Hi there
Whatever system you have you need a SOURCE file and a TARGET application
For example when you stream a movie to the PC from the internet you are reading from the remote server and playing via the application (Internet explorer or another browser).
So you need AT LEAST two pieces of kit to make this work -- a SERVER of some sort to dish up your multimedia files and a Target application on which to play them.
Using the phone was for me the easiest solution -- reading the IP address of your NAS server would simply have worked whether or not the server was attached to the PC or not - so long as it was connected on your network.
The problem is as I see it is what application do you use say on the smart TV to play the media -- is there a "browser" type app. That's why I suggested using the HDMI adapter since you wouldn't need anything special on the smart TV (and this method will also work for "Non Smart" TV's too !!!).
For Audio there are various devices that receive the audio signal - but you still need a piece of hardware to connect the audio to your surround system (the old LOGITECH SQUEEZE system was one idea).
For multi-media you could also use a system knows as SLINGBOX
Buy SLINGBOX PRO-HD Media Streamer | Free Delivery | Currys
this is STILL a piece of kit you need to connect to your TV though.
Another possibility
How to enjoy multimedia contents sto... - Synology Inc. Network Attached Storage - NEW NAS Experience
(I still think the phone solution is the cheapest and easiest though !!).
You control what to play via the application ON THE PHONE -- the file browser via FTP or LAN can access the NAS files just as if it were a disk attached to the laptop --using a NAS and the phone can cut the PC right out of the equation completely !!! You don't need to download anything to the phone -- merely ensure the NAS is connected and active on your LAN. On the cloud it's even easier.
ES-FILE-EXPLORER has settings also to access your cloud servers -- as I said you can keep the whole PC just stored away it its case or whatever - you don't need one for this type of streaming. Download the app from Google play store and just check it out - it's quite FREE .
To repeat - you don't need to download ANY file to the phone - the player applications will just play the remote files as if they were stored on the phone itself -- and with decent Wi-Fi speeds you won't have a problem with decoding given the processing power of modern smart phones.
I agree if you want to avoid cables completely then that's another ballgame - Blue tooth isn't high enough quality for decent audio - especially uncompressed FLAC / WAV files - however the phone adapter is such a tiny piece of kit the inconvenience of the HDMI cable isn't a hassle - especially if you already have one for say a satellite box etc.
For a Samsung phone though you can do this for Wireless connection:
How To Connect Samsung Galaxy S4 To TV
Cheers
jimbo