Uncompressed For Colour Correction

Loki

Loki

Veteran
I am at a stage in my post production, where I need to start painting out a few things that made it into some frames of the final film. And I am also wanting to the final colour grade on my footage.

My question is two fold, does any have experience colour grading/correcting on Uncompressed 8bit - 4:2:2 footage, converted from miniDV?

I notice a small degradation of my image when I have 2 sets of filters applied in FCP, which is why I want to try my final effects work on Uncompressed images. But I really cannot see too much of a difference in the quality.

Is it worth it to convert my whole film (sans effects) to uncompressed format and then apply the effects? or would it really only be useful for the frames in which I need to make modification, ie painting someone out of a background.?

This boil down to opinion, but I have never tried this option before, and it is a lot of HD space to commit for a 20min project length.

Also on this topic, is it possible to export a sequence so that each clip in the sequence gets exported as a separate file? somehow this is probably wishful thinking on my part.

thoughts?
 
I am not sure that I understand the value of editing DV uncompressed unless there are tools available for the uncompressed footage that are not available for native DV.

In both cases you incur the same number of compression/decompression steps. If you go 4:2:2 over SDI from DV you have to upsample the chroma/luma info and interpolate. If you edit native DV you can just apply a filter that does the same thing.

In FCP I believe it works like this:

Native DV -> uncompress -> apply billion filters -> done

Not:
Native DV > uncompress -> apply filter 1 -> recompress ->uncompress->apply filter2->etc


If you were working 4:2:2 it would be:

Native DV ->(uncompress upsample to 4:2:2) -> apply billion filters -> done


I think the only difference would be the quality of the conversion (SDI capture VS whatever smoothing filter you used in FCP).




There is a fairly interesting article related to this topic here: http://www.lafcpug.org/Tutorials/basic_chroma_sample.html
 
All depends on what type of manipulation and if you're planning to do a lot of processing.
If you're going out to film or DVD you might consider bumping to 10 bit uncompressed to avoid getting quantizing, especially in the darker areas. take your worst case scene and do a test to see wether it's going to be worth it.

If you're just doing paint work output to Animation compressed Qt and output it from your paint program same way so you can do final import into FCP.
 
tigeba said:
In both cases you incur the same number of compression/decompression steps.
Click to expand...

It all depends on your final output medium.

If it is DV or DVD, uncompressed is not going to add anything apart from smoothing the DV's 4:1:1 chroma during CC or chroma keying. You can do this with a chroma smoothing filter in a DV timeline anyway.

From FCP, Compressor uses your original footage to encode the DVD, so there is the absolute minimal loss. Printing to DV tape is also only a single stage recompression, which is again the ABSOLUTE minimum possible if you are going to add filter effects.

If you take the footage out of FCP for rotoscoping etc, export it uncompressed if possible.

If you are outputting uncompressed to Digibeta or Beta SP, there is an advantage of going uncompressed before CC, as it prevents a recompression to DV.
 
I think my main concern is that I am using the widescreen matte filter in FCP and it causes a noticeable decrease in image quality, which I am assuming is because of the Non-standard frame size created by the crop, which is perhaps a limitation of the DV codec itself?

After doing a little test I have found that there is a perceptable difference when I apply the widescreen matte, it is small, but it is there.

Though I don't think the time/gigabyte vs output ratio is a winning one... for such a small difference. I am thinking that perhaps just a straight matte , no crop, would yield a cleaner image.
 
You could edit your whole project in DV to keep real time benefits and then export the whole thing as Quicktime movie, but choose uncompressed as output codec. From my understanding this will uncompress your DV clips, apply a million filters and then save as uncompressed. Which would be the same result as uncompressing your footy first, but without the hassle.
And the media manager can copy all your clips as they are used in the sequence into a destinated folder.
 
If it's the widescreen matte that's causing problems, you may want to look to Nattress Film FX. I noticed his widescreen matte does not cause the same softening that seems to occur with the stock filter in FCP. Is that what you are noticing is a softness once you apply the filter?

Steve
 
Hey Loki,

Everytime I make DVDs, I'll do all my color correction to my project in the DV timeline. Whne I am completely done with the project, I copy the project (w/o filters and cc) and bring it into an uncompressed 4:2:2 timeline. In that timeline, I first apply the G-Nicer Natress chroma upsampler first to all the footage. Then I copy all the cc and filters from the dv timeline and paste them over the uncompressed footage with the Nattress filters ... and then proceed to render and output to mpeg2.

Although there are extra steps involved and increased rendering because of it being uncompressed, I do find that the DVDs come out noticeably cleaner, thanks to the chroma upsampler. Rendering does increase a couple folds but its worth it (I'm running a pimped out Dual 2.5Ghz G5 and still had to render a little ... so you'd need a pretty hefty system for this workflow).

Hope this helps.
 
Can you not copy the clips into the new uncompressed sequence with the CC and other filters already applied and then just re-render? Does that not work the same? I'll need to know this because I'm about to employ this workflow on a current project.
Thanks
Steve
 
Thanks, Mgalvan for the workflow explanation! One question... When you copy the CC and filters from the DV timeline into the Uncompressed timeline, do you have to do it one clip at a time? Or is there a way of copying all the filters at once so they are then placed on their respective clips in the uncompressed timeline?

I'm in the middle of color correcting a full-lenght feature right now, and it's a LOT of different clips to have to copy one by one from one timeline to the other. I'll do it if I have to, but I'm wondering if there's a faster way, like stevesherrick mentioned above, that could work just as well.

Thanks!
 
Does it make a difference if the G Nicer filter is applied before or after CC? Because I would simply duplicate the sequence, set it to uncompressed, re-render and apply G-Nicer. If it does make a difference, couldn't you duplicate the seq, apply G-Nicer on every clip and manually change the order in which the filters are applied?
Thanks,
t
 
Hm , I wonder if this 4:2:2 workflow would be good applying to my DV Project which I have to output on Digibeta? Does the GNice Filter also enhance my PAL material?

Also where can I quickley lear about the differences of compression, I really don`t knwo to much about 4:2:2 etc...
 
PAL is 4:2:0, and hence G Nicer, which is designed for 4:1:1 won't help. G Nice in set 1 has a 4:2:0 mode that you could try though. It's not as complex a fix that it does compared to G Nicer, but it might help a fair bit. Also, the chroma sharpening filters in Film Effects all have a 4:2:0 mode and they can help.

Graeme
 
jrv3034 said:
Thanks, Mgalvan for the workflow explanation! One question... When you copy the CC and filters from the DV timeline into the Uncompressed timeline, do you have to do it one clip at a time? Or is there a way of copying all the filters at once so they are then placed on their respective clips in the uncompressed timeline?

I'm in the middle of color correcting a full-lenght feature right now, and it's a LOT of different clips to have to copy one by one from one timeline to the other. I'll do it if I have to, but I'm wondering if there's a faster way, like stevesherrick mentioned above, that could work just as well.

Thanks!
Click to expand...

Hey,

You can copy all the filters at once. Just go into the filters windowand click on the top filters tab within the window. This should highlight all the filters you have applied. Copy the filters and then go into your uncompressed timeline and paste it into the corresponding clip's filter window (click on it and paste it in). It should all go into place and you're set.
 
Graeme_Nattress said:
I'd think that G Nicer would work best first in the filter stack, but I'd do a comparison and see for myself!

Graeme
Click to expand...

Yes, I found that the G-Nicer filter is better when applied first in the filter stack as Final Cut Pro applies the filter effects in sequence (hencem having it first makes it the "core").
 
Hey Graeme,

Does G-Nicer work on native 4:2:2 footage like DV50 to help bring it up to 4:4:4? That would be interesting for upcoming HVX footage.
 
I still wonder if the quickest method is to put the G-nicer plugin on the clips as you are color correcting in your DV sequence, making it the first filter on each clip (quickest way to do this is to highlight the first clip you apply it to in your sequence, highlight and copy that clip in the timeline, then paste attributes onto all your other clips, selecting filter as the attribute you want to paste)., just make sure it's deselected when you work on the clips. Do all your color correcting in your DV timeline and when finished, copy that sequence into an uncompressed one. Turn on the G-nicer plugin for each clip, and then render. This should work right?

Steve
 
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