Variable frame rates? at DVinfo.net

Joe Carney · July 27th, 2005, 08:48 AM

Did I misread the brochure, or did it state the hvx200 will have variable frame rate similar to the Varicam (3 to 24, 60p down to 24...)?

Chris Hurd · July 27th, 2005, 09:11 AM

Hi Joe,

You didn't misread it, the HVX200 will have variable frame rates. What exactly those are going to be has not yet been locked down at this time, but Jan C. (the product manager) told me she was lobbying for 4, 23, 24, 25, 48 and 60 fps.

Charles Papert · July 27th, 2005, 09:42 AM

23...? what's that all about?

Chris Hurd · July 27th, 2005, 10:04 AM

Can't exactly remember, I'm kinda distracted at the moment, but that's what I had in the notes I took during Jan's seminar at DV Expo East last week.

Kevin Dooley · July 27th, 2005, 11:48 AM

I'm hoping there's one or two between 4 and 24 and that you can smoothly ramp from 4 up to 60... of course, nevering having used a Varicam, I have no idea if you can do that with the Varicam... But that's what I'd like to see...

Barry Green · July 27th, 2005, 12:08 PM

There will definitely be variable frame rates, although exactly which frame rates will be included is a detail that hasn't been announced. We're pretty sure it's not going to be every frame rate, as Jan already said on another forum that ramping is a feature that won't really be possible since it won't have *every* frame rate between 4 and 60.

23 and 22 would be quite useful for Hong Kong kung-fu style action moves, where you want the action to be just a little faster than normal, etc...

Gary McClurg · July 28th, 2005, 08:49 AM

Barry,

I can't remember the company, but at HDEXPO last year a guy had a remote that he plugged into the Varicam and he was able to do some ramping, etc., if I remember right.

I had the guys card (the company who was marketing this) but in my move who knows which box its in.

But do you think this could be possible with the HVX?

Thanks,
Gary

Robert Mann Z. · July 28th, 2005, 08:58 AM

varicam basically has a dial that has no pre set frame rates turn the dial up it goes higher turn it down it goes lower, if what you guys are saying is true i would say that statement is misleading, it should say the hvx has multiple frame rates, pre-set rates are by no means variable...

Wesley Wong · August 23rd, 2005, 03:27 AM

what I want to know is how the HVX achieves this.

The Varicam shoots on variable rates and then goes to a 'processor box' to convert all that info back into another DVCpro HD tape, am I right ?

Since the HVX does not use a tape transport for HD shooting, how is the variable frame rate info going to be processed , straight into a DVCpro HD enalbe NLE on p2 cards ??

Very very curious.

Barry Green · August 23rd, 2005, 05:39 AM

The HVX will record exactly the frames necessary onto a file on the P2 card. So if you choose 24fps, it will make a file that has 24 frames per second in it. If you choose 60fps, the same file will have 60 frames in it (and, obviously, it will take up 2.5 times as much space on the card as the same file would have if it'd been shot at 24fps).

If you wanted to shoot at 4fps, you could get two hours of recording on an 8gb card. At 60fps, you get 8 minutes.

But in all cases with 720p, there's no "pulldown", no "duplicate frames" or anything like that -- it stores exactly the frames it needs, and nothing else.

Scott Anderson · August 23rd, 2005, 09:19 AM

At NAB this year, Jan C. gave an invitation-only Q&A session after hours in the Panasonic booth. As she kept rattling off the features, it became more and more apparent that this camera was a handycam version of a Varicam, plus some. The audience kept ferreting out every small difference between the two cameras. Jan was a great sport, and seemed to be answering each question as honestly as she could: "Yes, No, or We don't know-yet". She confirmed multiple frame rates at that time, but when pressed on smoothly-variable frame rates ala the Varicam, she seemed highly skeptical. Here's the quote: "Let's call that a $60,000 feature for the Varicam".

I think it's a lock we'll get 23.97, 24 and 60, as well as a few ultra-slo speeds in the 1-12fps range. I really wonder what the deal is with 48? is it just a simple, round number to hit for 50% slo-mo, easy to implement in the electronics, or is there more to it? The newly released digital cinema specifications include 4Kp 24, 2Kp 24 AND 2Kp 48.

Could 720p 48 be an attempt to address filmmakers? I wonder which would make for a better conversion: 720p 48 to 2K, or 1080p 24 to 4K?

Wesley Wong · August 23rd, 2005, 10:30 AM

Hmmm... ok. But how does a typical NLE handle all that information ? I mean its is different frames rates all , so how will the NLE interpret it ? wouldn't it need settings of different frame rates pre-installed to make it work ? I really can't grasp the concept for the NLE. It's not like under and over cranking film while it runs at 24fs to show 'slow-mo' and 'fast-mo' since the mechianism stays the same.

Sorry if this sounds stupid.

Quote:

Originally Posted by Barry Green

The HVX will record exactly the frames necessary onto a file on the P2 card. So if you choose 24fps, it will make a file that has 24 frames per second in it. If you choose 60fps, the same file will have 60 frames in it (and, obviously, it will take up 2.5 times as much space on the card as the same file would have if it'd been shot at 24fps).

If you wanted to shoot at 4fps, you could get two hours of recording on an 8gb card. At 60fps, you get 8 minutes.

But in all cases with 720p, there's no "pulldown", no "duplicate frames" or anything like that -- it stores exactly the frames it needs, and nothing else.

Steven White · August 23rd, 2005, 12:17 PM

Presumably you'll just be able to adjust the frame rate in the the interpretation rules for the file. It's all just simple software patching to do it properly. Pitch-shifting the audio may be the larger challenge.

-Steve

Scott Anderson · August 23rd, 2005, 12:28 PM

Wesley, it's just like under-or-overcranking film. If you're shooting at these alternate frame rates, and them place them in a 24FPS timeline, you'll get an undercranked or overcranked shot. The DVCProHD Codec has a well-established workflow for this. The P2 format will also have additional metadata available that may include such things as framerate, f-stop, lens settings in addition to a date and time stamp, etc.

Basically any NLE that is capable of supporting DVCProHD and P2 will import the files natively, and be able to use the metadata contained in the MXF file on the P2 card.

Wesley Wong · August 23rd, 2005, 09:53 PM

hmmm...
ok, I think I'm beginning to understand now.

another question :
So why do we need to pitch-shift the audio, when most of the time we don't want audio for overcrank (slow-mo) and undercrank (fast-mo) sequences ?

July 27th, 2005, 09:11 AM	#2
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,368 Images: 513	Hi Joe, You didn't misread it, the HVX200 will have variable frame rates. What exactly those are going to be has not yet been locked down at this time, but Jan C. (the product manager) told me she was lobbying for 4, 23, 24, 25, 48 and 60 fps. __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

July 27th, 2005, 09:42 AM	#3
Charles Papert Wrangler Join Date: Jan 2002 Location: Los Angeles, CA Posts: 6,810	23...? what's that all about? __________________ Charles Papert www.charlespapert.com

July 27th, 2005, 10:04 AM	#4
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,368 Images: 513	Can't exactly remember, I'm kinda distracted at the moment, but that's what I had in the notes I took during Jan's seminar at DV Expo East last week. __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

July 27th, 2005, 11:48 AM	#5
Kevin Dooley Major Player Join Date: Dec 2003 Location: Fort Worth, TX Posts: 414	I'm hoping there's one or two between 4 and 24 and that you can smoothly ramp from 4 up to 60... of course, nevering having used a Varicam, I have no idea if you can do that with the Varicam... But that's what I'd like to see... __________________ Kevin Dooley Media Director, Pantego Bible Church

August 23rd, 2005, 03:27 AM	#9
Wesley Wong Regular Crew Join Date: Mar 2004 Location: Singapore Posts: 143	what I want to know is how the HVX achieves this. The Varicam shoots on variable rates and then goes to a 'processor box' to convert all that info back into another DVCpro HD tape, am I right ? Since the HVX does not use a tape transport for HD shooting, how is the variable frame rate info going to be processed , straight into a DVCpro HD enalbe NLE on p2 cards ?? Very very curious. __________________ Do more, learn more

July 27th, 2005, 08:48 AM	#1
Joe Carney Inner Circle Join Date: Jul 2002 Location: Centreville Va Posts: 1,828	Did I misread the brochure, or did it state the hvx200 will have variable frame rate similar to the Varicam (3 to 24, 60p down to 24...)?

July 27th, 2005, 12:08 PM	#6
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	There will definitely be variable frame rates, although exactly which frame rates will be included is a detail that hasn't been announced. We're pretty sure it's not going to be every frame rate, as Jan already said on another forum that ramping is a feature that won't really be possible since it won't have every frame rate between 4 and 60. 23 and 22 would be quite useful for Hong Kong kung-fu style action moves, where you want the action to be just a little faster than normal, etc...

July 28th, 2005, 08:49 AM	#7
Gary McClurg Major Player Join Date: Jul 2004 Location: Springfield, MO, USA Posts: 389	Barry, I can't remember the company, but at HDEXPO last year a guy had a remote that he plugged into the Varicam and he was able to do some ramping, etc., if I remember right. I had the guys card (the company who was marketing this) but in my move who knows which box its in. But do you think this could be possible with the HVX? Thanks, Gary

July 28th, 2005, 08:58 AM	#8
Robert Mann Z. Skyonic New York Join Date: Nov 2001 Location: NYC Posts: 614	varicam basically has a dial that has no pre set frame rates turn the dial up it goes higher turn it down it goes lower, if what you guys are saying is true i would say that statement is misleading, it should say the hvx has multiple frame rates, pre-set rates are by no means variable...

August 23rd, 2005, 05:39 AM	#10
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	The HVX will record exactly the frames necessary onto a file on the P2 card. So if you choose 24fps, it will make a file that has 24 frames per second in it. If you choose 60fps, the same file will have 60 frames in it (and, obviously, it will take up 2.5 times as much space on the card as the same file would have if it'd been shot at 24fps). If you wanted to shoot at 4fps, you could get two hours of recording on an 8gb card. At 60fps, you get 8 minutes. But in all cases with 720p, there's no "pulldown", no "duplicate frames" or anything like that -- it stores exactly the frames it needs, and nothing else.

August 23rd, 2005, 09:19 AM	#11
Scott Anderson Major Player Join Date: May 2003 Location: Phoenix, AZ Posts: 327	At NAB this year, Jan C. gave an invitation-only Q&A session after hours in the Panasonic booth. As she kept rattling off the features, it became more and more apparent that this camera was a handycam version of a Varicam, plus some. The audience kept ferreting out every small difference between the two cameras. Jan was a great sport, and seemed to be answering each question as honestly as she could: "Yes, No, or We don't know-yet". She confirmed multiple frame rates at that time, but when pressed on smoothly-variable frame rates ala the Varicam, she seemed highly skeptical. Here's the quote: "Let's call that a $60,000 feature for the Varicam". I think it's a lock we'll get 23.97, 24 and 60, as well as a few ultra-slo speeds in the 1-12fps range. I really wonder what the deal is with 48? is it just a simple, round number to hit for 50% slo-mo, easy to implement in the electronics, or is there more to it? The newly released digital cinema specifications include 4Kp 24, 2Kp 24 AND 2Kp 48. Could 720p 48 be an attempt to address filmmakers? I wonder which would make for a better conversion: 720p 48 to 2K, or 1080p 24 to 4K?

August 23rd, 2005, 12:17 PM	#13
Steven White Major Player Join Date: Nov 2004 Location: Canada Posts: 547	Presumably you'll just be able to adjust the frame rate in the the interpretation rules for the file. It's all just simple software patching to do it properly. Pitch-shifting the audio may be the larger challenge. -Steve

August 23rd, 2005, 12:28 PM	#14
Scott Anderson Major Player Join Date: May 2003 Location: Phoenix, AZ Posts: 327	Wesley, it's just like under-or-overcranking film. If you're shooting at these alternate frame rates, and them place them in a 24FPS timeline, you'll get an undercranked or overcranked shot. The DVCProHD Codec has a well-established workflow for this. The P2 format will also have additional metadata available that may include such things as framerate, f-stop, lens settings in addition to a date and time stamp, etc. Basically any NLE that is capable of supporting DVCProHD and P2 will import the files natively, and be able to use the metadata contained in the MXF file on the P2 card.

August 23rd, 2005, 09:53 PM	#15
Wesley Wong Regular Crew Join Date: Mar 2004 Location: Singapore Posts: 143	hmmm... ok, I think I'm beginning to understand now. another question : So why do we need to pitch-shift the audio, when most of the time we don't want audio for overcrank (slow-mo) and undercrank (fast-mo) sequences ? __________________ Do more, learn more