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The Art And Technology Of Listening, Part 4
Final output of audio
By Carmen Borgia

In the life of your project, the content youíve produced may take many forms: NTSC or PAL video, high definition broadcast, 35mm film prints, DVD, QuickTime movies, streaming video and whatever other formats compose this hill of beans we call media. When you complete your mix you will have some number of discrete (separate) tracks at the fullest resolution possible waiting in your authoring system. Pro Tools, Final Cut Pro, Avid, audio tape such as DAT, DA88 or as sound files of the mix; whatever it is must be transferred to the final format(s) to be made audible by civilians.

Mono & Stereo
Stereo is the most common channel configuration; it consists of two channels, a left one and a right one that plays over two corresponding speakers. All editing systems be they funky or fine support two channels of output. Stereo is a baseline format, so even if you do a surround mix a stereo version will accompany it in the event the playback system has only two channels. Mono refers to a single channel of audio played through one or more speakers.

You may mix in stereo, but if the playback system is mono, it will sum the two stereo tracks into one channel and play them out of its one lonely speaker. This applies to any format that you play through modest systems including television, radio and content for the Internet. It is important that you mix the stereo tracks properly with no phase issues, as these will cause the mono playback to sound different (sometimes quite different) from the stereo playback.

Surround is trickier than stereo, if only for the need to monitor on a more complex speaker setup. I wonít say that it canít be done with modest means, but there isnít enough room here to go into all of the details. One strategy is to do your best in stereo and then take it to a post facility to finish and output.

Leaders and Beeps

This is the part of the process where countdown leader and a two beep save the day. While time code useful, it is not to be trusted alone for sync. You need something more basic to confirm it is working. Use countdown leader with a beep on one of your audio tracks at the number 2 (two seconds before the first frame of action). At the end of the piece add a flash frame a few seconds after the program ends with another beep to go with it. Include these ď2 popsĒ any time you are moving sound and picture between systems. It allows you to quickly insure that your systems are running at the same speed.

The completed audio must be synchronized with the picture and laid back to the master tape. How it is done depends upon what system youíre using and your workflow.

Mix in a video workstation, output from a video workstation: Output the picture and sound to your master tape or export compressed files for DVD authoring. No muss, no fuss.

Mix in Pro Tools or other workstation, output from a video workstation: Output a left/right pair of 48khz/16 or 24 bit files of the entire mixed project from Pro Tools. Each of these files will be the length of your entire program. Import those files into your video editing system, line up your beeps and output to your master tape or export files for DVD authoring.

Mix in Pro Tools or other workstation, output to the final master tape: The onlined master tape is locked up to Pro Tools and the audio is laid back directly to the master tape. This can be done with pricier DVCAM decks as well as Digibeta and HD formats, but not with VHS & mini DV.

DV, DVCAM, DigiBeta, and HD as well as DAT play the same type of digital audio, which is uncompressed PCM stereo or more tracks recorded at 48 Khz and 16 or 24 bit resolution. This is the same quality that your mixing system outputs, so you should have no quality loss going from mixing system to master tape. The big variations are in the quality of the playback system and the longevity of the tape stock.

Other Audio Elements:
In addition to a master tape with a full mix, you may create split tracks (D/M/E) a mix minus narration or a music and effects track (M&E).

Split tracks: Also called a dialogue / music / effects mix, this arrangement splits the various elements of the mix onto separate tracks of a DA88 eight channel tape or set of sound files in .WAV or .AIFF format at 48khz. Different types of films have layouts particular to their needs.

Narrative film:
1- dialogue left
2- dialogue right
3- effects left
4- effects right
5- music left
6- music right

1- narration (mono)
2- interviews (mono)
3- effects / b-roll left
4- effects / b-roll right
5- music left
6- music right

Documentary, no narration:
1- interviews (mono)
2- effects / b-roll left
3- effects / b-roll right
4- music left
5- music right

Play a set of tracks together and youíll hear the original mix. The purpose of split tracks is for re-cuts, cut-downs and trailers. Import these tracks into your video workstation, sync to picture from your master tape and start cutting. You will be able to easily smooth out music and effects transitions and then re-output. Split tracks are also useful if music rights are in question since cues can be swapped out quickly.

Music & effects tracks: Another element is the M&E, which is used in the case of foreign language dubbing. All of the music and effects are left untouched, but the dialogue and narration is removed from the mix, clearing the way for your film to be dubbed for release in other languages. When the dubbing is complete, a new mix and master tape is created.

In a documentary, a mix minus narration is used. The narration track is turned off and the music and effects are undipped, which is to say that where the volume of backgrounds and music has been turned down while the narrator is speaking, they are now flattened out. This is because the new foreign language narration that is added may not be the same length as the original narration. On and off-camera interviews are left in the original language and are not typically dubbed, though dubbed interviews are not unheard-of.

M&Eís for narratives are more difficult. All of the dialogue and any shred of original language (in crowds, etc.) are removed. Since some sound effects and ambience is often supplied on the track along with the dialogue that has been removed, they must be replaced. The film is meticulously foleyed, new room tone and ambience is added and a new mix is created. This is called a fully filled M&E, and it can be quite time-consuming to create. You may say, ďI hate dubbed films, Iím doing subtitles!Ē If your distributor consents to that arrangement, more power to you. M&Eís are usually delivered as a stereo mix on tracks 3&4 of a textless master tape.

How Do You Know What Youíll Need?
If you suspect that your film requires additional cutting at some future date, donít make split tracks or M&Eís until all picture editing has ground to a halt. Amending sound elements after they have been created costs time and money. If you are cutting the primary version of your film down, donít use split tracks as you lose some mixing options and your audio may be degraded by subsequent outputs. Instead, re-conform the original mix session in your audio workstation. If your film is picked up, the distributor or broadcaster will be able to provide you with a deliverable sheet, which spells out in detail what is required. The most cost-effective path to generating final, deliverable sound elements is to obtain the deliverable sheet before ordering or creating anything.

Output for DVD:
Elements submitted for DVD authoring may be either a completed master tape with audio or sound files delivered separately from the picture. Having the sound on an approved master tape is probably the best way to go because you can refer to it in the event of sync or other discrepancies. DVD encoding compresses the audio and picture, making compromises in quality to fit all of the information onto the DVD. This encoding breaks the data into packets that span several frames, so frame accurate adjustments of picture are not possible in a DVD authoring system (although sound may be adjusted frame by frame). It is best to insure that the sync of your picture and audio is set prior to the DVD stage.

Quality Control (QC):
Because many steps go into a film an operator might not notice a mistake from one step while working on another. A missing effect or a tiny digital tick in the sound track of a 90-minute program can easily slip past an engineer, especially if he or she is not familiar with the program. I was once involved with a mix where the director did not notice missing off-camera dialogue until the second screening. A do-over is costly if youíve made a load of copies for release or dubbed a small number of expensive duplicates for protection. In all cases, the finished master tape should be screened in its entirety to insure that the audio got there ok. Close the doors, turn off your cell phone and listen. Check for clicks and crackle (symptoms of digital issues) and for sync. Keep in mind that some playback systems such as DVD players and plasma screens can introduce delay into the picture, so exercise caution when working with untested setups.

If you mix your film in a facility that does not have the ability to play your Digibeta or HD master tape and the final layback is done elsewhere you should be prepared to check the sync on the finished tape prior to screening or duplication. This may mean paying the facility that does the layback for screening time or making yourself available for the final layback. It is only reasonable to expect that time is precious on a video deck that costs upwards of fifty thousand dollars. The bottom line of QC is that you as producer of your project are ultimately responsible for the quality of the final product.

The final task is to archive your finished project. Consolidate the mix elements from your workstation, in the case of Pro Tools that would be sessions and media and burn them to CD or DVD. Render out the final mix and split tracks as .WAV files and burn those as well. If youíre feeling conservative in a good way, dedicate a FireWire drive to backups and keep a second copy there. Lay a copy of the mix to DAT or DA88 and make a safety clone of your finished video master. Label all elements clearly. Box up the sound (and picture) elements you have and make a detailed list of everything. Include the list as a text file on a CD and print out a copy for each box you have filled. Discard any useless material. Do you really need to keep DVCAMís of your first three rough cuts? Make a duplicate set of master tapes and split tracks and store them in another location.

This may seem like a lot, and for simple projects a clone of the master tape may be sufficient, but if you own your material, the day you spend wrapping things up will pay off three years later when the distributor finally calls and you canít remember what version you last screened. Additionally, the longevity of digital media is in no way certain - I have eighty-year-old 78 records that I can still play, but some of my DATís from 10 years ago are unusable. Be especially wary of content that is proprietary to a given piece of software; while you may not one day be able to open a Pro Tools session with all of its tracks and plug-ins intact, .WAV and .AIFF files will probably persist for some time, if only because they are so ubiquitous. Hard drives are prone to mechanical failure, and besides, who knows when theyíll come out with something so zippy and huge that weíll dump our FireWire drives like a moldy bag of 8 track tapes? CDís and DVDís are cheap and drives come with almost every computer you buy, but nobody really knows how long the dyes on the disks will last. Your best bet is to archive a number of copies on a variety of formats and to check in on them every couple of years. And if you buy a new computer, itís not a bad idea to make sure it will read some of your old CDís.

To Summarize:

  • Your final product can exist in a variety of formats with differing audio capabilities.

  • Countdown leader with a two beep and a tail beep greatly aid in insuring sync.

  • You may create a variety of outputs including full mix, split tracks and an M&E.

  • QC your master tapes.

  • Archive your project in an orderly manner on several formats.


Carmen Borgia is the head of audio services for DuArt Film & Video in New York City. He oversees a post production sound department that provides mixing, sound design, restoration, transfer and printmastering. His department caters to independent projects in all formats from mono optical up to digital 5.1.

Editorís note: If anyone has any questions, please submit them to cborgia@duart.com. Carmen will do his best to answer any of your queries.


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