I am currently using AVC-HD material, and when I transcode to DNxHD, I want to make sure AVID does not transcode it again upon import.  I am using MPEG Streamclip to get the job done.

What are the proper settings that I should use, outside of Color being set to 709 and making sure the correct frame rate and size are set?

Set the codec to an Avid codec.  (ie DNx145) and when you import, set your import resolution to match.

I have the Avid DNxHD codec selected, at 145 1080i (1440x1080) at 59.94fps.  The project is set up with the same specs.  A 45 second clip took several minutes to import, which suggests it was transcoded.  What could be going wrong.

If you render the clip out 601/709 and then try and import as RGB, it won't fast import and will take more time.

Make sure your settings are identical and it will fast import and not re-compress.

That was the problem.  Thanks!!!