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Different HDTV Standards and Multiple Aspect Ratios

Mon, 21 Apr 2008 22:30:00 GMT

The Digital Television (DTV) standard allows broadcasters to choose among several different formats that they can transmit. There are three common high definition formats: 720p and 1080i, and 1080p � and more to come!

Presently, broadcasters have only adapted two High-Definition (HD) formats which allows them to choose the format that provides the best technical quality for their particular mix of programming. The 720p format makes a picture with 720 vertical lines, each with 1280 pixels horizontally, so in computer display terms, it has a resolution of "1280 x 720". 720p uses progressive scanning, like computers, which sends a complete picture 60 times per second. 720p provides the smoothest possible motion rendition, but it does not have as much resolution as 1080i.

The 1080i format makes a picture with 1080 vertical lines, each with 1920 pixels horizontally, so in computer display terms, it has a resolution of "1920 x 1080". 1080i uses interlaced scanning, like traditional TV, which alternates sending odd lines and even lines and thus sends a complete picture 30 times per second. 1080i provides the highest possible resolution, but has the same motion rendition as traditional TV.

For those of you are really technically inclined, think about this: movies and many primetime shows that are produced on film are made with only 24 pictures per second, so 1080i actually becomes progressive scan when film-based material is being broadcast.

In additional to the two HDTV formats, the Digital Television (DTV) standard also includes several Standard Definition Television (SDTV) formats. The Standard Definition formats provide DVD-quality pictures and sound, in both widescreen 16:9 and traditional 4:3 aspect ratios. This leads me to aspect ratios.

Wide Screen (or "Letterbox") is a way of watching a movie on your TV as the movie was originally shown in the theaters. A normal television has a screen ratio of 4:3 also called 1.33:1. This means that the TV is 1.33 times wider than it is high.

Most movies are filmed in a format where they were shown in ratios of 1.66:1 all the way up to 3:1 where the movie was three times as wide as it is high. Unfortunately, because TV screens are not that wide, we have been subjected to movies having visual portions completely cut off so that the image will fit on our screens.

This is where wide screen videos and DVDs come into play. The wide screen transfer process actually shrinks a movie down so that the entire visual image fits on your television screen. This results in what are inaccurately called "black bars".

There are seven (7) different aspect ratios, because not every movie is filmed in the same aspect ratio. The different aspect ratios will however impact how wide screen movies are viewed on the screen. Here is a list of the different aspect ratios. Please note that many of these formats are obsolete. However, they are listed here because movies which were filmed in these formats are available on video.

1) Cinerama - 2.77:1 to 3.00:1 aspect ratio. When transferred to video in its full ratio, this format produced the most "letterboxing" effect. This method of filming actually used three cameras, after which the three images were interlocked together. Any transfer to video (and the only one is "How the West Was Won") would be from a 35mm 'scope reduction print and therefore have a 2.35:1 ratio.

2) CinemaScope - 2.35:1 (originally 2.66:1) aspect ratio. This was once the most commonly used method of filming movies because its only major requirement was a special CinemaScope projector lens, which was available at virtually every movie theatre. CinemaScope was originally created by 20th Century Fox, but it is no longer in use by studios other than Fox. All of the original 3 "Star Wars" movies and even the 1997 animated version of "Anastasia" were filmed in CinemaScope.

3) Panavision - 2.40:1 aspect ratio. The Panavision company became the most successful maker of wide screen lenses, and in the 1970s their Panavision lenses became the "standard" for wide screen. Panavision still makes the lenses for most of the major studio productions today. Panavision also makes lenses for films made with matting as opposed to true wide screen. These matted films are not necessarily 2.40:1, but are most likely 1.85:1.

4) VistaVision - 1.70:1 aspect ratio (approx.). This one was filmed with a specially designed camera which was mounted on its side and it required a special projector, but its image quality was better than standard 35mm. Films shot in VistaVision were photographed on a double width frame of 35mm running right to left horizontally. The uncropped aspect ratio was 1.5:1. The films were generally reduction printed to 35mm 4-perforated (four sprocket holes per frame) in dye-transfer Technicolor and projected with a 1.85:1 ratio - the image area extracted optically from the full frame. For some special venues the double-frame 35mm film was cropped to 1.85:1 during projection.

5) Todd-AO - 2.2:1 aspect ratio during filming, but 2.35:1 after the transfer to a 35 mm print. This process uses a 65mm negative printed onto 70mm film, with a six-track soundtrack, producing a very high quality picture. Many of the great epics and musicals of the 50s and 60s used this format.

6) Technirama - 2.2:1 (70mm prints) or 2.35:1 (35mm prints). This process was developed by the Technicolor Corporation, as a way to continue using its three-color process in the wake of competing Eastman Color. It required both a specially developed sideways camera (like VistaVision) and a wide screen lens (like CinemaScope). Technirama was shot with VistaVision cameras and an anamorphic lens squeezing the image by 25%. The entire 1.5:1 image area was then either optically unsqueezed to 70mm yielding a 2.21:1 aspect ratio, or given an additional squeeze to 35mm 2.35:1 4-perforated (four sprocket holes per frame) Panavision.

7) Academy - 1.33:1 aspect ratio. The Academy ratio (1.37:1 before a soundtrack was incorporated onto the film) was the primary original aspect ratio. Most movies (if not all) that were released before "The Robe" (the first movie to be shown in wide screen) were shown in this ratio.

When televisions first came on the scene, they were (and still are) designed with an aspect ratio matching the Academy ratio so that movies would be shown in the same way as in the theatres. Movies that were filmed in an Academy ratio will not have a "wide screen" version because they fit perfectly on the TV. Such movies include "The Wizard of Oz", "Casablanca", "Citizen Kane", and many, many others.

8) Super 35 - This process does not involve wide screen lenses, but rather it involves framing the picture to fit the ratio of the screen. The top and bottom of the frame are "matted" out and removed from the picture completely, resulting in a rectangular picture. Many movies made in this format are transferred to video with the top and bottom of the frame *restored,* so that you actually see more of the picture on video than you did in the theater. But this is not always a good thing, because the director did not intend to use the top and bottom of the frame in the first place! This is why people talk about boom mikes appearing on video, when they were never there in the theater. However, in almost all circumstances, scenes which include special effects in them are almost always filmed hard-matted in the appropriate wide screen ratio.

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Mon, 21 Apr 2008 22:29:00 GMT

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How to make your Lighting Green.

Thu, 17 Apr 2008 16:15:00 GMT

Here are 10 highly effective ways to go greener.

1. CFL Bulbs

Compact florescent bulbs (CFLs) are those swirley little guys that look like soft-serve ice cream cones. Actually, they come in a myriad of different shapes, sizes, and colors of light. Economically speaking, they�re a great deal, too. CFLs cost a bit more than an incandescent, but use about a quarter as much energy and last many times longer (usually around 10,000 hours). It is estimated that a CFL pays for its higher price after about 500 hours of use. After that, it�s money in your pocket.

Also, because CFLs release less heat, not only are they safer, but your cooling load is less in the summer. CFLs aren�t hard to find anymore, and many cities will give them away for free.

2. LED Lighting

LEDs, or light emitting diodes, are a technology that allows for extremely energy efficient and extremely long-lasting light bulbs. LEDs are just starting to hit the consumer market in a big way and still cost quite a bit more than even CFLs, but use even less energy and last even longer.

An LED light bulb can reduce energy consumption by 80-90% and last around 100,000 hours. They even light up faster than regular bulbs. They are usually more expensive, but the cost has gone down steadily.

3. Materials

Light isn�t all about the bulbs, though. Having eco-friendly lamps and light fixtures is key to greening your lighting. When scouting for new gear, keep your eyes out for lamps made with natural, recycled, or reused materials. Lights made from recycled materials include metal, glass or plastic, and natural materials can include felt, cloth or wood.

4. Disposabulb

Fluorescents last a long time, but when they�re dead, they have to be properly�disposed of. CFLs, like all florescent bulbs, do contain a small amount of mercury, which means they definitely can�t be thrown in the trash. Every city has different services for recycling, so you�ll need to see what�s offered in your area. LEDs, to our knowledge, do not contain mercury, but the jury may still be out on how to best recycle them.

5. Wall warts

Power adaptors, or �wall warts� as they�re affectionately called, are those clunky things you find on many electrical cords, including those attached to lamps and some light fixtures. You�ll notice that they stay warm even when their device is turned off. This is because they in fact draw energy from the wall all the time. One way to green your lighting is to unplug their wall warts when not in use, attached lights to a power strip and turn off the whole switch when not in use, or get your hands on a �smart� power strip that knows when the devise is off.

6. Day-lighting

By far, the best source of light we know is the sun, which gives off free, full-spectrum light all day. Make the most of daylight by keeping your blinds open. If you want to go a little farther, put in some skylights, or, of you are designing a home or doing a renovation, put as many windows on the south-facing side of the house as possible (or north-facing if you live in the southern hemisphere). To take it even further, sunlight can be �piped� inside via fiber optics and other light channeling technologies.

7. Good habits

As efficient as your lighting equipment might be, it doesn�t make sense to have lights on when no one�s around. Turn out lights in rooms or parts of the house where no one is. Teach your family and friends about it too and it will become second nature. If you want to get a little more exact, follow these rules:
Standard incandescent: turn off even if you leave the room for just seconds. Compact fluorescent: turn off if you leave the room for 3 minutes. Standard fluorescent: turn off if you leave the room for 15 minutes.

8. Do it yourself

We�re always encouraging people to take matters into their own hands. So much great eco-innovation comes when people create the things they can�t find elsewhere. Lighting is an especially accessible and rewarding thing to tackle.

9. Dimmers and motion sensors

Motion sensors can be a good way to keep lights turned off when they�re not needed, and dimmers can give you just the right amount of life, and timers can be set to turn things on and off when needed.

10. Get green power

A great way to green your lighting is to buy green power. More and more electric utilities are offering customers a green power option on their bill. Signing up for green power usually means paying a few more dollars a month to support energy in the grid that comes from renewable sources like wind, solar, or biogas.

Refference - http://green.yahoo.com/global-warming/treehugger-142/how-to-green-your-lighting.html

What is LEED Green Building Certification?

Thu, 17 Apr 2008 15:53:00 GMT

LEED is the nationally accepted benchmark for the design, construction and operation of high performance green buildings. LEED gives building owners and operators the tools they need to have an immediate and measurable impact on their buildings' performance. LEED promotes a whole-building approach to sustainability by recognizing performance in five key areas of human and environmental health: sustainable site development, water savings, energy efficiency, materials selection and indoor environmental quality.

Is EDTV or enhanced definition TV the same as HDTV?

Mon, 14 Apr 2008 21:50:00 GMT

No, EDTV has a slightly higher picture resolution than a standard definition TV, but it is not capable of displaying content in high definition, and therefore is not considered an HDTV.