Postproduction suite

In audio for video postproduction, synchronization needs are an everyday concern. Very often users need to synchronize with a 9-Pin VTR in order to work with video material. At the same time the audio clock has to be synchronized with the video clock source to ensure that both audio and video run at the same speed.

Finished audio can then be recorded back onto the digital audio tracks of a VTR in perfect sync with the video (known as a “layback”). In this example, 9-Pin machine control is used. The audio clock is a word clock signal generated by the house sync generator that also generates the video sync signal. Timecode is handled by a SMPTE to MTC reader, such as the audio interface.

• The house sync generator creates both the video sync and audio word clock so that the VTR and Nuendo play at the same speed.

  When laying back digital audio to the VTR, the AES signal will already be in sync with the VTR’s digital audio inputs.

• 9-Pin machine control is used to manipulate the VTR’s transport.

  The VTR can shuttle, locate, play, and record from commands issued by Nuendo. Also, Nuendo can arm audio tracks on the VTR for layback.

• When the VTR enters play, LTC is fed back to Nuendo which locks to that incoming timecode.

  If the LTC reader is part of an audio card that is APP compatible, sample-accurate synchronization is possible in this scenario.