Working with Video in Pro Tools

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Pro Tools Notes & Technique

Published in SOS March 2006
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Technique : Pro Tools Notes

Before and after: the sync audio as imported from the OMF file (left), and after it has been reorganised (right). Before and after: the sync audio as imported from the OMF file (left), and after it has been reorganised (right).

Over the last couple of months, I've explained how your Pro Tools system needs to be set up to work to picture, and how to get audio and video into a Session using an OMF or other source file. In this month's workshop we are going to look at what happens in the audio post-production workflow once we have imported the OMF into our Session, and the typical steps you might go through to get from this OMF to finished, mixed programme audio. We left off last month at the point where we had created a video track and imported the OMF file into our working Session. So now what?

Getting Organised

Take a look at the two screens below. Both are screenshots from the Edit window of a TV audio post-production Session. The first is how the Session looked immediately after importing the OMF file into it and the second is from the completed programme. Notice that the former consists of just mono tracks, like a Pro Tools Session from the days before we had stereo tracks. The track names are generic (A1, A2, A3 and so on) and those tracks that appear stereo don't always contain stereo material, as with A3 and A4 in the middle of the window: there is audio on A3 that isn't on A4.

To get everything in order, I look at how the tracks have been laid up by the video editor and start to rearrange them to suit my way of working. I create a batch of stereo tracks and name all the tracks to help navigation. I knew from the video editor that in this case tracks A1 to A4 were original sync sound. That is sound that was acquired 'in sync' with the original pictures. Note this may, or may not, be any use. The sync sound may have the director talking all the way through the shot, it may have been badly recorded, if there was no specialist sound recordist on the shoot, or it may simply be unusable because of unseen extraneous noise like a lorry passing just out of shot. In TV the director will rarely allow time to wait for a 'quiet window'. In music work it's 'we will fix it in the mix'; in audio post it is 'we will fix it in the dub'! In this example most of the sync sound was 'dual mono' where the same signal was recorded on both tracks. However some scenes were 'twin mono' where a different mono signal was recorded onto each track — in this case, the camera mic on one track and a personal radio mic on the other.

In my Digibase database of sound effects, I've used the 'Database Comment' field to enter information on each file that can be searched. Here are the 19 entries that are found by searching under 'lorry pass'. In my Digibase database of sound effects, I've used the 'Database Comment' field to enter information on each file that can be searched. Here are the 19 entries that are found by searching under 'lorry pass'.

Having rearranged my tracks, I start working through the Session looking at what has been laid up by the video editor. Some choices are easy. For example, I move all the music onto stereo tracks and label them Music, Music 2 and so on. I do the same with any Commentary track too. I also create some stereo sound effects tracks ready for the extra sound effects I will add later, either to replace poor sync sound or to cover non-existent sync sound.

I check each region in the Session to find out what it is and how useful it is. If the sync sound is 'dual mono', I get rid of one half to save cluttering up the session. If it is 'twin mono' then I listen to each track separately and decide which one to use; alternatively, if the shots are cut so there are both wide shots and close-ups, I may choose to keep both tracks and mix between them to suit. Even if the sync sound is unusable I will listen to it to help me select a suitable sound effect to replace it with.

The opening shot of this example had a lorry coming into shot from the background and passing from right to left, followed by a shot of a combine harvester. The sync sound was in mono, probably from the camera mic, and I chose to replace most of it with stereo effects from my library. The only sync sound I kept in this section was a close-up of the combine harvester coming into shot at the end. I needed a 'new' lorry and a combine-harvester effect and so went to the library to find suitable candidates.

Post-production work is thus a matter of systematically working through the Session adding and replacing sound effects, massaging the transitions with cross fades and so on, and then mixing the effects in with the sync sound, commentary and music to produce the finished programme.

Useful Links Sound-Effects-Library.com www.sfx-gallery.co.uk/ Sonomic www.sonomic.com/ Soundminer www.soundminer.com/ Mtools www.mtools.info/ Doctor Who story www.digidesign.com/news/details.cfm?story_id=2949 'You Are Surrounded' series in SOS www.soundonsound.com/sos/aug01/articles/surroundsound1.asp

Sound Effects

Post-production facilities have libraries of sound effects. These will be a combination of commercially available libraries from companies like the BBC, DigiEffects, Sound Ideas and the like, and their own specially recorded sound effects. A growing third source of sound effects is on-line downloadable libraries like Sonomic and Sound-Effects-Library.com (there are some 200-plus of my own sound effects available on the latter!). These sites allow you to search for a particular sound effect, audition it, buy it and download it to use it in your project.

In the early days sound effects were stored on vinyl and quarter-inch tape and you searched through books for a particular sound effect, then went and got the tape or disc off the shelf and played the effect from that. Then CDs came along, first with paper directories and then searchable databases, but now the most common storage technique is to keep them on hard drives, either as MP3s or WAV files, and use dedicated software such as Soundminer or Mtools from Gallery Software to search, audition and import them directly into Pro Tools.

Files can be dragged straight from Digibase into the Edit window. The larger grey outline shows where the region will be created when I drop the file. Files can be dragged straight from Digibase into the Edit window. The larger grey outline shows where the region will be created when I drop the file.

Alternatively you can do as I do and use Digibase Pro from within Pro Tools TDM. This enables you to search and audition your sound effects library without ever leaving Pro Tools, but isn't available on LE systems. I have all my sound effects (over 20,000 and growing!) on one drive and I have used Digibase Pro to catalogue them all, so from the Catalog section of the Workspace window I can select my Sound Effects catalogue and open it in another window.

From this window I can search for a suitable sound effect, for example for the opening shot in the Session described here. Click on the magnifying glass button on the Catalog window and 'Find' row will appear towards the top of it. You can do a search in any of the fields. On my system, the sound effect details are in the 'Database Comment' field, so I enter a suitable set of keywords in this field (in this case I chose 'lorry pass'), hit Enter and Pro Tools searches my catalogue of 20,000-plus sound effects and comes up with 19 items. Now I can audition any of these possible candidates in two ways: clicking and holding on the 'speaker' icon for that file plays that item from the start, whereas clicking and holding anywhere in the Waveform section plays the file from that point. Once you have identified a suitable file, you can drag it from the Catalog window across into a suitable track on the Edit window. Note that as you drag it around the Session, the video will scroll backwards and forwards, so helping you place or 'spot' the sound effect more accurately even though the region is still an 'outline'. Once you let go, Pro Tools will then automatically import and convert the file in the background. Whilst it is doing this it shows the region in light blue. Once the conversion process is finished, this will change to a normal region with name and waveform. At this point, I rename the region with an appropriate name for the Session.

Thanks to Digibase Pro I have been able to search for, audition and import a sound effect into my Pro Tools Session all without leaving Pro Tools or my seat! With sample CDs, I would have to had to switch out of Pro Tools into a separate sound-effects database, in my case Filemaker Pro, search for an effect, get the list of 19 effects, then get up and pull the appropriate CDs from the shelves, listen to each track to decide which one was right, and finally load that into Pro Tools, and it would have been so much slower.

Spotting Above: I've added a 'sync point' to the effect region at the significant point (in this case, where the lorry passes the listener). This can then be used to 'spot' the region to a timecode value. Above: I've added a 'sync point' to the effect region at the significant point (in this case, where the lorry passes the listener). This can then be used to 'spot' the region to a timecode value. With Spot editing mode active, moving a region opens the Spot dialogue. With Spot editing mode active, moving a region opens the Spot dialogue. An alternative way of placing sound effects within a Pro Tools Session is to establish the point at which you want the sound effect to play and use the Spot feature in Pro Tools to locate the effect in the correct place. Using the example of the truck passing, as covered in the main text, you would first put a 'Sync point' on the region at the point the lorry passes using Command+',' (Mac) or Ctrl+',' (Windows) — in the screenshot, the sync point is the triangle on the bottom edge of the region. Remember you can only have one sync point per region. Now place your cursor at the point on the timeline you want to line up this sync point with (in this case it's a lorry passing in the video). Choose Spot editing mode from the toolbar, click on the time code in the Counter to highlight it and copy it into the clipboard using Command+C (Mac) or Ctrl+C (Windows). Trying to drag the region will now open up the Spot window. Paste the timecode value from the clipboard into the Sync Point field and Click OK. The sync point of the region will jump (spot) to the timecode point you identified with the cursor, and the sound effect of the lorry should work 'in sync' with the video.

Digibase And LE

You can use Digibase with Pro Tools LE but you won't be able to make or use searchable catalogues. You can, however, search filenames from the Workspace window, so providing your sound-effect filenames have suitable key words in them, you can search for files that way. Failing that, use a separate database like Filemaker Pro to handle the search and then navigate your way to the correct location from within Pro Tools and drag the chosen files from the Workspace window into the Edit window. Apple's iTunes makes an excellent free ripping software package that puts each CD into a nice convenient folder for you.

M&E Tracks

In audio post-production it is usually necessary to provide two mixes: a main mix, which is a mix of the all the elements for the programme, and an 'M&E' mix. M&E stands for Music and Effects and is similar to an instrumental mix for a vocal album project. The M&E track is created to make foreign-language repurposing as easy as possible and so is a partial mix, which contains all the music and effects elements but not the dialogue or any commentary. When it comes to producing a foreign-language version, you have a mix of all the universal elements and all that is required is to add the dialogue and commentary elements in the desired language. Moving material onto specific effects and music tracks makes it much easier to create these M&E mixes.

Going Deeper

In this article, I have outlined some of the basic procedures that go into the audio post-production of nearly all the TV programmes, adverts, and films you will watch. If you want to go into greater detail, I recommend again the book Pro Tools For Video, Film & Multimedia by Ashley Shepherd (Muska Lipman: ISBN 1-59200-069-X). There are also regular articles on the Digidesign web site, including an interesting one about the post-production of Doctor Who in the Users section of Digidesign's UK site. Digidesign's Digizine also has articles and a regular feature called 'Post Scripts'.

Next month I am going to concentrate on recording and mixing in surround for both music and broadcast post-production using Pro Tools. If you feel like doing some homework, I recommend the excellent series of articles called 'You Are Surrounded' published in Sound On Sound from August 2001 to April 2002 (see 'Useful Links' box). 

Foley If you watch the credits from a film you may have wondered what Foley is all about. Foley is the name given for recreating sounds needed to match the action in shot and is done by a person 'acting' rather than assembled from pre-recorded sounds. It is named after Jack Foley, who invented the process when movies were changing from silent to 'talkies'. Foley would be called in to create all the action sounds for adding to a silent movie by watching the movie and re-enacting the actors' movements. Although I tend to use pre-recorded sounds, there was a sequence in a project recently where I needed to add the sound of people eating crackers. I couldn't find a suitable effect in my library, so I miked myself up and played the video from within Pro Tools whilst recording myself first breaking and then eating the crackers, trying to keep in sync with the action on the video track in Pro Tools. I then went back and tidied up the crumbs and the sync errors and all was well! It reminds me of the time when I was working for a commercial radio station and they wanted to make pancakes on air for Shrove Tuesday one year. The station no longer had a kitchen, which was how it had been done in the past, so my solution was to go home the night before and make pancakes in my own kitchen. I must have looked very strange beating the batter and then tossing the pancakes whilst recording it all, wearing headphones of course. The following morning I played the sound effects in as the presenter 'acted out' the process and no-one was any the wiser!