what is the difference between 720p and 1081i?

Question

Which one is better is you had the choice to run something in either one?

Answer 1

I have been reading HDTV magazines over the year... u can find out which is actually better by calculating the exact pixels both of them have. This is the way:

1080i = 1920 x 1080 x 25* = 52 million pixels
720p = 1280 x 720 x 50** = 46 million pixels

*1/25 second is the time taken for interlaced piture to scan its top+bottom fields
**1/50 second is the time taken for progressive scan picture to scan both fields

Conculsion - at a time, 52million pixels and 46million pixels of details are displayed on a 1080i and 720p respectively. Although 720p loses out 6million pixels of details, but because of its Progressive Scan, movements/motion on 720p are displayed more naturally. U can say that 1080i will only be better than 720p if a still image is being displayed. =)

Answer 2

Currently ABC and Fox use 720p, other broadcast networks use 1080i. As stated earlier, 720p is considered preferable for sports or other fast moving action, because the complete picture is drawn in one frame. In interlaced pictures, two fields make up a frame, with odd-numbered lines (1,3,5,7... displayed the first and even lines (2,4,6,8...) in the second. The two fields are 1/60 second apart in time. Any significant motion occurring within that time will show jagged edges of the moving objects.. However for staionary and slow -moving images, 1080i has better resolution; in addition the horizontal resolution of 710p is 1280 pixels, while 1080i has 1920 pixels.

Edit: changed 1250 to 1280 for 720p horizontal pixels

Answer 3

720p would be 720 lines, progressive scanning. However, there is no source like that.
1080i is 1080 lines, interlaced. This is the current rating for HDTV.
So, given the choice, the 1080i feature would be more useful.
Next year, the HDTV standard will be 1080p.
There are a few TVs like that now.

Answer 4

p=PROGRESSIVE MEANS THAT YOU SEE 720 LINES ALL AT ONCE.
i=INTERLACED MEANS YOU SEE 540 LINES AT A TIME SCANNING ODD/EVEN VERY QUICKLY.
IT WAS THOUGHT LONG AGO THAT THE EYE COULDN'T SEE THE DIFFERENCE...BUT IT CAN.
WITH PROGRESSIVE YOUR LESS LIKELY TO SEE VIDEO "NOISE" LIKE THE ARTIFACTS YOU SEE AROUND STRAIGHT LINES OR TYPE FACE.
UNFORTUNATELY THE POWERS THAT BE CHOSE 1080i AS THE HDTV STANDARD AND WE'RE STUCK WITH IT. THE ONLY SOURCES THAT ARE 1080i ARE HD-DVD & BLURAY.
IF YOU HAVE A DVD PLAYER THAT HAS A HDMI OUTPUT YOU CAN SELECT WHICH YOU PREFER (I USE 720p) OTHER WISE YOU ARE AT THE MERCY OF THE BROADCASTERS.

Answer 5

both are hd signals 720 progessive lines is used for fast moving pics abc and espn broadcast in 720 p sports fast moving pic is less likly to have artifacts1080i is the other standard for hd broadcast and now we have 1080p which comming in blueray and hd dvd there are now new dvd players that upconvert the dvd signal to 1080p thats a good bet right now