JVC Professional APRIL 2007 NAB-2007 The ProHD Report
Copyright 2007 JVC Professional Products Company All rights reserved Page 9 of 43
The SD (NTSC) standard aspect ratio is 4:3 (1.33:1) while the HD (ATSC) aspect
ratio is 16:9 (1.78:1), presenting a formidable challenge to broadcasters as they must
maintain delivery to viewers of 4:3 services while transitioning to HD providing 16:9
wide screen service. Screen Viewing Area comparison between SD 4:3 and HD 16:9
at equal Picture Height, indicating that 16:9 viewing area is 1.3x larger than 4:3 area.
Of course, equal picture height is not the norm as the consumer will nearly always
replace the SD TV set with a HD TV set with a much larger screen.
Fig. 1: Screen Viewing Area comparison between a 32”
SD 4:3 TV set and a 56” HD 16:9 TV set, indicating that
16:9 viewing area is nearly 3x larger than the 4:3 area.
Viewing distance is the same.
If we expand the exercise of Fig. 1, considering the most popular sizes of larger SD
direct view TV sets (from 25” to 36”) and the most popular of the new HD TV sets
(from the 37” flat LCD to the 62”+ rear projection D-ILA/DLP), we’ll find that we
can use a viewing area comparison factor of 3x for the living/family
room environment with the assumption that the viewing distance has not materially
changed. In other words, the average home audience screen viewing area
increases 3-fold when the SD set is replaced with a HD set. (The 25” 4:3 SD set
may be replaced by a 50” 16:9 HD set/monitor; the 32” SD with a 56” HD, and
so on as perhaps an average.)
An important observation is that high (broadcast) quality SD originated
programming up-converted to HD is nothing more than high quality SD when
displayed on a HDTV set, and as such is insufficient to create a real and total HD
viewing experience. (Even when using a top quality up-converter.)
4:3
100% area
16:9
270% area
56”
32”
49”
27.5”