25P or 50i? Mix or not? 720 or 1080?

spudgun · Post by **spudgun** » Fri May 30, 2008 10:52 pm

I'm planning to make a documentary which will incorporate both surface and underwater, (scuba), HDV footage.

It is preferable to shoot underwater in interlaced mode, (50i here in Pal land),as it tends to give a smoother look as animals move through the water. but for the above water shots I would prefer 25p to create a more 'filmic' look.

My problem is, can Videostudio 11+ mix the two comfortably? Certainly, Canon seem to recommend not mixing the two on the same tape.

Should I set the outage for 720p or 1080i?

Help is most desperately needed.

Very many thanks for an excellent forum.

Post by **Ron P.** » Sat May 31, 2008 12:02 pm

I've never had the opportunity to try this, but I would think that mixing the them as Canon advised is not recommended. Progressive (720p) is the same as Frame based, still images, where the 1080i of course is interlaced video, having Upper and Lower fields.

While VS may be able to handle mixing them, the output will depend on how you have your project setup. You can't have a video file that displays both non-interlaced and frame-based, it's one or the other. So if you place your progressive scan video in an interlaced project, they will be interlaced. This may result in the loss of quality, the crispness and clarity. On the other hand, using a progressive scan (frame-based) project, interlaced video clips, will be de-interlaced.

Then you need to take into consideration is the intended audience going to be viewing your documentary on progressive scan TVs or SD TVs that use interlacing.

spudgun · Post by **spudgun** » Sat May 31, 2008 3:37 pm

Hello Ron, and thank you for your response. I will be submitting the finished project to HD DVD, probably Blu Ray. This does now create a problem for me. I understand that the BBC, in some of their Natural History documentaries, shoot underwater scenes in 50i, with above water scenes in progressive. Perhaps I shall have to re-think.

skier-hughes · Post by **skier-hughes** » Sat May 31, 2008 9:53 pm

vidoman wrote:Then you need to take into consideration is the intended audience going to be viewing your documentary on progressive scan TVs or SD TVs that use interlacing.

This is the important bit, as p will look poor on a interlaced tv set, whereas i will look poorer on a p tv set.
So, yes you can mix, but each part will look totally different on the different tv sets.
Then you also need to check what resolution your tv set displays at, most tv channels are at 720p, but some sets will show 1080p.

I'd need to check to be certain, but I'm pretty sure the BBC does not mix i and p in the same show.

spudgun · Post by **spudgun** » Sat May 31, 2008 11:15 pm

Thank you so much for your advice. Now I'm truly perturbed, because ultimately, I may be rendering DVD's for commercial sale!! Surely here in PAL land, 25p and 50i do not NEED the same de-interlacing procedures applied as the NTSC system?