PluralEyes- Help for that Syncing Feeling


If you’ve ever edited multi-cam shows where the production crew’s attitude seemed to have been, “Sync! We don’t need any stinkin’ sync!” – then this software is for you. Without a doubt, every editor friend I ran into at NAB that happened to pass by Singular Software’s booth raved about this product. “You have GOT to see it,” was the comment I often heard about PluralEyes during that week.


What’s the need?


When you work multi-cam shows, proper sync is essential to line up the camera iso recordings in post. Obviously timecode is ideal, but this only works properly when all cameras were fed from a genlocked master timecode generator. In the case of digital run-and-gun projects (like a low-budget rock concert or reality TV productions), the cameras are running wild and not necessarily synced to each other.


Under the best of circumstances you might be able to get the crew to internally sync the cameras to time-of-day timecode at the beginning of the day or get them to occasionally shoot a large LED timecode display somewhere within a concert venue. In a film-style shoot, they might have started each take with clapsticks. More often than not, this doesn’t go according to plan once in the thick of the production – or the timecode starts out close and drifts out. The latter often happens when a camera gets powered down and back up in the course of the production.


Most modern NLEs have multi-cam editing tools. Typically these let you sync clips by matching timecode or by marking an in-point at some common event and aligning the source clips accordingly. In the film example, the point where the sticks clap shut provide a good mark-in-point. In the absence of either clapsticks or valid timecode, you often find yourself looking for things that become a common reference point. For instance, the same frame in each camera angle, just where the singer touches his nose in a unique way! Obviously this can become incredibly time-consuming and often not very frame-accurate.




Enter PluralEyes


PluralEyes is designed for Final Cut Pro editors. It synchronizes clips based on common audio. It’s not a plug-in, but a standalone application that works in tandem with FCP. The software analyzes the waveform of a clip’s audio track and processes sync based on the commonality of the tracks among clips from different camera angles. In order to work, you must have in-camera sound, even if it’s only a scratch track. Picture-only (MOS) recordings still have to be lined up manually or by timecode.


On the other hand, audio-only clips can be synchronized. If you are shooting a concert, the wild audio from the cameras can be synchronized to the clean audio recording fed from the mixer to an audio recorder. PluralEyes won’t adjust for any sync drift, so such audio tracks still need to be properly recorded. In the examples I’ve seen and tested, the camera tracks can be pretty distorted, which means PluralEyes can still perform the analysis with less-than-pristine audio tracks, as long as it can sufficiently interpret the waveform to establish sync.


The bottom line is that PluralEyes gives you a way to quickly and accurately sync cameras without the use of timecode or manual reference marks. This makes it possible to use smaller, prosumer camcorders in multi-cam projects without creating a synchronization nightmare in post. It also lets you use full-blown pro camcorders in situations where establishing common timecode sync is impractical.




Working with PluralEyes


The way PluralEyes works is so simple for the editor, that it takes longer to explain “why” than to explain “how”. You start out by importing or ingesting all the clips into a Final Cut project. PluralEyes can synchronize clips in a sequence or in a bin, but the key is that you have to name the target to be analyzed “pluraleyes”. Either the bin or the sequence (whichever you want synced) has to be named “pluraleyes” and the project must have been saved for PluralEyes to work.




The most common approach would be to sync a sequence. To do this, place all your camera clips at the start of the timeline. Make sure there are no in or out marks. Stack the different camera angles (with audio) onto ascending video tracks. Camera 1 goes to V1/A1-2, Camera 2 to V2/A3-4, Camera 3 to V3/A5-6 and continuing up with more cameras. All cameras should be lined up at the head of the sequence and on separate tracks.




If you stopped and restarted the camera recordings during the production, then you can place all clips from a single camera onto the same video/audio tracks. I haven’t seen any Singular documentation that addresses this, but I was successful when I did this on a test project. In other words, Cam 1 clips can stay back-to-back on V1, Cam 2 clips on V2 and so on. I also haven’t seen any mention of a limitation as to the number of cameras. My tests included 2-4 cameras, but I’ve seen other internet posts where six cameras were used.




Once you’ve created the sequence to be synced and have saved the project, launch the PluralEyes application and select “sync”. The software takes a few minutes to analyze and process the tracks and to create a new synced sequence, as well as multi-clip groups. Singular’s short, downloadable sample project (3 cameras, 1 minute clips) only took several seconds to sync. Another project that I tested, which was a 3-camera, half-hour interview show, took a couple of minutes. These tests were both on a MacBook Pro.




Once PluralEyes is done, return to FCP and you will have a new synced sequence and source multi-clip groups. In my interview show test, the studio crew recorded it in segments, so each section was broken into a separate multi-clip group by PluralEyes. In the tests I’ve done so far, syncing has been fast and successful in each case. I have had one editor tell me it didn’t work when he tested it, but I have no idea if he was doing everything correctly. In any case, Singular lets you download a trial version to see for yourself.




I will offer one caveat about sync. Since the clips are aligned based on the audio, there is no guarantee that the audio recorded by the camera itself will be in perfect sync with its own video. For instance, if you are recording audio of a concert and the cameras are only picking up the ambient audio from the PA system, it’s quite likely that each camera will be visually out of sync by a frame or two (or more) when synced against a master audio recording from the board feed. This is due to the natural delay inherent in such live venues. Fortunately Final Cut offers some quick functions to adjust clip sync, either for the master clip itself or when trimming clips later during the edit.


Using PluralEyes is a no-brainer for any editor who works with multi-cam projects in Final Cut. There’s also an interesting bundling deal right now with the folks at CoreMelt and they’ve even done a quick tutorial showing how the two projects might be used in conjunction with each other. Check it out.


On another note, Singular is also working with post solutions for the Canon 5D Mark II, which can be found here and here.


© 2009 Oliver Peters