This page references a previous configuration of this video reference and sync that has changed in new releases of Previzion. Please reference External Genlock: Integrated Internal Frame Synchronization for the latest configuration.

Multiple Camera Setup Overview

Previzion is capable of integrating with other Previzion systems to allow for multi-camera setups.  This becomes most useful in multi-camera episodic television shows and telenovelas that ordinarily employ 2 or more cameras.

Each “chroma” camera (cameras that require Previzion’s compositing capabilities) requires its own Previzion system.  We recommend using the rack mountable configuration with up to 3 systems (+ spare) per rack installation.

Taking Into Account Frame Delays

Passing a video signal through Previzion, like any other video devices, causes a minor delay in the video.  Previzion delays the footage by 5 frames.   In multi-camera applications,  cameras that do not see the green or blue screen in its framing do not require Previzion and, hence, do not get this 5-frame delay.

Ordinarily, this is not an issue.  However, if the intention is to mix or cut in real-time in a specialized mixing/cutting board, we need to delay the non-Previzion signals before it gets to the mixing board.

This is also the case when using specialized recorders that are able to record several cameras at the same time.  Offsets in timecode and reference (sync) are not accepted by these recorders.

To take this into account, when recording in specialized multi-signal recorders, the Previzion video signals would require their own recorder separate from the non-Previzion recorders.

And in live or “live to tape” applications, where the camera signals are cut in a specialized mixing table, the clean video signals need to receive 5 frames of delay to match the timing of the Previzion signal.

To add this delay, we recommend using a separate signal processor that is delay capable.

  • From For.A, the FA-9500 is handy to add this delay and is guaranteed to pass ancillary data packets (as long as input/output formats are the same).


Taking Into Account Sync Offsets

Previzion currently does not sync its output to its input.  Whatever the incoming video signal is, the Previzion output will not match its output 100%.

Although all 8 of Previzion’s video signals are verified signals, the reference sync in these outputs do not match the input’s sync.  In most general applications, this does not pose any issues.

However, as previously mentioned, in live or “live to tape” applications, where all cameras signals are mixed and cut in a specialized table, all sync references must match to prevent horizontal “rolls” from one signal to the next.

This means that in these applications, every Previzion signal must be re-synchronized in an external frame synchronizing device.

To process the signal and synchronize it to a given reference, we recommend the following external signal processors:

  • From Harris, the X50.
  • Also from Harris, their 3GB/s line, X75 or X85, also are very capable of performing this task.
  • From For.A, the FA-9500 is also rated to re-synchronize video signals.

It is part of Lightcraft’s road map to sync the Previzion output to its input so that no external devices are necessary.