difference between 720p and 1080i?

[Colin Wyers]

<<<-- Originally posted by Kevin Shaw : Hmmm, I guess that makes the United States military a "less discerning customer," since they decided some time ago that 720p is preferable to 1080i for purposes of surveillance videos. No matter what else you may say about tbe 1080i format, when you do a "freeze frame" it looks like crap compared to a decent progressive-scan format. -->>>

Uh... huh.

I don't think you can say "the United States military" has standardized on any one system. In my time in the Marine Corps I saw everything from the VX-1000 to the PD-170, as well as quite a few DVCAM cameras. I saw exactly one HD camera, and it was 1080p24. Every service is different, and every command has its own variations.

[Douglas Spotted Eagle]

I can tell you the Marine Combat Camera Group in Coronado is using PD170's and moving to the Z1. They've been testing it with the radars on the carriers and other ships. It's pretty scary how the camera vibrates when that sucker sweeps. I was allowed on board to experience it.
I can't imagine the military locking down to 720p, they have too many different places to deliver to.

[Patrick King]

<<<-- Originally posted by Colin Wyers : Every service is different, and every command has its own variations. -->>>

Amen.

Thinking the US military is some homogenous organization is like thinking the US on-air broadcast industry is one happy homogenous household. Even the terminology is radically different between services. If you tell a member of each service to "secure a building" here are the different results you'll get:

Airman will turn off the lights on the way out.
Sailor will lock the windows and door upon exit.
Soldier will surround the building and permit none to enter or exit.
Marine will kick in the front door and ensure no living thing remains in the building.

So you think they could agree on a standard video format?

[Colin Wyers]

Patrick: Never heard that one before. Got a good laugh out of it.

[Graeme Nattress]

I think you mis-read my post. What I'm arguing is that, practically, there's very little absolute quality advantage for either 720p or 1080i, and that 1080p is visibly superior to both, and that all new video formats should be progressive because all modern display methods are progressive.

Graeme

[Patrick King]

<<<-- Originally posted by Graeme Nattress : I think you mis-read my post. What I'm arguing is that, practically, there's very little absolute quality advantage for either 720p or 1080i, and that 1080p is visibly superior to both, and that all new video formats should be progressive because all modern display methods are progressive.

Graeme -->>>

Graeme, I think everyone did get what you were saying. What we are saying is that EVERYTHING requires a series of trade-offs between cost, performance, unique requirements, etc. As they say, that's why they make Fords and Chevys. 1080p may be the best, but thank goodness it isn't the only.

[Graeme Nattress]

Absolutely!! Choice is great. And really, there's not a wrong choice, but just that one format or the other might be better for your specific needs, and the good thing is, you can convert from one to the other without much loss either way if you pick the "wrong" one.

Graeme

[Brandon Murphy]

some complex stuff talked about. Is this basic synopsis correct?

720p is cheaper because it requires less bandwidth. It is better for screen grabs. It doesnt look quite as good as 1080i on tv broadcast.

1080i looks a little better on tv. It is more expensive and is harder to work with.


why is it harder to work with? And as a prosumer, what would be the top reasons for myself to shoot with a camera that used one or the other?

thanks for all of the replies!

[Ignacio Rodriguez]

> 720p is cheaper because it requires less bandwidth. It
> is better for screen grabs. It doesnt look quite as good
> as 1080i on tv broadcast.

> 1080i looks a little better on tv. It is more expensive
> and is harder to work with.

No. They can both use the same bandwidth. The main difference is that 720p is progressive and 1080i is interlaced.

Thus, on a lower cost progressive display (i.e. an LCD TV), 720p can look better without much of reprocessing. There is the potential for an LCD to show interlaced video which looks good, but it will need to have expensive circuitry to deinterlace (bad) or interpolate (almost as bad).

If there were a massive abundance of HD CRT display systems with 1080 vertical lines of resolution, then there is a chance 1080i would make a lot of sense because they wouldn't need any special circuitry to show the image in full resolution. Actually this is why 480i made sense. But since CRTs are being phased out... we have to think of a better reason. And as it turns out there is: the added spatial resolution will make for a better conversion to 1080p from 1080i than from 720p.

Dirty little secret: Guess what happens when you see 720p on a 1920x1080 progressive display, it looks WORSE than on a native 720p display. So the really really important question is... by the time HD is commonplace, what resolution will most TV sets have?

It seems the EBU is leaning in favor od 720p because they think there will be more native 720p displays in Europe soon.

I don't. I think by the time HD becomes universal, mosts sets will be 1080p. So even though nobody will be able to transmit 1080p yet... 1080i will look better on most TV sets than 720p. So... in my opinion 1080i is the better of the two.

Now I wonder... does 24fps film look better transferred to 720p or 1080i?

[Steven White]

>>Now I wonder... does 24fps film look better transferred to 720p or 1080i?<<

My understanding is that the 1080i standard has provisions for 1080p at 30p and 24p. Hence no one transfers film to 1080i, but rather to 1080p. The actual "i" business will be determined more by the player and the display than the format... and obviously 1080p @ 24p has significantly higher resolution than 720p.

[Joe Carney]

Watching content originally shot with film on my 42" crt based 1080i system (prime time network TV), it looks great. 480p/1080i systems are 95% of the HDTV market in the USA, and 1080i sourced material looks fantastic (travel shows,sporting events, Tonight Show with Jay Leno...) Whats really amazing is the stuff converted from IMAX.

I think 1080i will be around for a long long time. It is visually appealing, less cost to manufacture (for Home theater), lends itself to existing technologies for improving picture quality (digital comb...) and content that originated from either film or HD progressive looks great too.

I've seen 1080p projection using 1080p sourced material and yes it looks even better, but way out of the price range of what most consumers will be willing to pay for.

I hope Europe sees that 1080i is really an excellent format for just about anything you would want. It's also more affordable from a home theater purchasing standpoint.

One negative thing about all the new hd stuff. I watched some of the HD version of the E! oscar red carpet program. Star Jones has a large scar on her chest that doesn't show up in SD. Not something people want to look at for 2 hours. It was broadcast live on one of the InHD channels.

[David Kennett]

It isn't just the price most are willing to pay, it's what actually becomes available - at any price. While some select few can look at original material on a high priced commercial monitor, most of us will look at what the broadcasters, cable companies, and satellite companies deliver to us. The broadcaster is limited to 19.6 Mb/s, and cable and satellite will use even less. In fact all will be trying to get as much as they can into what they've got. I've read that all 1080i broadcasts are reduced to 1080 x 1440 to lower the data and require less compression.

Right now virtually all LCD, DLP, and LCOS use 720 x 1280 chips, so 1080i is a downconversion. there is supposed to be a 1080 x 1920? DLP from TI - don't know if it's out yet. I think we are getting to the point of diminishing returns with the higher resolution (1080i). I know I've seen some really good stuff on Fox and ABC - as well as some pretty marginal stuff on NBC and CBS. I think 1080p-60 will be too extravagent with data rate, the broadcasters, etc. will not go for it.