Remote Color Correction in DaVinci Resolve

Color Grading has long been driven by “superstar” colorists whom top-paying clients are clamoring to work with. While high-end clients might be located in geographically disparate places (Detroit car clients, home goods in Cincinnati, an oil company in Texas), top color grading talent tends to concentrate in major markets like New York, Tokyo, London, and especially Los Angeles. Clients will also develop long-term relationships with a colorist such that, if a colorist decides to move, they want to continue working with them. Top colorists are often in such high demand that traveling to the client doesn’t make financial sense; they would prefer to do a local client Monday, then a Detroit client Tuesday, and a local client Wednesday and not lose two days to travel if they can avoid it.

Thus Da Vinci Resolve has long worked on a toolset for linking together color suites across distant locations to enable a colorist/client relationship not tied down to a single location. There are two major hurdles to doing this: keeping video in sync, and communicating smoothly between colorist and client. Resolve solved the more complicated one quite elegantly.

Lagging Real Time Video

The biggest hurdle is keeping video in sync over the internet between rooms. While we think of video as being relatively easy to send over the Internet (Netflix does this all the time, for instance), it is important to remember that that video is pre-compressed. Before a video is shown on youtube, Hulu, Vimeo or Netflix, a compression process is applied, optimizing that video for internet pipes. The video you are generating when doing color grading is a raw signal, and if you want to stream it live, you need to compress it. If you have watched live streaming on many platforms, you will have noticed that it tends to be low quality and also tends to lag, sometimes by up to several seconds, but always at least a few frames.

That low-quality image is a nightmare for color grading, since it’s impossible for a colorist and a client to accurately judge if they are pushing the image too far together if the client is looking at a low-res live stream that doesn’t accurately reproduce noise, grain, texture or movement. Even worse than the low-quality image of a live stream is the lag. A color grading session involves a lot of back and forth between colorist and client, asking “how does that work” or “is the sky closer to what you were thinking now?” If you are constantly wondering, “are they seeing the thing I just did, or looking at the image from 5 seconds ago?” It makes a session nearly impossible to operate.

To get around these difficulties, a remote session in Resolve doesn’t depend on compression and streaming the video across the internet. Instead, Resolve requires both rooms (the client room and the colorist room) to have Resolve running and working from a pool of local media with matched conformed timelines open on both systems. Once you link together the two rooms, the video doesn’t need to be sent over the internet; only the commands. While a command like “create a new node, draw a circle, feather it” seems like a lot, once reduced to pure computer code it’s a relatively small amount of data to push through internet pipes. This process, only communicating user activity back and forth between rooms, not pushing the full data, is the magic that makes a remote session possible.

Of course, this makes a remote session more setup-intensive than a client simply opening their laptop at their own office and watching the colorist work. The most common scenario is one where a colorist works in their home facility (for instance, in Los Angeles), and then the client goes to a partner facility (let’s say for argument in Detroit) that has been specifically prepared for this workflow.

Preparation

Preparing a pair of suites for a remote workflow requires media, monitoring and Internet preparation. The simplest pairing is ensuring that both facilities have access to identical media to be working off of. With feature films, sometimes having hundreds of gigabytes of data involved, it may be necessary to ship a hard drive. With smaller projects like commercials and music videos, it’s now often possible to use the internet to deliver the smaller volume of media.

Matching the monitors between both facilities is another vital step to ensure that both colorist and client are looking at the same identical monitored image. If possible, most prefer to have the same brand, model, and generation of monitor in both rooms. To go even further, some facilities ensure they are using the same calibration hardware in both rooms to be as confident as possible that the monitors are matching. In a pinch, any monitor calibrated to a certain standard (such as the HD Standard, Rec. 709) should be able to work. Most experienced post professionals, however, have noted that even calibrated monitors differ a bit brand to brand and model to model, and prefer to match monitoring precisely where possible.

Internet setup requires not only fast internet on both sides of the connection, but also someone in both facilities who understandings assigning IP addresses. IP, or “internet protocol,” are the addresses that are used by computers to route information to other computers. Networks have both a local address, which is how computers on one network find one another, and also a public address, which is how computers find each other on the internet.

You will use the IP address to link the two Resolve sessions together. This is not as simple as using a utility like “find my IP address” to identify your public IP address. Your public IP address only points towards the router for your facility. You need to then map the route from that router to the computer that is hosting the Resolve session in order to successfully link the two machines together. You do this by assigning a dedicated port for resolve sharing in the router (by default it’s 15000) to the machine hosting the resolve share. That way, when you put in the IP address and port in the colorist’s Resolve, it has a path to lead it all the way to the client’s resolve.

Port routing is not complicated, but it sometimes requires admin access that is outside the domain of many in a post house. Any competent IT professional can help with the setup, and you should be able to work with your IT department quite quickly to set the correct port mapping for Resolve sharing to work.

Client Communication

The other technical hurdle to overcome is the conversation between colorist and client that is vital to the creative process. Communication between colorist and client is something that is best solved by third-party applications like Skype, Facetime, Google hangouts, or a phone call, although it’s common to see a setup that allows for the client and colorist to see each others faces while they work.

Seeing faces is considered vital since it is often hard to read how people actually feel, and who is in charge, without being able to see them. For instance, it’s not uncommon for a junior creative to be quite chatty, but if you can’t see the whole room of clients you can’t watch as the lead creative director grows less and less satisfied with the direction the grade is going.

Interpersonal dynamics among teams is a large part of navigating a color grade, and that video link is an essential part of the process. Without the ability to talk smoothly and watch each other, it’s very difficult to navigate a remote session. Many post houses invest in dedicated chat applications such as BlueJeans, and some even invest in dedicated cameras and real time hardware encoders that create a more robust conversational link between the two suites.

Limitations

There are some important limitations to the live grading experience. While Resolve guarantees that the two rooms will stay in sync with each other while the machine sits on a freeze frame, it can’t guarantee they will stay in sync during playback. In addition, at this time it only supports color features, and so you cannot make edit, fusion or Fairlight changes while the two machines are linked together. Despite these boundaries, when properly set up a remote session can be a great way to work with the color talent a client desires without paying travel expenses.