[opendtv] Re: More NTSC B&W to NTSC Color

  • From: Cliff Benham <flyback1@xxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Wed, 06 Feb 2013 23:45:53 -0500

The supposed need for 1000/1001 occurred when RCA feared the chosen color subcarrier signal of 3583125 Hz would cause visible moire in the pictures on their B&W intercarrier-IF TV sets.


The change to 3579545 made the moire less visible, but it was still there. What RCA didn't forsee was the damage 3579545 with its accompanying 29.97 vertical rate would cause with videotape editing
and the greatest horror of them all drop frame time code.

In hindsight, they should have stayed with 3583125 thus making the TV world of the 1960s and 70s much
easier for the engineers. Can you say cycle hop?

As long as original NTSC videotapes survive and are still being digitized to all the new standards as they evolve, there will be 29.97 Hz vertical sync complete with hum bars moving up through the pictures if you have an old color monitor.

No matter what the new standard is, it will have to support 1000/1001 if any old NTSC tapes are to be digitized to it.

Cliff


On 2/6/2013 11:28 PM, TLM wrote:
So if a new standard were to be developed today for, say, high frame rate
video (48, 60, 72, 120), or whatever - should it support 1000/1001 or just
go integer and just cut the cord?

-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] On
Behalf Of Cliff Benham
Sent: Wednesday, February 06, 2013 8:03 PM
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: More NTSC B&W to NTSC Color

The FCC rules for b&W broadcasting about shutting off the color burst
remained in place until the late 1970s or early 1980s when they were changed
because newer broadcast equipment could not deal with a video signal that
didn't include color burst. [Newer equipment was synchronized with a single
'black burst' signal instead of the five H. drive, V. drive, sync, blanking
and subcarrier.]

I'm sure the networks as well as all the local stations continued to
broadcast at 30.00 Hz for B&W, switching to 29.97 for color broadcasts
during the B&W to color transition period which lasted well into the 1970s.
I doubt there was any complete switch countrywide 'all at once'
switch to 29.97 until well after the to the B&W rule was changed.

Cliff Benham


On 2/6/2013 6:13 AM, Kirk Bayne wrote:
I still don't understand how the transition from 30.00fps NTSC B&W to
29.97fps NTSC Color was accomplished.

Example: CBS broadcast some programs in Color from late 1953 till
(full prime time color) 1966, did CBS switch from 30.00 to 29.97 for
the Color broadcasts, then back to 30.00 for the B&W programs, or did
CBS use
29.97 for all Network broadcasts (B&W and Color)?

Kirk Bayne




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