Pro Tools Tip
Preparing Reels for Dialog Editing
Part 1 - Loading Master Audio
by Douglas Murray
Preparing to cut a reel of dialog can be a time-consuming and frustrating process for both sound editor and assistant. The auto-conforming process invariably results in sloppy sync, and too often requires extensive trouble-shooting of the EDL and sound rolls to sort out discrepancies in timecode and tape-labeling.
In this two-part article, I will discuss how best to prepare a reel for dialog editing. I will also explain how to facilitate the process using a valuable utility called Titan, which is made by the English company Synchro Arts.
The OMF Option (When We Can!)
A very positive trend is for picture departments to hand over an OMF composition and media files directly from the Avid. When conversion of the OMF into a Pro Tools Session works correctly, it results in a complete and sample-accurate clone of the Avid tracks. I always encourage picture departments to load sound digitally from the location DATs in any way they can. That way, they can
When we don’t receive an
OMF turn-over, the sound
assistant must make sure all
the takes are digitized,
conformed, and in precise sync.
Loading the cut sequence
with handles isn’t enough. give me a master quality OMF turn-over, which can save the sound department a couple of person/weeks. When we are lucky enough to get an OMF turn-over, we don’t need to go through the steps described here.
But there are various reasons that picture departments can’t or don’t load the master audio D-to-D into the Avid. The most common is that the sound is already in sync on the same videotape that the picture is being digitized from. Whether the rushes are synced, screened on film and telecined, or synced on tape by the telecine house, once sound and picture are in sync it seems wasteful to sync again in the Avid. Most picture departments have enough to do during the shoot without this extra task.
PostConform
Digidesign makes a useful program called PostConform that can read an EDL, then auto-load and auto-conform the sound for the reel. It adds a user-defined handle to each clip specified in the EDL, then uses machine control to automatically load each clip, prompting the user to insert a new tape, as required. The problem with this auto-load approach is that the editor doesn’t get complete takes and can’t take advantage of useful material outside the auto-loaded area. Also, clips are named automatically by PostConform in a meaningless way that has nothing to do with the takes. The only way to get each take onto your drive from start to stop with a meaningful name is to digitize manually, as described below. Even though this takes longer, the results save time and a lot of head-scratching later on.
Back to the Grindstone
When we don’t receive an OMF turn-over, it becomes the sound assistant’s responsibility to make sure that all the material required for the reel is digitized, conformed, and in precise sync with the guide tracks. When I’m cutting dialog for a feature film in Pro Tools, I have my assistant prepare the reel with the following steps:
Load All Required Takes From Masters
Each scene and take used in the reel must be separately digitized in its entirety from the master recordings, stamped with timecode from the sound roll and named so that it can be found again. In order to do this, you need to make a list of all the takes used in the reel in sound roll order.
First, get an EDL from the picture department in CMX 3600 format with clip names as comments. If you want a head start on loading, the EDL doesn’t even need to be the final version. Jot down all the takes named in the EDL along with their sound roll numbers. Then after eliminating duplicates, rewrite the list of slates in the order in which they were shot (the most efficient load order) by referring to the sound reports. This will save time in the long run, because handling the sound rolls and finding takes is the most time consuming part of loading, and it’s most efficient to go through the tapes only once per reel if you can. It is also possible to get the picture department to give you an Avid Media Log, or a scene pull list, which might save time.
Now comes the fun part – digitizing all the takes on the list. Create a load Session and make sure that the sample rate matches that of the DATs. In the Session Setup Window, make sure you have LTC (Linear Time Code) selected for positional reference and digital input selected for tracks one and two. Cue each take up at the beginning of the recording and load the whole slate up to the point where the recordist stopped the recorder. The takes will end up in the Audio Files Folder within the Session folder, but they can be moved somewhere else when you finish loading, if you wish.
For mono masters, load only one side of the pair of tracks on the DAT. If material was recorded with two different tracks, digitize both. Examine the sound reports for guidance here, but sometimes the recordist forgets to note whether the recording is mono or split, so look at the meters on the DAT to double check. If in doubt, digitize both.
It is essential that you digitize the sound using "on-line" recording into Pro Tools, so that each digitized take gets time-stamped with the DAT timecode. After cueing the tape, put Pro Tools into "on-line record" mode (click the appropriate buttons on the Transport Window or use the Command-Option-Spacebar key combo). When you play the DAT, Pro Tools will start recording as soon as it sees a moment of timecode. Pro Tools will stop recording when there is a break in code, so stop the tape manually at the end of the take. Turn on the Preference for "Record at Time Code Lock," and make sure that you have a short timecode freewheel amount (maybe 10 frames) in the Session Setup Window. (Do not use jam sync mode, or your files may be time-stamped incorrectly.)
Finally, each take must be named consistently. Titan, which I’ll cover in detail next time, requires that digitized files are named beginning with the sound roll. The file name should also contain the scene and take so that the files will make sense in Pro Tools and on the hard disk. (Because of the way Pro Tools works with file names and sub-regions, it’s best to use a slash for scene/take punctuation.) In order for Titan to recognize a two-track recording, the name for track one (left) must end with ‘.L’ and for track two (right) ‘.R’. Here are a few examples: "001 1/1" (for mono), "027 43/6.L" (for channel 1) and "027 43/6.R" (for channel 2).
Load All Likely Alternate Takes, Too.
This may seem like a luxury, but a little extra digitizing can save hours of searching through the masters later on. One brute force method to accomplish this is to load all circled takes for all scenes in the reel. If time is critical, you can load all circled takes just for scenes with obvious problems.
The next step is to conform the digitized master takes to the picture editor’s guide tracks. In the second part of this article, I will explain how to do so using Titan.
Part 2 - Using Titan to Conform and Fix Sync
by Douglas Murray
Go to Part 1
In the last issue, I outlined some of the basic steps an assistant editor goes through to prepare a reel for a dialog editor and explained how to sort an EDL and load and name the audio from original masters. In this installment I’ll explain how to conform to the EDL using Titan, a utility that will make the process much simpler.
Titan is made by Synchro Arts, a company started by an American programmer named Jeff Bloom. It will auto-conform the picture editor’s guide tracks so that each region of sound is separated from the rest of the track and named according to the EDL. Titan calls this "Flash Conform." It can also automatically "Fix Sync" by phasing the master dialog into perfect sync with the guide tracks.
Using Titan
Launch Titan and switch to its Flash Conform mode. Click on the "Open EDL" button to point Titan to the EDL that the picture assistant gave you, and also click on the "Audio Folder" button and direct Titan to the folder containing the sound files you have digitized.
Your EDL must be in CMX 3600 format and in A mode (sorted in show order). The clip names (scene and take) in the Avid must appear in the EDL as comments. The normal standard for scene and take names is to use a dash as punctuation, but because of Pro Tools’ bad behavior with region names you should use a slash instead.
In the "In/Out" panel, the setting for "Load Stereo" and "Report" should be on, while "Checker Board" and "Name Using EDL" should be off. For a feature film shot at 24 fps, the frame rate for both the EDL and the Session should match the original DATs. In the "Settings" panel, the defaults usually work fine for most situations (Figure 1). (If you select "Use Actual File Length," Titan will properly work with takes digitized in ProTools’ destructive record mode.)
Figure 1. Titan’s Flash Conform default settings for autoconforming an EDL. The options allow flexibility with a range of possible Pro Tools region definitions and file folder organizations.
The result, if all goes well, will be a Pro Tools Session file with all the appropriate regions in the right places on the right tracks to match the picture editor’s work. To see how well Titan did, look at the report it generates in a text editor such as BBEdit or Microsoft Word. The report will contain a list of files found in the Audio Folder, followed by a list of events and any errors in the auto-conform. You can then compare this list of errors to a print out of the EDL.
The most common kinds of errors are:
* The file’s sound roll name as given by the sound assistant doesn’t match the name in the EDL. This could be a typo by picture or sound assistants or some confusion in the naming convention.
* The take loaded by the sound assistant isn’t the same as that used by the picture editor.
* The take was digitized incompletely, so part of the take required by the EDL is missing — due to a timecode dropout during digitizing, for example.
* It’s not dialog! Temp effects and music are not going to be on the location DATs, so you won’t have them.
The digitized guide tracks you use should be the same as what’s on the picture editor’s system. On Avids, editors typically cut four or more tracks of sound, and that’s how many individual guide tracks you should get. The picture editors should output their tracks to DA-88 (eight tracks in one pass) or onto DAT in several passes. You can also use an OMF as a perfect guide track, even if the Avid audio was digitized from a low-quality source. Either method is much better than taking audio from a videotape output because the tracks are kept separate, and digital tape or OMF will be much quieter than audio on video. Phasing the auto-conformed material against the guide track will be quicker, easier and more reliable whether it is done by hand or with Titan.
Fixing Sync
When a time-stamped piece of audio is transferred from one frame-rate to another (30-fps audiotape to 24-fps Avid to 30-fps EDL), sync is subtly disrupted, and the problem is compounded with multiple transfers. The cumulative offset you’ll see can be as much as a couple of video frames, but is usually less than one film frame.
To avoid sync problems, we have to laboriously resync the auto-conformed tracks against the guide track by shifting the position of the master clip until the doubling of the sound is replaced by the distinctive phasing of the higher frequencies canceling each other. In Pro Tools, you can use waveforms to facilitate the process and move clips into perfect alignment visually. Actually listening to the track becomes optional. But to do it properly can still take about half a day per reel.
Titan performs this task automatically in minutes! To set up Titan, switch to the "Fix Sync" mode, click the "Open" button to select the conformed Pro Tools session, and then indicate which tracks are the guide tracks and which are the auto-conformed tracks. Set the maximum search amount (the smaller the search, the faster the processing) and click the "Process" button. The default settings on the "In/Out" panel are good: "Move Audio," "Insert New Tracks," "Autoname" and "Report" should be selected (See Figure 2).
Figure 2. After autoconforming, ‘Audio 1’ and ‘Audio 2’ will need to be phased against the guide track (or ‘Work Track’ here). With these default settings, Titan’s Fix Sync will create new tracks with audio regions nudged into precise sync with the guide track.
Fix Sync works flawlessly for most material, but you should always audition the output session. Two types of errors can occur. If the picture editor has used a piece of very quiet fill or soft breath or cloth movement, Titan may have trouble finding enough detail for proper line-up. Also, if a clip is very low, Titan may throw it further out of sync. I consider this a bug in Titan, but one that is manually correctable.
Another problem occurs when the guide track is a mix of more than one source — either an Avid "mixdown" or a single track turned over via videotape. Titan can’t properly adjust the
To avoid sync problems, we have to laboriously resync the auto-conformed tracks. Titan performs this task automatically in minutes.
sync of one sound against a guide track that contains two or more sounds.
In order to deal with these errors, the assistant must carefully tab through each track of adjusted clips, paying particular attention to low level sounds. I usually have three tracks displayed on the screen: the guide track, the Titaned track, and the un-Titaned conformed track. When Titan makes an error, usually the un-Titaned track is in better sync than the Titaned one. Select the un-Titaned clip and control-nudge it by a quarter frame or less until it is in precise sync with the guide. Then control-option-drag it onto the Titaned track, duplicating it over the error and fixing the problem. This may take about half an hour per reel — still a fraction of the time it would take to fix sync by hand.
Cut Up and Name the Guide Tracks
Finally, I should mention a very useful additional feature of Titan: "Flash Cutter." It is much easier to match the picture editor’s work and to find missing audio if the clips in each guide track are separated, defined and named as in the editor’s system. (Remember hand-marked mag film guide tracks?) This may seem like a novel and unnecessary requirement, but it can be extremely handy, especially if your guide track is a mix of two or more tracks in the picture editor’s system. In "Flash Cutter" mode, Titan will edit and name the guide tracks into regions that correspond to the EDL. When you compare the Flash Cut regions to the Flash Conformed regions, you can instantly see if there are any missing clips and know what track they are from, what they are called and what they sound like.
Titan can play three very important roles in prepping a reel for the dialog editor: auto-conforming, tightening sync, and making the guide track more readable. Assistants can focus on getting the right tracks loaded and named, finding and loading alternate takes and checking that everything is ready before handing over to the editor. In short, Titan is a superior tool for a superior turn-over. Synchro Arts also sells other handy sound tools, including VocALign (formerly Word Fit), which can micro-adjust sync on ADR lines and match them precisely to the guide track, and ToolBelt, a program that, among other things, can generate long chunks of very smooth fill from tiny bits of dialog "air" too short and loopy to use otherwise. I hope to cover their use in a future article.
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Douglas Murray, a sound editor and mixer, has been working in Ireland
for four years but is now back in California.
He can be reached via email
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Reprinted from
The Motion Picture Editors Guild Magazine
Vol. 22, No. 4 - September/October 2001
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Copyright © 2001, All Rights Reserved, The Motion Picture Editors Guild, IATSE Local 700