I agree that the move away from "traditional" TV devices, video interfaces and delivery
methods in favour of non-interlaced and computer-based options is slowly making interlaced
video a legacy format. I also suspect that the speed at which interlaced formats become
deprecated will be different in almost every country.
Having said that, a vast majority of people I provide video to are still running AV equipment
which relies on standard PAL interconnects - and that means interlaced video. For such
people, providing a deinterlaced 25 fps program (25p) will result in an obvious drop in
quality compared to 25i (and is in fact a lossy operation if starting with 25i source
material). Obviously everyone's situation is different, but in this case 25i is a format
which provides the best result for everyone: those with 25i equipment get the best result they
can hope for, and those with gear capable of 50p will still get an acceptable picture due to
deinterlacers in their players/tvs (which aren't all that bad even now). Note that
distributing with 50p isn't really an option yet since few people have players capable of
dealing with this format (DVD doesn't).
While the above refers (obviously) to PAL land, similar statements apply to NTSC.
It should also be noted that in our editor's case (as in mine), the source material was almost
certainly interlaced, so his deinterlacing operation from 30i to 30p was in fact lossy.
This whole area is a minefield and looks set to remain that way for some time to come.
Ideally interlacing would just go away, but there's a huge installed base of interlaced
equipment which guarantees that this will be a long drawn out process. Until that process
completes one has to be aware of all the issues and make a call based on their particular