| AudioREVIEW's Forum Archives - Home Theater |
|
|   Woodman, question about 720p vs 1080i?? | Smokey
May 5, 2003 11:51 AM | | Hey Wood
As to not confuse anybody, I am referring to vertical resolution as scan lines.
I was reading up on HD formats and their specifications and one question came up regarding horizontal resolution of 720p and 1080i. It seem that for 1080i, there are 1920 Horizontal Pixels per scan lines (1080), and for 720p there are 1280 Horizontal Pixels per scan lines (720).
So just considering pixels per line alone, wouldn't that make 1080i have better horizontal resolution than 720p??
Thanks. |
| If I may be so bold..... | Monstrous Mike
May 6, 2003 10:49 AM | | You are correct in saying that 1080i has a better resolution than 720p. It simply has more pixels and thus more information per frame.
Now your next question might be, why even bother with 720p. Well you obviously know that 720p is progressive scan as opposed to the interlaced scan of 1080i. But progressive scan excels when the video content is in motion.
In other words, a still mountain scene will be more brilliant in 1080i while Marion Hossa streaking down the left wing will look better in 720p. So in technical comparions, you must take into account the number of pixels PLUS the video display method.
And to take it a step further, at any given moment in time, the 1080i displays more pixels than 720p but 720p changes all of its pixels when the next frame is presented while 1080i only changes half of its pixels per frame.
Oh oh, I can hear Woodman's footsteps.... |
| A real-life observation... | Keith from Canada
May 6, 2003 12:36 PM | | CBS -- NFL playoffs in 1080i vs. ABC -- NFL Superbowl in 720p.
Technical mumbo-jumbo aside (no offence to those who post technical stuff...I find that fascinating as well), the difference between the two is minimal at best. Fact of the matter is, you'd be spending the first 20 or so minutes of any sporting event picking your jaw off of the ground before you even started to notice any differences. And yes, I have seen both of these formats in their native resolution (no upconvert).
P.S. If all goes as it should, we should be seeing Marian Hossa and the rest of the Sens flying circles around their opponents (hopeful the Canucks!!!) on ABC during the SC finals! |
| "Technical mumbo-jumbo aside"...LOL | Smokey
May 6, 2003 1:41 PM | | Talking technical mumbo-jumbo is the only way to get Wood and Mike's attention :) |
| Stop rubbing it in... | Monstrous Mike
May 6, 2003 2:55 PM | | Or I'll find out where you live and drink all your beer the next playoff round while watching the games on your HDTV.
Now you are right about the real life observations. It would probably take some pretty specific circumstances to notice any difference, kinda like DTS vs DD.
Besides, the moment somebody stares at either format and says "Hey, this could be a little better." we will have seen the birth of the first videophile. Then we'll have pennies on top of the TV and little component video cable elevators for better clarity. |
| re: Woodman, question about 720p vs 1080i?? | woodman
May 6, 2003 11:48 AM | | Yeah Smokester ... 1080i has the
b potential
for greater "resolution" - both horizontally and vertically than 720p, but so what? The two cannot be compared directly because of the fact that one is progressively scanned and the other is interlaced. Mike the Monster was 98% correctamente in his reply - right up to the final paragraph, where he incorrectly stated that 720 changes all of it's pixels every
i frame
whereas 1080 only changes 1/2 of it's pixels every
i frame.
In an interlaced scanning format, a
i frame
still contains ALL of the scan lines, but it does so by displaying the frame as two
i fields
- each containing only alternate scan lines.
He should've used a TIME reference rather than a FRAME reference when comparing the two. 720p displays ALL of it's pixels every 1/60th of a second, while 1080i only displays 1/2 of it's pixels in that same time period. His comments about 720 being the better format where a lot of motion is going on is right on the mark, however.
But all of this is veering away from the original question, which in the final analysis is pretty much irrelevant. As I said in the beginning, 1080i has the
b potential
for greater resolution, but that doesn't mean that the potential is ever realized! Very seldom (how about never) is any video scene shown where there are 1000 different pixel illuminations - side by side across a scanning line. This makes the mere "potential" for greater resolution a big, fat so what?
Clear?
woodman |
| Thanks Wood, Keith, Mike. | Smokey
May 6, 2003 1:37 PM | | I don't know why, but I was under impression that 720p and 1080i had same number of pixels per line until I found out that isn't so (isn't Internet great). I agree with both of you that progressive will be superior on some material (motions) and 1080i will probably be better with still material (although probably very subtle).
But being that 1080i have better horizontal resolution, one can say that 1080i have potential for better picture (vs 720p) if we take out the progressive factor....or can we? :) |
| |
|
|
