[Fwd: 16:9 Aspect Ratio]

[Brian Vita]

> If the TV that displays the four-way videoconference were 
> equipped with, say, 5.1 surround sound (I'm not positive I 
> understand what that technogibberish means--but I think I 
> have an idea),

5.1 Surround sound is defined as follows:
Left (viewer's left side of the screen)
Center 
Right
Surround Left
Surround Right
Subwoofer - this is the ".1" channel as its limited bandwith (typically
125hz to the lower limit of the system)

7.1 Surround Sound adds:
Left Back Surround
Right Back Surround

In the cinema world 5.1 stereo (Dolby, DTS or SDDS) is discrete in that each
channel is recorded on the medium separately.  7.1 is a kluge where they
matrix the L/R Right surrounds to produce the back center channel.  This
technology actually leaves an extra, unused channel which is typically
dubbed VOG (Voice of God).  It has been speculated that some enterprising
producer will ask for ceiling mounted surrounds and use the VOG channel for
that.

As a sidebar, while the above formats are essentially discrete (except for
the 7.1 witchcraft), the original Dolby stereo in movie theatres which later
became MTS stereo on your TV and "pro-logic" on your home theatre receiver
is actually stolen from the old Sansui patent for quadriphonic stereo.  It
is a matrixed format where:

L=L
R=R
When L=R then you get center
L-R is surround (there is only a mono surround in this format)
The subwoofer channel is produced by a bandpass filter on the L/C/R
channels.  That is to say, its not recorded discretely as it is in the 5.1
and 7.1 formats.

Dolby or Dolby A - Dolby A type NR (analog)
Dolby SR - Dolby Spectral Recording NR (analog)
Dolby SR-D - Dolby Digital
Dolby SR-Dex (Dolby Sex) - Dolby Digital with the bastardized 7.1 described
above
With all of the Dolby formats the sound is on the film

DTS - Digital Theatre Systems digital stereo (sound comes on a synced disk)

SDDS - Sony Dynamic Digital Stere (or still don't do sh..) Obsolete format -
Sony stopped making processors 4 years ago.  Flakey as hell.

Lest we forget, my favorite:

Panavision Blue - an industry inside joke where someone took a bad 16mm B/W
adult film and blew it up to a 70mm release print.  They took the original
mono "grunt" track and placed it on all 6 channels.

Any questions?

We now return to our regularly scheduled discussion.

Brian Vita, President
Cinema Service & Supply, Inc.
77 Walnut St - Ste 4
Peabody, MA  01960-5691
 
Office:  (978)538-7575
Fax:     (978)538-7550

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