User Manual

Preparing the Hardware for Capture
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To check the sync source, do one or both of the following:
1. Check the lights on the front of the Avid Nitris.
If the Avid Nitris is locked to a valid sync signal, the Lock light and either the HD REF or
SD REF light are constantly on. For more information, see “Avid Nitris Front Panel” in the
Help.
2. Check the Video Lock icon or the Ref Lock icon in the Capture tool.
For more information, see “Setting the Video and Audio Input in the Capture Tool” on
page 191.
Establishing Sync for Audio-Only Input
When you capture audio with video, the video input signal provides the timing reference for
capturing analog audio. This ensures that the audio and video remain in synchronization.
When you capture audio only, the audio timing reference is taken from the same source as the
video output timing. You set the sync source for capture and output timing through the Video
Output tool. For more information about connecting a reference signal, see “Selecting the Sync
Source for Output” on page 1039.
If you are capturing audio only, and the audio must be resynchronized with video, you must
make sure that the audio captured remains synchronized with the associated video. There are
several cases to consider, depending on whether the input is analog or digital, and (in the case of
digital input with some Avid input/output hardware) whether sample rate conversion is involved.
Analog Audio Input
If you are capturing audio-only from an analog source, sync is taken from the sync source, either
black burst or tri-level, depending on the selection in the Video Output tool. If no sync source is
connected, sync is generated from internal timing.
With some Avid input/output hardware, you can view the selected sync source in the Hardware
tab of the Audio Project settings dialog box, in the Sync Mode field. To be sure you see the
correct sync source, view the Audio Project settings with the Capture tool active, or with
channels armed for passthrough in the Audio tool.
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If you need to synchronize audio with video clips captured separately, Avid recommends
that you connect a sync source to both your Avid input/output hardware device and the
audio deck. Otherwise you might experience drifting of the audio during editing.