possible lead into 24p problem

L

lmerino

Active member
So i've been trying to figure some tech issues out lately regarded dv and the 24p problem in PPro.

We know that the strobing problem when editing 24p in PPro is because particular frames that must be rendered (i believe its every 2nd and 5th) to playback 24p-standard have the white levels crushed to fit within "legal" limits (about 100 IRE).

When editing 24PA, this does not happen because the original 24 frames can be extracted without having to process any of the data (no mixed fields).

I also found that some DV codecs will allow to use the full black/white range of DV, and some will not. I believe a codec like Canopus will limit the range, where a codec like Quicktime will give the option to use limited or full range. This is the option in Final Cut Pro called "superwhite." If you turn this on, it will go above legal limits, giving the full range of what DV can handle.

OK, so... we also know that the dv codec in PPro is the Mainconcept codec... although I do not know which version. The newest version on the Mainconcept website to purchase is 2.4.16

But Mainconcept also has this press release ( http://developer.mainconcept.com/press-releases/dv-codec-244.html?pr=dv_codec_244)
stating that a version 2.4.4 which came out on July 29, 2003 supports the option for "clipped and unclipped black/white levels."

So, I foolishly purchased the Mainconcept DV codec, version 2.4.16, in hopes that maybe I can somehow access these options to use "unclipped" black/white levels.

I haven't been able to experiment too much, but I think the main problem will be getting Ppro to use the newer version of the codec, rather than the version it comes with.

In any case, if the version of the Mainconcept codec with PPro happens to support "unclipped" black/white levels, I would think there would be some option of turning this on. This way, there would be no crushing of the whites in rendered footage. (btw,this may be one reason why editing in QuicktimeDV on Final Cut may be superior to Ppro)

Regardless, this does not solve the problem of being able to use 24p footage as 29.97 and mixing with non-24p material.

If anyone actually read all this, I hope it makes sense.
 
Re: possible lead into 24p problem

Thans for your continued research, Lucas.

It's hard to tell where the problem creeps in ... perhaps in the dv codec. But remember, you are using the DV codec any time you look at your frames on your computer monitor -- Premiere has to decompress to display as RGB pictures.

Since the problme can be seen in those on-screen RGP frames, we know the problem can't be caused by the codec's *decompression* -- otherwise all frames would be affected equally, not just the "assembled" frames.

A problem with the codec's *compression*, on the other hand, might affect just the "assembled" frames, but that would mean the strobing RGB image we see would be a result of Decompression->Pulldown Removal->Recompression->Decompression. Maybe PPro is doing all of this but I'm not sure.
 
Re: possible lead into 24p problem

Agreed, we will see. I also stumbled across this article on dv.com. It speaks of how different NLE's handle 24p. It doesn't mention PPro, but I can assume it handles 24p like Blade2, read below:

"{Blade 2} It lets you play back to 29.97 tape or export to 29.97 DV, but it does so by adding back in those frames removed when pulldown was processed. Those frames are still present in the clips, just skipped over when the clips are processed as 24p, so they're easily resurrected. Unfortunately, this is an inelegant way to insert pulldown; cadence isn't preserved across cuts, so you're pretty much left with using DVFilm Maker or After Effects to convert 23.98 to 29.97 with the proper pulldown inserted."

the full article is here:
http://www.dv.com/news/news_item.jhtml?LookupId=/xml/feature/2004/wilt1203_tech

I never had a grasp of this cadence problem till I read it here. To me, this doesn't sound good for 24p with Ppro in the future unless they make some serious changes in how they handle it.

What do you think?
 
So with this problem should I film in 24p Advanced (if the problem is not apparent in this mode)? If so what do I gain/lose? Or should I use Vegas Video 5 until PPro resolves the strobing?

I definitely want to use the 24p or 24p Advanced film mode for the look it gives but certainly don't want any strobing on my edited/captured footage.
 
I can’t produce the strobing problem you speak of. I wonder if everyone has this problem. Maybe I have it but just don’t see it.

Anyway it now concerns me. I am about to start shooting a reality TV show and we have decided to shoot in 24p not 24pa mainly because it is for the interlaced world of cable TV.

I have shot some test footage and it looks great I just don’t see the strobing.

Should I be concerned that I am missing something?
 
Film something overexposed. Turn on a light bulb and film directly at it... or film an interview outside where the sky will be overexposed a bit.
 
kappa22 said:
If you know PPro, going to Vegas is like putting on a pair of shoes that are 5 sizes too small.
Click to expand...

Well, then you wouldn't have the clown shoes on anymore.

:shocked: :laugh:
 
Yeah, it's true; I wear 13's...:laugh: but still, it's a big switch, and when I tried to make it, I found that Vegas was just too backwards for a good workflow... again, that's personal experience (I use ACID 5 too, so it wasn't that hard to pick up).
 
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