David Gibbons, Project Manager at Soundtracs, gives an overview of post-production working methods.

1. Betacam master tape comes in for dubbing, accompanied by Beta source tapes which have location audio.
   
2. Location audio is grabbed from source tapes according to which segments are used on the master tape. A list is created during video editing which identifies each segment by timecode and tape or reel number. This is called the EDL (Edit Decision List) and can be used by most pro HD systems (e.g. DAR Soundstation) to automate the process of grabbing the audio. This is called autoconforming.
   
3. The grabbed audio is effectively pre-synced in the HD (since the timecode it was grabbed from is stored with it) and the dubber decides which segments to use and which to replace, where to add effects from a sound FX library (usually from CD), grabs the music (CD) which the director has selected, and also grabs the VO (voice-over) if applicable (usually from DAT from another studio). This is the pre-dub stage.
   
4. The director and dubber sit together and mix all the audio assets assembled above. The director usually makes decisions regarding which sound FXs to use, where to replace FX or dialogue, where to bring music and VO in and out and other artistic judgements assisted by the dubbing engineer. The engineer will operate the console and faders, make sure everything is synced and at appropriate levels. He will also be matching the EQ from scene to scene so that everything sounds continuous even though the shots were probably taken hours apart. All this is done with the Betacam on-line (obviously) to make sure everything looks right and in context with the picture. This is the dubbing stage. VO is sometimes recorded at this stage under direction and with reference to the rolling video master tape.
   
5. As the dubbing progresses the engineer will record a 2-track master of each scene once the balance of music, FX, dialogue etc is correct. This is done by continuously dropping in each scene on the 2 track master media (usually HD but sometimes DAT). As each scene is left behind therefore, it is irretrievable. If director and engineer review the project at the end and don't like the change in tone of a VO between two scenes, they have to return to that section and try to duplicate the exact EQ, dynamics, effects and fader balances at that point so that it can be corrected and dropped in again on the master. There can easily be 400 scene changes in a 52 minute program.
   
6. When dubbing is finished a 2 track master exists which has all audio assembled and synchronises perfectly with the master betacam. The betacam's audio tracks are dropped into record and the whole project is re-recorded using the 2 track master to replace the guide audio, and produce a final master audio track. This betacam is then used for broadcast or duplication. This last process is known as layback. For broadcast projects in the UK, an additional mix is then created known as the M&E (Music and Effects) mix. This consists of the same mix without the VO and other language elements. This is done to make it easier to localise the project to another country. If the director sells it to France for example, they can use this M&E master as the basis for their soundtrack, by simply adding french VO and translators over the top. The ducking (places where music is dimmed to make VO or dialogue more audible) is removed as the French version will have longer paragraphs and require ducking at different points. This is recorded alongside the final master (Betacams have four audio tracks).