common LCD Projector questions

What is 480p or progressive scan?

Progressive scanning is basically drawing a picture on a TV screen 1 line at a time, 1, 2, 3, 4, 5... The difference between this and interlaced scanning is that interlacing only draws 1, 3, 5... then comes back and does 2, 4, 6... in a second pass. Interlacing (e.g. 480i) only really becomes a big problem when you have very large screens such as 50" and above. On large screens (such as one from a projector) things can easily be unwatchable when you use an interlaced signal. This is why you should always use the 480p with large screen projectors and ensure your DVD player supports a progressive scan component output.

You can however buy LCD projectors with hardware on board (e.g. deinterlacer or line doubler) that will take an interlaced signal and convert it to non interlaced so everything looks good on the screen. The more you pay the better de interlacing performance you get.

What is the best Aspect Ratio?

These are the aspect ratios which the projector can display. The native aspect ratio is usually listed first, followed by other aspect ratios the projector can output.

Native Aspect Ratio - Because a projector is a "fixed resolution" display device, they have what is called a "native aspect ratio." The most common aspect ratios for projectors are 4:3, 5:4 and 16:9. That means that the chip (or panel) inside the projector is shaped in the specified 4:3, 5:4 or 16:9 proportions. Think of the chip as a miniature version of the image you will see on your screen. Currently the most common aspect ratio in projectors is 4:3, which is the same as most televisions and computer monitors.

A 16:9 native aspect ratio is designed primarily for home theater use. This is because widescreen DVD and HDTV signals are broadcast or encoded in the 16:9 format. Home theater enthusiasts tend to prefer 16:9 aspect ratios because they are closer to original 35mm film format. 4:3 projectors can also display widescreen images however, and can also be a good choice for home theater use.

What is Scaling?

The projector's process of converting a different input format to its native output format. For example converting 1024 by 768 VGA input from a computer to a projectors's native 800 by 600 resolution.

What is HDTV? Do I need it?

A type of television signal, which is scheduled by government mandate to replace the current US standard, NTSC, by the year 2006. HDTV is different from NTSC in several ways. First, HDTV is broadcast in the 16:9 aspect ratio as compared to NTSC's 4:3 aspect ratio. Second, HDTV resolutions are increased from (if expressed in computer resolution terms) 640 x 480 to either 1922 x 1080 (or 1080i) or 1280 x 720 (or 720p). Thirdly, because the signal itself is digital rather than analog, it can carry a lot of information, including full digital audio with multiple channels.

I think HDTV is over rated. The specifications are amazing but the costs for full HDTV support are ridiculously high at the moment. Besides the cost you actually would be hard pressed to see the difference between 480p and HDTV. That's why we highly recommend you simply go for a 480p projector and DVD combo at the moment. By the time HDTV is implemented the prices for full HDTV spec. equipment will be 1/10th what they are now and you can upgrade then (if you feel you need to).