Basic Question on Screen Resolution

[jerryyyyy]

All this talk of HD has gotten me thinking. What is the basic resolution of a typical analog TV versus HDTV. Are they comparable? I know what the screen resolutions are of all my computers monitors, but how does that relate to TVs? How much is gained by going to HD andf is it much better that satellite input and S-video to the analog set????:confused:

[mbart0656]

There are a lot of different screen resolutions and that is why the ATSC standard is so confusing (18 types in all) plus the the original NTSC stabdard (over 40 years old). Basically a true HD picture is 6 times the resolution of a NTSC picture. Main formats to know are:

1) 480i: This is 480 lines interlaced which means all odd lines are sent in a frame and then the even lines are sent. This is what creates the lines on old TVs. You can also see what is called motion artifacts which is that straight lines get jagged as they move across the screen. This is often referred to as Standard Definition (SDTV).

2) 480p: This is 480 lines progressive. This is like most computer screens in which all lines are displayed in each frame. Progressive scanned DVD players use this as well as the infamous Fox Widescreen. This is referred to as Enhanced Definition (EDTV).

3) 720p: This is 720 lines progressive and like other progressive signals displays the entire picture in each frame. This is a defined HDTV signal. ABC uses this, they claim it is better for sports (fast motion) due to the progressive nature.

4) 1080i: This is what most people talk about as consumer brand HDTV. It's 1080 lines (so that is more that 2x the old 480). Pictures are definitly better. Main point is that for a true HD picture, you have to start with a HD source (be it film or an HD camera).

I haven't talked about the horizontal part yet. Since a 4:3 picture is SDTV, that would mean the horizontal resolution is 4/3 of the vertical but that is for computers and digitally driven devices. Since the old standard was analog, that is not a true comparison since you would get roll off of the analog signal. The signals were also combined for transmission and when they are taken apart for display, errors are created (the infamous comb filters). For the sake of this long winded reply, using 480 lines times the screen size of 4:3, recould say there are approximately 640 horizontal lines for a total of 480 x 640 or 307,200 pixels. A true HDTV is 16:9 or this multiplies out to 1080 x 16/9 or 1920 horizontal lines. Multiplied together (1080 x 1920), that is 2,073,600 pixels or 6.75 times a SDTV picture.

Sorry for being so long winded. :hi:

[mbart0656]

Sorry, forgot about your satellite and s-video questions.

Satellite signals are broadcast in 480i format (digitally) except for HD broadcasts. If you have an analog TV, the set can only display a maximum of 480i. The best connection for that is s-video. If you upgrade everything (sat receiver and TV), you will only get a few channels in HD (more are coming), all the rest are still SDTV and if they are upconverted on your TV, they look a little out of focus and some are even washed out. Only an external scaler will improve this. It also depends upon where you live and if your local channels are starting to broadcast in HD. They may be broadcasting in digital but it may not be HD. Phoenix is a great example. All channels are digital but most are not HD. Local CBS is the worst. A summary of that is:

1) ABC: All scripted prime time is in HD (movies and regular TV shows, not reality or game).
2) NBC: Some are, some aren't. Jay Leno is and is a great way to see true HD.
3) CBS: All primetime is HD.
4) FOX: They use 480p on some shows.
5) WB: It has been reported that Smallville and Everwood are in HD.
6) UPN: It has been reported that Enterprise is in HD but my local channel doesn't use HD.

HBO and Showtime have HD channels.

In summary, it is really a personal choice if you want to spend the money to upgrade now. A lot of people believe that 2003 is the year for a large increase in the technology and then the prices should come down some more. I spent the money for a few good broadcasts and my DVDs look great with a progressive scan player into a HDTV.

[jerryyyyy]

Great reply. This one should be archived somewhere as a reference.

[Tony Trent]

A very good synopsis Mike B! The National Association of Broadcasters (NAB) uses "six times the resolution of NTSC" as their definition. Don't forget though that HDTV has "ten times the color resolution" of NTSC. That is the part that impresses me. Look at a field of red roses in NTSC and HDTV. They will appear to all be the same shade, more or less, in NTSC. You will be able to discern many, many shades of red in HDTV.

[mbart0656]

Tony, I know what you mean. The colors are deep and rich and almost look 3D. I didn't want to get into too much detail with my synopsis though. When color television was invented, it was pretty amazing but now with HDTV, it's incredible. It's too bad there is so much misinformation out there in the stores to not really show people what the technology is capable of. I remember reading a history of television and it was mentioned that back in the 30's the TV engineers could not even imagine a televison that was larger than 19". That is why a lot of the specs were chosen for NTSC.