720p vs. 1080i

[Atreyu]

I've heard it said that the picture made by 720p is of better quality than 1080i Why is that? Is it because the 720 is progressive and the 1080 is interlaced? I do the difference between progressive and interlaced scanning but why would the progressive make the 720 better PQ wise?

[oppopioneer]

Originally Posted by Atreyu

I've heard it said that the picture made by 720p is of better quality than 1080i Why is that? Is it because the 720 is progressive and the 1080 is interlaced? I do the difference between progressive and interlaced scanning but why would the progressive make the 720 better PQ wise?

I have Comcast HD cable, and all cable companies and satellite providers go up to 1080i max. From all the tv viewing I have seen is that 1080i is better than 720p. 720p isn't that bad, it looks damn good on the National Geographic Channel. 1080i is one step above 720p and 1080p is obviously the highest but you can only get 1080p/60 on tv if you have an outboard video processor like the DVDO Edge.

DVDO Edge:

http://www.anchorbaytech.com/dvdo_edge/

[McGarnigal]

With 720progressive you are getting 720 lines of resolution continuously. With 1080interlaced, you are seeing 540 lines of resolution, two sets of 540 lines are taking turns appearing on your screen, but at a rate too fast for the human eye to discern the switch. 720 lines > 540 lines. A lot of tv channels are 1080i, as well as crt hd tvs are capable of native 1080i, but not 720p. Hd video (not film) looks very nice in 1080i as well.

[edelgiud]

Hmm, odd to see this old topic again. But for what it is worth, I could switch between ABC (720p) and NBC (1080i) at times when the same Football game or Presidential event is going and and could assure you that it terms of clarity at least, the 1080i looks better.
The 720p is clearly more blurry.
I have also done the same comparison with a Fox (also 720p) versus TSN (Canadian sports channel in 1080i).

Perhaps I am just not that interested due to Blu-ray being so much nicer and so I try to stick to that, but the only time 720p will look better is during a fast moving Football camera pan shot or maybe during Nascar....

[dobyblue]

1080i = 1920x1080 frame (2 1920x540 interlaced fields)
720p = 1280x720 frame (1 1280x720 progressive field)

1080i has more resolution, but because of the ability to do 60Hz with 720p you may find for faster moving sports like NASCAR that 720p is more desirable.

What your cable company does is a different matter. Plenty of providers convert everything. If you want the native resolution the broadcast was in you better get an HD Antenna and get free OTA.

Fox/ABC = 720p
NBC/CBS = 1080i

Bell TV in Canada is one such culprit - they convert everything to 720p before they broadcast, so it doesn't matter what you set your set-top box to, the incoming signal is 720p. For NBC, CBS and Canadian channel CBC that means 50% of the resolution is thrown away.



LOST is filmed and archived at 1080p24. It is broadcast at 720p60. There is no advantage gained here and you're losing half the resolution. If LOST were broadcast at 1080i60 you would be able to reconstruct the full 1080p24 sequence. However you also open your signal up to interlacing artifacts.

[Anthony P]

Originally Posted by Atreyu

I've heard it said that the picture made by 720p is of better quality than 1080i Why is that? Is it because the 720 is progressive and the 1080 is interlaced? I do the difference between progressive and interlaced scanning but why would the progressive make the 720 better PQ wise?

In theory 1080i should be better. But in reality it is more complicated.

For example if we are talking a BD that is 1080p then you would use 1080p. If you don't it is because of one of two reasons
1) You have a 1080p TV but you use component or you have one of those very old 1080p TVs that to accept 1080p. Then 1080i would be best
2) Your TV is not 1080p and is ~720p, then it gets more complicated it could be that the BD player has the better scaller then the cheap crappy TV so by sending 720p you are using the better functionality of the BD player. But you should really test it to see which one does the better job.

[wilky61]

If you're viewing something with a lot of fast motion (e.g., sports or action films), you'd probably get more benefit out of 720p.

[DIGITALBATH]

Originally Posted by wilky61

If you're viewing something with a lot of fast motion (e.g., sports or action films), you'd probably get more benefit out of 720p.

This is the old adage, but on my Hitachi 42HDT79, I never once thought that while watching 1080i CBS NFL football, or NCAA Basketball. What I can tell you is that even if you use 720p, that won't prevent pixelation from the compressed TV cable signal.

Unless you're TV is terrible ALWAYS choose the higher resolution. I had my 720P/1080i TV for 3+years and PS3 games, Blu-ray, and HDTV always looked best at 1080i.

Also, on ABC they have Wheel of Fortune at 720p, yet at the same time CBC shows it at 1080i, and it looks so much better it's not even close.

[mugen302005]

Hi folks...

I certainly have no idea where to post this maybe stupid question. Is directv offering FULL HD broadcasting? I came across a site where people are simply kicking people's ass when someone tells them there is no such thing as 1080p over cable tv stations. Or isthere?

Sorry to bump in.

[blueshadow | Kosty]

Most cable and sat is 1080i60. Some VOD options are 1080p but its a lower bitrate than Blu-ray.

[lobosrul]

Originally Posted by DIGITALBATH

This is the old adage, but on my Hitachi 42HDT79, I never once thought that while watching 1080i CBS NFL football, or NCAA Basketball. What I can tell you is that even if you use 720p, that won't prevent pixelation from the compressed TV cable signal.

Unless you're TV is terrible ALWAYS choose the higher resolution. I had my 720P/1080i TV for 3+years and PS3 games, Blu-ray, and HDTV always looked best at 1080i.

I think what he meant is, sports on 720p stations are better than from 1080i. Not that a 720p TV is better than a 1080i or 1080p television. Its been years since any 1080i sets have been made anyways.

This is because 720p has 60 frames per second versus 30 from 1080i. Also, and this is the MUCH larger issue, is that 720p looks better at lower bitrate MPEG-2 streams that we're typically receiving. I've still yet to see a really clean 1080i sports broadcast, theres always nasty looking blocks when the camera pans or when theres a lot of action going on.

Originally Posted by DIGITALBATH

Also, on ABC they have Wheel of Fortune at 720p, yet at the same time CBC shows it at 1080i, and it looks so much better it's not even close.

Wow you must be in a very rare market that has Wheel of Fortune on two channels (edit now I see you said CBC not CBS so you must be on the Canadian border or in Canada). I'm almost positive that Wheel of Fortune, and most other syndicated programs, are sent to the affiliates at 1080i. Your local ABC station is then converting it to 720p which leads to a big loss in quality.


I know this because for the longest time, in my market, we didn't get Entertainment Tonight in HD on our ABC (KOAT). This is because the feed is sent in 1080i, and they didn't, until recently, have the equipment to convert it. I know this because of an email from their engineer.

Also CBC is probably broadcasting at a higher bitrate than ABC.

[4K2K]

Originally Posted by lobosrul

I think what he meant is, sports on 720p stations are better than from 1080i. Not that a 720p TV is better than a 1080i or 1080p television. Its been years since any 1080i sets have been made anyways.

This is because 720p has 60 frames per second versus 30 from 1080i

But sports in 1080i are 60 fields per second - updated 60 times per second - just like 720p60 is - but 1080i has higher spatial resolution than 720p.

But I agree that at lower bitrates 720p will most likely look better - for one thing it's less pixels. But at the higher bitrates that Blu-ray is capable of, 1080i would most likely look better, assuming both used the same codec.

But 1080p60 would look better than 1080i and 720p given enough bitrate.

[DIGITALBATH]

Originally Posted by lobosrul

I think what he meant is, sports on 720p stations are better than from 1080i. Not that a 720p TV is better than a 1080i or 1080p television. Its been years since any 1080i sets have been made anyways.

This is because 720p has 60 frames per second versus 30 from 1080i. Also, and this is the MUCH larger issue, is that 720p looks better at lower bitrate MPEG-2 streams that we're typically receiving. I've still yet to see a really clean 1080i sports broadcast, theres always nasty looking blocks when the camera pans or when theres a lot of action going on.



Wow you must be in a very rare market that has Wheel of Fortune on two channels (edit now I see you said CBC not CBS so you must be on the Canadian border or in Canada). I'm almost positive that Wheel of Fortune, and most other syndicated programs, are sent to the affiliates at 1080i. Your local ABC station is then converting it to 720p which leads to a big loss in quality.


I know this because for the longest time, in my market, we didn't get Entertainment Tonight in HD on our ABC (KOAT). This is because the feed is sent in 1080i, and they didn't, until recently, have the equipment to convert it. I know this because of an email from their engineer.

Also CBC is probably broadcasting at a higher bitrate than ABC.

You're correct, I live in Seattle, about 3.5 hours from Vancouver BC. I still stand behind my statements that the 1080i stations will look the best, sports included. 90% of the population would never notice the difference for 1.) , 2.) they're watching the game, 3.) They're drinking 4.) They're not even the right distance from the TV.

The theory always sounds better that the fast motion sports look better on 720p, what real life experience in my opinion tells a different story. But then again, I've read countless of these very 1080i vs 720p arguments, and now clearly see it for what it is.

[ScuseMe]

Originally Posted by Anthony P

In theory 1080i should be better. But in reality it is more complicated.

For example if we are talking a BD that is 1080p then you would use 1080p. If you don't it is because of one of two reasons
1) You have a 1080p TV but you use component or you have one of those very old 1080p TVs that to accept 1080p. Then 1080i would be best
2) Your TV is not 1080p and is ~720p, then it gets more complicated it could be that the BD player has the better scaller then the cheap crappy TV so by sending 720p you are using the better functionality of the BD player. But you should really test it to see which one does the better job.

My Elite "formally" accepts 720p and 1080i (converting to 768p native resolution). However, it can accept the undocumented 1080p/24 resolution for blu-ray. When I first got the tv and paired it with my PS3, I naturally set the PS3 to output 1080i - the maximum advertised resolution. When I later discovered that the Elite can accept 1080p/24 by forcing the PS3 to output that resolution, I decided to critically compare 1080i to 1080p/24 (blu-ray). Going in I assumed that there wouldn't be any noticeable difference, but I was wrong. The picture was definitely more film-like, probably due to the lack of judder in the 1080p/24 configuration; it was much more pleasing to the eye. So, my Elite does a better conversion from 1080p/24 to 768p than the combination of the PS3 doing 1080p to 1080i, then the Elite doing 1080i to 768p. Less conversions in the video path seemed to be the way to go for me.

Now with broadcast HD, 1080i looks much better in all aspects than 720p to me, although I don't watch sports. YMMV.

[lobosrul]

Originally Posted by 4K2K

But sports in 1080i are 60 fields per second - updated 60 times per second - just like 720p60 is - but 1080i has higher spatial resolution than 720p.

Yes, but only half of the frame is updated each 1/60th of a second.

[dobyblue]

Originally Posted by lobosrul

Yes, but only half of the frame is updated each 1/60th of a second.

That is what he said...60 fields per second (1920x540).

[Weirded Wonder]

Originally Posted by dobyblue

That is what he said...60 fields per second (1920x540).

I thought it was, that's what she said...

[volcomsocal]

720p>1080i

[OrlandoEastwood]

I prefer 1080i over 720p. Before my cheapass HDTV died on me, I had it set to 1080i.

[dobyblue]

Originally Posted by volcomsocal

720p>1080i

Care to explain?