Synchronization to Digital Beta process has replaced, as years go by, traditional transfer. It consists in transferring the original sound on an NLS station hard drive (AVID Media Composer, Lightworks Touch, Apple Final Cut Pro), and then, depending the rolling speed, in transferring it from the hard drive,
A) for 25 fps:
- on one hand, to a "mute" Digital Beta tape coming from the motion picture lab after direct telecine-tansfer from the negative film, provided with continuous and increasing Timecode.
- on the other hand, digitally to a DAT tape (called "mirror"), on which the same Timecode has been laid down.
This DAT is thus, regarding audio data and time code, a true copy of the Beta SP tape which will be fed to the picture-editing workstation (NLS) and will afterwards be used for the EDL sound conformation process.
B) For 24 fps rolling speed, the original sound is transferred to NLS workstation hard drive, then transferred from that one to a "mute" digital Beta tape which comes from the motion picture lab provided with continuous and increasing Timecode. However, as image transfer to video implies a 25 fps rate, sound must be speeded up (4.1666%) to preserve synchronism. For a 24 fps filming, a "mirror" DAT tape has absolutely no use.