Assuming issue is not smbios.plist related, at least not directly, as I've tried every variation and the issue persists. Tried updating bios to F5 for my GAZ87N-WIFI board, no change. Interestingly, I CAN stream the video from iTunes to an Apple TV via home sharing.
I'm guessing the issue is that our GPU's don't have whatever the OS is expecting in terms of h264 decode capabilities, so it gets stuck. Perhaps the issue was resolved in previous iTunes builds by going to 32 bit because it disabled such additional decode abilities. Can anyone think of another way to limit what iTunes uses to decode video, or a better explanation? Super frustrating issue as it's my last major problem with my build.