CinemaDNG workflow with raw proxies

A "proxy" is a representation of a video file which is less resource intensive to work with than the original video. This usually implies lower resolution, significantly smaller file size and intra-frame compression for ease of scrubbing. Proxies have been the traditional way of doing offline editorial video work, where the edit happens in one application, and coloring/finishing is done in another application (and often at a different post facility). You'd use proxies to do the editing work, then the cut is transferred to the originals through the use of an EDL or a similar mean, and coloring/finishing is done using the high resolution original media. In general, anytime the original media stresses the post production hardware beyond its capabilities, proxies would come to rescue.

Recently there's been a convergence of editing and coloring/finishing features inside different video post-production applications. For example, Blackmagic Design's Davinci Resolve, which was traditionally a coloring and finishing application, is now also a fully-fledged editing platform. And Adobe Premiere Pro, which is an editing application by lineage, has improved its coloring features through the addition of the Lumetri Color panel. These multifunctional environments naturally suggest an online editing workflow using the original video (as long as the hardware can handle it). They also blur the boundaries between editing and coloring, which no longer need to be thought as strictly separate stages.

Raw video at high resolutions can be a challenge to many computer systems. It needs fast storage for streaming, good CPUs for decompression and high end GPUs for debayering. Higher compression ratios, as made available by slimRAW, help reduce requirements for storage throughput and CPU power. But GPU needs are dependent on resolution only. That's why high resolution raw work can often benefit from a lower resolution proxy workflow.

Traditionally, proxies would use one of the popular intermediate video codecs like Apple ProRes or Avid DNxHD. slimRAW puts forward a different paradigm geared specifically for high resolution CinemaDNG raw video production: it can generate "raw" files at 50% the horizontal and vertical resolution of the original CinemaDNG raw files. Coupled with lossy compression, this would result in ratios as high as 28:1 when using Lossy 7:1. For example, raw proxies created by slimRAW (using 7:1 lossy) from 4K CinemaDNG will have a 2K resolution and data rate smaller than 1080p ProRes422. Raw proxies created by slimRAW (using 7:1 lossy) from 4.6K CinemaDNG will have a 2.3K resolution and data rate smaller than 1080p ProResHQ.

So what is different with raw proxies and what are the benefits?

• For all practical purposes, raw proxies look and behave like straight off the camera raw files. Lower resolution proxies created by slimRAW are in the CinemaDNG format, the same as the original video.
• Since raw proxies are the same format as the raw originals, the raw workflow inside the post production application is preserved.
• Because the file and folder structure of the proxies mimic the original video, it is very easy to relink back and forth between originals and proxies. All you need to do is change the top media folder. No actual conforming needs to be done.
• Raw proxies allow modification of raw processing related parameters, like white balance, exposure, highlight recovery, etc. at any time. This is particularly nice in the context of unified video environments mentioned above. Going from editing to coloring and back just works. For example, you don't need to re-render proxies to observe an exposure compensation adjustment in the raw settings.

Davinci Resolve is probably the best environment for working with CinemaDNG video at the moment. It is highly capable, performs great and supports both lossy and lossless CinemaDNG. Davinci Resolve is also resolution independent, in the sense that it can seamlessly change source media resolution. You can crop, resize, track power windows, etc. and then relink the media from proxies to originals (or vice versa) and all previous adjustments will be preserved.

In order to relink the raw media in Resolve, all you need to do is select the clips in the Media Pool, then right click them and choose "Change source folder" from the context menu. That's it. Note that it doesn't matter if you start the project with the originals or the proxies. For example, you can start with originals, switch to proxies if you encounter performance issues, then switch to originals again.

When producing CinemaDNG raw proxies for use in Resolve you can use any of the compression modes that slimRAW provides. The smallest data size will be achieved when using Lossy VBR LT and Lossy 7:1.

Premiere Pro isn't as smooth as Davinci Resolve when working with CinemaDNG video. But should you choose to use it for online editing CinemaDNG, here is how you can do a raw proxy workflow. Similarly to Resolve, you can go from proxies to originals (and vice versa) all the time:

1) In the Project panel select the clips you want to switch to originals, right click the selection and choose Make Offline from the context menu. This makes the clips “offline” and enables the Link Media option for them. You can also use Make Offline on a sequence in the Project panel, which is a shortcut for offlining all the clips used in the sequence.

2) In the Project panel, with the offline clips selected, right click the selection and choose Link Media. The Link Media dialog opens with all the selected clips listed. Make sure the "Use Media Browser to locate files" checkbox is not checked. Click Locate, and in the file browsing dialog that appears point Premiere Pro to the folder containing the first clip in the list of clips. Click the first frame and choose Select. As long as the proxy clips in the selection share the same parent folder (and the same should be true for the respective originals), Premiere Pro will then auto relink all of them.

When you relink to the high resolution files you will likely want to have them scaled to fit the sequence frame size. "Scale to Frame Size" and "Set to Frame Size" in the context menu which appears when right clicking a clip (or a selection of clips) in the timeline can help with this. See, for example, here about the difference between the two. More on relinking in Premiere Pro you can find here.

Since lossy compression is not yet supported in Premiere Pro, when producing CinemaDNG raw proxies in slimRAW you have to use one of the Lossless compression modes and make sure the "Premiere CC compatibility" checkbox is ticked.