1080i / 720p broadcast HD debate revisited
By Richard Lawler 
posted Jan 6th 2009 8:33AM
posted Jan 6th 2009 8:33AM
posted Jan 6th 2009 8:33AM
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Sorry to see Fox and ABC use 720p, on my 1080p 60" set you can really see how it is inferior to 1080i, heck i wish they would use 1080p, but ill settle for 1080i in the meantime.
720p just isn't as good quality, it is almost like those networks picked it because it was cheaper than going full 1080i.
i cant help but laugh at this lol... 720P isnt good quality? oh god... And next youre gonna tell me that 1080P upconverted DVD are better than Blurays...
Did you forget about the Pioneer VS 120hz shootout where the 720P Pioneer plasma whooped up on every single 1080P LCD on the market???
Also, Unless you have a monster huge TV, there is absolutely no dramatic difference btwn 720P and 1080P. Also, remember, most movies are also filmed in 720P/1080i... Only recently are you seeing more action movies shot in full 1080P...
And one more thing... The reason why your signal is horrible is more than likely because you are getting it from your cable carrier... That means your signal is compressed and you get a lower quality HD picture... Throw an antenna on your TV for a full uncompressed signal and THEN come back and tell me 720P is not good quality..
I'd agree with you about cable overcompressing their HD broadcasts and suggesting to get an antenna instead to enjoy a better signal with higher audio and video quality. However, you lost me when you said "most movies are shot at 720p. Most movies are shot on film, which once scanned and digitized, it has over four times the highest resolution available to consumers.
@numerwan - "Also, remember, most movies are also filmed in 720P/1080i... Only recently are you seeing more action movies shot in full 1080P..."
Uhh...no....
Movies are filmed on...wait for it...FILM! Very few movies are actually digitally captured these days. Most film stocks have resolution capabilities far beyond what we call 1080p.
Analog film is transferred to digital generally at 2K or 4K resolutions, and is then treated and downrezzed for inclusion on a disc.
It's not that simple. For certain types of content, 720p60 is going to look awful compared to 1080i60, especially if the 1080i60 is being rendered by a TV able to see pulldowned content and reverse it. Most dramas and movies are filmed using 24fps cameras. 720p60 does an awful job of representing that, not so much because of the resolution, but because there's no easy translation between p24 and p60.
For other types of content, news programming and sports, i60 is going to be awful. Anything with a lot of movement is going to show up the interlacing on modern TV sets. Want to show a car chase in 1080i60? Expect to see lines as the highway shoots past the camera. Want to show a sporting event? Expect to see lines every time you pan the camera across the field. The only way to get around it is to film in 1080p24, pulldown it, and then hope the TV set will deinterlace the content, but you can't guarantee that'll happen, and the image will jerk when it pans instead of showing the lines.
The really funny thing is that with ATSC it really doesn't have to be "either/or". The channels could switch mode. The problem is they're worried about badly designed TV sets screwing up the change-over. Bah.
"Throw an antenna on your TV for a full uncompressed signal "
Ohhh no no no no. Over the air ATSC uses the MPEG2 codec and in most markets are broadcast using a very low bitrate (well, low for MPEG2 HD). Still, it beats the pants off of what we used to have over the air. I'm happy.
Dude, the networks that use 720p look the best on cable. The 4 ESPN HD channels are the best looking of all of them and it's 720p. What are you smoking?
I can not decide... I want both options!
Progressive makes sense for a lot of networks that show fast actions, like sports. It makes sense why ABC, Fox and ESPN would choose 720p, because 1080p wasn't really an option when they made the commitment. Other networks would rather have the higher resolution, like Discovery network for example. Watch Planet Earth or the Sunrise show they have and you'll see why they made the right choice for them.
The 1080p infrastructure is slowly rolling out now though. ESPN's new studios in LA for example, will have the hardware to handle 1080p, whenever the network decides to make the switch.
Funny how many people complain about 1080i yet NONE of the current television technologies actually can display natively display 1080i content. The only sets that were capable of this were CRT-based HD sets. Remember those?
Ummm, you do realize that most, if not all, TVs are perfectly capable of de-interlacing a 1080i signal making it a 1080p signal. The information is there, it just comes split in two. Obviously some sets are better at this than others.
To add to this, 1080i is better for 1080p sets as there is less processing involved.
I honestly feel that 1080i looks leaps and bounds better. I watch alot of sports, especially the NFL. Each Sunday my wife turns to me and ask why is Fox so blurry?
We also watch shows such as CSI and the clarity is amazing. As far as my set up goes, for disclosure I have DirecTV H22 DVR, 60" Mitsubishi 1080p (60hz), and a 800 watt Samsung home theatre. I feel my system is very solid.
CBS and NBC are just plain prettier to look at.
I, like most people who actually know what they're talking about (and as Richard stated), am mostly concerned with bad compression rather than resolution. I only have a 50" Plasma so 720 vs. 1080 is a useless argument for me. I can't tell the difference anyway. If you've got a 65 incher and you're sitting fairly close, maybe MAYBE 1080 is noticeably better, but for the most part you're gonna be limited by your carrier's compression anyway. And like another poster said, I'd take a KURO 720 set over any other 1080 set any day of the week.
Loban,
I agree with you that the major problem with all broadcast media is compression. I also agree that most people will not notice a difference in 720 and 1080 on their sets.
However, despite the fact that 720p Kuros are beautiful televisions there are many 1080p televisions that look better. You can most assuredly tell the difference between a 720p Kuro and a 1080p Kuro. Comparing 1080 plasma to other 1080 plasmas, I would take the Panasonic Viera over the Kuro at this point, it would certainly be cheaper for at least equal quality.
The exception would be if you are stepping up to the Elite Pro Kuro series. At which point $5000 can be spent in a lot of ways and I would start considering something like the Samsung SP-A800B projector for just a little more money.
You have a point and I do mostly agree with you. Let me change my statement just a bit then.
I would take a 720 KURO over NEARLY any other 1080 set. I do love the VIERA line (I have one) and I would definitely consider a 1080 VIERA over a 720 KURO, but only if it were over 50 inches would that choice be a simple one. At or under 50 inches, I would PROBABLY still take the KURO.
As for a 1080 VIERA vs. a non-elite 1080 KURO (the two best in the HDTV arena at this point), I have no idea what I would take. I guess I would have to read reviews and look at test results of each set and go from there. It would be a tough decision if the prices were similar.
I guess my overall point is that I would easily take a 720 KURO or VIERA over any other TV of any brand.
Don't make any conclusions about 1080i vs 720P unless you are dealing with high quality signals without restricted bandwidth.
Since we all have progressive displays, interlacing is a distortion of the video that is impossible to undo perfectly.
It's too bad they didn't implement true frame-by-frame *variable* resolution and frame-rate.
I have a new 58 inch panny, and my cable goes through a Reon processor to make everything 1080P. I can notice a difference on 720P material. This is with FIOS. I think its more of an issue that my box like most cant send signals at their native resolution. So all that 720p stuff gets a crapy conversion to 1080i in my box, and then it gets exploited by the Reon. But I will not get a full 1080 lines from 720p content and have to set my tv to overscan which is annoying.
Its all about the bandwidth and the real time compression of MPEG2. When your FOX affiliate is showing a football game its compressing the MPEG2 in real time, which is not going to be as good as "offline" MPEG2 compression which is better optimized. Then its up to each individual station how much bandwidth the channel gets based upon whether they are using secondary HD channels. They can have two additional channels and those chunks of bandwidth come out of the primary channel, degrading its quality significantly.
So this argument is kind of stupid, because you will never see "full quality" 720p or full quality 1080i broadcast over the air....
this is a useless argument; you never know exactly what kind of compression a signal goes through before it hits your tuner or set top. (even OTA gets compressed). then, is your cable box interlacing your 720p to 1080i? oh, and how well does one's display do with 720p & or 1080I? 720p on a pioneer looks different than 720p on a samsung. as far as your blu ray player goes, how does it do with deinterlacing 1080i into 1080p or 720p? so many variables...
While I like the resolution of 1080i over 720p (yes I can tell), the interlace issues are not too good. Especially since a lot of content being broadcast on the "HD" channels is upconverted SD. Basically you end up with 2x interlace/deinterlace artifacting, and it often shows.
At least with 720p, the station can (in theory) deinterlace the signal using very high quality hardware.
The 1080i discussion as it relates to the general consumer is a bit unnecessary. There are really only two types of HD sets available today: Most are 1080p, meaning that all incoming signals (if not already 1080p) will be converted to a 1080p signal. The other (on the less expensive plasmas mostly) are the 720p sets, which like 1080p, turn the incoming signal into a native 720p. Which is really better? We'll leave viewing distance, the TV size, and the human eye for another discussion. The answer is 1080p… 99% of the time.
Now the networks, as discussed, transmit in either 720p or 1080i. Which one of these looks better on an ideal 1080p set? That's usually 1080i. The 1080i signals are sent at 60 fields per second. On movie material (which was filmed progressively and not interlaced) , 3:2 pulldown is required to reconstruct the original frames from the interlaces signal and what you end up with is 1080p. Pretty much the same as if the network had sent 1080p to begin with. 1080i60 is turned into 1080p30 (ignore 1080p24 for this discussion). So movies at 1080i on a 1080p set look like 1080p.
On video-based material which is recorded interlaced (usually 1080i) at the source, the end result may differ a bit. Video is recorded with interlaced fields, each different from the previous, making reconstruction into full progressive frames a task for the decoding chips on the TV (or your cable/DirecTV/DRV - depending on where the 1080p reconstruction occurs). You see, since no two fields are the same, the computer needs to figure out how best to put them together into the progressive frames. And there are always going to be residual image issues to the discerning eye (most consumers won't notice, though). You may get deinterlacing artifacts like jaggies, motion blur, etc. If however, the source material was recorded in 720p (or 1080p), then converted and sent as 1080i (at CBS, for example), then the reconstruction will likely work better. Regardless, the TV you have is progressive and the reconstruction issues are going to be on either set. So, again, 1080p sets are superior.
Obviously, the format that results in the best image is a true 1080p source like Blu-Ray. But BD disks use much less compression that your cable company uses, and that by itself, results in much better quality, separate from the 1080i vs 1080p signal issue.
Those with a discerning eye, on a large enough TV (say 46” and above), will be able to see the added detail in a 1080i signal displayed on a 1080p set (roughly double the data of 720p). And if you’re in the market for buying a new TV, then a 1080p set is a better choice if funds are not an option. For 42” and smaller sets, however, you can save $200-400 and get a 720p set.
Happy viewing.
Wait, then how come NFL Sunday and March Madness on CBS looks so bad broadcasting 1080i vs 720p Fox, ESPN, ABC....
Maybe on your CBS station... I'd pick the NFL on CBS over FOX any day...
*WITH 60 FIELD-PER-SECOND MATERIAL* (like sports) if the TV's deinterlacer is as powerful as the AVISynth's LeakKernelDeinterlace, then 1080i will look superior to 720p *where there's no motion*. if there is motion, the material will essentially be 540p. so for most "video sourced" .. er .. video, 720p will be superior.
now if the source material is film sourced 1080i, and the video editors haven't done retarded stuff like speedups or slowdowns that mess up an easy IVTC, you will get 1080p from 1080i 3:2 pulldown'd film.
"And while you might think bandwidth comes into play, it actually doesn’t. 720p/60 shows 55.3 million pixels per second (1280x720=921,600x60=55,296,000) while 1080i results in 62.2 million pixels per second (1920x1080=2,073,600x30=62,208,000). Looking at the math, the pixel count per second is actually only about 12 percent higher for 1080i."
This is a huge misunderstanding in the debate, and it's gotten wrong almost 100% of the time. In a 1/30th time slice, you see 1920x1080 unique pixels in 1080i, and 1280x720 pixels in 720p.
The 720p/60 (or 1080p/60) math does not apply to filmed material. All that happens is in two 1/60th of a second slices, it displays the SAME image twice... So you see the same amount of unique pixels in 720p/30 and 720p/60. So you'd actually about 27 million pixels per second in 720p vs. the 62.2 million in 1080i.
Film is shot at 24fps. But when it's shown in the theater, it's actually displayed at 48fps to eliminate flicker. All they do is duplicate each frame. And note that it's never referred to as "48p" but always "24p."
-Pie
i'm not sure i'd call it 48fps which, as you said, they aren't discreet unique images. it's more of a holdover to physical film projection .. where they're making the time the light is shining thru the aperature(?) plate + film vs the time the film is advancing to the next frame .. making it seem more even
John I think you just proved David G's point and some others...
Most people I know think football on CBS and NBC looks so much better than on Fox and ESPN.
I think this issue is not based on what format is better I vs. P... but which format matches with you television better. On My Samsung 52 1080p 120 Hz tv, 1080i looks better, because (I think and I'm no expert) because the tv is formatted better for that, but on those that have 720p tvs, 720 of course would look better because the 1080i gets downgraded on your set virtually making look like you have a 720i tv.
Plus here is the way I am looking at it. A video game looks better in 1080p or 1080i... most would say 1080p. So if shows were able to do 1080p i think all would say that 1080p is better than 1080i and he 720 would not be part of this conversation.
You can't compare apples to oranges.
Progressive scan would inherently be better at any resolution in comparison to interlace at the same resolution. But, 720p is ideal for high-speed action/sports unless 1080p is available. Until 1080i is outmoded, 1080 lines of resolution of a still or slower moving image will always look better over 720 lines. Interlace is the past and present, progressive scan is the present and future -- the delay is in the limited bandwidth to deliver all the channels to your home in the highest quality possible (the better the quality, the more bandwidth it takes up).
Anyone who has gone to film school (or studied up) can tell you that a movie shot on film and projected on film in a theater is just 24 frames of still photos per second animated to give the viewer the sense of motion. Television is the same except consider a digital picture you take with your digital (still not movie) camera, in essence a video still as opposed to a film still -- in the old days of black & white TV it was 30 frames per second interlaced, since you're not rolling film through a projector, the video transition between frames for television was like a Venetian blind (faster than the eye can see), all odd lines and then all even lines, thus "interlaced," each frame containing half the image of the next frame and half the image of the last frame. With the advent of color TV (but still interlace then), they actually slowed down the framerate to 29.97 to squeeze in color info. So if you want to figure out picture quality, which would look better: a still digital picture at a resolution of 1080 (put in motion at 30 frames per second, i.e. 30 pics per second to give the appearance of motion) or 720? Obviously 1080. But the transition between frames in progressive mode (new frames appearing line by line from top to bottom instead of every other line, remember at about 1/30 per second) is a lot smoother visually than interlace, and thus ESPN broadcasts in 720p because they have sacrificed lines of resolution for sharper appearance of motion that exists with progressive scanning between frames of video.
Everything we watch at the movies or on TV is just still frames in motion, and can be frozen (i.e. paused, with the right equipment) to show you individual still frames. Historically, the chosen framerate all came to pass at the dawn of filmmaking, through experiments with the first movie cameras -- 24 frames per second ultimately looked the most natural to the human eye as normal motion. If you've ever used an old 8mm movie camera and shot film at 16 frames per second, you know how goofy it looked when projecting it, a person walking in frame looks like an old silent movie star (Chaplin, Keaton, et al), when much of their early work was shot in camera slower (16 fps) but appeared faster as there was no standard for projector playback until 1926, so the projector playback was often faster than the camera shooting speeds prior to standardizaton. The choice of 30 fps for television was more technical reasons than for accurately natural appearances of motion.
Until 1080p is transmitted for broadcast (don't hold your breath), it will be a sacrifice between resolution and frame transitions (p or i). Blu-ray is an exception at 1080p (for those who have seen it, but the nature of DVD authoring is entirely based on compression). Previous posts were accurate that the level of compression significantly contributes to picture quality. Our TV providers (satellite, cable, fiber-optic) add compression to fit all of the programming into their alotted bandwidth. DirecTV, for example, can provide more HDTV because they can just launch additional satellites into space to add bandwidth (of course, at significant capital costs). Don't get too comfy with the latest because technological advancements in Japan willvinclude the advent of Super HD (something like 4000 lines of resolution instead of 1080 -- film doesn't have lines of resolution, rather grain (or microscopic dots) that react to light exposure, which adds up to about 2+ million lines, in comparison). So, one day our HDTVs and peripheral equipment will be outdated like our 4:3 standard def TVs and other non-HD equipment are today. Spend less, create more :)