golias wrote:Ah, crap. I spoke too soon. The file I saved to the local drive DOES have a couple playback glitches. My eyes must have missed them when I was watching the first time.
After EXHAUSTIVE testing, I've determined that the issues on that one file I copied to the local drive were unrelated. Then I found some interesting posts over on the Plex forum which supported what I was thinking.
Here's the bottom line: If you are going to build a large media library, STAY AWAY from the 2TB MyBook drives from Western Digital.
These drives are essentially a pair of 5400 RPM "Green" 1TB SATA drives in a RAID 0 array. It can connect to your mac via USB 2, eSATA, FW400 or TW800.
Each of these drives is made up of four platters, so you essentially have eight 250MB platters sharing a single logical volume.
For most uses, these drives do just fine, but it appears when you write LARGE files a little bit at a time, such as creating a Handbrake rip or downloading a multi-GB torrent file, it ends up mangling small chunks of those files.
This is more guess-work than theory, but it seems that once the drive gets a little bit on the full side with mostly large files, it can start to get very fragmented and distribute new incoming files all over it's many platters (in spite of the efforts of HFS+ to keep files together as much as possible)... Which would be perfectly fine, except one of the reasons these drives are "Green" (which is nice: less power consumption, less heat, less noise, warm fuzzies, etc.) is because they tend to park the heads A LOT more often than you would normally want from a high-performance drive serving up media files. Also, it does seem to mangle the files a little bit in the writing process somehow.
I found a pair of single-unit 7200 RPM 1.5 TB Seagate drives at Best Buy for $187 a pop. They are a pain to set up for Firewire use (I had to flip to my Windows partition to run the config software and turn the "sleep after 15 minutes" feature off), but my mysterious video problem appears to be solved at last.
As for the WD... I'm either going to re-format it as RAID 1, to be used as a 1TB backup drive, or else I'll sell it off to somebody who will use it for something less demanding than media files. All's well that ends well.
Thanks for all your help to those who aided with the troubleshooting. It might seem like a waste of time, but for me at least, it was worth it to eliminate software from the possible sources of the problem. Maybe my story can save somebody else a lot of aggravation.