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Ingest workflow: Alexa / ProRes HQ / Avid / Windows

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Jon Hensen
Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 22, 2014 at 9:34:16 pm

Hello! Thanks in advance for all the wonderful intelligence about to be expounded..

So I have been doing as much preliminary research as I can before the date when this particular footage returns... And I've read (with mixed conclusions) and tested (with mixed results) as to what the best way will be for me to bring in ProRes HQ Alexa footage in MC7 running Windows 7.

I know there are many different constituent factors to consider for ingesting, all for which I've seen many sides of the story...

...Consolidate vs. Transcode vs. "Fast" Import, the pros and cons of editing in ProRes vs. DNxHD, how to maintain the metadata for the correct color space or profile, being able to offline edit without encountering serious headaches upon re-link. That said, my only real concern is the surest way to ingest this footage in it's truest form with the least amount of headaches before, during, and after edit. If necessary we have the drive space to edit in HD, it would be nice to have the offline option.

I am wondering if I have any limitations given the footage is ProRes HQ and we're cutting on PC. I understand ProRes is supported in MC7 but to what extent? Am I losing functionality on Windows? I've had mixed results consolidating ProRes HQ, sometimes working, sometimes not. I've been able to transcode ProRes to DNxHD successfully (not ideal as I am then going through a decode/re-encode process). I haven't been able to "Fast import" which from my research is the best way to leave the footage untouched and avoid any generation or metadata loss.

I don't have months of footage or hundreds of hours. It's a nice self contained edit. I may be paranoid, but I want to treat the footage (and our rental costs!) with the respect it deserves to make sure everything looks its best.

I understand LUTs may be a potential big player in this scenario, but for now I'm worried about the mere brass tacs of ingesting ProRes HQ in MC7.

Thanks!
-Jon


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Job ter Burg
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 23, 2014 at 6:56:04 am

I would not opt to work in ProRes on Win, You cannot generate ProRes on Win (thank you, Apple), so your titles and renders would need to be in a different codec, which is not great when you need to do self-containee exports. Also, you would only be able to import as ProRes if they shoot 1920x1080 – if they shot 2K, it needs to be scaled back to 1920, so that wouls require a transcode anyway.

I would say there are two ways to go about this.

1. AMA-link to the files, select the clips in the bin, apply LUT as needed, select Clip-Transcode and transcode the clips to a DNxHD flavor of your liking (DNxHD36 would be great for offlining in HD. Conform can be either done in MC by relinking to the original ProRes files after completing the cut, or via AAF or EDL to a third party conform and grading tool (Resolve, Scratch, BaseLight, NuCoda, etc.).

2. Use a 3rd party tool (many available, Resolve Light does this as well) to apply LUT and transcode to DNxHD Avid MXF media. Conform can be done inside MC by relinking to the original ProRes files (slightly more hassle as you need to relink source file names to tape names), or in a 3rd party conform & grading tool.


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Pat Horridge
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 23, 2014 at 8:06:32 am

I'd agree with Job. Avoid Prores on the PC. Go the dnx36 offline route. Dnx36 looks really good and your system will be more responsive with dnx low bitrate media.
Check the conform process with who ever is doing the conform and grade and ideally do a test first.

Pat Horridge
Technical Director, Trainer, Avid Certified Instructor
Free online Tutorials at VET digital media academy online http://vimeo.com/channels/752951
VET
Production Editing Digital Media Design DVD
T +44 (0)20 7505 4701 | F +44 (0)20 7505 4800 | E pat@vet.co.uk |
http://www.vet.co.uk | Lux Building 2-4 Hoxton Square London N1 6US


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Jon Hensen
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 23, 2014 at 4:05:30 pm

Job and Pat thank you.

DNx it is. I just spoke with the DP and they baked in a LUT for the footage. Will I need to do anything additionally during transcode to make sure that information is retained? Will the transition through offline to online pose any problems for this?

In a perfect world I'd like to do everything within MC. Possible? Probable? Advised?

Thanks!


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Pat Horridge
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 23, 2014 at 8:24:11 pm

Yes you need the same LUT and apply it in the source settings for the AMA'd clips before you transcode.

Pat Horridge
Technical Director, Trainer, Avid Certified Instructor
Free online Tutorials at VET digital media academy online http://vimeo.com/channels/752951
VET
Production Editing Digital Media Design DVD
T +44 (0)20 7505 4701 | F +44 (0)20 7505 4800 | E pat@vet.co.uk |
http://www.vet.co.uk | Lux Building 2-4 Hoxton Square London N1 6US


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Job ter Burg
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 23, 2014 at 8:44:14 pm

Not if that LUT is already baked in, methinks.


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Job ter Burg
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 23, 2014 at 8:43:40 pm

"they baked in a LUT for the footage" – if they baked in the LUT, there's nothing for you to add or change. Unless they don't really mean they baked it in. A bit vague, the idea of a LUT is NOT to bake it into the production source files.

"I'd like to do everything within MC. Possible? Probable? Advised?"
Can be done. If they did in fact bake in a LUT and you're getting Rec709 sources that they want to finish in Rec709, you can just pull everything through MC.

If they did not bake in the LUT, you can still work in MC, add the LUT there, but you will not have the advantage of the Log-C color space that you would in finishing tools.


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Pat Horridge
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 23, 2014 at 9:34:14 pm

If the DP was supplying Transcoded files then baked in LUT makes sense. if it's the source files then surely they mean a LUT has been applied and therefore the LUT needs to be used to ensure the Transcoded footage now looks "normal"

Pat Horridge
Technical Director, Trainer, Avid Certified Instructor
Free online Tutorials at VET digital media academy online http://vimeo.com/channels/752951
VET
Production Editing Digital Media Design DVD
T +44 (0)20 7505 4701 | F +44 (0)20 7505 4800 | E pat@vet.co.uk |
http://www.vet.co.uk | Lux Building 2-4 Hoxton Square London N1 6US


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Jon Hensen
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 24, 2014 at 12:09:55 am

The picture is getting clearer.

I've just done my first preliminary batch of transcoding to assess the results.

What I'm seeing is this...

COLOR SPACE:
Arri ALEXA LogC (AMA CLIP)
ARRI Log-C gamma [64-940 (8bit)] (Transcoded DNxHD36 clip)

COLOR TRANSFORMATION:
ARRI ALEXA LogC to REC 709

I was provided with source ProRes HQ files. It was confirmed they did in fact apply a look in the field. The resulting REC709 image is incredibly crushed and saturated which is worrying. I remove the color transformation in the settings and get back to the LogC look taking us back to a blank canvas.

I guess my next question is if I am missing anything metadata-wise during ingest? Is MC seeing the applied look correctly? Is this REC709 just a stock LUT in the camera which is the culprit for the across the board satuaration issues?

One more little piece of information is that this was all shot on an AMIRA not an ALEXA (apologies). I don't know how much that changes things. I found little literature on this latest and greatest of ENG cameras.

Thanks Job and Pat.


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Pat Horridge
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 24, 2014 at 6:55:45 am

That doesn't sound correct. Looking at Log-c footage as REC709 with no LUT applied at your end should give you washed out de-saturated images. Blacks lifted whites low.

It sounds to me like the footage you have is actually REC709 but flagged as having a Log0C LUT applied. Applying the Log0C to REC709 LUT your end is expanding out what is a REC709 image already.

You need to resolve this ASAP as it's likely something is wrong at the acquisition end.

If you have a way of uploading a small clip I can look and let you know what's what.

Pat Horridge
Technical Director, Trainer, Avid Certified Instructor
Free online Tutorials at VET digital media academy online http://vimeo.com/channels/752951
VET
Production Editing Digital Media Design DVD
T +44 (0)20 7505 4701 | F +44 (0)20 7505 4800 | E pat@vet.co.uk |
http://www.vet.co.uk | Lux Building 2-4 Hoxton Square London N1 6US


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Pat Horridge
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 24, 2014 at 6:22:24 pm

Got the smaple clip you sent.
It looks fine.
The source setting window identifies it as Arri Log-C and adds the log-c to rec709 transformation. on the RGB display levels look good.
If you click bypass transformations you see sat up blacks and lower whites but more detail in the sky and clouds as expected.
So with the transformation in place it looks more "normal"
Good to go I'd say.

Pat Horridge
Technical Director, Trainer, Avid Certified Instructor
Free online Tutorials at VET digital media academy online http://vimeo.com/channels/752951
VET
Production Editing Digital Media Design DVD
T +44 (0)20 7505 4701 | F +44 (0)20 7505 4800 | E pat@vet.co.uk |
http://www.vet.co.uk | Lux Building 2-4 Hoxton Square London N1 6US


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Jon Hensen
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 24, 2014 at 6:37:55 pm

Thanks for taking a look, Pat.

So does that mean I have to click bypass transformation for the material to look "normal" as you say?

Or are you saying that the LogC to REC709 transformation is good? It is not usable in the state I see it. It was immediately alarming to the DP upon looking at the footage within MC. Incredibly over saturated and crushed.

Sorry I'm just a bit confused.


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Michael Phillips
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 25, 2014 at 1:17:45 pm

What monitors are you using for reference when looking at this images? I would never trust the source/record GUI monitors for any critical or even pseudo-critical color decisions. If you are using a LUT>709 then you should be looking at a Rec.709 calibrated monitor. The GUI viewers are truly for editorial reference. They don't even show the full frame, it is either 1 field in interlace projects or 1/2 frame (segmented) in progressive projects which is something to keep in mind when doing motion effects, and judging frame rate conversions and FluidMotion. I still get caught by that myself.

Michael


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Pat Horridge
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 25, 2014 at 2:33:05 pm

Uhm I posted a long reply and it vanished so heres the shorter version..

With the LUT applied in camera the content is compressed in the dark and light areas (mainly the light) this give more dynamic range during shooting. If you look at the footage with no LUT on you system on a good grading monitor and external scopes as I did it looks sat up in the blacks and low peak whites (around75% max) and low saturation (washed out)
With the Log-s to rec709 LUT in (ie NOT bypassed) it looks more correct. peak whites up near 100% and a better contrast range plus more saturation (possibly too much) and some clipping in the whites.

You have 2 choices either make your transcoded media with the LUT and have the more contrasty look or transcode without and have the washed out look. No point the DP looking and making judgements shooting with Log-c only produces the look in the grade. Not the offline.
There is an option to transcode and not bake in the LUT so the transcoded media still has the option to remove or bypass the LUT but the media won't playback as well as you effectively have a realtime effect applied.

I'm not quite sure the folks your end quite understand the impact using Log-C to shoot with has but this is it.

Pat Horridge
Technical Director, Trainer, Avid Certified Instructor
Free online Tutorials at VET digital media academy online http://vimeo.com/channels/752951
VET
Production Editing Digital Media Design DVD
T +44 (0)20 7505 4701 | F +44 (0)20 7505 4800 | E pat@vet.co.uk |
http://www.vet.co.uk | Lux Building 2-4 Hoxton Square London N1 6US


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Jon Hensen
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 25, 2014 at 8:04:59 pm

Thanks Michael and Pat.

Funny thing. I've been trying to get in an edit bay with a broadcast monitor for days. I finally did and the color is just fine as you said, Pat.

Side note. I brought the same material into Premiere Pro and didn't have this "accurate preview" issue. It previewed fine in Premiere.

Do you know if AVID as opposed to other NLEs requires a broadcast monitor to see LUT transformations? I understand that in reality all NLEs require this to see true levels, but AVID wasn't even close without, whereas Premiere Pro was on the money.

Thanks again.


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Pat Horridge
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 25, 2014 at 8:48:33 pm

If it looked right in premiere without a LUT then it premiere must be way off. It should look wrong without the LUT. It is wrong without the LUT applied.

Pat Horridge
Technical Director, Trainer, Avid Certified Instructor
Free online Tutorials at VET digital media academy online http://vimeo.com/channels/752951
VET
Production Editing Digital Media Design DVD
T +44 (0)20 7505 4701 | F +44 (0)20 7505 4800 | E pat@vet.co.uk |
http://www.vet.co.uk | Lux Building 2-4 Hoxton Square London N1 6US


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Jon Hensen
Re: Ingest workflow: Alexa / ProRes HQ / Avid / Windows
on Jul 25, 2014 at 9:19:07 pm

LUT was applied in Premiere.


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