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-   -   PAL and NTSC help (https://www.dvinfo.net/forum/open-dv-discussion/26115-pal-ntsc-help.html)

Mitch Buss May 17th, 2004 11:42 AM

PAL and NTSC help
 
I know that this is going to be a very amature question, but I am still quite new at all of this, but could someone shed some light as to what exactly PAL and NTSC formats are. What is their quality and anything else that might be helpful. Please.

Frank Granovski May 17th, 2004 01:50 PM

You can read up about these 2 major broadcasting types here:

http://www.adamwilt.com

You indicate, "WI" USA as your location. North America uses NTSC so I wouldn't worry about PAL.

Rob Lohman May 18th, 2004 02:44 AM

For a quick technical comparison see this page.

Basically NTSC operates at a higher framerate but lower resolution
than PAL does.

Or to keep it a bit geared towards DV:

NTSC: 720x480 at 29.97 frames per second (or 59.94 fields per second)
PAL: 720x576 at 25 frames per second (or 50 fields per second)

Mitch Buss May 18th, 2004 11:41 AM

Thanks for your replies. Now I have another question, what are the fields that are scanned? I did not understand this and have been wondering about it. Thanks for your help.

Ken Tanaka May 18th, 2004 11:48 AM

Video is composed of two sets of lines, called "fields". Analogously, the lines are like teeth in a comb. Each field's lines fit between the others', just like taking two combs and meshing their teeth together. This is called "interlacing".

Mitch Buss May 18th, 2004 11:55 AM

Thanks Ken, I appreciate the help.

Rob Lohman May 19th, 2004 02:26 AM

To futher expand the thought:

We think in full still frames most of the time. Ie, a picture we take
is one full frame of content.

Analog video we see on a TV is interlaced (the reason lies in the
problems they had when developing TV systems and signals way
back, especially with color). What they do is send one half of your
picture first and then the second half 1/60th (NTSC) of a second
later. Each picture "interlaces" the other, so you get:

line 1 is line 1 from picture 1
line 2 is line 1 from picture 2
line 3 is line 2 from picture 1
line 4 is line 2 from picture 2
... etc.

But each half of the picture is acquired at a different point in time
(1/60th of a second apart which yields a 30 frames per second rate)
and thus if you have small movement it will produce interlacing
jaggies where a line can be in a different place from field to field
due to it moving.


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