Re: 405 to 625
Optical conversion from 405 to 625 lines might present more problems than those of simply recording a 625/50 picture from a 625/50 monitor.
At least that is the impression that one gets from the attached Wireless World 1953 June article, which describes what was probably the first professional 405-to-625 conversion apparatus, developed by Philips. For example, spot-wobble on the 405-line monitor would seem to be a requirement.
I wonder whether any broadcasting organizations ever did 405-to-625 conversions electronically? By the time that electronic conversion became a reality, the daily requirement was more the other way around, namely 625-to-405. (Although I imagine that 625-to-819 was required in France.) If not, then maybe not much work has been done anywhere on the 405-to-625 electronic conversion case.
Regarding digital storage without initial standards conversion, what happens if a 405 baseband video signal is fed into a PAL 625 DVD recorder. Something I have discovered is that when an NTSC 525 video baseband signal is fed into a single-region PAL 625 DVD recorder, it can be recorded, and then plays back as a vertically shortened picture, occupying about the top 80% of the screen, with below it a black band populated by white horizontal bars. It looks though as if all of the picture information has been retained. Still, then converting that back to the correct standard from the HDMI output might be a more complicated affair than initial conversion. So maybe a 405-line input would be treated somewhat similarly.
Cheers,
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