24fps vs. 30fps

Dennis Hingsberg · November 12th, 2003, 08:16 PM

I have to agree with Jacques anbout shooting 60fps all the time, and worrying about achieving alternate looking frame rates after the fact.

This is the same reason why even if I had a DVX100 I would not be inclined to shoot 24P with it. I'll just stick with my VX1000 & XL1s!

Anyone here really like the DVX100 or what?

Brad Horner · November 12th, 2003, 08:54 PM

Here is someone that has shot with the dvx100 and he discusses 30fps and 24 fps.

http://millimeter.com/ar/video_crossplatform_plan

Jacques Mersereau · November 12th, 2003, 10:14 PM

Yes, I LOVE the DVX100. More so than the XL1 or the
VX2000. I own both.

Yang Wen, another list member, brought his DVX100 over
to do a shoot with a local student group.

I fell in love with this ~$3K camcorder. Very very nice images and
I love 'real' progressive frame anyway. A large step up over
my own aging XL1. Impressive IMO. I'll take 30 full frames
over NTSC any day.

If I were shooting a 'movie', the DVX100 is the camera I could afford and
would buy. I thought it held it own against another recent visitor,
the Ikegami DV7 ($10K+lens).

I am praying for Canon to pony up with the XL2 soon.

Dennis Hingsberg · November 13th, 2003, 08:14 AM

<<<-- Originally posted by Brad Horner : Here is someone that has shot with the dvx100 and he discusses 30fps and 24 fps.

http://millimeter.com/ar/video_crossplatform_plan -->>>

The actual link to the trailer was posted in the DVX100 board, but here it is for those who want to see it http://www.american-yearbook.com/dow...downloads.html

Ted Springer · November 13th, 2003, 04:06 PM

That trailer does not do ANY justice to the DVX100. The trailer Quicktime is very choppy and very small. Check out my post HERE and download the Quicktime to see true DVX100 24fps.

David Ziegelheim · November 14th, 2003, 04:51 AM

<<<-- Originally posted by John Jackman :

On a related and interesting note, I just heard of some research on cat vision that seems to explain why some cats watch TV and some don't. I've had two or three cats that watch TV, most have not. Cat vision is much better than ours, and their brains process rapid motion better -- more like a sensitive camera with a fast shutter speed, less persistence of vision. Apparently the refresh rate of TV is right near the bottom range of cat vision -- so cats that process vision a little more slowly than normal actually see a picture on TV. The oither cats don't -- they just see the the flying spot, perhaps several raster lines, but not a coherent picture. Those are the cats that are completly disinterested in TV.

-->>>

Does that mean that cats will watch progressive TV images: DLP and LCOS?

John Jackman · November 17th, 2003, 09:05 PM

<<<-- Originally posted by Jacques Mersereau :
What Panasonic has choosen to do is different. The Varicam ALWAYs shoots/records at 60fps, but in the CAMERA's processor, _IF_ you choose a different frame rate in the menu, that change of frame rate is made in the camera (certain frames are repeated) *before* the signal is recorded or output. So, you can't really go back and change it later. >>>

I'm not sure exactly how you meant this statement, Jacques, but let me clarify something. The VariCam always records in 60i, but the CCD is operated at the chosen frame rate -- the cam does not "select" frames from 60fps for recording. So saying that it always "shoots" in 60fps isn't correct. It shoots in true 24p and then adds 3:2 pulldown prior to recording to tape. I can double-check this with one of the engineers at Panasonic if you wish.

The method you are talking about -- of shooting 60i and then interpreting to lower frame rates -- is precisely what software like Magic Bullet does. However, in my judgment the results are NOT optimal. 24fps already has horrid motion artifacts that must be dealt with by using careful shooting techniques. The nearly impossible math of converting 60i to 24p generally is "fudged" by regularly dropping and repeating fields. The result is an exaggerated jerkiness to motion that is significantly worse than real 24p. All the film DPs that have watched my "acid test" footage run through several of these processes agree that the results are significantly worse than footage actually shot at 24p.

This process CAN be done with very high quality using the motion interpolation techniques developed for PAL-NTSC conversion. This is really expensive, however! The S&W Alchemist starts at $150K last I checked. Similar results can be accomplished with Twixtor, but you'll be rendering for weeks.

Jacques Mersereau · November 18th, 2003, 09:10 AM

<<<-- Originally posted by John Jackman :
I'm not sure exactly how you meant this statement, Jacques, but let me clarify something. The VariCam always records in 60i, >>>

Hi John,

you mean in 60P? (Boy, I hope so. Interlace . . . yeach.)

>>>but the CCD is operated at the chosen frame rate -- the cam does not "select" frames from 60fps for recording. So saying that it always "shoots" in 60fps isn't correct. It shoots in true 24p and then adds 3:2 pulldown prior to recording to tape. I can double-check this with one of the engineers at Panasonic if you wish.>>>>

I wouldn't mind if you did. This is somewhat confusing.
Also, if you do check with them, be sure to ask about that
expensive outboard box that does conversions and how it works.

Thanks John

PS I wish we could afford an Alchemist too!

Stuart Kupinsky · November 18th, 2003, 12:47 PM

I've been searching and have not found a side-by-side comparison of 24p v. 30p or 30p v. 30i or 24 p v. 30i with the same camera (presumably dvx100) and where you can actually watch the two in juxtaposition. I saw the post on the JVC v. DVX100 and that's as close as I've seen (where the footage is alternated). I'm sure this must be out there somewhere, could someone point it out? It would seem this would be the only way to really compare the motion effects of 24p.
Thanks

Dennis Hingsberg · November 18th, 2003, 12:53 PM

To the critical eye it should be easy to point out interlaced footage from progressive footage. But still I say it is difficult (not impossible) to see the difference between 24p and 30p.

John Jackman · November 18th, 2003, 09:53 PM

Jacques, the VariCam (and the DVX100) both record standard interlaced video in most modes -- the content of the fields depends on what the scan rate of the CCD is set to. When the CCD is running interlaced, then there is motion difference between the fields (60i). When the CCD is run in progressive mode, the end effect is 30 p. When the CCD is run in 24p mode, then 3:2 pulldown is applied internally before being recorded as standard 60i with pulldown, as in telecine'd film.

Barry Green · November 18th, 2003, 11:48 PM

<<<-- Originally posted by Stuart Kupinsky : It would seem this would be the only way to really compare the motion effects of 24p.
Thanks -->>>

The motion effects of 24p are identical to film motion.

Ted Springer · November 19th, 2003, 02:07 AM

Yes and no. Film flashes twice onscreen at 48hz, thanks to dual bladed shutters. Some projectors with an incredible amount of light have 3 bladed shutters. You see black between each frame...twice. With 24p, you only see a line quickly drawing each frame from top to bottom. And that only happens once per frame. The motion artifacts/jerkiness are the same. It doesn't bother me, though.

Jacques Mersereau · November 19th, 2003, 07:10 AM

>>>Jacques, the VariCam (and the DVX100) both record standard interlaced video in most modes -- the content of the fields depends on what the scan rate of the CCD is set to. When the CCD is running interlaced, then there is motion difference between the fields (60i). When the CCD is run in progressive mode, the end effect is 30 p.<<<

So to achieve 60P the other half of the frame is interpolated?!

Barry Green · November 19th, 2003, 10:04 AM

The VariCam shoots 60p. The DVX shoots 60i, so if you wanted to make it 60p, then yes, the other half of the frame would be interpolated.

November 12th, 2003, 08:16 PM	#31
Dennis Hingsberg Trustee Join Date: Oct 2003 Location: Toronto, Canada Posts: 1,055	I have to agree with Jacques anbout shooting 60fps all the time, and worrying about achieving alternate looking frame rates after the fact. This is the same reason why even if I had a DVX100 I would not be inclined to shoot 24P with it. I'll just stick with my VX1000 & XL1s! Anyone here really like the DVX100 or what? __________________ Blog: www.hingsberg.com Ultimate Exposure Guides for FS5/F7S/F5/F55

November 12th, 2003, 10:14 PM	#33
Jacques Mersereau Trustee Join Date: Mar 2002 Location: Ann Arbor, MI Posts: 1,334	Yes, I LOVE the DVX100. More so than the XL1 or the VX2000. I own both. Yang Wen, another list member, brought his DVX100 over to do a shoot with a local student group. I fell in love with this ~$3K camcorder. Very very nice images and I love 'real' progressive frame anyway. A large step up over my own aging XL1. Impressive IMO. I'll take 30 full frames over NTSC any day. If I were shooting a 'movie', the DVX100 is the camera I could afford and would buy. I thought it held it own against another recent visitor, the Ikegami DV7 ($10K+lens). I am praying for Canon to pony up with the XL2 soon. __________________ Jacques Mersereau University of Michigan-Video Studio Manager

November 13th, 2003, 08:14 AM	#34
Dennis Hingsberg Trustee Join Date: Oct 2003 Location: Toronto, Canada Posts: 1,055	<<<-- Originally posted by Brad Horner : Here is someone that has shot with the dvx100 and he discusses 30fps and 24 fps. http://millimeter.com/ar/video_crossplatform_plan -->>> The actual link to the trailer was posted in the DVX100 board, but here it is for those who want to see it http://www.american-yearbook.com/dow...downloads.html __________________ Blog: www.hingsberg.com Ultimate Exposure Guides for FS5/F7S/F5/F55

November 17th, 2003, 09:05 PM	#37
John Jackman Great DV dot com Join Date: Sep 2003 Location: Lewisville, NC Posts: 78	<<<-- Originally posted by Jacques Mersereau : What Panasonic has choosen to do is different. The Varicam ALWAYs shoots/records at 60fps, but in the CAMERA's processor, _IF_ you choose a different frame rate in the menu, that change of frame rate is made in the camera (certain frames are repeated) before the signal is recorded or output. So, you can't really go back and change it later. >>> I'm not sure exactly how you meant this statement, Jacques, but let me clarify something. The VariCam always records in 60i, but the CCD is operated at the chosen frame rate -- the cam does not "select" frames from 60fps for recording. So saying that it always "shoots" in 60fps isn't correct. It shoots in true 24p and then adds 3:2 pulldown prior to recording to tape. I can double-check this with one of the engineers at Panasonic if you wish. The method you are talking about -- of shooting 60i and then interpreting to lower frame rates -- is precisely what software like Magic Bullet does. However, in my judgment the results are NOT optimal. 24fps already has horrid motion artifacts that must be dealt with by using careful shooting techniques. The nearly impossible math of converting 60i to 24p generally is "fudged" by regularly dropping and repeating fields. The result is an exaggerated jerkiness to motion that is significantly worse than real 24p. All the film DPs that have watched my "acid test" footage run through several of these processes agree that the results are significantly worse than footage actually shot at 24p. This process CAN be done with very high quality using the motion interpolation techniques developed for PAL-NTSC conversion. This is really expensive, however! The S&W Alchemist starts at $150K last I checked. Similar results can be accomplished with Twixtor, but you'll be rendering for weeks. __________________ John Jackman www.johnjackman.com

November 18th, 2003, 09:10 AM	#38
Jacques Mersereau Trustee Join Date: Mar 2002 Location: Ann Arbor, MI Posts: 1,334	<<<-- Originally posted by John Jackman : I'm not sure exactly how you meant this statement, Jacques, but let me clarify something. The VariCam always records in 60i, >>> Hi John, you mean in 60P? (Boy, I hope so. Interlace . . . yeach.) >>>but the CCD is operated at the chosen frame rate -- the cam does not "select" frames from 60fps for recording. So saying that it always "shoots" in 60fps isn't correct. It shoots in true 24p and then adds 3:2 pulldown prior to recording to tape. I can double-check this with one of the engineers at Panasonic if you wish.>>>> I wouldn't mind if you did. This is somewhat confusing. Also, if you do check with them, be sure to ask about that expensive outboard box that does conversions and how it works. Thanks John PS I wish we could afford an Alchemist too! __________________ Jacques Mersereau University of Michigan-Video Studio Manager

November 12th, 2003, 08:54 PM	#32
Brad Horner New Boot Join Date: Nov 2003 Location: Berkeley, California Posts: 19	Here is someone that has shot with the dvx100 and he discusses 30fps and 24 fps. http://millimeter.com/ar/video_crossplatform_plan

November 13th, 2003, 04:06 PM	#35
Ted Springer Regular Crew Join Date: Aug 2003 Location: Glendale CA Posts: 328	That trailer does not do ANY justice to the DVX100. The trailer Quicktime is very choppy and very small. Check out my post HERE and download the Quicktime to see true DVX100 24fps.

November 14th, 2003, 04:51 AM	#36
David Ziegelheim Major Player Join Date: Jul 2003 Location: Warren, NJ Posts: 398	<<<-- Originally posted by John Jackman : On a related and interesting note, I just heard of some research on cat vision that seems to explain why some cats watch TV and some don't. I've had two or three cats that watch TV, most have not. Cat vision is much better than ours, and their brains process rapid motion better -- more like a sensitive camera with a fast shutter speed, less persistence of vision. Apparently the refresh rate of TV is right near the bottom range of cat vision -- so cats that process vision a little more slowly than normal actually see a picture on TV. The oither cats don't -- they just see the the flying spot, perhaps several raster lines, but not a coherent picture. Those are the cats that are completly disinterested in TV. -->>> Does that mean that cats will watch progressive TV images: DLP and LCOS?

November 18th, 2003, 12:47 PM	#39
Stuart Kupinsky Regular Crew Join Date: Jul 2002 Location: Princeton, NJ Posts: 82	I've been searching and have not found a side-by-side comparison of 24p v. 30p or 30p v. 30i or 24 p v. 30i with the same camera (presumably dvx100) and where you can actually watch the two in juxtaposition. I saw the post on the JVC v. DVX100 and that's as close as I've seen (where the footage is alternated). I'm sure this must be out there somewhere, could someone point it out? It would seem this would be the only way to really compare the motion effects of 24p. Thanks __________________ DVX100A/AT4071a/Vegas/After Effects Dual 2GHz Xeon PC

November 18th, 2003, 12:53 PM	#40
Dennis Hingsberg Trustee Join Date: Oct 2003 Location: Toronto, Canada Posts: 1,055	To the critical eye it should be easy to point out interlaced footage from progressive footage. But still I say it is difficult (not impossible) to see the difference between 24p and 30p. __________________ Blog: www.hingsberg.com Ultimate Exposure Guides for FS5/F7S/F5/F55

November 18th, 2003, 09:53 PM	#41
John Jackman Great DV dot com Join Date: Sep 2003 Location: Lewisville, NC Posts: 78	Jacques, the VariCam (and the DVX100) both record standard interlaced video in most modes -- the content of the fields depends on what the scan rate of the CCD is set to. When the CCD is running interlaced, then there is motion difference between the fields (60i). When the CCD is run in progressive mode, the end effect is 30 p. When the CCD is run in 24p mode, then 3:2 pulldown is applied internally before being recorded as standard 60i with pulldown, as in telecine'd film. __________________ John Jackman www.johnjackman.com

November 18th, 2003, 11:48 PM	#42
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	<<<-- Originally posted by Stuart Kupinsky : It would seem this would be the only way to really compare the motion effects of 24p. Thanks -->>> The motion effects of 24p are identical to film motion.

November 19th, 2003, 02:07 AM	#43
Ted Springer Regular Crew Join Date: Aug 2003 Location: Glendale CA Posts: 328	Yes and no. Film flashes twice onscreen at 48hz, thanks to dual bladed shutters. Some projectors with an incredible amount of light have 3 bladed shutters. You see black between each frame...twice. With 24p, you only see a line quickly drawing each frame from top to bottom. And that only happens once per frame. The motion artifacts/jerkiness are the same. It doesn't bother me, though.

November 19th, 2003, 07:10 AM	#44
Jacques Mersereau Trustee Join Date: Mar 2002 Location: Ann Arbor, MI Posts: 1,334	>>>Jacques, the VariCam (and the DVX100) both record standard interlaced video in most modes -- the content of the fields depends on what the scan rate of the CCD is set to. When the CCD is running interlaced, then there is motion difference between the fields (60i). When the CCD is run in progressive mode, the end effect is 30 p.<<< So to achieve 60P the other half of the frame is interpolated?! __________________ Jacques Mersereau University of Michigan-Video Studio Manager

November 19th, 2003, 10:04 AM	#45
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	The VariCam shoots 60p. The DVX shoots 60i, so if you wanted to make it 60p, then yes, the other half of the frame would be interpolated.