Tag Archives: compressor

Quick and Easy Dialogue Cleanup with RTAS

Quick and Easy Dialogue Cleanup with RTAS

On Star Trek Into Darkness I had the opportunity to break out of my usual Assistant Editor responsibilities and tackle a new experiment in temp sound editing. Will Files, Matt Evans, Robby Stambler and I formed a new mini-department within Editorial that was tasked with temping out the Editors’ sequences and mixing them in 5.1. There’s a lot to the process that is new and interesting, and I hope to get another post up soon that more fully flushes it all out, but for the moment all I want to talk about is a method for basic, global dialogue cleanup that is probably old hat to some (and par for the course for professional sound mixers), but was new and amazing to me.

This tip comes courtesy of Will Files, who as a loan-out from Skywalker Sound was the guy who guided this whole process on Trek and helped teach me, Matt, and Robby the ropes of the sound world.

RTAS Is Your Friend

Before this show, I didn’t really know what RTAS was useful for, much less how awesome it really is. It allows you to use many of the AudioSuite plugins that you would normally apply to a clip, and apply them to an entire track instead, without rendering (thus the RT in Real-Time Audio Suite). Up to five RTAS plugins can be chained together per track. When applied to dialogue tracks, you can chain together 3 RTAS plugins that will make your dialogue much more understandable and leave more room in other frequencies for your sound effects and music.

So, to get started, you have to show the expanded audio controls in your timeline, and make your track size big enough that you see the little RTAS boxes:

RTAS

You can see that I have an EQ, a Compressor, and a De-Esser, in that order, on my dialogue tracks.  Let’s go through them:

1) EQ

The EQ you add here is basically a band pass with a little customization. Everything below 60Hz is gradually stripped away, as well as everything above 12kHz. This is because your typical dialogue won’t produce any audio in those frequencies that you want to keep, but by throwing it away you can start to address issues of boominess, high frequency hiss, and other technical problems with your production audio that get in the way of understanding the dialogue.

Aside from the band pass, this EQ also lowers frequencies around 120Hz by 2db, and raises frequencies around 4kHz by 2db. Again, this helps with boosting the frequencies of your dialogue that are most useful for comprehension, and removing frequencies that tend to get in the way, but without being as blunt as the band pass since these are frequencies you do want to hear.

RTAS EQ

2) Compressor

Now that you’ve removed unwanted frequencies, it’s time to normalize the volume. For that you use a Compressor, which will actively limit how loud your dialogue can get. If it gets too loud and crosses our set threshold, the Compressor will bring it back in line. The more the volume goes past the threshold, the more it will be reined in. This helps make sure there are no loud surprises in your dialogue, and will save you some of the hassle of mixing loud clips down to a more comfortable listening level.

In this case, we’ve modified three of the settings from their default states:

  1. Knee = 6.0 db.   This adds a little curve right at the threshold point, so that the ratio of a loud input level to its compressed output level is approached more smoothly. Without it, the compression would switch on at full force when the volume crosses the threshold. For a better explanation of this, read this article.
  2. Threshold = -20db.  By moving this up 4db from the default -24db, we’ve allowed our audio to be a bit louder before it activates the compressor.
  3. Gain = 4db.  This knob controls the output level of all audio passing through the Compressor, even audio that is below the threshold line. Since compression only reduces volume and can leave your dialogue levels feeling too low, adding a bit of make-up gain can help keep it at a good baseline.

Compressor

3) De-Esser

This one does exactly what its name implies, and helps with any S sounds in your dialogue that can be particularly piercing to listen to. It’s basically another type of compressor that handles high frequencies instead of high decibel levels.  On this we’ve set:

  1. Frequency = 5.4 kHz.  This means the De-Esser will be triggered for frequencies above 5.4kHz.
  2. Range = -3.0db.   When the De-Esser is triggered, it will reduce the gain of the signal by up to 3 db, which should help reduce the effects of any piercing audio.

De-Esser

As Quick as A-B-C

For those short on time, I’ve attached an Avid bin called Dialogue RTAS Effects.avb to this article which contains these three presets. They are labeled A, B, and C and should be applied to your RTAS chain in that order.

Tip: To quickly copy RTAS effects from one track to another, hold down Option and drag the effects you want to copy from one track’s RTAS chain to another.

 

 

Attachments:

Converting Avid Locators to DVD Studio Pro Chapter Markers

Converting Avid Locators to DVD Studio Pro Chapter Markers

I have two methods for making DVDs for directors, depending on how quickly the DVD is needed and what quality level or features are required. For faster but lower-quality DVDs, I just play out to a standalone DVD Recorder. For higher-quality DVDs I usually export a Quicktime, run it through Compressor, and ultimately bring it into DVD Studio Pro. When I go the DVD Studio Pro route, I also like to take the opportunity to appropriately chapter my DVDs. It’s a pretty quick and easy thing to do, and provides a more meaningful set of chapter points than the automated ones you get on a standalone recorder. My favorite method for quickly chaptering a Quicktime uses Avid locators to provide Compressor and DVD Studio Pro with my chapter points. Below is the process I use, or for the shortcut just use the online tool I created.

TOOL: Locator to Chapter Marker Converter

Converting Avid Locators to Compressor/DVDSP Chapter Markers

In order to convert Avid locators to chapter markers, a little knowledge of regular expressions is required. You also need an advanced text editor that can handle regular expressions (I use the free and multi-platform jEdit). You do not need to add locators to your sequence before you export it. Exporting your sequence and making locators suitable for chaptering can be done in either order. You do need to have exported and processed your locator file before you go into Compressor, though.

Adding Locators to Your Sequence

To prepare your sequence, change the sequence Start time to 00:00:00:00. I normally clear out all the other locators in my sequence as well, and since I always copy a sequence to a new bin before I export it, removing the locators isn’t an issue for me. If you’d like to keep your existing locators, then just add a new video track and put all of your chapter locators there.

Once your pre-existing locators are cleared and/or you’ve got yourself a new video track to work with, go ahead and add a locator at every point you’d like to make into a new chapter on your DVD. Once all your locators are added, go to the Locators window and export them to a text file. If you’ve chosen to add your locators to a new track while keeping existing locators on other tracks, then sort the Locators window by track, select all the locators you just added, and export only those Selected locators to a text file.

Exporting Avid Locators

Exporting Avid Locators

Converting the Locators Text File to a Chapter Marker File

Once you’ve got the text file with your exported locators, it’s time to open it in your advanced text editor. An exported locator file initially looks like this:

Evan Schiff    00:02:18:09    V4    white    Chapter1
Evan Schiff    00:03:11:11    V4    white    Chapter2
Evan Schiff    00:04:57:18    V4    white    Chapter3
Evan Schiff    00:06:41:16    V4    white    Chapter4
Evan Schiff    00:07:37:06    V4    white    Chapter5
Evan Schiff    00:08:29:05    V4    white    Chapter6
Evan Schiff    00:12:33:04    V4    white    Chapter7
Evan Schiff    00:13:33:23    V4    white    Chapter8
Evan Schiff    00:15:19:11    V4    white    Chapter9
Evan Schiff    00:16:14:15    V4    white    Chapter10
Evan Schiff    00:17:44:20    V4    white    Chapter11

Using a regular expression search/replace, you can instantly reformat your locator file to conform to Compressor and DVDSP’s required marker file format, which looks like the text below:

00:02:18:09 Chapter1
00:03:11:11 Chapter2
00:04:57:18 Chapter3
00:06:41:16 Chapter4
00:07:37:06 Chapter5
00:08:29:05 Chapter6
00:12:33:04 Chapter7
00:13:33:23 Chapter8
00:15:19:11 Chapter9
00:16:14:15 Chapter10
00:17:44:20 Chapter11

If you don’t label your locators, all you’ll see in the marker file is timecode. This is fine, the only required data is the timecode, and DVDSP will automatically add chapter labels if you don’t supply them.

To reformat the file, you would use the following regular expression:

^[\w\s]*(\d{2}\:\d{2}\:\d{2}\:\d{2})\tV\d\t\w+\t(.*)$

Your text editor’s dialog box would look something like the image below. I usually do a couple Replace & Find clicks just to make sure the pattern is working before I hit Replace All and save the file.

Regular Expression Search/Replace

N.B. In the Replace dialog box, your text editor may use either $1 or \1 to make back-references.

Importing Markers into Compressor

After you’ve saved your new marker file, open up Compressor and load your Quicktime into it. Make sure the Quicktime is selected in the main window and displaying in the Preview window. To the right of the Preview window’s timeline, you’ll see the marker button, under which you can Import Chapter List. Select your file, and if everything’s been done correctly, you should see markers pop up in the appropriate places in your movie.

Compressor Menu to Import Markers

Compressor Menu to Import Markers

Successfully Imported Markers

Successfully Imported Markers

Once your markers and DVD export settings are ready to go, Submit the job. Once the render finishes, you can import it into your DVDSP template file, and as soon as you lay it down onto a track you’ll see that the markers/chapter points appear automatically.

Why can’t I just add chapter points directly in DVD Studio Pro?

You can, but there are several limitations you’ll be imposing upon yourself. First and foremost, if you make your m2v without adding the markers first, you will not always be able to add a chapter point at the exact frame you want to. To get technical for a minute, when you encode an m2v file the frames of your source Quicktime are compressed into three types of mpeg frames. These are I-frames, P-frames, and B-frames (read your Compressor or DVDSP User Guide for more detail). You can only place a chapter marker on an I-frame, and if you don’t tell the encoder where you want an I-frame to be, it will put them wherever it sees fit, and this may or may not be on the frame that you want to make into a chapter point.

Second, the Compressor and DVDSP timelines are not nearly as precise as Avid’s, and don’t give you the visual identification of where clips start and end. I find it much faster to put accurate chapter points on the Avid timeline than in either Compressor or DVDSP.

You can put your chapter points wherever you like in DVDSP if you import the Quicktime directly and let DVDSP make your m2v file, but then you lose all the advantages of using Compressor, not to mention still having to deal with DVDSP’s clumsy timeline.

Hellboy 2 Turnover Workflow

Introduction

Turning over reels from HD material in your Avid to sound, music, and marketing departments is a process that requires a lot of rendering time no matter which way you do it. At the outset, your two options for getting your Avid material into Quicktime format are to either export the reel directly to QT, or to play out in real-time to another computer running the capture tool in FCP. Below is a table of all the turnover specs for each department, which I think are pretty standard requirements, followed by a discussion for what we tried on Hellboy 2 and how we ultimately chose to accomplish all of these turnovers.

[TABLE=2]

Exporting a QT vs. Playing Out to FCP (for SD Turnovers)

As you can see in the table above, the majority of our turnovers were Quicktime-based. If the Marketing Department hadn’t required an unmasked image, I probably would have used my sound turnover QTs to make their DVD, too. And if I had more time to experiment, I probably would’ve devised a way to export ‘blank’ QTs without a matte and then apply the matte in Compressor, which I actually did do on a few isolated occasions but never ended up incorporating into the workflow. But anyway, moving on…

As I mentioned above, there is no part of making an SD turnover from your HD material that is quick and painless, unless you are going to something with a 29.97 frame rate. The problems are basically these:

  1. Exporting an average-length reel (~20 minutes) from 1920×1080 in the Avid to a 720×486 (or similar-sized) QT takes an average of 1.5 hours per reel.
  2. Playing out via an SD output on the Adrenaline to another computer running FCP means that you’re going out of the Avid at 29.97fps, without giving FCP a way to know where your A-frame is and so reliably bring you back to 23.976. If all you need is 29.97 SD, then the biggest drawback to this is just the quality of whichever type of video output you use (SDI, Composite, S-Video, etc.)
  3. If you play out via HD-SDI to an FCP station capturing in HD, you still face the task of compressing the HD QT that FCP creates down to SD. If you figure 20 minutes to play out, plus roughly an hour to trim the QT and compress to SD, you’re looking at about the same amount of time as an export.

A black box hardware solution that takes HD-SDI and outputs a QT of the specified size in real-time without adjusting frame rate would be great. There must be something like this in existence, but I haven’t heard about it yet and haven’t seen anything in my searches that sounds like it does what I want. So since I couldn’t find a box like this, and since the tedious process of rendering, playing out, and compressing down to SD was roughly equivalent in time to exporting a reel directly to QT, I chose to go the direct export route. Ultimately, that meant a simpler turnover process for us in Editorial, as well as higher quality video for the departments who would be receiving the turnovers.

An Exception:

When we started our turnovers, I did go the playout route for our Composer and Music Editor. Their specs had originally asked for 320×240 QTs @ 29.97, but when I sent them a 720×486 QT just to test out, they decided they liked the higher quality files (who wouldn’t?) and changed their spec. So I played out through a Canopus box to FCP, trimmed the QTs and sent them on their way until one day we decided to test exporting a 29.97 from our 23.976 Avid project. The frame rate test worked (going from 24.000 -> 29.97 still doesn’t, I believe), but at the same time the Music Editor was testing the new QT he was noticing how much higher quality the exported video was. And so the workflow changed again…

Exporting Reusable Quicktimes Efficiently

One of the biggest tricks I developed on HB2 was to create Quicktimes that I could reuse. Since the biggest outlay of time required in turning over is exporting HD material to an SD Quicktime file (AAFs, guide tracks, and EDLs require much less time, and can all be done while the QTs are exporting with time to spare), the more work you can divert to Compressor instead of Avid, the better. We ended up exporting “blank” Quicktimes, which contained almost all of the visual burn-ins required for all of our turnovers except for individual initials. We also exported these Quicktimes without any audio, since it takes time and rendering to pan audio tracks in the Avid (and problems multiply if you have any Time Compression effects), and since you’re limited to 2-track stereo on any QT export from Avid.

This is what our “blank” Quicktimes looked like after they were exported mute from the Avid. They have a 1.85 matte covering the key numbers, the requisite “Property Of”, the version of the reel, and the date.

blank_qt_burnin1

After these Quicktimes finished exporting, we would then take them into Quicktime Pro and add the audio guide tracks we had exported on a different Avid while the QT was rendering out. Each guide track was added as a separate audio track to the QT, which in the end gave us a QT with three audio tracks (DX and FX as mono AIFFs, and MX in stereo). We would then go in and set the channel of each audio track to either Left or Right depending on what we needed (this is changeable at any time, including after running through Compressor), and do a Save as Self-Contained Movie (~1 minute per file).

Once the audio was added and panned appropriately, we would then take it into Compressor for creating individualized Quicktimes. Our basic Compressor settings simply kept the video codec as it was (Motion JPEG A, Medium Quality), and set the audio as Pass-through so as to keep our discrete three-track audio. We then added a text overlay, saved the setting and started the render. Each reel takes approximately 10 minutes to render (keep in mind that results vary by codec), and produces a new, basically identical QT file that looks like this:

personalized_qt_burnin

HD Turnovers

There’s a lot less to talk about when making HD Quicktimes from an HD Avid project. Given the appropriate equipment, which I probably could’ve gotten on HB2 but never did, I think playing out HD-SDI would be the fastest way to go. Video quality is obviously not an issue when playing out HD-SDI, and there are no tricky frame rate issues to tackle. We generally only had to export a single set of HD Quicktimes, just for our mixing stage, so in that case we included the personalization in the Avid title we applied to the reels before export, and eliminated the need to go to Compressor afterwards. As the show neared completion we had a few HD-capable sound and foley stages requiring turnovers, so only then did we use the “blank” QT export -> Compressor personalization process. But again, given an AJA or Kona card, I’d probably would’ve just played each one out.

Summary

It is a lot of steps to create template Quicktimes, but what this workflow gave us was the flexibility to make multiple, customized copies of our reels quickly, easily, and in batch. I can’t count the number of times we were asked to create additional copies with slightly varying specs or burn-ins, and being able to do that without re-exporting from Avid was a life saver. Additionally, Compressor can be happily processing copies in the background while you continue to work in Avid. It may slow down the Compressor renders a little, but as long as you’re not doing anything too processor-intensive in Avid, you should have no problem with running both programs concurrently.

Timewise, the following are pretty accurate estimates, although it will clearly take some more time when you first set up your Compressor workflows or go through the Quicktime Pro process.

  • Prep burn-ins and matte in Avid – 2 minutes / reel
  • Export from Avid – 1.5 hours / 20-min reel  ** (This will change as processor speeds increase. Also, some people have had luck with creating Reference Quicktimes, but I haven’t.)
  • Export Guide Tracks – 5 minutes / reel (assuming you’ve split out your tracks before starting to turnover)
  • Add audio tracks to exported QT file in Quicktime Pro – 3 minutes / reel including time to save as Self-Contained Movie
  • Add individual burn-in using Compressor – 10 minutes / reel

Bonus

Aside from just sticking someone’s name on a QT, here are a few other things you can do with QTPro and Compressor:

  • Make a DVD of the whole feature
    • In QTPro, mark an IN/OUT on each of your ‘blank’ reels at the FFOA and LFOA, then copy and paste in reel order into a new movie. Verify your audio panning and reel breaks (wouldn’t want the reels in the wrong order!), then just Save as a reference movie. Take your reference movie into Compressor, make a new workflow (you can resize/add a matte or text as needed), and render to MPEG-2 and AC3 and burn to DVD in the software of your choice. Voila, 45 minutes of rendering to make the MPEG-2, ~10 minutes for the AC3, and you’ve just made a high quality DVD in less time than it would’ve taken to play it out analog.
  • Save time by rendering two halves of a reel simultaneously (Verify your results. 90% of the time this works flawlessly, 10% of the time there are inexplicable problems at the split point after Compressing)
    • If you have multiple Avids available and are short on time, you can render half of a reel on one Avid and half on the other. Make sure you render with the Use Marks option checked, and that your OUT mark on Avid #1 is adjacent to the IN mark on Avid #2. Once you have each half reel as a QT, copy/paste one half into the other, add your audio, and continue with the process by doing a Save as Self-Contained movie before bringing into Compressor. If you don’t have audio, you can just save as a reference movie. Always verify your results after running through Compressor, I’ve run into unexplained repeated frames at the splice point in my output QTs when doing this and have not been able to reliably recreate the conditions that cause them. But if you’re in a rush, it can be worth the risk.
  • Letterbox
    • I usually output my 720×486 turnover QTs as anamorphic, in part because it’s faster than making everything letterbox, and so far no one’s cared. On my next show I’ll use 864×486, since that’s the proper aspect ratio, and I don’t think I need to take NTSC client monitors into account anymore. Anyway, if you need to do a letterboxed 720×486 QT from an anamorphic original, Compressor can do this for you during your export. Just add the Letterbox option to your workflow and select either Matte or Resize accordingly.