[LEAPSECS] TV frame-rate in 60Hz countries

Peter Vince petervince1952 at gmail.com
Sat Jan 18 16:14:31 EST 2014


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. 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.)

Regards,

Peter Vince
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