[Matt Wilson] “I have some AVCHD clips so I need to transcode to ProRes 422 to get best performance in FCPX. I got Edit Ready 2.0 software…I transcoded the files to ProRes 422, but the ProRes 422 files are actually a bit smaller than the original AVCHD files…I thought transcoding to ProRes 422 was supposed to increase the file size by about 3-4 times the original?…”
You possibly re-wrapped the files, not transcoded them. EditReady can do either, but rewrapping is normally preferred for AVCHD. It is much faster than transcoding and does not alter the true bit rate, although it’s conceivable the reported bit rate could vary based on how you’re inspecting that. Verify what you did and that you selected the rewrap (not transcode) option. That is in EditReady, top right of window, under “Preset”. It should say Rewrap.
On a decently-equipped editing machine you normally don’t need to transcode 1080p AVCHD or H264 content to optimized or proxy media to obtain good editing performance. After rewrapping the AVCHD files you can import those with “leave files in place”, which is very fast.
If the AVCHD files are “bare”, e.g, they’ve been removed from the AVCHD file bundle, you do *not* want to import those with “leave files in place”, since that can cause performance problems — unless they are first rewrapped with EditReady.
You have two main methods to handle the AVCHD content:
(1) If it’s within the AVCHD file bundle, import from FCPX. “Leave files in place” is not allowed in this case, and the media will be automatically re-wrapped and copied to the library.
(2) Rewrap with EditReady before Import. This works whether the AVCHD files are in the bundle or already removed. That makes the import much faster and enables the option of “leave files in place”, without any performance problems.
For either of the above, FCPX can optionally create proxy and/or optimized media during import or afterward. In general this isn’t necessary for 1080p content on a good machine.