On 2014-01-18 16:14, Peter Vince wrote:
Stephen Scott has just mentioned his involvement in the TV industry in
the USA, with its problematical 29.97 Hz frame-rate. I also work in
the TV industry, but in the UK where we are lucky to have a nice
integer 25 Hz rate. Although historically we still had a problem with
leap seconds, as the 625 PAL system had a 4-frame ("8-field") sequence
(due to the exact colour subcarrier frequency being offset from a
multiple of line frequency to avoid static patterning on monochrome
displays), and so there were three and one-eighth of these 4-frame
sequences per second. When editing, this frame-sequence had to be
maintained, else there would be a small sideways jump when the replay
machine kept the signal synchronous with the colour subcarrier phase.
Anyway... those problems have largely gone away now that we have
stopped broadcasting the analogue PAL signal.
Is there any attempt to maintain the PAL 8-field sequence when aligning
the timestamps with clock time?
I was wondering if Stephen, or anyone else, has any information about
the possibility of 60 Hz countries changing the nasty NTSC-based 29.97
Hz frame rate to a nice integer 30 Hz rate, as I believe analogue has
also all but been switched off in the USA too (no knowledge of other
60 Hz countries.)
This would be one of my fondest dreams. However there is an enormous
reluctance to do so. With the advent of higher frame rates 60/1.001 Hz
has been adopted for UHDTV and there is a proposal for 120/1.001 Hz
being proposed.
Regards
Stephen
Regards,
Peter Vince
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