You are not alone noticing that USB and network decoding don't match up. Almost all of this has to do with DLNA.
Not to repeat all that's been written the bottom line is you're right. And no, so far no sign of this being updated.
Recently purchased the Samsung C7500 Blu-Ray player, and so far it's worked flawlessly, except for the fact that when I attempt to play avi videos from a NAS drive, I receive an error claiming the format is not supported - yet playing the same files from a USB drive works perfectly.
I can play my MP3s and my avi files from a connected usb device with no problem.
I can play the same MP3s from my DLNA certified NAS server, but I cannot play the same avi files. They are listed in the videos section and the device has generated a thumbnail for them, yet they just won't play.
The thing I find odd is that the videos play from a USB drive, yet when accessed from a network location, I receive an error message claiming the file format is not supported, even though this logically can't be the case.
Does anyone have any ideas as to how I can play the videos on my NAS server without having to copy them all to a USB drive first?
Note: I am using the latest firmware and have enable automatic updating.