720p vs. 1080i: A Fascinating Argument by ABC's Randall Hoffner

[Jerry Jones]

If I understand the argument being made by Randall Hoffner of ABC-TV, 720p may actually be better than 1080i:

http://www.bluesky-web.com/numbers-mean-little.htm

I offer it because it's a fascinating argument.

Not sure if I can agree with it, yet; need to think about it.

Jerry Jones

http://www.jonesgroup.net

[Jerry Jones]

How the American TV networks are adopting HDTV:

http://www.alvyray.com/DigitalTV/Network_Plans.htm

Fascinating.

NBC and CBS are going with 1080i, although NBC is keeping the options open for 720p.

Fox and ABC are going with 720p, it appears.

Jerry Jones

http://www.jonesgroup.net

[Jerry Jones]

More arguments in favor of 720p:

http://www.alvyray.com/DigitalTV/Progressive_Quotes.htm

http://www.alvyray.com/DigitalTV/Progressive_FAQ.htm

Jerry Jones

http://www.jonesgroup.net

[Jerry Jones]

Another fascinating page:

http://www.alvyray.com/DigitalTV/Naming_Proposal.htm

It was written by Dr Alvy Ray Smith who apparently cofounded - or was present at the beginning of - four centers of computer graphics excellence, including Altamira, Pixar, Lucasfilm and NYIT.

Jerry Jones

http://www.jonesgroup.net

[Mehen]

arghhh, why cant they just go 1080p? I guess it would start to cause bandwidth problems, but then it would totally eliminate the controversy!

[Jerry Jones]

Dr. Alvy Ray Smith answers that question:

http://www.alvyray.com/DigitalTV/DTV_Compression.htm

"1080p has so much information that it doesn't make sense to try to broadcast it."

"It is a DVD format."

"If you were to try to squeeze it through a broadcast channel, the compression ratio required would be 111:1."

"There's not much left after that much compression."

"The advantage of the higher resolution over lesser formats disappears under such compression."

Jerry Jones

http://www.jonesgroup.net

[wkulecz]

After watching HDTV as delivered via Time-Warner cable on a 65" rear projection set, theory aside, its my opinion that HD broadcasts on CBS and NBC generally have better image quality than ABC and FOX. Most noticable with sports programming.

--wally.

[Dr Mordrid]

My feelings exactly. IMO this guy is blowing technological smoke. It may be tough to broadcast 1080i, but not impossible. Tougher with MPEG-2 than with MPEG-4, which is the future anyhow.

Dr. Mordrid

[Jerry Jones]

If I understand Dr. Alvy Ray Smith's argument correctly, he isn't saying that it's impossible to broadcast 1080i.

He's saying it's practically impossible to broadcast 1080p, which is what he considers to be a high def DVD format.

Jerry Jones

http://www.jonesgroup.net

[AlgoRhythm]

There's no difference in the bandwidth required between 1080i (60 fields per second) and 1080p (30 fps). So, if they broadcast in 30p, it would be fine. I've recorded film-source HDTV broadcasts that are easily IVTC'd back to 24p, and they look great. (Well, as good as broadcast HD can get given the nearly 20Mbps limit)


AlgoRhythm

[Jerry Jones]

Are you sure about that?

Please read this Web page:

http://hdtvexpert.com/pages/realitypf.htm

Jerry Jones

http://www.jonesgroup.net

[Jerry Jones]

Also this Web page:

http://www.cedmagazine.com/article/CA422050.html

"The biggest issue standing between 1080p and commercial service reality is transport bandwidth."

"By combining the higher resolution of 1080 with the greater refresh rate of progressive, 1080p is even more data-dense and could soak up even greater bandwidth."

"That starts with the video produced from 1080p cameras."

"At present, 720p and 1080i cameras output video at about 1.5 Gigabits per second, but 1080p would roughly double that to 3 Gbps, Pagano says."

"To convert that into a standard 19.4 Megabit per second channel for transmission across a cable network, 'there's a whole set of other technologies that have got to be accomplished in between there.'"

"That's one reason Starz! Encore Group ISN'T actively looking at the 1080p format, according to John Beyler, executive vice president of technology operations at Starz!."

"'It would take too much bandwidth to do it.'"

"'1080i barely fits for some types of content–for example, sports–and concerts and specials,' Beyler says."

"'For some types of content there just are not enough bits with 1080i. 1080p would be even that much more demanding.'"

Jerry Jones

http://www.jonesgroup.net

[mmp121]

Forgive my seeming ignorance, but I was under the impression that 1080P was really 1080/30FPS PROGRESSIVE. The articles you cite from http://www.alvyray.com/DigitalTV/DTV_Compression.htm which points to http://www.alvyray.com/DigitalTV/DTV_Bandwidths.htm, are defining 1080P as 1080/60 FPS PROGRESSIVE.

After doing some hunting on the internet for what the real standard should be, I came across a PDF on the www.atsc.org web site, and in this PDF document http://www.atsc.org/standards/cs_doc...CS-TSG-674.pdf Table A3 on page 6 states that 1080P can be at most 30 Hz ie 30FPS.

So if this is true, then what AlgoRhythm said is also true, and therefore 1080P should take no more bandwidth than 1080i to broadcast, if I did my math right. That is all. Thanks for reading, and good night.

[Jerry Jones]

Please understand the difference between BROADCAST formats and ACQUISITION formats.

For BROADCASTING, there are 18 digital television formats under ATSC (Advanced Televisions Systems Committee).

You can scrutinize those 18 formats at the following link:

http://tinyurl.com/3jfvl

For ACQUISITION, there is a format called 1080/60p and you can read all about it on the Sony press release here:

http://tinyurl.com/cgn7y

Mr. Hoffner of ABC-TV makes the following points:

"We well know that the ATSC broadcast standard can accommodate 1080/24p and 1080/30p, but not 1080/60p."

"There does not currently seem to be any movement toward producing equipment that can record or transmit 1080/30p."

"There is a 1920 x 1080 studio/field video camera capable of 4:4:4 RGB output at 1080/60p, but no mention is made of any device that might be used to record or edit the images."

"It is, at this juncture, impossible to successfully compress 1080/60p to fit into a 6 MHz U.S. television channel using the MPEG-2 compression tools available to us."

"It is, in fact, quite difficult to successfully compress some 1080/30i material to fit into a 6 MHz television channel using these tools."

http://tinyurl.com/cyt89

Here is an interesting bunch of visual comparison observations from several HDTV users:

http://tinyurl.com/clv7k

Jerry Jones

http://www.jonesgroup.net

[Jerry Jones]

CBS and NBC have chosen 1080i.

ABC and FOX have chosen 720p.

It seems the sports network, ESPN, now supports 720p as preferable over 1080i:

http://tinyurl.com/cqgmf

I have to wonder, if 1080i is so great for sports as some in this thread seem to believe, why would ESPN choose 720p instead?

ESPN's answer:

"ESPN chose 720p because of the "p," which stands for progressive scan technology."

"Progressive scan technology produces better images for the fast moving orientation of sports television."

Jerry Jones

http://www.jonesgroup.net