Published: TV Technology

Issue: 3/27/97



Debate Sparked by FCC's Table 3



Written by Joe Fedele



When the FCC adopted the long-awaited standard for Digital Television using the Advanced 

Television Systems Committee (ATSC) proposal, the move was hailed by many as a milestone in 

television history, yet there are some who view the standard as incomplete and wanting for 

closure.



Some will argue that the battle over the standard was actually won by the computer industry. In 

Novemer of last year, just prior to the adoption of the standard, the FCC found itself fielding 

strong objections from representatives of both the computer and film industries, each with its own 

agenda and both equally unwilling to back down from their demands.



The primary focus of both groups was a section of the ATSC proposal called Table 3, that 

specified technical requirements for aspect ratios, horizontal and vertical resolution and frame 

rates. 



The computer industry vehemently opposed the adoption of any standard that specified the use 

of interlaced scanning and has been attempting to expunge any mention of it for years. The 

National  Telecommunications and Information Administration (NTIA) stressed the need for a 

single mandatory DTV standard in comments to the FCC, but "recommends limiting a standard to 

only those elements necessary to provide certainty, encourage adoption, ensure the opportunity 

for technological developments, and promote evolution to an all-progressive scan system."

        

Interlaced scanning was instituted in the early days of TV development as a means of providing 

525 lines of video into a narrow 6 Mhz channel.  Had this early form of "video compression" not 

been adopted, broadcasters would have had to either compromise on line resolution or expand 

to wider bandwidths. The result may have been devastating to this newly developing medium.

        

On the other hand, the computer industry never faced the problems associated with terrestrial 

transmission, hence, progressive scanning was their format of choice.  Computer proponents 

view interlaced scanning as an impediment to their ability to merge television and computers, 

and have spent considerable resources to derail the broadcasters' efforts to include Table 3 into 

the standard.

        

The exclusion of Table 3 is viewed by some as a compromise because neither progressive nor 

interlaced scanning is specifically called for in the final standards.  But others view it as a loss for 

the TV industry as it fights to maintain control of its own fate. Moreover, broadcasters face the 

prospect of having the last 50 years of archived footage literally ripped apart, broadcast 

proponents say, "as interlaced source material will continue to be widely used for many years 

and progressive scan receivers, such as those advocated by computer interests, will have to 

include a de-interlacer even if only to display NTSC transmissions during the simulcast period," 

the Grand Alliance propoasal states.

        

Computer interests also object to the use of non-square pixels and maximum frame or "refresh" 

rate of 60 Hz.  Computer proponents claim that these features "hinder the compatibility of the 

system with computer applications, drive up the cost of receiving equipment, and delay the 

convergence of computer and television technologies."

        

The "Grand Alliance" countered that if the frame rate is increased to 72 Hz, the maximum bit rate 

of approximately 19 Mbps would be exceeded, causing trade-offs in picture quality. Table 3 

proponents point out that PC/TV products using interlaced NTSC are already on the market and 

say that claims of incompatibility with computers are without merit. 

        

While cinematographic groups also opposed the inclusion of interlaced scanning, due to the 

"perceived deficiencies" in image reproduction, the main thrust of their argument with the 

standard relates to the aspect ratio.

        

The film industry zeroed in on standards that limited screen dimensions to 4x3 and 16x9.  This 

was deemed to be completely unacceptable to an industry fighting to maintain its product in its 

original form. Gary Demos at DemoGraFX (see Q&A, 10/25/96 TVT) urged that "the Standard 

require transmission of films in their original aspect ratio and colorimetry and prohibit cropping."  

This is an obvious reaction from an industry that has seen its product cropped over the last half 

century to fit the 4x3 aspect ratio of NTSC.

        

Film proponents maintain the inclusion of "only two aspect ratios (4:3 and 16:9) will lead to 'pan 

and scan' of wide screen films, cropping significant portions of the original image and damaging 

the film makers' artistic vision."

        

The fight over the DTV standard wasn't limited to only video issues.  Dolby Laboratories found 

itself defending the AC-3 audio standard against a competing system presented by Digital 

Theater Systems (DTS).  DTS is insistent that their system is superior to the Dolby system. They 

suggested that "the standard we adopt should exclude audio formats completely."  But the 

attempt by DTS remained unsuccessful.