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Re: Do I need 'Optimized' media?

COW Forums : Apple Final Cut Pro X

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Joe Marler
Re: Do I need 'Optimized' media?
on May 6, 2017 at 11:20:26 am

[Brian Thomas] " I do indeed copy the structures to one of my fast G-Drive Thunderbolt disks and, as mentioned, I create Proxy files during the import. I edit these proxies on my top-of-the-range (as it was in Mid 2015) machines with 16GB RAM and I've never noticed any performance issues with as many as seven camcorders plus two external sound recorders."

The performance issue happens if importing AVCHD content with "leave files in place", and without using proxy.

If you copy the entire card structure to your G-Drive, you cannot do an "in place" import. You'd have to then copy only the AVCHD video files out of the folder tree, and import from that location to enable "leave files in place". That is what causes the performance problem -- if you don't use proxy AND import "in place". FCPX apparently tries to dynamically re-wrap each file upon each reference, causing a large number of small I/Os when browsing the Event Browser in filmstrip mode. This is crucial because even a small % of non-proxy "in place" AVCHD files within a database can poison overall I/O performance.

This can be seen using the command-line Dtrace utilities bitesize.d, iosnoop and iopending. When scrolling down the Event Browser in thumbnail mode, the I/O histogram from bitesize.d and file access data from iosnoop shows an excessive number of small I/Os. Removing and re-wrapping those MTS files with EditReady eliminates this. It seems that using proxy may also avoid this, but this essentially requires proxy files for all imported media, otherwise you can't easily browse library content. This behavior is AVCHD-only, I have not seen it on XAVC.

Likewise importing the AVCHD content without using "leave files in place" will automatically re-wrap the files, which also avoids the problem whether you use proxy or not.

On a 2015 MBP (I have one) FCPX is fast enough to edit 1080p AVCHD content without using proxy -- provided that content was either imported from the original folder tree without "leave files in place" or was externally re-wrapped with EditReady then imported with "leave files in place". IMO the fastest method of handling this content is re-wrap with Edit Ready then import with "leave files in place", although the other method will also work.

Note the Dtrace utilities cannot be used starting with El Capitan unless System Integrity Protection is first disabled:

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