August 28, 2001
Tech-Note – 088
Sponsored by: Bloomfield & Associates
Thanks to our regulars and welcome to
the new folks.
We have a great deal of information. This is the first of two Tech-Notes that will be issued in short succession. See you again tomorrow or the next day.
RE: Parting Shorts Tech-Notes #87
I agree. However, the rich seem to have taken on so much power that it's going to be downright tough for the rest of us to live decently, I'm afraid. Sooner or later, the progressive social sabotage (you may quote me) done by these companies will degrade our ability to compete internationally, maybe. That is, if globalization doesn't also degrade all the other companies similarly.
Nevertheless, I do think that some smart people are putting up a good fight; there are some good and smart folks using the 'Net well. There's a new, easy- to-use scheme afloat (name escapes me for now) that will circumvent the likes of Chinese attempts to censor access. I was reminded that Marshall McLuhan said WW III will be fought [in cyberspace].
When the talent becomes fed up with corporate insults, it will form its own, more-benevolent, initially small organizations. I'm sure that is happening, already.
Were Bill Hewlett and Dave Packard alive, they would have been much kinder, I'm sure. H-P used to be a dandy place to work. Carly must not be the person we hoped she would be.
Doesn't Lucent support what used to be Bell Labs? Can you foresee closing [Bell Labs] down?
On a personal basis, the store where I buy most of my food is very impartial about providing generous rack space for any and every point of view. I'm quite surprised to be reading the IWW (!) newspaper, and even Marxist/neo- Communist newspapers and finding myself agreeing with much that they have to say.
One among many current scandals is our national prisons-for-profit obscenity. Slave labor, sweatshops, and little if any rehab., and a dismally high proportion of black people.
At heart is that when the wealthy crossed the Atlantic many decades ago, they left behind the concept of noblesse oblige, that it is a solemn obligation for the well-to-do to look after the rest of the people.
I burn to think that I may die prematurely just so somebody already wealthy can become a bit more wealthy.
I burn to learn that it's illegal to wear a gas mask in some U.S. cities; Canada has little honor. Try this one: http://www.utne.com/bSociety.tmpl
Blessings, and keep the faith! Name with held on request
RE: Different views of HDTV Tech-Notes
This is in regard to your piece on "Different views of HDTV" in the most recent Tech-Notes. I appreciate the kind words, but want to correct a couple of the details (including the spelling of my name) in your description of our DTV Transition diary. I am immensely proud of what we as an organization have been able to accomplish to date, but am loath to take credit for the handiwork of others, including the referenced web site. It isn't ours, to start with, but is the product of Trac Media Services, a public television audience research firm, and underwritten by a grant from the CPB Television Future Fund. Its purpose is not to keep the public apprised of what we're doing, but to share our experiences with other PTV programmers. Regrettably, we haven't had the time to spare to prepare similar material for our own web site, www.kpbs.org, although it is "in the works". The particular page that is an ongoing description of our transition to the brave new world of DTV is authored by Keith York, KPBS Director of TV Programming. The non-programming material is derived from information provided him by Leon Messenie, Acting TV Chief Engineer, and myself.
We've had the good fortune to have assembled a management team of very creative, resourceful and far-sighted individuals, not the least among them Doug Myrland, our General Manager and a self-confessed "early adopter", whose imagination and vision have made raising the millions necessary for the transition possible. And, of course, all credit is due contributors like Dr. Andrew Viterbi's family who have actually provided much of this funding. Most other stations in similar circumstances are having a much tougher row to hoe. I suspect that many think that public broadcasters needn't be concerned about "ROI" in the same way that someone like the Meredith station in Phoenix that you talk about does. Not true. We don't have to show a profit, but otherwise, we're a business like any other and wouldn't survive long if we didn't make prudent and rewarding uses of our resources. The differences may be that we are afforded more time to realize that return and that dollars are not always the only way to measure success.
Best Regards, John
(EdNote: We stand corrected)
RE: 88 RE Tech-Notes 84 Low cost
HDTV (and more)
Peter N. Glaskowsky wrote: “Still, the rest of my comments still hold true. A little empirical observation will prove that a top-quality 30" HDTV- resolution screen can be moved as far away as twenty feet or so before a good pair of human eyes is no longer able to resolve the pixels. The "32 x 18 degrees" recommendation you make is far, far too large; HDTV at this angular size will show its pixels quite clearly to most people, especially on displays such as plasma and LCD screens that have clearly defined pixels.”
Peter must have superhero vision if he can resolve the pixels on a 30" HDTV at distances between 4 and 20 feet. And I might add that to date, nobody has built a 30" HDTV that comes anywhere close to resolving 1920 x 1080 pixels. Sony has a 24" 16:10 computer monitor that comes close, but even it falls short, especially when MTF is taken into consideration. Sony's 34" WEGA HDTV cannot even resolve 1000 pixels across the screen width (something to do with the fact that the shadow mask has only about 850 stripes :-) CB
John J. Stapleton, StapleVision Inc. wrote: “Frankly, after 36 years in digital imaging I believe HD and DTV is more "contrast limited" than resolution limited... It is true one might detect a single star subtending "0.5 arc seconds" (sic) or such acute disparity in stereovision, but when one speaks of resolution the Rayleigh diffraction limit in the eye is consistent with the "shrinking raster method" of measuring picture tubes. If the spot size equals the TV height divided by the number of active raster lines, the MTF modulation transfer function will be 40% or limiting resolution (2-2.5%) at double that number of lines. Assuming these things can be made readily equal, the awesome field of view is what our customers need to experience and our numbers must be basic and factual to induce them to visit places where the HDTV is viewed properly as in the home setting, not like bargain stores with hundred ugly pictures blamed on the antenna.”
John is on the right track here. Contrast is critically important to the perception of sharpness and the ability of the human observer to actually resolve fine details. The human visual system can resolve detail over a wide range of resolutions, but this is highly contrast dependent, and it helps if there is a temporal element at work as well. The example of the star, is a good one. There are stars up in the sky on a 24/7 basis. For some reason we don;t see them when the star that gives life to this planet is visible...it's the dynamic range thing. That star will not even be visible if the observer is around a city where there is significant light diffraction in the atmosphere (it also helps if you are at higher altitudes and the air is not polluted). Only when you are viewing that dot of light against a black sky on a very clear night will you be able to see it.
I prefer the measure of human visual acuity used by vision scientists. They talk about the ability to resolve details in terms of "Cycles Per Degree" of the viewing field. The way this is typically measured is by exposing the test subject to optically generated high contrast line pairs. The lines are moved closer together until the observe can no longer distinguish them as separate lines. The distance between the lines is then calculated in terms of the number of line pairs that can be resolved across one degree of the field of view.
Human observers can resolve fine details at resolutions of up to 40 Cycles Per Degree (CPD); most observers top out at less than 30 CPD. As I mentioned, a temporal response can help with perception of fine details. I like to use the example of the blinking red stop light down the road, against the sky. Clearly during daylight hours or twilight you must be much closer to the light to see it. Against a black sky without other interfering stimuli, you will see it at a much greater distance - perhaps at resolutions of 30-40 CPD. Without the temporal stimulus, it is likely that you will need to be closer to detect the light.
Vision scientists tell us that the average human observer will perceive a sharp image when detail reaches about 22 CPD. A good way to calibrate this is to consider the resolution target for NTSC. At full NTSC resolution a 19" display viewed from 7 picture heights (about 80 inches) will provide a maximum delivered resolution of 22 CPD.
IF, and its a big IF, you could actually resolve 1920 pixels on a 30" display, the viewer would need to be about 42 INCHES from the screen to resolve that detail (which calculates out to about 30 CPD).At this viewing distance the screen would cover about 35 degrees of the field of view (which corresponds to the 32 x 18 numbers mentioned earlier in this thread).
The big problem with this is that other studies have shown that the average observer will not sit 3 picture heights from a 30 inch screen. In tests of preferred viewing distances, where observers were allowed to place their chairs at any distance from a variety of displays, it was shown that the preferred viewing distance for a 30 inch display is about 5-6 picture heights. Viewers did not choose to sit 3 picture heights from a dislay until that display was greater than 100 inches in diagonal - the preferred viewing distance was 17 feet!
For purposes of comparison, consider a 15 inch diagonal computer display with XGA (1024 x 768) resolution. At a viewing distance of 30 inches this display will deliver about 20 cycles per degree resolution. Now try moving back to four feet, then 20 feet and see how well you can read this text.
HDTV is about the big screen viewing experience. When they were doing their research into the system, NHK determines that an HDTV image should cover at least 30 degrees of the field of view. For 1920 x 1080, that works out to 64 samples per degree, or a bit more than 30 CPD (actually a good bit less when we take into consideration the filtering required to prevent aliasing and the poor MTF of the typical display).
Regards -- Craig Birkmaier
By Roy Trumbull
I realize it’s news to some, but the FCC has been carving up the TV channels like a fat goose for decades. Long gone are the days when UHF extended to 80+ channels. Where do you think they got the spectrum for cel phones? Land mobile and public safety radio have been channel squatting too.
The original channel allotment for DTV went from channel 7 to channel 56. Those on lo-band channels (2 – 6) pleaded for reconsideration and the current scheme of 2 – 51 was adopted. Now it appears that lo-band won’t work at the presently specified power levels. According to the tables and formulas contained in the 6th Report and Order Appendix (pp E29, 30, 31), The power levels in zones II and III should range from 10KW @ 2000 ft to 45KW @ 1000 ft. In going through the DTV allocation table, the highest power level I found for lo-band was 11.2 KW (Las Vegas, NV and Butte, MT). The bulk of the allocations were for 1 KW. Not good. Impulse noise has increased over the last 40 years and lo-band VHF is where most of it lives.
In the event that higher power is granted for lo-band DTV, either channel 3 or 4 should be eliminated from use in a given market. Those channels are used for cable box output. At WBBM-DT, Chicago, their operation on ch3 was quickly taken off the air because it interfered with the use of cable system set top boxes. (See FCC order dated March 28, 2001 re extension of DTV construction deadlines)
Between channels 4 and 5 is a 4 mHz hole (72 – 76 mHz) assigned to fixed radio services. Use of either channel may require special filtering to avoid interference.
UHF channels 14,15, 16, 17, 18, 19, and 20 are assigned in different markets to land mobile radio and a UHF station lighting up next to the local land mobile channel requires a special filter to keep from desensitizing land mobile receivers.
Channel 37 isn’t assigned anywhere because it’s reserved as a quiet channel for radio astronomy.
Channels 63, 64, 68, and 69 are assigned in various markets to public safety radio. While those channels are out of the long-term core spectrum of ch2 to ch 51, they are used by existing NTSC broadcasters and have been assigned as temporary channels for DTV. They may prove problematic to DTV for the reasons cited above.
Eighty-one million television sets in the U.S. receive programming exclusively from free, over-the-air TV stations, the National Association of Broadcasters announced.
In comments filed with the Federal Communications
Commission, the NAB noted that:
NAB's filing with the FCC noted that during an era of consolidation in the cable industry, local broadcasters "continue to provide a guaranteed minimum of local and diverse voices for subscribers."
Subject: Inventor of the TV Remote Control
Amateur Radio Newsline #1250 reports that Robert Adler, 81, was recently inducted into the Chicago Television Academy's prestigious Silver Circle for the year 2000. Adler is the engineer who invented the first practical wireless remote control device for TV sets that we all take for granted today.
Adler was an engineer for Chicago-based Zenith Radio Corp. in 1956 when he developed the famed "Space Command" remote that used a single audible tone to actuate stepper motors in a TV set to turn the set on and off, change the channel and adjust the volume. Space Command was quickly emulated by other set manufacturers eager to keep pace with Zenith.
Subject: D-Cinema The Next Big
Dr. Joseph Flaherty is senior vice president of technology at CBS. In this position, he advises CBS management on issues and strategies related to broadcast technology, and represents CBS nationally and internationally with major manufacturers and on government and industry committees and organizations. Flaherty joined CBS in 1957, and has directed the Engineering and Development Department since 1967-first as general manager, then, since 1977, as vice president and general manager. During his career he inaugurated electronic news gathering that made news at 11 cheaper and faster to process. Little did he know then that his penchant for economy would spawn live coverage of news as it happens from all parts of the world sent to all parts of the world.
Flaherty is also the undisputed father of HDTV in the United States. For the exact same reason - make programs cheaper for his company - did he champion HDTV production, which led to HDTV distribution to our homes. Under his tough minded and brilliant guidance the U.S. has now led the way for commercialization of HDTV. He is among the first to understand the enormous difficulty of the transition from NSTC to HDTV, and has now taken the next step, which he says is always required if you are to see the first step done.
For many years the most capable minds in HDTV development believed that electronic cinema - HDTV at the movies - would be the great demonstration vehicle for HDTV. There you would see on a theater-size screen just how good the best of HDTV can be. Electronic cinema promises not only a means for acquainting the uninitiated with it, but delivers economic wonders to the bottom line of Hollywood. This allure of new billions of dollars has produced still another titanic struggle for power among the seven great movie studios, each vying for the best part of the D-cinema benefit. No one wants to be disadvantaged, and all want to be advantaged by any means they can. Technology standards, and who has control of it, has always been a chief method for securing new power. Once again Flaherty steps into one of the most contentious arenas in the world - motion picture standards - and this time on a global scale. Below is an article that Dr. Flaherty penned as he entered that lion's den.
What's next in television technology? What's beyond wide screen DTV and HDTV broadcasting? It's not 3D, or even widespread interactive TV! It's the digital cinema or D-cinema.
Following on the heels of the HDTV, the VCR, DVD, and HD-DVD, the large electronic screen in the motion picture theater will revolutionize movie exhibition and turn the theater into a D-cinema multi-media center. Television is coming to the movies! Of course the film industry doesn't call it television, but what's in a name? As Shakespeare observed: "That which we call a rose, by any other name would smell as sweet." The D-cinema is a sweet form of television, and it begins where HDTV leaves off!
In a hundred years of cinema and fifty years of television each medium operated with a totally incompatible delivery and exhibition system. Videotape could not play through the mechanical film projector, and the motion picture studios had a de-facto monopoly in the World's theater. Only film could be played to a cinema audience, but the D-cinema will change all that!
Over the years, many efforts were made to bring TV projectors into the theater for special events, but the quality, brightness, contrast, and reliability of early electronic projectors was poor and could not support a large screen theater display. Moreover, the electronic system was an 'add-on' because it did not replace the film, the film projector, or the projectionist.
The D-cinema's modern, high definition, 'electronic screens' will deliver feature movie quality to large cinema size screens. The 'electronic movies' can be delivered by satellite, fiber, terrestrial broadcast, or via recorded media, and can be played from HD video servers in the theater without the need for a film, film projectors, or project labor. Moreover, the cost avoidance of producing thousands of 35mm color prints, shipping, and replacing them is seen to more than offset the costs of the electronic projectors and digital distribution. The D-cinema electronic screen will replace film in the cinema and bring an electronic compatibility to the movie theater, extending its multi media reach.
Live HDTV programs, stage productions, concerts, cultural, and sporting events will play at the local bijou side-by-side with, and in competition with, digital movies. In addition to new digital high definition programs, electronic promos, commercials, and other short program elements can be seamlessly integrated into cinema theater presentations avoiding the difficult and costly film methods used today to combine such program elements with feature films. Satellite operators, cable systems, terrestrial broadcasters, and program distributors can play a profitable roll in programming the digital cinema.
In fact, the first foray into a new world of 'Broadway Cinema' took place with great success on March 10, 2001 when a one-night-only HDTV showing of the hit Broadway musical, Jekyll & Hyde, was exhibited in four National Amusements cinema theaters in key markets, Boston, Cincinnati, northern Virginia near Washington, DC, and in New Jersey. Following this success Shari Redstone, President of National Amusements, Inc. noted: "We can expand the traditional notion of 'a night out at the movies', and bring communities together for a variety of events." Expect more multi-media presentations in cinema theaters. In fact, 21 D-cinema theaters are already in operation in the U.S., with more to come.
Supporting the move to D-cinema exhibition, digital HDTV technology is already finding ever-widening applications in motion picture production and postproduction. The 1080/1920/24P HDTV format is having a growing impact on filmmaking. A number of major features are being produced in whole, or in part, electronically, using the 1080/1920/24p high definition format. Much cinema postproduction is already being conducted in the electronic 24P HD format. A final master 24P tape is readily convertible to film or to electronic media for theatrical distribution. Star Wars II is an example of this technique.
Major studios are converting their archival and their new feature productions to HDTV for the HD-DVD and for the D-cinema markets. Warner Bros. reports that last year four major productions were released electronically in several digital test theaters. They were 'The Perfect Storm', 'Space Cowboys', 'Pay It Forward', and 'Miss Congeniality'. Sony Pictures has made similar D-cinema tests and is working on the D-cinema developments.
The D-cinema standards are now under study in a several standards organizations around the World (MPEG, DVB, SMPTE, ISO, IEC, NIST, etc.) and in a couple of industry groups (MPA and NATO). In addition to these groups, the International Telecommunications Union (ITU), as a UN treaty organization, is responsible for international standards involving radio frequency spectrum, satellite, cable, and terrestrial broadcasting as well as for international production, postproduction, and recording standards for international program exchange. The merging of the TV and Cinema technologies brings the ITU into a prime position influencing worldwide D-cinema standards to ensure international interoperability and quality. From the viewpoint of the ITU, the D-cinema encompasses more than what is normally thought of in the American cinema. The ITU sees D-cinema as group viewing on large screens, be that in classrooms, training facilities, small theaters, industrial facilities, or in other non-residential areas.
In March 2001, the ITU in its Study Group ITU-R SG-6, established an Ad Hoc Group on D-cinema studies, and I was appointed Chairman with four Vice- chairmen. The first progress report of this Ad Hoc Group is due to be presented to the ITU this September.
For earlier articles from Dr. Flaherty on HDTV: http://hdtvnews.com/flaherty.htm
Subject: SDTV Usage Well Underway at
Production & Post Facilities, According to New SCRI Survey
One in three facilities already have an all SD facility -- SCRI International, Inc., announced the results of a new DTV Migration Survey of Production and Post Facilities, which shows that usage of standard definition digital video is starting to take off.
Production and post facilities are bullish on SD, with one in three (33.6%) already reporting having an all-standard def digital production facility – by 2003, this will increase to two thirds of all facilities, and by 2005, to almost three out of four. Production 43.2%) and post facilities (38.5%) lead the field in term of SD conversion already in place, as do facilities in the US (42.7%) compared to their ROW counterparts (17.9%). There is little question about the increased flexibilities that digital brings to any television facility, especially the non-broadcaster production and postproduction houses. With these thoughts in mind, and considering the statistics presented here, it will be difficult to find very many non-broadcast facilities that won’t be nearly all digital in the not too distant future; then they’d be no advantage to remain analog. In commenting on the results of the survey, SCRI's Research Director, Des Chaskelson, noted that: "In spite of the slow progress of HDTV, the usage of standard definition digital among the production and post community is gaining ground at a rapid pace. It will be difficult to find very many non-broadcast facilities that won’t be nearly all digital in the not too distant future; then they’d be no advantage to remain analog. SCRI has surveyed production and post houses worlwide to determine their currant and future plans for the migration to digital and the impact this will have for equipment manufacturers." The recent 2001-2006 DTV Migration Report Series conducted by SCRI International includes the Production / Post Production DTV Migration Trends Report, plus TV Station Trends and Products Reports. To view the table of contents for the DTV Migration Reports online, go to: http://www.scri.com/sc_reprt.html
Scaling the Heights of Digital Cinema at SIGGRAPH 2001
In February of this year, the Digital Cinema Consortium (DCC) was established to promote the development, test, evaluation and standardization of very high quality digital cinema formats and related infrastructure.
The DCC includes representatives from leading universities, equipment manufacturers, network providers and the motion picture industry. Tomonori Aoyama, PhD, and Professor in the graduate school of information science and technology at the University of Tokyo chairs the consortium and is also Chairman of the Photonic Internet Forum of Japan.
The DCC is providing support for at least three planned demonstrations of the new 2Kp/24 digital cinema format during the remaining months the year 2001. The first demonstration was in the NTT Network Innovation Laboratories booth at the SIGGRAPH 2001 conference on computer graphics and interactive techniques held last week in Los Angeles, California, August 14th through 16th.
NTT Network Innovation Laboratories was established in March of 1999 and given a five to ten year mission of creating innovative services as well as the network concepts that will support these services, provide new technologies that will be required to compete successfully in the global networking business and lead the networking field with innovative, fundamental research and development.
NTT believes that they will provide a key role in the building of the next generation photonic Internet and must support all aspects of the human endeavor, including cinema, which is now going through a historical transformation to digital media. NTT believes that digital cinema is an important new broadband network application and, as such, is committed to its ongoing development.
After successfully proving the concept of super high definition (SHD) digital still imaging over the last decade, NTT set its sights on the “top” of the global media mountain – cinema. Major motion pictures produced for large screen theatrical release are potentially the ultimate broadband network application if the technology can be developed to successfully scale the quality level of 35mm film for digital cinema.
The new 2Kp/24 format equates to 2,048 pixels of vertical resolution and 3,840 pixels of horizontal resolution. This gives it roughly a 2K x 4K resolution of just under 8 million pixels. This comes very close to formats already under discussion within the current movie industry.
The 2Kp/24 format is progressively scanned and runs at 24 frames per second (fps) with equal bandwidth RGB with 24 bits per pixel.
The images used for the demonstration were digitized from film originals shot in a 1.85:1 aspect ratio and then compressed from a base bandwidth of 4.5 Gigabits per second down to 300 Megabits per second using M-JPEG as if to send the bit stream over a Gigabit Ethernet, and was recorded onto a local disk drive.
On playback of the bits from a local disk drive at SIGGRAPH, the images were decoded in real time and fed to an advanced super high definition JVC prototype D-ILA projector. The projector was equipped with three 3,840 x 2,048 D-ILA arrays, one for red, green and blue. Each array has a 1.875:1 aspect ratio. No anamorphic lens was required. In order to eliminate any perceptible flicker, the projector displayed each individual frame four times for an effective frame rate of 96 fps.
NTT in comparing formats pointed out that HDTV at 1080i /30 fps or 720p at variable frame rates and the relatively new 1080p/24 fps just do not come up to 35 mm films resolution requirements of the 2Kp/24 format.
Both NTT and DCC feel that by eliminating the need to print-to-film for distribution, digital cinema will open new doors for very high-resolution movies shot on 35mm film until digital cameras supporting this new format appear.
That’s it for this time; let’s go to press!
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