I used to run PMS on a MacBook Pro mid-2012. A lot of files would direct play. Some I had to add a different audio file to. But for the most part, things went well. I recently built a NAS and it runs XPEnology. It has a quad core i5-2320 and asus motherboard. I run my PMS off of it now. But files that used to direct play, now transcode the video. In the "Now Playing" area it says for the file playing "Video-transcode(x264). Nothing changed, except running off the NAS. Same client and same files. (Vizio smart TV's) I point my MacBook at the files on the NAS and they direct play.
The MacBook and the NAS are running the same version of PMS. (1.0.3.2461) The NAS transfers files at around 120M/s.(copied several of the larger videos back and forth. NAS has gig NIC) When I watch the transfer rates on NAS during playback they are about 1-2M/s.
I can't seem to find a way to make the NAS playback with direct play without dropping the file size to less than 4gigs.