Matching HD 60i with 3k 60fps?

[michael zaletel]

Footage captured at 60 interlaced fields per second would have more motion information (albeit interlaced) than 4K footage captured at 30 fps. In order to match the 60i stuff, is it necessary to shoot 3K at 60 fps and then convert that footage to 60i. What is the best way to convert 60p to 60i?

The reason I'm asking this question is that I read in another thread that perhaps the reason some networks haven't yet added the RED as an acceptable acquisition source for broadcast was because if they are broadcasting 1080i, the motion on 30p or 24p converted to 60i would not be as smooth. I was thinking then why not just capture 3K at 60p and convert that to 60i and then export as ProRes422 60i. There's no way a network would know the footage was captured on a RED at that point assuming all colors and levels are legal and etc. right?

Please advise,

-michael zaletel

 

[michael zaletel]

Anyone?

-michael

 

[David Mullen ASC]

That would work fine, 3K RAW 60P to 1080/60i -- you could shoot with a 360 degree shutter for that 1/60th look that most 60i video has.

Just don't know the exact steps you'd take to convert 60P to 60i. I mean, you could transcode to 1080/60P and then convert to 60i I guess.

 

[Terry VerHaar]

Footage captured at 60 interlaced fields per second would have more motion information (albeit interlaced) than 4K footage captured at 30 fps. In order to match the 60i stuff, is it necessary to shoot 3K at 60 fps and then convert that footage to 60i. What is the best way to convert 60p to 60i?

The reason I'm asking this question is that I read in another thread that perhaps the reason some networks haven't yet added the RED as an acceptable acquisition source for broadcast was because if they are broadcasting 1080i, the motion on 30p or 24p converted to 60i would not be as smooth. I was thinking then why not just capture 3K at 60p and convert that to 60i and then export as ProRes422 60i. There's no way a network would know the footage was captured on a RED at that point assuming all colors and levels are legal and etc. right?

Please advise,

-michael zaletel

Wouldn't 60P normally be running at 2x speed on playback, i.e. it is by definition overcranked? So, you could slow it down by half and interlace it and it would be 60 fields per second, interlaced?

 

[Graeme Nattress]

You'd want to turn each frame to a field, doing some row pair summation on the frames to reduce interlace interline twitter. Presumably there's some box that does this for 720p60 to 1080i60. It's not a hard process.

Graeme

 

[David Mullen ASC]

Wouldn't 60P normally be running at 2x speed on playback, i.e. it is by definition overcranked? So, you could slow it down by half and interlace it and it would be 60 fields per second, interlaced?

Not necessarily -- 60P is only slow-motion if played back at a lower frame rate like 24 fps, 30 fps, etc.

But people shoot 60P for normal motion for 720/60P broadcast, for example.

 

[michael zaletel]

You'd want to turn each frame to a field, doing some row pair summation on the frames to reduce interlace interline twitter. Presumably there's some box that does this for 720p60 to 1080i60. It's not a hard process.
Graeme

Thanks for responding Graeme. Can you explain what you mean by "to reduce interlace interline twitter"?

Also, why would 360 degree shutter produce best results? Just trying to understand.

Thanks in advance,

-michael zaletel

 

[David Mullen ASC]

Also, why would 360 degree shutter produce best results? Just trying to understand.

Not the "best" results, I think a 180 degree shutter would still be better... it's just that most 60i footage is shot without the shutter on, at 1/60th of a second, so that's part of the standard 60i look. But you can shoot at 1/120th if you wanted crisper motion, less blur. And even 60i shooters use other shutter speeds, for the same reasons. I'm just saying that the default look is 1/60th shutter time. Besides, shooting everything at 60 fps requires more light if you use a 180 degree shutter.

 

[Terry VerHaar]

Not necessarily -- 60P is only slow-motion if played back at a lower frame rate like 24 fps, 30 fps, etc.

But people shoot 60P for normal motion for 720/60P broadcast, for example.

Thanks for the info, David. I was/am unaware of any device that plays back at 60 fps, especially broadcast. You learn something new every day! (although, I admit, I am still a little confused about it.)

EDIT: Does this mean I will be able to shoot at 60 fps (or 120?) on my Scarlet and there will be somewhere to deliver it at that speed?? Can I author a DVD with 60 fps "native" playback? I am still confused as to even what broadcast facility would accept 60P material for 60P broadcast. Having lived in an analog broadcast world I am stuck thinking in 29.97.