dpx questions
January 14, 2009 10:04AM
Hi all!

I need some help here.
We´re going to shoot a commercial and deliver it to a post production house
so they can put some 3d stuff in it.
I need to deliver dpx files. I have no experience of this what so ever.
How do I do this?
We probably are going to shoot it on RED.
What´s the workflow on delivering dpx?

Can someone please help me out here?
Re: dpx questions
January 14, 2009 10:36AM
DPX is more or less the industry standard for high-resolution work. Film, when scanned, comes out as a sequence of images in DPX format, one image per frame. In broad strokes, DPX is basically an image file format like TIFF. What makes it special is that it's usually 10-bit logarithmic, making it a really good choice for material scanned from film.

Red is 12-bit linear, not 10-bit log, if I remember correctly. So you have two ways of converting R3D to industry-standard image sequences. You can either convert to 10-bit log DPX, or you can convert to 16-bit linear TIFF. I'm not experienced enough with Red to say whether one choice is better than the other for any reason.

A whole Red production pipeline tutorial is beyond the scope of this message board, and I'm not qualified to give you all the ins and outs anyway. But generally what people do is offline the Red footage using either camera proxies or (I think more commonly) ProRes files transcoded from the camera proxies. Since this is just an offline it can be at any resolution. Then one of a number of tools is used to take the Final Cut XML file and do a neg cut off the Red files, generating 2K DPX sequences with handles. Then those sequences are conformed to the offline cut just as they would be if they'd come off a film scanner.

Re: dpx questions
January 14, 2009 10:37AM
Read this:


Re: dpx questions
January 15, 2009 11:22AM
Thank´s Jeff for the info!
"Then one of a number of tools is used to take the Final Cut XML file and do a neg cut off the Red files, generating 2K DPX sequences with handles."
What do you mean? Neg cut? This is not going to got to film, digital all the way or do you
mean something else?

How do I get my edited movie out to dpx from Final cut? (disregarding shooting format)

deremok: thank´s for that link!

Re: dpx questions
January 15, 2009 11:56AM
I'm sorry, Göran, but a step-by-step "here's how you do Red" tutorial is way beyond the scope of what I'm qualified to offer. There's a reason why post houses all over the world have spent weeks or months developing and honing their Red production pipelines.

A neg cut was my way of making an analogy. When you shoot film, you do a one-light transfer of all the rushes and make your offline cut. Then you take the EDL of your offline and match it back to keykode, and use the keykode numbers to cut the negative to assemble the final film. If you're doing a DI, you still do all that, you just scan the cut negative. You don't scan all the rushes at full resolution. Red workflow is like film: You don't typically transfer all of your shot footage for your DI. You do a "neg cut" based on your offline to reduce the amount of footage that gets transferred to your DI format. There are several tools for this. A google search for information about conforming Red footage for online should probably be your next step, because you'll find way more detail than I'm qualified to offer.

I'm sorry I can't give you all the details myself, but I'm trying to point you in the right direction so you can know what questions to ask.

Re: dpx questions
January 15, 2009 01:11PM
Thank´s Jeff!
Actually I´m trying to figure out how to get dpx out of Final cut
regardless the format. All I know is that we are going to shoot it on HD
and likely on RED.
The post house have requested dpx log from us.
I guess it is a similar workflow getting dpx from FCP?

I have tried to find some anwers on the net but since this is a completely new terretory for me I really don´t know where to begin.

Re: dpx questions
January 15, 2009 01:22PM
You ? wouldn't ever take DPX sequences out of Final Cut. I literally can't imagine a scenario in which you would ever do that. Of course, since I can't, that means somebody somewhere must be itching to tell us all how it's a great workflow for them, so maybe somebody else can chime in here.

If you're onlining on a non-Final-Cut system with DPX sequences, then you must be using Final Cut only for your offline. If you're shooting on Red, then your offline media, which you use to make your offline cut in Final Cut, will be ProRes Quicktimes transcoded from the camera proxies. That's the equivalent to your one-light transfer of all your rushes. The DPX sequences you online with won't be generated from the camera proxies at all, but from the original R3D files that come off the camera. There would be no point whatsoever to generating 10-bit log files from the 10-bit linear proxies you cut with in Final Cut. What you want there is to go back to the 12-bit-linear R3D files and generate the 10-bit log DPX sequences from them.

I think with the latest everything, it's possible to skip the step of using camera proxies and just use the original R3Ds in your Final Cut timeline via log-and-transfer, but I've heard this isn't the best workflow. Take that with a grain of salt, though, as I have never actually done it myself. I'm still not aware of any way of getting Final Cut to generate DPX sequences with handles directly from R3D files. But again, maybe somebody with more knowledge can jump in here. Hint hint, guys. ;-)

Re: dpx questions
January 15, 2009 02:05PM
I think I really opened a can of worms here : )

Since it seems common for post house to work with dpx files
There must be a reason for them to request it.
My big question is how do I achieve this?

Re: dpx questions
January 15, 2009 02:08PM
At this point, all I can do is recommend strongly that you start googling about Red-to-DPX workflows. There's a lot of information out there, provided by folks who can go into much more detail than I can.

Sorry I couldn't give you step-by-step instructions.

(You can also try asking if your post house can take a set of R3D files and the offline EDL. They might have a pipeline already in place, saving you from having to build your own. It's worth asking.)

Re: dpx questions
January 16, 2009 01:10AM
Thank´s Jeff, I will check it out.

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