If you’re shooting a feature with a Red camera, the obvious format choice is 4K REDCODE RAW at 24 fps. The question is, what next? The announcements Red and Apple made at NAB clarified a lot of this (even for people who aren’t using Final Cut), but not everything.

What do we know? Well, we’ve known for a long time that the camera would ship with REDCINE, a program for doing “one light” color correction and exporting footage to other formats. But working with 4K (or even 2K) uncompressed requires far too much storage for low-budget indies to reasonably manage, and there was never a really obvious choice for a high-quality compressed format. (Well, except, possibly, for CineForm, which I admit I don’t give the attention it deserves, since I’m Mac-based and CineForm was until recently Windows-only.)

The ideal case for low-budget indies is a fully-compressed workflow starting with native REDCODE support in commonly used applications. And the way to get that is through supporting REDCODE in QuickTime, which Red has been discussing for a long time. Until NAB, though, we didn’t really know how that would work. Now we know a lot more. And the news is good.

Actually editing online at 4K is presently unreasonable on commodity hardware, and there wouldn’t be much point, as you couldn’t monitor 4K anyway. At the same time, rendering out proxy files to edit, and then doing a conform process once editing is done, is a big hassle. Fortunately, there is a solution here. As I’ve discussed before, REDCODE is a wavelet codec, and one of the interesting properties of wavelet codecs is that they make it possible to extract fractional resolutions very efficiently. That is, if you have a 4K file, you can easily extract 2K, 1K or even .5K footage directly from it, without having to decode the full 4K data and then scale it down.

The question on a lot of people’s minds has been how you’d take advantage of this neat ability for QuickTime apps with no REDCODE-specific support.

We now know Red’s answer: reference movies.

What’s a reference movie? A reference movie is a tiny little QuickTime movie consisting of a pointer to a file containing REDCODE data, and instructions on how to decode it. If you’ve got some 4K REDCODE RAW data and you want to work with it in a QuickTime app at 2K, instead of loading that file into the app directly, you point the app at the appropriate reference movie, which will tell the REDCODE QuickTime component to extract 2K from the 4K file, and pass that to QuickTime. To get 1K data, you point the app at a reference movie that instructs the REDCODE codec to pass 1K data, and so on.

While this is a little less clear, I would expect reference movies will also be able to specify what quality image is to be passed, so if you’re just editing you can get the results of a wavelet fractional resolution decode (which is fast), or if you’re doing a final conform (at, say, 2K), you can get the results of decoding the full 4K and using a high-quality scaling algorithm to produce 2K (which is slower).

Another important piece of the workflow puzzle is the fact that the REDCODE QuickTime codec will support both REDCODE RAW and REDCODE RGB interchangeably. This is very important for a compressed workflow. Remember, you can’t output to REDCODE RAW on a computer. A RAW format encodes unprocessed sensor data, which isn’t at all like the pixel data that comes out of a rendering pipeline. What this means is, a compressed workflow starting with REDCODE RAW is going to necessarily need to mix RAW and non-RAW clips. The fact that Red is supporting both RGB and RAW variants seamlessly within what appears (to QuickTime) to be a single codec, is what enables this.

Finally, while REDCODE uses a 12-bit linear color space internally, different apps will work best with data presented in different color spaces. In Shake, for instance, you’ll probably want to bring in REDCODE data as 16-bit RGB. In Final Cut, in contrast, you’ll want to bring in 32-bit YCbCr (which is still 4:4:4 in FCP, by the way), because Final Cut doesn’t support RGB at anything above 8 bits. The REDCODE QuickTime codec will also accommodate these requirements, converting between color representations as appropriate. (Which isn’t nearly as problematic in these larger color spaces as it is in an 8-bit world.)

Where do these reference movies come from? They’ll be generated automatically by the camera, and they’ll be sitting on your digital magazine, along with your actual footage. I’d assume there will also be a desktop utility which you can point at a REDCODE file to generate an appropriate reference movie as well.

When you put all of this together (and assuming I’ve understood it all correctly; this is basically synthesized from a large number of posts over on RedUser.net), you get a solution which lets the large number of QuickTime apps out there work with REDCODE RAW and RGB data in a flexible, largely transparent way.

Up next: 2K and 4K workflows on the desktop.

This entry was posted on Saturday, May 5th, 2007 at 3:08 pm and is filed under Apple, Red, Workflow. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.