SHOWDOWN: Audio Sync in FCP, Resolve and Premiere (The Results Will Surprise You)
Audio Sync has Never Been Much Fun.

SHOWDOWN: Audio Sync in FCP, Resolve and Premiere (The Results Will Surprise You)

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No one thinks about audio sync when choosing a Non-Linear Editor to use. Most folks figure that NLEs do audio sync automatically. Well, they do and they don’t. In this article, we’ll take an in depth look at three of the most commonly used NLEs and how they really do it.

Why Do We Care?

Well, we don’t care…

…Unless you were smart and recorded your audio to a separate recorder (not on the lousy audio provided on cameras who’s bodies cost less than $6,000). Then you do care, because how are you going to get your audio synced up with the video? Sure you can do it the old fashioned way and just find the “smack” of the slate or someone’s hands and manually drag the audio into place. There’s nothing wrong with that. Unless you’ve got 3,140 dialog lines that you need to sync, in which case doing it by hand will take you weeks just to sync audio. Of course you can use PluralEyes, which is a great way to go if you like that workflow. But if you’ve got something simple or need to drop odd files in and deal with audio on the fly, PluralEyes isn’t going to get you there. You’ll have to use the capability of the on board synchronization of your NLE. I’ll admit that if you did have 3,140 dialog lines, you’d better use something like PluralEyes until the NLEs get better at syncing multitrack audio (more about this later), but if you’re in the 1 to 100 line zone, read on:

The Process

In the standard, sub-standard, “Good Old Days,” we’d take the image of the arm of the slate, smacking the slate, and align it manually with the sound of the “Clack” of it recorded on whatever channel had a microphone recording at that time. Then align the rest of the tracks (which have the same start time as the microphone reference) to the start of that synced audio track. Easy. Simple. Time consuming. But it worked. Now, we have software which can scan both the video file with reference audio (you did record reference audio to camera, right?) and the separate audio files, and than magically line them up. You actually don’t need the “slate reference” clap any more. It’ll figure it all out on its own. Although it’s ALWAYS a good idea to do it, just in case you DO have to sync things manually once in a while. I promise, the take you don’t do the slate clap on is the take you’ll have to sync manually in post.

Regardless of the NLE or syncing software wizardry, you need the following items in order to take advantage of automated computer syncing processes:

  1. Clean recorded sound on the audio recorder. No giant wind noise or rustling. It needs to be 75% clean.
  2. Clean recorded sound on the camera. Ideally, the audio recorder’s output was sent to the camera via cable or wireless connection (read this article for more) to give maximum fidelity. If that wasn’t possible, then it might be permissible to use the camera’s on board mic (if it has one), but you’ll suffer a great deal of fidelity loss which will tax the audio synchronization program/NLE to the breaking point. You must not use the on camera mic if the subject is further than 10 feet away. Read this article to find out why. But this needs to be 50% clean.

Apple Final Cut Pro X

I’ve gone on record saying that FCPX is the most difficult NLE to use when it comes to audio. Although I’ve found some cool fixes to deal with some of this, audio syncing is no different. In FCPX, you should know that you cannot sync more than either a:

  • single mono track or a
  • single stereo interleaved track

If you have multitrack audio, you’ll doing quite a bit of manual baloney using multiclips and worse. For the basic single recorded track, it’s no problem: In your Event window – where all the files are – you select the single audio clip and single video clip you wish to synchronize. Go to Clip/Syncronize Clip. Insure that “audio” is selected unless you have timecode on your video in which case it may be better to use that by unchecking that box. FCPX will then go through the audio of both selections and search for similar audio material. Once found, it creates a “synchronized clip” which has the audio you just selected BURIED in a nested clip. This nested clip buries all audio tracks within it into a singular audio file – no matter if there’s two stereo tracks or mono tracks, FCPX treats them as one single track. I’m happy to have someone prove me wrong on this, but I’ve been unable to “split out the audio tracks” once they’re synced… While you can certainly detach the audio on the whole for L-cuts and the like, you’ll still have your horrible reference camera audio blasting away with your nice clean recorded audio unless you go the inspector (command-4), scroll down to the audio section, locate the reference audio and mute it from there. You’ll need to do this on every track you sync. Did I also mention that you can only sync one video at a time!? Yeah. Boo.

If you have multitrack audio, then you’ll need to pray that you pressed record on set BEFORE the camera went into record. Why? Because there is no way to separate the audio of the reference from the recorded audio, and if the reference started first, you’ll have to hand sync the first track of additional multitrack audio, then align the rest to it. But if recorded audio began first, then it’s a simple matter of dragging all the multitrack audio files to the timeline and start them at the beginning of the synced clip (which will be before picture begins). You’ll have to do this with each track separately. So if you have 8 tracks of audio recorded, you’ll be doing this 7 times per clip. Yeah. Nice.

This isn’t an official CS rating for FCPX, but I’d give it a 45 for sound sync.

BlackMagic Designs Davinci Resolve

In the world of audio sync, Resolve works in much the same way as FCPX, with some notable improvements. I’m speaking here of version 12.5, and we eagerly await the official version 14 with all of the audio enhancements which have been promised. In DR under the “Media” page, you select the audio and video clips you wish to sync. You have several choices in doing this. You can append the recorded audio to the camera reference audio or have the recorded audio replace the reference audio. Once selected, you’ll again want to choose timecode only if your picture and audio have timecode, otherwise choose audio. DR will search the files and place synchronized audio onto the video track in the fashion in which you’ve chosen. There is no additional synced clip or compound clip created. You’ll notice the audio track count of the video file will have changed to reflect your appending or merging of recorded audio with camera audio.

And here is where DR gets a major advantage over FCPX. You can do this to any number of files at once. That’s right: batch sync. If you DO have 3,147 dialog tracks to sync and (important distinction) you have 3,147 video tracks to sync with them, you can dump all the audio and all the video into a single bin, or via a creative manner of command/control clicking from multiple bins have all the audio and video files selected, you can have them all sync at once! Totally dope. If you have audio tracks which span or intersect with multiple video takes, you’ll likely have to manually sync those.

If you are using timecode to sync your audio, DR will sync any number of multitracked clips to a single video clip as well. I’ve had no luck doing this with audio search/syncing alone. If you have not recorded audio with timecode, then you’re limited to a single stereo/mono track which can be synced just like in FCPX.

Once your video clips have the audio synced, you just click over to the “Edit” page and drag them into the timeline and Voila! All the audio tracks magically arrive! Do note that just like in FCPX, DR requires that you do any syncing from the media or events page. There is no capacity for doing this from the edit page.

I give DR a 80 for being able to do a ton of clips at once and to start cracking the shell on being able to do multitrack syncing. I still hate that I can only do it from the Media page, and that the interface is SUPER clunky and…sadly…the audio search and sync function works about 60% of the time. Boo.

Adobe Premiere Pro

The good folks at Adobe have a completely different way of doing synchronization for Premiere: from the timeline. It’s a method I really appreciate, because I can take any number of multitrack audio files and just line them up in the timeline in a reasonably close fashion to the reference clip audio, select Clip/Synchronize then select audio for the criteria, and watch it analyze and snap all the files perfectly. I’ve never used the timecode function in PP, because the audio searching function is so good. What’s the problem with PP? There’s no way to batch sync all the clips in the timeline. You can only do them one at a time. Boo. But doing manual syncing of any kind is never required in PP unlike in the other two applications where it’s likely you’re going to be doing that. I would hope that Adobe creates a way to batch sync from the project window the way that DR does, because then we’d have the best of both worlds.

Don’t forget that PP has a way to do sync from the project window as well: in exactly the same way DR has. Select the audio and video clips you want to sync and select “Merge clips” by right clicking on one of the clips. When you drag the video clip to the timeline, you’ll see all audio tracks present.

I’d give PP an 85, because it completely solves two major issues: multitrack sync and timeline sync, but neglects the more regularly occurring need of batch syncing multiple files.

The Solution

The solution for me is always knowing which NLE you’re going to cut in.

  • If you’re in FCPX, then you’re screwed. Good luck. You’re having to use PluralEyes – which is pretty cool on one hand,  because it’ll actually port its syncing results into a project directly into FCPX while it’s running. Pretty cool. But that’s Pretty Cool PluralEyes – another several hundred dollar application – not cool FCPX.
  • If you’re in DR, you’re in good shape as long as you don’t need multitrack syncing (and don’t have timecode). In this case, you’re back in PluralEyes, and lugging through xmls which DR doesn’t always read. You may, in fact, have to import your PluralEyes xmls into PP (not FCPX BY GOD!!) and then export into a format DR can read.
  • If you’re in PP you’re in good shape as long as you only have a few clips to sync. If you have 3,147, then you’ll need to use PluralEyes. Another good thing is that PluraEyes does the same thing for PP as it does in FCPX: a dynamically linked timeline can be ported directly to PP while it’s running. Dope. The other option is that you import your files into DR, batch sync there, drop everything into a timeline, export as .xml, then open the .xml into PP. You still won’t have multitrack support (unless you have timecode), but at least the bulk of your single tracks will be synced and ready to be cut into a master timeline…although you wont have the great bin structure PP is known for.

All in all, the real solution is someone coming out with an NLE which does all of the following:

  • multitrack syncing
  • batch syncing
  • both bin and timeline syncing

Should this occur, I promise Cinema Sound will be one of the first places you should go to find out about it, because I’ll be screaming it from the rooftops.

Have a different experience syncing audio in your NLE? Tell us about it, or Tweet about it!

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