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DTV Tech Notes

% Larry Bloomfield & Jim Mendrala

(408) 778-3412 or (661) 294-1049

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May 24, 1999

DTV Tech Note - 030


Talent does what it can  -- Genius does what it must!

What are we about?  The sharing of experiences, knowledge, observations, concerns, opinions or anything else relating to Electronic Cinema, DTV, HDTV, etc., with fellow engineers and readers.  We publish when there is something to share.  We only send the DTV Tech Notes directly to those, like yourself, who have asked to be on our mailing list, however feel free to forward them, intact, to anyone who might be interested.  There is no charge for this Newsletter.  No one gets paid (sigh!), there is no advertising and we do not indorse any product or service(s).  The ideas and opinions are those of the individual authors.  We don't use any "majordomo" automatic servers.  We administer everything manually.  We do hope that everyone will participate with comments, experiences, questions and/or answers.  We now have over 370 subscribers.  This is YOUR forum!  Past issues are available at: WWW.SCRI.COM


Welcome to all the new subscribers.  Our list has recently grown substantially.  If there are any discrepancies, please let us know so we may correct them. Please invite your associates to e-mail us also so we may include them on the mailing list as well.


Subj:  Senate Passes DTH Legislation

By:     Compiled from several news sources - edited by Larry Bloomfield

Congress is one step closer to having a new DTH bill now that the Senate has passed the proposed DTH legislation that will enable Direct to Home Satellite companies to compete more effectively with cable companies.  It was late Thursday (May 20th) after Senators wrapped up their work on gun control laws that they got to the business of our industry.

Judiciary Committee Chairman Orrin Hatch (R-Utah) acted as floor manager for the DTH legislation.  He attached an amendment to the bill that was presented by Sen. John McCain (R-Ariz.).

All that remains is for the legislators to move forward and reconcile the Senate bill with similar legislation passed by the House last month. It is hoped that this will all be completed prior to Independence Day.


Subj:    FYI only


As always, we appreciate your mentioning Leitch, but I'm a little worried that your Tech Notes recipients will misunderstand the NFL's press conference "unveiling" (DTV Tech Note #29) as an open event.  Would you mind sending a brief note to your subscribers clarifying this as a press-only event?  I sincerely appreciate anything you can. 


(Ed Note: Done!  This event was published for information purposes only.)


Subj: SMPTE Task Force On Electronic Cinema

By     Jim Mendrala

The Society of Motion Picture and Television Engineers (SMPTE) has announced the formation of a task group to examine areas of needed standardization for electronic cinema to become a reality.  Recent demonstrations have shown how rapid has been the improvement in technical quality from electronic projectors.  This has opened the gateway into the probability of a complete electronic cinema system.  A complete system, however, contains a large number of transmission and storage elements that require industry wide discussions.

The SMPTE is creating a Task Force, charged with a brief to identify areas of the system that require standardization.  The group will not be responsible for actual standards documents.  Those will be structured by the relevant SMPTE Engineering Committees, including the existing Electronic Projection committee.  This is hoped to enable a fast track approach to the issues, with different groups of experts working in parallel.

Obviously, something as revolutionary as electronic cinema affects the whole movie industry, and consequently the SMPTE is taking steps to include as many sectors of the industry as possible.  In addition to the announced electronic cinema proponents, participation is being invited from members of key industry trade groups, including ASC, DGA, ITEA, MPAA, and NATO. The Electronic Cinema Task Force will report to the SMPTE Film Steering Committee P3.


Subj: Managing Over A Million Clips of Archived News  

By:    Larry Bloomfield

"It isn't easy," were the worlds Gordon Castle, Vice President of Research and Development, used to describe how his company, news giant CNN, manages over one million clips of archived news material.  While listening to Krishna Pendyala, Executive Vice President of Islip Media, Inc., talk to Castle at NAB '99, his company would like to change all that with their new management software and the addition of a very large storage device.

The new system CNN is considering will permit nearly instantaneous access to the multiple-terabytes of information using picture, sound, text, or a combination, as addresses to the database.  In an exclusive interview with Mark Juliano, President and CEO of Islip Media, Juliano explained that some of the methods used in their retrieval are linked to the closed captioning which is associated with much of the archived material.  In addition to this, several other techniques, such as speech recognition are used, where the system recognizes key words.  But probably the most unique technique is in what Juliano called Geospacial mapping.  As stories are entered into the system, they are identified with a geographical map that identifies the latitude and longitude of the story and associates it with key names and the location.  When the story is pulled up and the clip is played back, the appropriate map is also made available for display and or use with the story.   Juliano said: "The key to effective video search and retrieval is in the up front cataloging.  In other words, what goes in is what comes out."

One other technique, image matching, was mentioned.  As material is entered into the system, thumbnails are generated at every major scene change or transition.  The image matching method is used when there is only a scene available to identify the subject or story.  The scene is entered, analyzed and the system then finds other scenes that most closely match what has been entered.  This helps immensely and speeds up the search process making it unnecessary to view entire clips when searching the library for a particular subject matter.  Juliano said that obviously combinations of these various retrieval techniques could be employed in the search for the "right" clip or story.  "Once clips are located, in many ways, the goal of video search is to NOT watch video, by making it fast and easy to scan through hundreds and thousands of clips," Juliano commented.

CNN is in the planning stages at this time and Islip is one of the data management contenders with Virage and Mate giving them a big run for their money.  Sony and IBM have been retained to construct the architecture for the system.  Once a marriage between CNN and a data management vendor like Islip Media, is consummated the project will take approximately five years to get all the material, 100,000 hours, into the new, more accessible format.  Castle says that by the end of the project, CNN expects to have twice that much material with no foreseeable cap.

CNN has extensive experience in the advantages of cataloging software with its Low Resolution Browsing system built by Virage, SGI and Informix.  Castle said:  "The low resolution system can handle 40 incoming streams and 300 1.5 MPEG-1 playback streams and it manages all incoming CNN video."

At last count, CNN had more than 550-television network affiliates here in the U.S., Canada and Puerto Rico, and more than 200 international affiliates.  Radio isn't doing too badly with 600 affiliates in the U.S. and international affiliates in 9 countries spanning four continents.  It takes 10 domestic and 24 international bureaus to service all these radio and television affiliates, with the affiliates contributing material from time-to-time.  Keep in mind that all the material they generate ends up in the archives.

Castle says that the project, in addition to making CNN's life easier, will aid in the education of countless students.  CNN Newsroom is available to 36,000 schools daily.  Not widely know are the CNN Student Bureaus (CNNSB) and the College Television Network.  There are 42 CNNSB's.  CNNSB is the official student newsgathering and reporting program for CNN, offering students (high school, college and university) an unparalleled opportunity to be published on the CNNSB Web site, on CNN NEWSROOM and possibly, on CNN itself.

The College Network is the largest private commercial television network, serving more than 250 U.S. college and university campuses, reaching some 12 million students on a daily basis.

For additional information, visit Islip Media's web site at:  and CNN's web page at:


Subj: What's Going On In The DTV World

By    Jim Mendrala

Last Tuesday, May 18th, there was a press conference up in Seattle, WA,  put on by Sony's Lisa Young regarding KOMO-DT Channel 38 now broadcasting their news in HDTV on a daily basis. This includes the studio as well as the remote pickups. The remotes are using the HDCAM cameras.

During the conference Larry Thorpe, Sony, was asked; "in the Sony cameras were they 1920 x 1080 or were they 1920 x 1034?" His reply was that yes they were full 1920 x 1080 the same as the cameras delivered to NBC for the "Tonight Show with Jay Leno".

The truth is that NBC was shipped the older 1920 x 1034 cameras. Since then the optical block and sensors for conversion of these cameras to 1920 x 1080 have been shipped. As of today, according to George Hamilton, NBC, these upgrades have not yet been installed as they are waiting for the "Tonight Show" to go into a hiatus so they can swap out the sensors and optics. After that the show will be shot and transmitted in full 1920 x 1080 16:9 aspect ratio.

Presently with the 1920 x 1034 the show has an aspect ratio of 1.85:1.  If the image is displayed in true 16 x 9 then the result would be a slight squeeze in the image and un-square pixels or a loss of 24 lines at the top and bottom of the image or 2%. 1920 x 1080 makes each pixel square. The number of scan lines per frame is still 1125 in either case.

For conversion to 4 x 3 the center section of the frame is extracted and converted down to SDTV (Rec. 601). The image fed to the network has no added aperture correction added and some say looks a little pasty compared with the old NTSC cameras. The video operator only adjusts the

HDTV cameras and doesn't have anything to do with the controls of the down converters aperture correction circuits.

Hope this answers some of the questions people tend NOT to ask.


Subj:  Facts, projections, interesting bedfellows and lessons to be learned 

By:     Larry Bloomfield

As of May 1st there are 61 digital transmitters on the air.  More are coming on daily.  According to John Morgan at the FCC, he thinks there may well be over 300 on the air by the end of this year. 

If you haven't heard, Mitsubishi Digital Electronics (MDEA) has made a major joint commitment with CBS to underwrite the cost to transfer all prime-time film-base shows on CBS this fall.  CBS will then broadcast them in the 16x9, 1080i-HDTV format.  For the details of who gets what in exchange for what, see Beyond the Headlines in Broadcast Engineering's, soon to be out, June edition.

Mitsubishi is not stupid.  Following the roadmap so skillfully devised and executed by RCA through it's subsidiary, NBC, history is destined to repeat itself.  Providing programs in order to promote the sale of HDTV sets is pure plagiarism of Sarnoff's now famous "radio jukebox" memo.  Hoping to reinvent the wheel, at every turn, the accursed bean counters, who think they run the broadcast industry, have lost sight of what Sarnoff knew only too well: the biggest part of the broadcast industry was and is directly owned and funded by viewers.  Go for it and the best of luck.  Hopefully more in our industry will take a lesson from history.  Mitsubishi's commitment is a mer drop in the bucket when compared to the benefits all will gain from their investment. 


Subj:    1.   Potential DTV Interference to existing secondary services

            2.   DTV receivers communicating with the viewer

            3.   Smart Antennas

By:  Ed Williams, PBS  >>  <<

(Ed NoteEd Williams has been involved in digital television from back in its very earliest planning days and is very involved in the DTV Express.)

1.  Potential DTV Interference to existing secondary services

As new DTV signals go on the air, some with very high power levels, secondary users of VHF and UHF TV channels will be affected by the DTV signal on the channel or by out-of-channel emissions on the adjacent channel.

Secondary users include wireless mics, cordless mouse (for PCs), remote control systems, MATV systems, which convert satellite signals to unused local VHF and UHF channels, video security systems, and a variety of low powered audio, video and data wireless systems used in homes and some businesses.

Advance warning of the start of transmission of a new DTV signal is essential if a station is to avoid as much as possible the adverse publicity that will occur from interference and likely have to be reported by the station's news department - adding insult to injury. Take out ads or post notices of the start date, channel and frequency - most important - post the frequency of operation.

Look carefully at cable headends that carry your signal now for potential interference from new DTV stations that may be well outside your grade B service area.  High receive antennas on cable TV towers will pickup up more interference than an antenna only 30-ft above ground.  Check the use of the lower UHF channels on local cable TV systems, which may be in use today and may be affected by ingress of the new DTV signal on that channel.

Work with LPTV and translators rather than just force them to terminate operations that are on or adjacent to the new DTV channel.  A proactive approach will lessen negative publicity caused by a minority station having to vacate because of a new high power DTV facility.

Let the entire technical community know of the station's DTV plans for start up.  This includes SBE, SMPTE, local technicians groups, SCTE, local appliance dealers, everyone.

The idea here is to avoid surprises.  The advance notice won't eliminate surprises but may head off the worst ones.

2. DTV receivers communicating with the viewer

So far the DTV receivers I have seen do not offer much in the way of indication of signal level or nature of distortion that could create problems with decoding the DTV signal.  A smart receiver could provide advance warning of impending loss of decoding capability by placing on the screen a message or bar graph or some other indicator for use by the viewer.

Inside the DTV receiver is a powerful digital signal processor, a portion of which could be assigned to received signal management.

When tuning from one DTV signal another of different levels, one may be received perfectly while the other may be just below the threshold.  An indicator that a station is present but not strong enough is needed.

The receiver could also indicate if failure to receive a DTV signal is due to 1) lack of signal, 2) distorted signal (multipath), 3) interference from NTSC or DTV, and 4) impulse noise.

3.  Smart Antennas

A single DTV receiver manufacturer could provide for 1) multiple antenna inputs for diversity reception or 2) a connector through which signals would be sent to a smart antenna that might be phased array or diversity elements.

There have been some suggestions along these lines but to my knowledge no development.  Maybe this is the time for some technology transfer from government or industry to the consumer sector in order to implement some space age technology for television receiving systems.

The use of circular polarization (or elliptical) is not likely to make any significant difference in the multipath characteristics of the received DTV signal other than to allow a vertical monopole a better opportunity to get it.  There are no commercially available CP receiving antennas that complement the transmit signal.  CP is useful at VHF because it doubles the signal density within the coverage area and makes monopoles more effective.  It is also a relatively low cost option for VHF stations.  Not so for UHF where costs for just horizontal polarization is high.  To double the power is to double the AC power costs.  Some stations are using or considering adding some percentage of vertical polarization (elliptical) to their DTV signal.

It would be very instructive to hear of reports of DTV reception on a first hand basis from readers of this column.  Such reports can help remove some of the rumors and myths about DTV reception.

Ed Williams, PBS


Note:  The folks at Sky Report have done an excellent job on their web site of showing where all the Direct To Home (DTH) satellites are at, what areas they serve and who owns them.  They've got other information there too.  You might want to check it out.    

(Ed NoteIf you know of other web sites that might be of help or use  to our readers, please let us know. Thanks.)


Subj:  Watching The HDTV Stuff Flying Around

By :    Burt I. Weiner  >><<

(Ed Note: Burt is a well-respected broadcast engineer who worked with Larry when Channel 9 in Los Angeles was KHJ-TV. He currently has his own company that performs broadcast services in So. California.  Burt has an interesting perspective on DTV, broadcasting and life. The following has been complied from several e-mail received from Burt.  When asked, he said:)  Yes, you have my permission to publish my comments.  Bert I. Weiner

(Observations): In watching the HDTV stuff flying around it seems to me that the real underlying motivation on the part of the broadcasters has become, how many channels can we squeeze into the mask (in trade for HiDef) and make a buck off of.

Maybe it's true that computers can do things faster and cheaper than a person, but what about the human experience?  Our sense of gratification was born out of creating.  Heritage, it takes age to begin to appreciate it. Our generation along with it's traditions, experiences and it's own form of gratification are on it's way out.

As a normal citizen, if the programs aren't going to be any better, I'm still not going to watch it let alone spend money on it.  Technical quality IS important, but I watch content.  Analog is a phenomenon of nature.  I believe we will transmit an analog signal, at least for the foreseeable future, anyway.  What we put on it may be digital information or modulation but the signal itself, the carrier, the RF thing, - analog.

(AM Stereo revisited! And more):  It's a sham(e) when bean counters call the technical shots.  It would be one thing if they outlined their goals and then the real thinkers could do their collective best to come up with a feasible way to accomplish those goals.  Blame the FCC or more properly, the bean counters for what happened to AM stereo.  It appears that the FCC is only a decoration of the real "stewards" of the airwaves, a limited precious resource.

(Speaking of some of some of his accomplishments): I wonder how some of these stories (truths) would look on a resume?  Most of the engineers I run into don't -- wouldn't have any idea of what were talking about.  Not to put them down, but unfortunately they are not growing up with the opportunities to do what we did.

(On self-improvement & NAB): It seems to me that in today's world very few are interested in learning or improving the art of craft as we knew it.  Unfortunately, today's industry is after instant gratification.  It's not interested in teaching or doing anything to perpetuate the craft/art of broadcasting.

I didn't go to NAB this year.  The last few years just got to be too much.  Dancing girls in front of cameras, digital "belchfire" gizmos and the like.  Unless you're a big spender, nobody wants to talk to you.  For the most part, salespeople will tell you how wonderful their product is and that it will save the world and make a hero out of you.

(Contrasts): Ya see, the real problem with me is, I'm an old dyed in the wool broadcaster.  I've been around it since I was about 6 years old.  Back then we did something with it.  Radio can still do a better job of painting a picture than television. 

I'm fortunate - I love what I do.  It's just that it sometimes saddens me to see what's become of this industry.  Programming, just good enough to hold you there between the commercials.  I have to admit, there are some good programs out there, but they're few and far between.

From one narrow-minded person to another, yes, Larry, it's good to keep in touch with you.  As you once said,  "cut from the same cloth".   Gads, I miss Heathkit!



Subj:  A Look Into the Old Xtal Ball   

By:     Larry Bloomfield

Get a couple of retired broadcast engineers together and you'll either hear several courses of "They just don't know how to do it right anymore," or war stories about their favorite near misses while doing a "live" show.  Occasionally, however,  you'll hear some rather insightful and sagged looks into the future from one or another of the good old boys who either has foresight, is clairvoyant or just watched too many of those Physic help line spots.   The following are my notes from one such  conversation.  The things suggested are truly interesting and may very well come to be.  Other newswires write about the future, why not us, besides if any of this comes to pass, you can say you saw it here.

  Each of the several gentlemen present at this session asked that I not reveal their identity, but rest assured they are respected members of the California television broadcast community.  I can only guess, their reasons for anonymity are so they can remain that way.    

When asked what will become of broadcast television, to the number they said it will take its place with along with AM radio with the main method of delivery into homes changing to either cable (fiber) and or satellite.  One gentlemen even suggested that terrestrial television will go away altogether because the spectrum is too valuable and needed for other types of services.  They all agreed that if it did, it won't die an easy death.  

The composition of television will change in that almost all television will be by subscription.  This will put the viewer in the driver's seat.  Since everything will be delivered in a data format, you will get your television by way of the same common carrier as you will your Internet or other data services. 

Since the viewer will be in the driver's seat, they will get a program listing, in advance, probably via an electronic program guide or some type of interactive device that will indicate the earliest a program can be viewed.  Only live programs, such as sporting events will be shipped to the customer in real time.  All other programs will be delivered at slower than real-time bitrates to make use of the least amount of bandwidth.  Actually the programs would probably be sent consistent with the traffic needs of the common carrier's transport media.  Who cares, you're not watching it in real time anyhow.  When a program is selected, the viewer will also indicate what time they will want to see it.  If they put heavy demands on the common carrier's transport media, they will simply have to pay for the additional bandwidth to get it to them. 

To accommodate this type of program distribution, all television sets would have some type of  video server as part of their Integrated Receiver Decoder (IRD) or set-top box for storage.  With this kind of reception scheme in place, and sufficient storage, you could even delay watching a program if you had something change your schedule.  No more missed X-Files.  You could even pause a program if you got an important phone call.  Can you imagine calling CBS and asking them to pause 60-Minutes or re-feed  it for whatever reason.  With the show in your storage, you can do as you like. 

Regularly scheduled network programs can be sent ahead of time and through conditional access or encoded entitlement messages, you would not be able to see it until or after the "scheduled" time.  That's better than today when you have to watch the program when the stations or networks say you have to. Viewer driven television -- unheard of today, but not tomorrow!

Other than power consumption and program or pay per view fees, all other costs would be related to renting bandwidth.  Three things will determine the cost; the quality of the picture (HDTV requires more bandwidth than SDTV), speed of the bitrates, (the greater speed, more bandwidth) and program content (length), how long it takes to get it to you.  If the program is a sponsored show, the cost would be less. 

You could conceivably ask for a High Definition program, send at slow speed, during times when the demands on the common carrier are low and get it for a much lower price.  Remember they can do some rather interesting things with bandwidth management.  Non-real time can mean that your program would get sent out in pieces as the system can accommodate it. How the program gets to the viewer is immaterial as long as it gets there.  What should they care, as long as they can look at it in one piece when they want to?

Here's another advantage of this kind of subscription TV.  If a person in California wanted to watch a local program from a station in, say Vermont, it could be live or via a slow bitstream for viewing at a later time and/or date.  The gentlemen kept going back to the uniqueness of the concept of delivery by say that the program could be delivered via copper (slow bit rate - because there's a lot of that still around that could be put to good use) or via fiber/satellite for more bandwidth demanding requirements. 

Again, the transport media is not important.  Even if it were interrupted, you'd never know it as the system would be smart enough to switch to an alternate means and continue, seamlessly, without the viewer ever knowing.  That's why they said that the delivery system would be so sophisticated that part of the program's bits could come via satellite until it's channels are needed for something of greater priority and the remainder could be delivered via cable - copper or fiber.  As long as the viewer's attention is never drawn to the system, so the viewer can sit, watch the program uninterrupted, unaware of what is happening, or how, it gets there, then the broadcaster has done his job properly.

It was even pointed out that ratings could be more accurate.  With the permission of significantly more viewers, Nielsen would have no problem downloading the activity of hundreds, if not hundreds of thousands of the set-top IRD's all across the country.  Tabulation would be faster and better.

Every one of us at that gathering agreed that we'd hardly begun to scratch the surface in ways of delivery, bandwidth management or transmission media.  And agreed that we truly are on the brink of a totally new era in television, Internet, and anything else in the way of entertainment, education and business. 


A Closing Note, a quote -- 

There are three roads to ruin; women, gambling and technicians.  The most pleasant is with women, the quickest is with gambling, but the surest is with technicians.

-- Georges Pompidou

Ed  Note: With attitudes like these, who needs the COFDM-8VSB controversy?


The DTV Tech Notes are published for broadcast professionals, and others, who are interested in Electronic Cinema, DTV, HDTV, etc., by Larry Bloomfield and Jim Mendrala. We can be reached by either e-mail or land lines (408) 778-3412, (661) 294-1049 or fax at (661) 294-0705.  (Note - Jim's new area code is 661). News items, comments, observations, opinions, etc., are encouraged and always welcome from our readers; material may be edited for brevity, but usually not. DTV Tech Note articles may be reproduced in any form provided they are unaltered and credit is given to both the DTV Tech Notes and the originating authors, when named.  If they are to be used by a publication that normally compensates their writers, please contact us first.