Just realized how to make some media work with PS4 client and low-end (non-transcoding) NAS.
Basically make sure that subtitles are discarded.
Is there any way to make the server realize that remuxing + burning subtitles (which technically becomes transcoding, I guess) is something that a low-end NAS should manage? (As long as the video and audio streams doesn't need to be converted)
Or will the PS4 client somehow support subtitles "on the side" to be overlayed?