Share The Speed

SHARING YOUR DRIVES

Q I’m really enjoying the speed I’m getting with the Thunderbolt on my new Mac. What’s also refreshing is that it seems a lot more reliable than what I was using before. I was using SATA connections and it worked pretty good—when it worked. Now I have a project where I’d like to share my drive between two edit setups. Since there are two connectors, can I just connect them with two cables? Would I need some software to make it work?
S.S.
Via email

A The SATA connections you were using are eSATA connectors. These are an external version of how many hard drives connect to computer motherboards. eSATA became a popular way to compete against FireWire before the widespread use of USB 3.0. Your mention of "when it worked" could refer to some systems’ lack of support for hot swapping. Hot swapping means being able to disconnect (and reconnect) a drive without having to shut down the computer.

With USB and FireWire, hot swapping was just taken for granted. All you had to do was "eject" a drive via the operating system and then you could remove the connector. But, with eSATA, particularly in its early days, some motherboards didn’t support this feature by default. Instead, for best results, you had to completely shut down the computer.

Now that you’ve moved on to Thunderbolt, let’s see about sharing your drive. You mention it has two connectors. They’re really there to be used in a daisy-chain configuration—looping from one device to another in a chain of up to six devices.

Although you could try to make the case for "chaining" two computers together, there’s the problem of a host (the controlling device for the chain). In this case, the host is your Mac. The host decides when to open a file on a hard drive, when to write to it and when to close it. If you connect two computers to the drive, which one has priority? What if they both try to modify a file at the same time?

Another way to understand the concept is to think about replacing the external hard drive with a monitor. If you hook up two computers to a single monitor, which computer would it display?

But, wait! You can use Target Disk mode. This connects two Macs together via FireWire or Thunderbolt. What about hosts in this situation, where there isn’t even an external drive involved?

With Target Disk mode, you’re really turning one of your Macs into a hard drive. Once booted up in this mode (holding down "T" when it boots up), the computer only functions as a hard drive. You can’t use it to edit or even to view a file. The only operation you can do is to shut down—so it can boot back up as a normal computer.

There’s another way to connect two Macs via Thunderbolt and still have them operate normally: Thunderbolt bridging. Beginning with the Mavericks version of the OS X operating system, the Thunderbolt interface can be used as a network interface.

To use Thunderbolt bridging, once the two computers are connected via a Thunderbolt cable, you go into the Network section of System Preferences on each machine and add a Thunderbolt Bridge service. Use the default settings, and the computers will see each other. If you then "share" the Thunderbolt drive that’s connected to one of the computers (using the Sharing section, also in System Preferences), both computers will have access to it. Of course, you’ll have to manage who gets to erase or modify files using the normal file permissions built into the operating system.

With the Thunderbolt Bridge setup, the computer with the Thunderbolt drive acts as a server. That implies some performance degradation. This can be noticeable if you also try to use that computer to edit. In short, it works, but you might be reminded of some of the early experiences of eSATA.

I’ve seen attempts at trying to daisy-chain three computers via Thunderbolt, but unless you have more than two Thunderbolt ports on the middle computer, you lose any Thunderbolt access and get even more of a performance hit.

All of these warnings shouldn’t make you ignore the concept of Thunderbolt bridging. It can be a useful tool when you want to transfer files quickly from one workstation to another, even if you never use it for real-time editing.

If you really want to share storage via Thunderbolt, you’ll want to check out Accusys (accusys.com.tw). They recently announced a shared disk array with four Thunderbolt ports. Note that this device still requires some additional hardware and software to manage file sharing.

SPEAKING UP ABOUT COLOR

Q I’ve finally arranged to have one of my films go through color grading in a couple of months with a real colorist, once I get everything shot and edited. I’ve done it all myself in the past with some plug-ins and presets, but I find it all looking the same. Anyway, I’m a little nervous about getting what’s needed and, quite frankly, also a little embarrassed to start asking questions now that it’s going to happen. How should I prepare?
M.R.
Via email

A Congrats on collaborating with a colorist on your next project! I know it can seem intimidating, with all the special control panels and the expensive monitors that are calibrated regularly. Oh, and the hourly rate. But the colorists I know don’t bite.

I recently tried out some grading software and realized that I really wanted to see an artist run it. I asked a friend if I could sit down with him and watch him use the software, and was amazed at what he could do with it. While I know that I’m not a colorist, I didn’t realize what a far cry I am from being one.

After a while, we began talking about the whole process of color grading. The art and science were fascinating, but I wanted to get into some of the pitfalls that my friend runs up against working on so many different projects with so many different people.

One of the biggest frustrations he expressed was directly related to what you’re afraid of: communication. He said it’s surprising how many times people will show up with a drive and expect to begin grading. It can be done, but it’s not usually such an efficient process. Instead of using all of his energy on the grade, half his time is spent getting things to the point where he can start grading.

Typically, the colorist wants an XML, AAF or EDL, or some sort of data sequence with links to the original footage. That way, he or she can grade the shots in edit order and see how they cut together. But before the colorist can work on the look, he or she has to conform the XML and make sure all the footage links up properly. That doesn’t always happen very easily.

For example, my friend recently graded a project with a number of drone shots. The fact that the footage was shot with a drone wasn’t the issue—it could have been any number of B cameras. The issue was that many of the original clips had identical names and identical time codes. This meant that, when he tried to automatically link the footage, there were lots of clips that were either offline or in the wrong place. With a sequence containing hundreds of clips, and an original footage drive containing hundreds of folders, the better part of the first day was spent trying to conform the sequence.

Another session started off on the wrong foot when the XML pointed to rendered files rather than original footage. And yet another session got bogged down because shots were synced with double-system sound in the timeline, and the XML was looking for audio files with names that didn’t exist.

Having a conversation about how you’re going to supply the "right stuff" is critical. You really want the colorist to work on grading, not media management. Make sure you give your colorist a rendered movie, with audio, of the locked cut, as well. Although you’ve been eating, drinking and sleeping your project for months or more, this is the first time the colorist has seen it. Having the rendered movie gives the colorist a chance to see your film. It also can be used to verify that he or she has conformed your sequence properly.

Finally, give the colorist time to see what you’ve shot. If you just sit down and say, "Let’s go," you aren’t letting the colorist help interpret the cinematography as it relates to the story. As a result, he or she can end up just following your lead, and that really isn’t collaboration. Obviously, you’re the director and the buck stops with you, but when you box people in by not giving them—and you—the opportunity to create, collaboration becomes just a word.

More about this next column, as I cover what the colorist has to work with once the grade begins.

To have your video production technical questions answered, send an email to [email protected]

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