24p interlaced artifacts
by Benjamin Jones
on
Oct 15, 2008 at 4:27:50 pm
Hi guys.
I shoot on a DVX100A and edit in Final Cut Pro. Whenever I use to shoot in progressive mode, I would shoot 30p and have no problem with interlacing in Final Cut. I just shot lots of 24p footage and cannot get around the interlaced artifacts in the edit. I've captured the footage at 24p and have set up a 24p sequence, but I still see the interlaced artifacts 1 out of every 4 frames. Is there a way around this? Using the de-interlace effect seems to reduce the quality and amount of information in the video.
Re: 24p interlaced artifacts by david bogie on Oct 15, 2008 at 5:21:05 pm
Hope you get better advice soon.
If you shot 24p and are using a 24p timeline, there is no interlacing by definition.
So you've got a setting wrong somewhere.
bogiesan
This is my standard sigfile so do not take it personally: "For crying out loud, read the freakin' manual."
Re: 24p interlaced artifacts by david bogie on Oct 15, 2008 at 6:01:15 pm
I got this in the Cinema Tools manual. Some cameras do a fake 24p by baking it into a 60i format. I do not know if the OP's camera can be set to shoot 24p absolutely.
> Adding and Removing Pull-Down in 24p Clips
Cinema Tools and Final Cut Pro have pull-down removal and addition features that
address issues specific to working with 24p video. Pull-down, as first mentioned in
“Frame Rate Basics” on page 22, is a process that adds redundant fields to video in
order to distribute 24 frames per second into the NTSC standard of 29.97 frames per
second. Some camcorders, such as the Panasonic AG-DVX100, are designed to shoot in
progressive mode at 24 fps (literally 23.98 fps), and then record the video to tape as a
60-field interlaced signal by applying a special kind of pull-down called advanced
2:3:3:2 pull-down. With Final Cut Pro or Cinema Tools, you can remove the redundant
fields created by the camera’s pull-down, so that you can edit at 23.98 fps or 24 fps.
When you edit 23.98 fps video, you may need to output it to an NTSC monitor, record it
to an NTSC videotape, or send it to another type of NTSC device. Because the NTSC
standard specifies a frame rate of 29.97 fps, Final Cut Pro gives you a way to add
pull-down back into the video as you output it. To accommodate various circumstances,
Final Cut Pro provides a few different types of pull-down patterns for outputting your
23.98 fps video as 29.97 fps video: 3:2 pull-down, 2:3:3:2 pull-down, and 2:2:2:4 pull-down.
(These pull-down patterns are described in “Pull-Down Patterns You Can Apply to
23.98 fps Video” on page 215.)
bogiesan
This is my standard sigfile so do not take it personally: "For crying out loud, read the freakin' manual."
Re: 24p interlaced artifacts by Bill Dewald on Oct 15, 2008 at 6:07:58 pm
[david bogie]" I do not know if the OP's camera can be set to shoot 24p absolutely. "
Well, no NTSC camera can shoot 24p "natively", or "absolutely". Like the manual explains, these cameras record 24p across 60i with a pulldown pattern.
My guess is that the OP may not have removed the pulldown, or has done it improperly somehow. Changing editing timebases isn't as simple as switching a mode on a camera...
If the OP isn't going to film, the quickest fix may be to just cut in a 29.97 timeline.
Re: 24p interlaced artifacts by Benjamin Jones on Oct 15, 2008 at 6:46:10 pm
I shot the material in 24p but not the 24p advanced. Could this have anything to do with it? Even when I capture using the pulldown removal preset this does not solve the problem.
The footage is not going to film. Keep the ideas coming, I appreciate it.
Re: 24p interlaced artifacts by Chris Borjis on Oct 15, 2008 at 7:45:40 pm
[Bill Dewald]"And - you are looking at this on an external monitor, right?"
thats the key.
you are probably seeing this in the viewer which is an all too common problem on
all video apps on the mac. It will likely look just fine externally monitored which
is what really counts.
Re: 24p interlaced artifacts by Benjamin Jones on Oct 15, 2008 at 7:58:03 pm
Thanks for the help Bill. Here's where I'm at..
When I capture the material at 24p and place it into a 24p timeline, it does not need to render, but I get the interlaced lined 1 out of 4 frames. I can see these lines on the canvas as well as on my external monitor. It does not allow me to apply the Cinema Tools Reverse Telecine because it says this only works on 29.97 clips.
So, if I capture the 24p footage at 29.97 and place it into a 29.97 timeline, I CAN apply the Cinema Tools Reverse Telecine and it gets rid of the 1 interlaced frame and smooths it out. Is this my solution? Although I shot the material at 24p, capture it at 29.97, place in a 29.97 timeline, and apply the cinema tools effect?
If this is the case, why would you ever capture 24p and edit in a 24 frame timeline?
Re: 24p interlaced artifacts by Bill Dewald on Oct 15, 2008 at 8:15:16 pm
Ok - I think I have it straight in my head where things went wrong.
You shot 24p standard (which is a 2:3:2:3 pattern), and then captured with "Advanced 2:3:3:2 Pulldown removal". Since the capture settings didn't match the footage, the cadence was incorrect, leading to a interlaced frame every couple of frames.
So, to ingest your 24p Standard footage, capture normally as NTSC-DV (anamorphic, if it applies). Once the footage is ingested, run it through Cinema Tools in order to remove the pulldown, and ta-da - 24p DV footage.
[Benjamin Jones]"If this is the case, why would you ever capture 24p and edit in a 24 frame timeline? "
Here's the diff - if you're finshing on NTSC tape (like D-Beta, etc.), you really don't need to have a 24p workflow. Just ingest the 24p footage like you'd handle your 30p footage, and enjoy the "film look". This will especially save you a headache if you need to use 60i footage in the project as well.
Re: 24p interlaced artifacts by Benjamin Jones on Oct 15, 2008 at 11:48:34 pm
I now understand the difference between shooting 24p and 24pa. Bill thanks for the specific directions, but something fishy is occuring.
When I capture the 24p footage at the regular DV-NTSC capture rate like you suggested, I can not apply the Cinema tools effect that gets rid of the interlaced frames. Is this just something I have to deal with when editing in a 29.97 timeline? I understand the benefits of being able to mix 60i footage, etc. My LCD monitor still shows the interlaced frames, but do they go away on a NTSC monitor?
As an experiment, I captured the 24p footage with the advanced pulldown setting. Even though you said this is incorrect, capturing it at this setting allows me to add the cinema tools reverse telecine, which gives me NO interlaced frames and I think it looks better overall.
Thoughts? The reason I posted this question in the first place was because a client complained that the Rough Cut DVD I burned looked a bit 'digital' and 'out of focus'. I thought it looked great (thought he may be seeing the strobing or interlacing) but since I don't shoot in this format often I wanted to check my bases and make sure I wasn't forgetting a step when dealing with 24p.
It 'splains a lot. Learn the difference between 24p and 24pa.
And know that while in the best of all possible worlds things work right, the DVX is at its heart A MACHINE. Machine parts can wear and screw up a tiny bit, perhaps a frame or two. You can turn the camera on and off to conserve power, or run the tape back to check out what you shot, and cue it up again. Maybe it'll hit the right spot, maybe it'll resume recording timecode to the precise frame.... and maybe it won't.
So: when recording 24p or 24pa -- any thing with a pulldown cadence -- you can take your chances capturing entire shots, or play it save and get it right EVERY TIME by capturing individual clips. It's your choice.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Re: 24p interlaced artifacts by Benjamin Jones on Oct 16, 2008 at 12:01:56 am
Dave, thanks for the link, it was helpful.
I just read the article and need clarification on one last thought. When shooting 24p normal and the 3:2 pulldown is applied, you still receive a frame of interlacing, correct? Here is a paragraph from the article:
//
24p Normal
When shooting in 24p Normal, the camera is adding normal standard 3:2 pulldown to the video, which results in 24p footage designed to work with any non-linear editing suite and it will play back and look good directly to any NTSC monitor. You can use 24p Normal footage just like normal video from any DV camera, and everything will work fine, but obviously, the footage will have a film look to it. If you’re just going straight back to NTSC video tape, then using 24p Normal is the simplest, easiest workflow. No special treatment of the footage is needed and you really can just edit as normal.
//
Now, when he says, "no special treatment of the footage is needed, he still implies you'll have splits, resulting in some bit of interlacing, correct?
Re: 24p interlaced artifacts by jaenet guggenheim on Oct 16, 2008 at 9:54:54 am
i am struggling with 24P. jeremy just advised me to try the compressor reverse telecine. which i will.
since the 24p is logged and captured at 29.97 i am wondering if going to 30P with it is a good idea?
i feel sad to think i will look all that pretty picture in compression and decompression. i have heard that is why shooting 720 24PN is just as good as shooting 1080i24P (long after i started this project)
-- because in the end, you will have either 24PA footage that looks jerky on most tvs or you will have (somehow) 24P footage that you got into your fcp timeline by compressing and decompressing it, and in that process, you really lose a lot of clarity.
my concern is if i send it to festivals overseas, they have different frame rates. and it seems that going from 24PN to 25 is not a stretch, and that footage would look good. but i am really worried if i have to make mine go from 29.97 to 24 to 25.
so -- can all this be done with 1080i 24p and still look good?
Re: 24p interlaced artifacts by Dave LaRonde on Oct 16, 2008 at 2:27:10 pm
[Benjamin Jones]"Now, when he says, "no special treatment of the footage is needed, he still implies you'll have splits, resulting in some bit of interlacing, correct?"
Correct. But if you intend to do ANY of the following:
* Put the video on the web
* Change the speed of the video
* Make a 24p DVD
* Do a film-out
* Incorporate motion graphics whose motion absolutely, positively MUST match that of the video
You have to remove the pulldown BEFORE you edit, and you have to edit in a 23.976 (aka 23.98 in FCP-speak) timeline.
Keep that in mind.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
