digital 8 / Mini SD Camcorder : < 330 lines

HD Camcorder: 1080i

Most downloaded stuff (read torrent) can be 720P or 1080P but during due to poor conversion it loses most of its clarity and a good DVD picture is better an 720P downloaded .MKV movies.. You may tend to argue with me if you use a smaller 32 /40” TV, but nobody can miss the difference in my 52” TV, Sony KDL-52NX800.

But now most of the TV manufactures are offering 1080P at very low prices. So please go ahead and buy it but do not expect any great video unless you start investing on HD videos (Blurays). DTH video is pathetic in many of these TVs (directly proportionate to the size of your TV) even if you do upscale this to HD. Infact most of the systems upscaled DTH video is worse than the original. Again you need to live with the aspect ratio issue. Most of the current DTH material is in 4:3 so you need to stretch the video to fill your 16:9 LCD TV. After some time you may get used to it J

There is a myth that Sony TVs are the best. It is not at all true. All AV gurus / gadget freaks knows that Pioneer Kuro Series Plasma TVs are widely considered as the benchmark / reference TV. Every other TV out there is aspiring to become a Kuro. I am not denying the fact that there are challengers like Mitsubhishi Laser TV, but not yet got wide acceptance…

Even Samsung is ahead of Sony in LCD TV technology as on today. Latest hot TV technology is LCD TV using Scattered LED with local dimming (not edgelit LED or CCFL) as backlight and 3D. Philips, Samsung and LG have TVs using LED with local dimming. Samsung 8500 series is supposed to be next to Kuro for clarity in video. Unfortunately it is not marketed in India. Samsung wants to be low cost player here. Philips 3D TV does not need glasses but the drawback of narrow viewing angle. Sony has an answer with their latest Signature series HX900 (not LX900) which is planned to be launched in US in this June ’10.

I have invested a lot in Sony, Apple and Philips gadgets thinking that they are very reliable products. Sony is anyway not known for features. I still have very high opinion about Apple and relatively good experience with Apple. But I had issues with these too, One 29CRT Philips TV model had a design defect which they refused to acknowledge. Sony’s latest product 52” TV KDL-52NX800 TV had showed a panel defect within two days of delivery. They are kind enough to replace it within one week. But I have very good experience (read reliability, not features) with most of their other products including their signature series (X) 40”TV ..

Last week Sony surprised me with a killer product at a killer price. Sony BDP-S370 an excellent Bluray player for Rs 9900/- So many things good about it ……..

Regards,

Tomy

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