Just as the question says. Is the resolution taken from the vertical or horizontal?

I thought that designation has always referred to Horizontal Resolution making DV 480i.

Actually I thought "horizontal" refers to the number of pixels per scan line (720) and "vertical" refers to the number of scanlines (480)... but I'm still new at all this stuff :-)

I was under the impression that 720i was 720x1080, presumably anamorphic 16:9 but that's always been a source of confusion for me too. Maybe someone can post a link to a website that explains all these different standards?

Boyd, I think you may be right...but isn't it L X W Length meaning vertical (720) Width being horizontal(480) and the designation refers to horizontal resolution since this is what they usually use a standard of measurement? I don't know...someone else please help!!

Nope.

DV and standard TV broadcasting is 480i. There are 2 kinds of HD, 720P and 1080i, people are still debating on whether 720P or 1080i is better.

480i = SD (DV & DVD), 720 x 480, 60 fields per second.
480p = SD, 720 x 480, 24, 30, or 60 frames per second.
720p = HD, 1280 x 720, 24, 30, or 60 frames per second.
1080i = HD, 1920 x 1080, 60 fields per second.

Some people include the field/frame rate in the designation, like "720/30p" or "1080/60i".

///d@

Ah so I was right...hehe, so the desgination does refer to the horizontal resolution and some will include the frame rate. 480i would be interlaced 720 X 480. In this case there is no debate, obviously, speaking of resolution, and resolution alone, 1080i is better than 720i.

Well I hope somebody that really knows will clear this up, cause I still think that 480 is *vertical* resolution (eg: the number of lines that are resolved when you move from the top to the bottom of the screen in the vertical direction).

When they give camcorder specs they mention the number of horizontal lines that are resolved. For example, the PD-150 has a stated horizontal resolution of 530 lines. I thought this meant that you could see (theoretically) 530 dots in a row across the 720 pixel width of the screen. Otherwise this spec wouldn't make much sense because the image only contains 480 scan lines.

So I think that VERTICAL resolution refers to the number of scanlines (480) and HORIZONTAL resolution refers to the number of pixels (720) on each line. This matches the terminology used on Adam Wilt's website as well...

<<<-- Originally posted by Garret Ambrosio : In this case there is no debate, obviously, speaking of resolution, and resolution alone, 1080i is better than 720i. -->>>

There is no ATSC spec for 720i; all the 720 line formats are progressive.

///d@

Arghh, this is more difficult than I thought. Wouldn't scan lines be the horizontal resolution? Anyone?

NTSC video has 525 lines from the top of the screen to the bottom of the screen. These lines are referred to as vertical resolution because they are counted vertically, from top to bottom. This number is fixed by the NTSC spec.

Horizontal resolution is measured or expressed as a number of black to white transitions or lines that can be differentiated (resolved). The lines run vertically but are counted across (horizontally). Horizontal resolution is limited by the bandwidth of the video signal or the equipment (lenses, chips, tape etc.).

What you are all talking about is the VERTICAL resolution
(480i, 720p, 1080i etc.)