Timecode Source

Previzion automatically searches for timecode in the following order:

• Timecode embedded in the HDSDI VANC metadata
• LTC timecode embedded in the incoming audio data

If neither of these options is found, Previzion will generate reference timecode internally. The UIabove is displayed in the Takes panel.

Analog LTC Input

To read the analog LTC timecode format into the Previzion digital audio inputs, a converter must be used such as the AJA HD10AMA or the AJA ADA4.

Settings for the ADA4:

• LTC is routed into Input B
• Output A of the ADA4 is routed into the AES Audio 1 port of the Previzion breakout box.
• All DIP switches on the ADA 4 are set to OFF.

Settings for the HD10AMA:

• LTC is routed into Input B

Timecode Channel

Under the Takes panel, set the LTC Source to the correct setting:

• AES1 Pair if using the AJA ADA4 plugged into the AES Audio 1 port
• Embedded Pair 0 if using the AJA HD10AMA to embed timecode directly into Channel 0 of the HDSDI video

Flickering Timecode

When the timecode light flickers between ‘Generate’ and ‘LTC’, it usually means that the timecode is coming in at a different frequency than the video frames. (Timecode is set to 23.98 instead of video 29.97, or vice versa.)

 

Recommended LTC Sources

In cases where a direct line to the LTC source is too lengthy, an external LTC sync box can be used. This connects to the original signal and ‘jam syncs’ to the timecode. The box can then be disconnected, and its internal crystal timer keeps timecode sync for several hours.

Models:

• Denecke SB-3
• Denecke SB-T (includes genlock output, not usually necessary)
• Ambient Lockit Box ACL 203

In addition, for debugging purposes, there are IOs apps capable of generating (but not jamming) LTC. The crystal inside LTC sync boxes are much more accurate and reliable than IOs devices, but having an iPhone App with LTC can be handy sometimes. We recommend JumpStart LTC (available from the iTunes App Store).

To input production LTC coming from a BNC cable, for instance, you will need a couple of adapters.  One to go from the iPhone/iPad headphone jack you will need: mini jack (male) to RCA (female) and another to go from RCA (male) to BNC (female).