[Kipp Jones]

I know in the past the battle between 1080i and 720p has been discussed but now that we have consistent 1080i and 720p programming on, which do you think is better and what do you prefer?


I am for 1080i. I like 720p, but ABC seems to be soft most of the time.

 

[Savageone79]

It's not a fair comparison. You need optimal shows of each type to compare and also the type of show matters wether it be high action or talking head. ABC may look soft but its not due directly to it being 720 its more they are not doing good HD tranfers yet.

 

[vruiz]

I don't know that there's enough variety of 720p material out there to make a definitive decision. Also, this comparison can only be valid if you have the equipment to view both signals natively. Otherwise the deck is stacked in favor of whichever one is your display's native resolution.


I can display both natively but unfortunately my only 720p point of reference would be last season's "NYPD Blue" episodes, since we lost ABC-HD in NYC on 9/11.


I did conduct some informal testing on some of those nights, comparing "NYPD Blue" in native 720p to "Judging Amy" in native 1080i, since they ran at the same time. At the beginning of the season "Blue" looked significantly softer, but the quality steadily improved to the point that, by the end of the season it looked quite similar to "Judging Amy". Not the same, mind you. The 1080i did look sharper, but not overwhelmingly so. Viewing the signal at its native rate makes all the difference. Overall, I'd have to say that for regular programming (dramas and sitcoms) which don't have much fast motion, 1080i looked better, but 720p also looked very good.


The wildcard here is sports. I see all kinds of interlacing artifacts all the time on CBS-HD football, specially on the sidelines and yard markers. I wish I had been able to see 1999's "Monday Night Football" in 720p for comparison. I'm sure those people that did see it will chime in with their impressions.

 

[dlarsen]

Here is a graph that I think shows what my eyes see. 1080i is better for static or slower motion images. As the temporal frequency rises, (motion or pans) the apparent vertical resolution drops. 1080i is also harder to compress and encode without artifacts. I don't really notice the interlace flicker after about 2 min. Just my 2c.


Dave







720P Offers Wider Range of Display

The ordinate indicates vertical resolution, and the abscissa shows the temporal frequency, which represents image motion speed. Ranges of imagery supported by the two approaches are indicated. 1080I, with 1,080 scan lines, can display a maximum of 1,080/2 black-and-white pixels in the vertical direction. If flicker can be ignored, the peak resolution is 540 cycles/height (1,080 TV lines). 720P offers only 360 cycles/height peak vertical resolution, but within this range can display images with temporal frequencies of up to 30Hz. This 30Hz temporal frequency means that a single point in the display changes between black and white 30 times a second. For still images, the temporal frequency is 0Hz. When image motion is fast, the temporal frequency rises. It is evident from the diagram that the range of expression supported by 720P only is wider than that supported by 1080I only, but the range supported by only 720P is in the fast-motion range. Generally, human visual performance falls off as image speed increases.
http://www.nikkeibp.com/nea/feb98/specrep/fig2.html

 

[R8der]

They both look awesome to me. Alias was just excellent last night in 720p....very very clear...the best it's been so far. The Practice was good but not up to snuff with Alias (which may be good considering how yellow some of these actors teeth looked in The Practice with the current quality level).


The problem with making these comparisons is the shows in question are produced with different artistic thoughts in mind. They obviously add grain to The Practice more than the producers of Alias do....but they both appear to do so. It's only with PBS and sports shows where the true "window" effect becomes evident. None of these are currently in 720p.


For the most part, those that don't like 720p are those that can't view it natively. I understand that postion, but it doesn't make 720p bad.


Chris

 

[PVR]

They are both very nice (sure beats NTSC!)


I prefer 1080i over 720p.


I can display both natively and have a display

that can resolve the full resolution of each.


Based on a lifetime of NTSC, I hate interlacing

but 720p is just too many less pixels for the

progressive scanning to win out.


Also, with 1080i there are enough vertical lines

that the interlacing artifacts are not very

noticable.


In terms of best programs out there (for picture

quality), try "The Tonight Show" on NBC or (if you can)

some PBS special events in 1080i like the

Smart Traveler series. Oh yeah - HDnet live sports

on DirecTV are very nice too.

(all of these are 1080i)

 

[CraigR]

Based on what I've been able to see up to this point in time I prefer 1080i.

 

[videoholic]

That HDNet football game was far better than any other CBS College game I've seen to date.


So I'll go for 1080i.

 

[Savageone79]

CBS college footeball was in 1080i as well so your saying that 1080i is better then 1080i? Makes no sense.

 

[Fred DeGrandis]

I like the 1080i format better, and (IN MY OPINION) I feel that HDnet is broadcasting the best PQ(with the limited programing avalible. Then again, I have only been an HD viewer for less then a month now.


Fred

 

[kyungkim]

please qualify yourself,

do you have

A) A video source capable of displyaing native 720p (@60hz) as well as 1080i.

B) A hd stb that outputs 720p and 1080i


If you do not have A and B, then frankly your opinion does not count.


How can you have an opinion of something youve not experienced?


If on the otherhand, you are comparing native 1080i vs 720p rescaled to 1080i then by all means lets discuss.


A quick analogy...


An alien lands on this planet and eats only pork chops and hamburgers. He immediately likes the pork chops and declares pork a superior meat than beef. Without eating beef in its native form, a ribeye steak for example, he does not know how great a nice piece of beef can be. The basis for comparison is all off.


When rescaled, any image can have artifacts and pq degradation. The equipment that does the rescaling is esp suspect in these situations. I doubt the upcoverter in my dtc 100 was doing such a bang up job when it rescaled nypd (when it was broadcast here). The finest example of 720p, mnf has probably not been seen by the people who've commented here.


Stop comparing pork chops to hamburgers.

When you say you like 1080i, be specific.

I like native 1080i compared to the rescaled 1080i from 720p sources.


K

 

[Rgb]

In the long run, 1080i is the format of choice.


Even though interlaced, every 1/60th of a second, you see:


1920x540 = 1,036,800 pixels


for 720p:


1280x720 = 921,600 pixels


Yes, most 1080i transfers probably contain only about 1440 pixels per horizontal line right now, but that's still more than 1280.


Film source or 1080p-source 1080i material can be inverse telecined back to true 1080p.


In the long run, probably nothing will be shot with 1080i cameras, but 1080p camera, as they get cheaper due to technology progression. Lucas is using 1080p cameras for the Episode 2.


In the near future, "1080i legacy" sources will be easily de-interlaced with Faroudja 5000-class 1080p deinterlacer chips that will be very inexpensive due to the application of Moore's law in silicon in the average HD capable projector or monitor. The average Best Buy 8Ghz-10Ghz HTPC in 3 to 5 years will easily deinterlace all interlaced sources from 480i through 1080i and output 1080p to capable projectors or monitors.


Therefore, think of 1080i as a stepping stone to 1080p. Remember that a 1080i signal carries a true 1080p signal when the source was shot progressive.


If the world standardized on 720p, we would never get to see 1080p film source material any time soon.

 

[videoholic]

Quote:

Originally posted by Fred DeGrandis I like the 1080i format better, and (IN MY OPINION) I feel that HDnet is broadcasting the best PQ(with the limited programing avalible. Then again, I have only been an HD viewer for less then a month now. Fred

Oh yeah. Well then what the heck is the difference? HDNet's game looked far sharper than the CBS games are.

 

[Torre]

I have also experimented with both many times.

I prefer 1080I. I don't know why. It just seems better to me.

 

[cwood]

Quote:

Originally posted by videoholic Oh yeah. Well then what the heck is the difference? HDNet's game looked far sharper than the CBS games are.

It could be as simple as differences between the HD cameras used by CBS and HDNet. Some HD cams are capable of full 1920x1080 resolution while others have reduced capability but still qualify as HD cams. Just as you can easily tell the difference between a mediocre and a good HD telecine transfer, you can see the differences in performance between HD cams as well. It is obvious that HDNet has outfitted their trucks with state of the art HD gear...it really shows.

 

[Savageone79]

I actually wish they would have gone with 1080p to begin with. It seems that they could have done so without to much extra cost. I actually would prefer 720p. I think if done properly it could be nearly as good as 1080i. Everyone keeps trying to point out that 1080i has so many more pixels but you have to realize that interlacing cancels out a lot of those pixels. In reality there is not that big of a difference in sharpness or detail especially with todays picture limitations. If you think about it progressive is how nature is. Your eye does not see interlaced it sees progressive. Also interlaced is more prone to compressoin artifacts and blockiness caused by high motion. Whoever decided that interlaced was the way to go was an idiot!

 

[Jerry G]

Quote:

Originally posted by Savageone79 I actually wish they would have gone with 1080p to begin with. It seems that they could have done so without to much extra cost. I actually would prefer 720p.

You have to ask why essentially no HD sets have 720p native. Panasonic did for a while, but dropped it. The reason I believe was cost. If it was so easy and inexpensive to do, I'd expect to see all manufacturers including 720p native, but they don't. 1080p would really add to the complexity and cost of the sets.

 

[BenBroder]

Quote:

Originally posted by kyungkim please qualify yourself, do you have A) A video source capable of displyaing native 720p (@60hz) as well as 1080i. B) A hd stb that outputs 720p and 1080i If you do not have A and B, then frankly your opinion does not count.

EH? Speak for yourself. I'm not on top of the sales figures, but I think it is pretty safe to say that the majority of HDTVs out there, especially the mass-market RPTVs that most people buy for HDTV, cannot display 720p natively. That said, I think it is very fair for broadcasters like ABC to consider how the format it broadcasts will look upconverted to 1080i by the Dish 6000, the RCA DTC100 and other popular STBs.

 

[jim209]

Quote:

Originally posted by Rgb for 1080i: 1920x540 = 1,036,800 pixels for 720p: 1280x720 = 921,600 pixels Yes, most 1080i transfers probably contain only about 1440 pixels per horizontal line right now, but that's still more than 1280.

1440 is larger than 1280 but 1440x540
Quote:

Originally posted by Rgb Film source or 1080p-source 1080i material can be inverse telecined back to true 1080p.

How that will happen for 1080P source? It can't be reversed back to P signal because half of them has already been lost. You maybe can do it for file based program because they only have 24 frames per second.


By the way, I have both A&B. It's really hard to say which one is better because there is not much to compare with. We may have to wait until the Hidef DVD comes out, which most likely will be 720P, to compare some action movies.

 

[Pete Putman]

This debate will go on forever. The only way to judge the quality of 1080i vs. 720p is with a reference-grade DTV monitor, such as Sony's $30,000 BVM-D32E1WU. This monitor has a dot pitch of about .3mm, which is extremely fine.


The quality of film transfers, the data compression, and quality of MPEG-II encoding and decoding are all factors which determine the final quality of a 1080i or 720p image.


I have watched "The Practice" and "Alias" in 720p/60 on both a Princeton AF3.2T and Sony VPH-D50HTU front projector. Both support 720p and 1080i. The source STBs were the Panasonic TU-DST51A and Samsung SIR-t150, both of which also support 720p and 1080i.


To me, "The Practice" doesn't look as sharp as "Alias". I attribute this to the use of low-light techniques, high-grain 35mm color negative film stocks, and shallow depth of field - all cinematographic elements of "The Practice".


It could also be a problem with 35mm film to telecine or datacine transfers.


I have seen varying quality in 1080i material, both live and transferred from film.


To my knowledge, there are no HD cameras equipped with CCDs of higher resolution than 1440 x 1080. There are, however, 1280x720 cameras.


For the reasons why ABC decided to go with 720p transmission, here is a frame from a presentation I have made on DTV at the past three INFOCOMM shows:


1080I VS. 720P TRANSMISSION

1920 pixels x 1080 lines x 30 Hz x 16 bits = 995.3 Mb/s

1280 pixels x 720 lines x 60 Hz x 16 bits = 884.7 Mb/s

1080i & 720p broadcasts are 4:2:0 MPEG

1080i compressed 51:1; 720p compressed 46:1


Fox carries this one step further by showing that 480p High Level, Main Profile MPEG-II is compressed only 16:1 before broadcast, so it is a perfectly viable format for DTV and represents a substantial improvement over 480i NTSC.


One last thought. The majority of direct-view TVs and rear-projection TVs do not have enough resolving power to show all the detail in a 1080i picture. Certainly not with .6 to .8mm dot pitch in a direct-view CRT, and 7" tubes in the RPTV sets. So the argument is largely moot from a technical standpoint.


Pete