User Manual

Capturing Directly from a DV Device
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RS-422 Controlling a DV Device Configuration
DV capture offset is primarily designed for configurations where an RS-422 controller is used to
control a DV device and the DV stream is captured over a FireWire cable. For example, you
might be working with an analog deck and a transcoder. You control the deck using RS-422, but
the data moves from the deck to the transcoder, and then into your Avid editing application as a
DV stream over a FireWire cable.
FireWire Configuration Without Timecode
You can also use DV capture offset in a configuration where the DV stream is captured over a
FireWire cable, but the timecode of the master clip is not received through an RS-422 controller.
When you adjust the DV capture offset in this configuration, results could vary, depending on the
number of devices involved.
FireWire Configuration with Encoded Timecode
A configuration in which FireWire control is used to control a DV device and the DV stream is
captured does not use this offset. In this case, the DV frames contain the encoded timecode.
Example of a Capture with Offset
The range of DV capture offset in your Avid editing application is from –6 to 24 frames with the
default value set to 0. To use DV capture offset, perform several captures with the DV capture
offset set to 0. Note the first frame of the master clip for each clip. If the first frame of the master
clip is not what you expect, adjust the DV capture offset to account for this variation.
For example, the following illustration represents a RS-422-controlled capture where the
timecode for capture comes in through an RS-422 controller. The first frame of the master clip is
the sixth frame from the IN point on the tape.
Example of a DV offset of 6 frames: tape frames (top) and master clip frames (bottom)
To adjust for this device behavior, set the DV capture offset to –6 frames. The result should be a
frame-accurate capture. However, the results are dependent on device behavior. If the device
behavior for sending streams across a FireWire cable is inconsistent, frame-accurate results on
capture are also inconsistent.