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The “Fallback frame count” setting is used for fallback scenarios, where the just:in mac channel buffers the number of frames (=fallback i.e. “Fallback frame count”), before switching to the fallback destination or before stopping the recording. We recommend a value between “100-150”.
The” LTC Audio Device” setting can be used to select an Audio In Device, such as a USB audio-in adapter, to sync all channels to a an LTC source.