Frame Rate of 702 - Page 3 at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > All Things Audio

All Things Audio
Everything Audio, from acquisition to postproduction.


Reply
 
Thread Tools Search this Thread
Old February 10th, 2008, 02:13 PM   #31
Major Player
 
Join Date: Jan 2008
Location: Calgary, Alberta
Posts: 265
understood. What if the film is to be hopefully one day be picked up for film release, is 23.976 best? this way one can edit at that rate for film release and insert pulldown for video release?
Roshdi Alkadri is offline   Reply With Quote
Old February 10th, 2008, 02:24 PM   #32
Inner Circle
 
Join Date: Mar 2005
Location: Hamilton, Ontario, Canada
Posts: 5,742
Quote:
Originally Posted by Roshdi Alkadri View Post
understood. What if the film is to be hopefully one day be picked up for film release, is 23.976 best? this way one can edit at that rate for film release and insert pulldown for video release?
I think it's generally done the other way around. Edit at 29.97 and remove pulldown if it's eentually picked up and released on film. Take a look at Wolf Seeberg's site - he 'wrote the book' on timecode for 24p.


http://www.wolfvid.com/html/lit.html
__________________
Good news, Cousins! This week's chocolate ration is 15 grams!
Steve House is offline   Reply With Quote
Old February 10th, 2008, 02:54 PM   #33
Trustee
 
Join Date: Mar 2007
Location: Sherman Oaks, CA
Posts: 1,259
Quote:
Originally Posted by Steve House View Post
No, it's an excellent question. I recall seeing somewhere - I think it was Wolf Seeberg's site - just within the last couple of days that with most, if not all, HD cameras generate timecode at 29.97 non-drop even though they're shooting at a 23.976 frame rate. So while 1 second of video has actually recorded 24 frames, the timecode recorded for that same second counts it as 30 frames. In other words, a frame of video is not equal to a frame of timecode - could it get any weirder!
... but it does make "sense."

FWIU, DV/HDV cameras (I don't know about the HVX) always output 60 fields per second no matter what frame rate you record in.

So while one second of 24P has 24 unique frames, those frames are repeated at a 2:3 cadance to fit into a 60 fields per second output structure.

And 60i blends two fields together to make a single frame, so you wind up with a frame rate of 30.

It has to do with the fact that no matter what frame rate you record in, DV/HDV always output to tape at 60i. And timecode for 60i has a rate of 30fps.

P.S. I hope I haven't left anything out or misrepresented something.
Peter Moretti is offline   Reply With Quote
Old February 10th, 2008, 03:20 PM   #34
Inner Circle
 
Join Date: Mar 2005
Location: Hamilton, Ontario, Canada
Posts: 5,742
Quote:
Originally Posted by Peter Moretti View Post
... but it does make "sense."

FWIU, DV/HDV cameras (I don't know about the HVX) always output 60 fields per second no matter what frame rate you record in.

So while one second of 24P has 24 unique frames, those frames are repeated at a 2:3 cadance to fit into a 60 fields per second output structure.

And 60i blends two fields together to make a single frame, so you wind up with a frame rate of 30.

It has to do with the fact that no matter what frame rate you record in, DV/HDV always output to tape at 60i. And timecode for 60i has a rate of 30fps.

P.S. I hope I haven't left anything out or misrepresented something.
Yep, makes sense to me, thought at first glance it is counter-intuitive.
__________________
Good news, Cousins! This week's chocolate ration is 15 grams!
Steve House is offline   Reply With Quote
Old February 10th, 2008, 10:03 PM   #35
Trustee
 
Join Date: Mar 2007
Location: Sherman Oaks, CA
Posts: 1,259
Quote:
Originally Posted by Steve House View Post
I think it's generally done the other way around. Edit at 29.97 and remove pulldown if it's eentually picked up and released on film. Take a look at Wolf Seeberg's site - he 'wrote the book' on timecode for 24p.


http://www.wolfvid.com/html/lit.html
Steve, I really don't think this correct. FWIU, you don't want to edit 29.97 with a pulldown if you think you'll be removing the pulldown down the road. In essence the pulldown is a broadcast/playback format. It's not really an editing one.

You first remove the pulldown from all the source media and then edit. Edits are dependent upon frames. If you remove the pulldown after editing but before rendering you will have deleted frames that some effects may depend upon.

An alternative would be to edit with the pulldown and then replace all the source clips with ones w/o the pulldown and render to get a 24P version. But I have no idea if that would still have glitches. I think you could run into timecode problems for one. And what happens to your audio? I believe you'll have to speed it up.

Lastly, you could render and then remove the pulldown, but now the effects have distorted the repeated frames and they are no longer identical. And if the footage does not have pulldown flags, the smart inverse telecine may not work b/c the process depends upon being able to identify like frames by comparing frames with adjacent frames.

But Roshdi, I am learning this whole process myself. I seriously recommend at some point talking to a post production house and running your workflow past them. You have done all this work and are spending money on timecode, etc, you have to be sure you get a real answer from a bona fide expert, which I am not.

Last edited by Peter Moretti; February 11th, 2008 at 02:07 AM.
Peter Moretti is offline   Reply With Quote
Old February 11th, 2008, 04:28 AM   #36
Inner Circle
 
Join Date: Mar 2005
Location: Hamilton, Ontario, Canada
Posts: 5,742
Quote:
Originally Posted by Peter Moretti View Post
Steve, I really don't think this correct. FWIU, you don't want to edit 29.97 with a pulldown if you think you'll be removing the pulldown down the road. In essence the pulldown is a broadcast/playback format. It's not really an editing one.

....
True, but how will you deliver your final film? If it's going to DVD, it's going to be NTSC with pulldown. If going to broadcast, it's NTSC with pulldown. The only time you can actually deliver at a true 24FPS is if your final product is either going to be converted to film for theatrical release or will be distributed via the web. And remember that the camera itself is recording at 60i/30FPS even though it's exposing 24FPS, adding the pulldown as it lays the frames down to tape so the pulldown is already going to be there when you ingest into the editor.
__________________
Good news, Cousins! This week's chocolate ration is 15 grams!
Steve House is offline   Reply With Quote
Old February 11th, 2008, 07:05 PM   #37
Trustee
 
Join Date: Mar 2007
Location: Sherman Oaks, CA
Posts: 1,259
Steve, I believe he hopes for a theatrical release--don't we all, LOL :). But seriously, if that's his expectation, then he should remove the pulldown before editing. You can always add it back once you have a final cut.

BTW, I went to Location Sound in North Hollywod today and picked up Wolf Seeberg's book "24P for Sound and Video Assist." I hate say this, but it was one of my worst of uses of $30 that I can recall.

It's very specific to actual cameras and equipment from five years ago. There are voluminous filler pages Xerox'ed from user manuals, and long lists of equipment--much of which is no longer made.

There is a lot of blowing about getting it right, which makes a lot of sense. But it's very short on explaining how things work in way that makes the info useful today.

JMHO and 3,000 cents.

P.S. Thanks for all your help. BTW, much of it has been more valuable than I can say ;) :).

Last edited by Peter Moretti; February 12th, 2008 at 01:37 AM.
Peter Moretti is offline   Reply With Quote
Old February 11th, 2008, 09:30 PM   #38
Major Player
 
Join Date: Jan 2008
Location: Calgary, Alberta
Posts: 265
Quote:
Originally Posted by Peter Moretti View Post
Steve, I believe he hopes for a theatrical release--don't we all, LOL :). But seriously, if that's his expectation, then he should remove the pulldown before editing. You can always add it back once you have a final cut.

BTW, I went to Location Sound in North Hollywod today and picked up Wolf Seeberg's book "24P for Sound and Video Assist." I hate say this, but it was one of my worst of uses of $30 that I can recall.

It's very specific to actual cameras and equipment from five years ago. There are voluminous filler pages Xerox'ed from user manuals, and long lists of equipment--much of which is no longer made.

There is a lot of blowing about getting it right, which makes a lot of sense. But it's very short on explaining how things work in way that makes in the info useful today.

JMHO and 3,000 cents.

P.S. Thanks for all your help. BTW, much of it has been more valuable than I can say ;) :).
can you believe that, i'm hoping for a theatrical release by being funded $33,000 next year for a film out with a whole bunch of professional actors looking for a demo reel and then they would be fed by like 5 of the sponsors for the film. Then another 7 businesses will pay for all the EPS.
I LOL'd really loud first time i heard it. what a loser i must have been :)
Roshdi Alkadri is offline   Reply With Quote
Old February 12th, 2008, 05:42 AM   #39
Inner Circle
 
Join Date: Mar 2005
Location: Hamilton, Ontario, Canada
Posts: 5,742
Quote:
Originally Posted by Peter Moretti View Post
...
BTW, I went to Location Sound in North Hollywod today and picked up Wolf Seeberg's book "24P for Sound and Video Assist." I hate say this, but it was one of my worst of uses of $30 that I can recall.

It's very specific to actual cameras and equipment from five years ago. There are voluminous filler pages Xerox'ed from user manuals, and long lists of equipment--much of which is no longer made.

...).
I'll agree that Wolf's book is almost unreadable. But with some effort, there is some good material and advice in there, particularly his workflow summaries. One of the reasons I posted the link to his site is he has put most of the more useful parts online so you don't have to spend the money for all the rest.
__________________
Good news, Cousins! This week's chocolate ration is 15 grams!
Steve House is offline   Reply With Quote
Old February 12th, 2008, 11:14 PM   #40
Trustee
 
Join Date: Mar 2007
Location: Sherman Oaks, CA
Posts: 1,259
Roshdi,

Can't the HVX shoot 24P w/o a pulldown? That would make your life a lot easier.
Peter Moretti is offline   Reply With Quote
Old February 12th, 2008, 11:29 PM   #41
Major Player
 
Join Date: Jan 2008
Location: Calgary, Alberta
Posts: 265
Quote:
Originally Posted by Peter Moretti View Post
Roshdi,

Can't the HVX shoot 24P w/o a pulldown? That would make your life a lot easier.
Yes the HVX can shoot 24PN which are pure 24 frames, which i suppose would be good if its strictly a filmout. Other users stated that 24pn rendered to 29.97 is stroby, i'll have to test that theory. I'll also be getting my 702T this friday, and will test the whole workflow.

thanks
Roshdi Alkadri is offline   Reply With Quote
Old February 13th, 2008, 12:30 AM   #42
Trustee
 
Join Date: Mar 2007
Location: Sherman Oaks, CA
Posts: 1,259
I have to say I really think you are being given some bad advice. 24P can always be converted to 24P with pulldown (technically called 24PSF, I believe) after you finished the final cut. Any stutter or strobing caused by the pulldown will be no worse (and probably better) than if you record with the pulldown to begin with and then edit.

By choosing to edit with the pulldown you are choosing to edit in a time line that does not match the frame rate, with timecode that does not match the frame rate and where every clip has two identical frames repeated, then three identical frames repeated. Where do you actually place a cut? When you want to trim, how many "frames" do you add or subtract? In 24P you can add 10 frames and you know that's what you get. With the pulldown, how many unique frames is ten frames? Well it depends on where you are in the 2:3 cadence. It's a mess.

IMHO, stay away from recording with the pulldown unless you really have to use it. BTW, you can easily make a DVD with 24P no pulldown.
Peter Moretti is offline   Reply With Quote
Old February 13th, 2008, 08:57 AM   #43
Major Player
 
Join Date: Jan 2008
Location: Calgary, Alberta
Posts: 265
Quote:
Originally Posted by Peter Moretti View Post
I have to say I really think you are being given some bad advice. 24P can always be converted to 24P with pulldown (technically called 24PSF, I believe) after you finished the final cut. Any stutter or strobing caused by the pulldown will be no worse (and probably better) than if you record with the pulldown to begin with and then edit.

By choosing to edit with the pulldown you are choosing to edit in a time line that does not match the frame rate, with timecode that does not match the frame rate and where every clip has two identical frames repeated, then three identical frames repeated. Where do you actually place a cut? When you want to trim, how many "frames" do you add or subtract? In 24P you can add 10 frames and you know that's what you get. With the pulldown, how many unique frames is ten frames? Well it depends on where you are in the 2:3 cadence. It's a mess.

IMHO, stay away from recording with the pulldown unless you really have to use it. BTW, you can easily make a DVD with 24P no pulldown.
alright, but how well will the 24p look when submitted at 29.97 after?
Roshdi Alkadri is offline   Reply With Quote
Old February 13th, 2008, 01:52 PM   #44
Trustee
 
Join Date: Mar 2007
Location: Sherman Oaks, CA
Posts: 1,259
The same way it would look if you recorded at 24P with the pulldown, probably better because you won't run into the frame related problems caused by editing 24P with a pulldown inside 60i (aka 29.97).

Illustration

Clip One: .5 seconds of 24P frames: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

Clip Two: Those same .5 seconds of 24P frames recorded inside 60i, aka 29.97: 1, 1, 2, 2, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 6, 7, 7, 8, 8, 8, 9, 9, 10, 10, 10, 11, 11, 12, 12, 12

Both clips are .5 seconds long. The frames are identical; frames 1 or 2 or 3 are the same in both timelines. But in the 60i version, frames are repeated 2 times then 3 times and so on to make it play like 24P at a 60i rate, aka 29.97. It's not prefect but it's works pretty good.

So when you add the pulldown after editing, all you are doing is repeating the frames like above. You aren't changing the frames, just replicating them.

So if you recorded Clip One and then added the pulldown in post before editing, it would look identical to Clip Two (unless there are some wierd codec issues with the HVX that I'm not aware of).

I would run my advice past experienced HVX users, etc. but I really think I'm shooting you straight.

Last edited by Peter Moretti; February 13th, 2008 at 02:50 PM.
Peter Moretti is offline   Reply With Quote
Old February 13th, 2008, 06:53 PM   #45
Major Player
 
Join Date: Jan 2008
Location: Calgary, Alberta
Posts: 265
Quote:
Originally Posted by Peter Moretti View Post
The same way it would look if you recorded at 24P with the pulldown, probably better because you won't run into the frame related problems caused by editing 24P with a pulldown inside 60i (aka 29.97).

Illustration

Clip One: .5 seconds of 24P frames: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

Clip Two: Those same .5 seconds of 24P frames recorded inside 60i, aka 29.97: 1, 1, 2, 2, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 6, 7, 7, 8, 8, 8, 9, 9, 10, 10, 10, 11, 11, 12, 12, 12

Both clips are .5 seconds long. The frames are identical; frames 1 or 2 or 3 are the same in both timelines. But in the 60i version, frames are repeated 2 times then 3 times and so on to make it play like 24P at a 60i rate, aka 29.97. It's not prefect but it's works pretty good.

So when you add the pulldown after editing, all you are doing is repeating the frames like above. You aren't changing the frames, just replicating them.

So if you recorded Clip One and then added the pulldown in post before editing, it would look identical to Clip Two (unless there are some wierd codec issues with the HVX that I'm not aware of).

I would run my advice past experienced HVX users, etc. but I really think I'm shooting you straight.
i understand peter thank you. So now i'm wondering if i'm shooting 1080p to be intermixed with 720p, what rate is best to record sound at.
24PN is only offered in 720p not 1080. That was my confusion to begin with and thats why i wanted to shoot with pulldown at 24pa in both 720 and 1080, easier to mix together.

I received my 702T today, the dealers gave me overnight shipping at a standard shipping rate. Im gonna get testing tonight, when i finish editing a video for a client
Roshdi Alkadri is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > All Things Audio

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 05:23 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network