1) I heard that the HDMI cable signal degrades if the cable is over a certain length, lke over 1.5 metres. If HDMI is a digital connection how can it degrade over such as short distance?
2) I see many tvs that say they play 1080p. but they dont have HDCP, so therefore if you play a Blu-ray your picture quality will be downgraded. If you have a copied Blu-ray movie where all the copy protection has been taken out, will the picture still be downgraded?
3)The signal between a normal dvd player and a tv is analog if you use a component or composite cable, so therefore the picture quality is degraded. But if you use a dvd upcoverter it keeps the signal digital between the tv and dvd player, but is using a up coverter provide the same picture qulaity as if having a dvd player with a HDMI connection?
4) How much resolution does an upconverter improve on a normal dvd movie, does it make it 1080i?
I'll try to answer your questions starting with #1 and 3 because they are related:
HDMI Signal integrity won't degrade much until you get over
6 meters (about 20 feet). This seems to be the accepted limit on HDMI. However, the quality of your HDMI cable plays a big part. When 6-meter HDMI cables from two different manufacturers were tested, one couldn't pass a 720p HDCP-compliant signal from source to display, while the other one had no problem.
Good component-video cables introduce minimal noise up to about 8 meters, or about 26 feet. Read the spec sheet to see if the cable is rated for the signal you're trying to send. Good-quality silver-clad OFC coax cable can produce very good results at distances of over 150 feet for projector applications. On the other hand, a badly- made component-video cable even as short as 2 meters can cause visible signal degradation. There are also several good custom cable builders on the Web, and many can help you on length for their quality of cable.
For really long cable runs, there are extender devices that transmit HDMI or component-video over Cat-5 or fiber-optic cable. Try Gefen, Audio Authority, and Black Box. They all make extenders that transmit over 100 meters (330 feet). Liberty Cable has an HDMI-over-fiber solution that can reach 1,760 feet. To install a mid-length run, you can get repeaters for HDMI cables that are now available from several manufacturers like Gefen and Ultralink. These install in between two standard HDMI cables and they "boost" or pump the signal down the line.
Some people install a wiring conduit from the source equipment to the display instead of in or through a wall knowing that it's better to play it safe when it comes to cabling.
Question 2 - It shouldn't be.
Question 4 - not so much that you would notice the difference.
In the tests that Consumer Reports ran, only HDTV sets larger than 50 inches benefited from the difference in picture quality between 1080p and other HDTVs, such as the 1080i or 720p. So is it worth forking out an extra $1,000 to get a 1080p capable HDTV? Perhaps if you have the extra money to burn or if you have a special theatre-style viewing room that must be able to wow your visitors or guests while you play the latest and greatest Full-HD movie. Most people will be more than satisfied with a 1080i or 720pHDTV. Both are clearly better values for your money in 2007.