19-02-2019, 10:13 AM
When the BBC investigated standards conversion in the 1970s they did experiments to determine how many lines to use in the interpolator. Summarising, 2 lines were essential, 3 gave signifcant improvement, 4 gave very slight improvement. More than 4 gave no visible benefit. So they used 4 lines on the CO6/509.
Since the BBC did those experiments the nature of source material has changed. Mostly it's about interframe effects, where modern cameras can have much shorter exposure times. This isn't relevant to a line converter but affects frame rate conversion. There's also a improvement to camera vertical definition though this is much smaller. Also there's much more electronically sourced material which may have rather sharp edges going down the screen. This suggests that a slightly softer aperture might be useful now when down converting. I doubt it makes much difference.
Since the BBC did those experiments the nature of source material has changed. Mostly it's about interframe effects, where modern cameras can have much shorter exposure times. This isn't relevant to a line converter but affects frame rate conversion. There's also a improvement to camera vertical definition though this is much smaller. Also there's much more electronically sourced material which may have rather sharp edges going down the screen. This suggests that a slightly softer aperture might be useful now when down converting. I doubt it makes much difference.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
