1080i or 1080p

[Paul Marschall]

When transfering film to HD D5 why would you choose one format over the other?

[Fulgencio Martinez]

Hi,

I think 1080p is better if you are going to output in 35mm print. One of the more tipical video artifact is due to interlace wich may give a weird look to the movement.

I don´t know if there is many diference when going to video (music video, advertasing..) but you will have to do the interlace at so point. Maybe a progressive image is better for post.

For example for a chroma or a mask maybe you can have more control having a non-interlaced image.

[John Sprung]

Absolutely 1080p is better than 1080i. Interlace has just barely over half the resolution of progressive. Everything we do is posted and archived in 1080p. You can always downconvert to interlace with no loss, but de-interlacing can be trouble.

 

 

 

-- J.S.

[Mike Brennan]

Exactly what is your question?

What 1080p format do you refer? compared to which 1080i format?

 

 

Mike Brennan

[David Mullen ASC]

If you transfer 24 fps film to 24P HD-D5 (24P/1080), you are essentially storing each frame of film as a progressive-scan HD frame, so making later 60i/1080 versions from the 24P/1080 master is relatively easy, plus you can make equally good downconversions to NTSC and PAL. If you transfer 24 fps film to 60i/1080, you end up with a 3:2 pulldown in the recording which has to be removed in order to be downcoverted to PAL.

[John Sprung]

It's not just the 3-2, which isn't too difficult to undo. The big thing is that the resolution has to be filtered down to where you don't get terrible small area (line) flicker. It's easy to throw resolution away, converting from p to i. But you can't really get back what you discarded. Long long ago, Bill Schreiber at MIT did some demos of presenting full resolution images on an interlaced display. The closeups of a dollar bill would hurt your eyes.

 

 

 

-- J.S.

[Adam Frisch FSF]

I don't understand - I always though interlaced had half the resolution, but twice as many times per second, i.e. the same resolution as progressive just at a different interval. Please explain how 1080p 25fps has more resolution than 1080i 50hz? It's the same, no?

[Alvin Pingol]

Because one format is interlaced, you're only seeing half of the resolution at any given moment. Your brain fills in the rest. This causes a drop in the overall perceived resolution of the image, versus a true progressive image.

 

There was a website that I can't seem to find that talks all about this, why it happens, how it happens, answers your exact question. And of course, I've no idea where it is.

 

If I recall correctly, an interlaced image/display can only resolve 75% of the maximum, i.e. with 1080i, you wont actually see all 1080 lines of resoltion...

[Alvin Pingol]

http://www.vxm.com/Progvsinter.html

[John Sprung]

If I recall correctly, an interlaced image/display can only resolve 75% of the maximum, i.e. with 1080i, you wont actually see all 1080 lines of resoltion...

<{POST_SNAPBACK}>

Actually, it's about 60% to 65%, depending on how much line flicker or "twitter" you're willing to tolerate. Thanks for the pointer to the Bill Schreiber paper, it brings back memories of the formative years of HDTV.

 

 

 

-- J.S.

[Mike Brennan]

Actually, it's about 60% to 65%, depending on how much line flicker or "twitter" you're willing to tolerate.  Thanks for the pointer to the Bill Schreiber paper, it brings back memories of the formative years of HDTV.

-- J.S.

<{POST_SNAPBACK}>

 

Yes twitter is pretty amazing if you get to see a prototype camera where it hasn't been tweaked.

 

Does the 1998 Bill Schrieber paper adress progressive capture of 1920X1080 24/25p and subsquent viewing on an interlace monitor?

 

The comparison seems to be between 720p and 60i/1080i capture, 24p 25p capture combined with an interlace dispaly wasn't around when the article was written?

 

 

 

Mike Brennan