a new(ish) cpu with the intel 600 series iGPU is the general starting point for (newly built) home brew servers.
the problem is many people don’t want to buy a new cpu (which often needs a new motherboard and ram) because they have an existing system that mostly works.
that is where nvidia gpu’s come in to play.
you can use a nvidia gpu to upgrade an existing computer/server to support transcoding.
rule 3 = ‘direct play’ is a plex term, which means that the client understands the native file/content without the server having to modify it (ie transcode or remux the container). even a low powered plex server can serve 4k content if the client can directly play it (no transcoding).
also, VLC is completely different than plex. They both play media, but they are designed completely different. VLC is a ‘thick’ stand alone app that has it’s own codecs and programming to support various content types. The load is on the VLC program (and device that it is running on).
plex is a client/server architecture, where the client is ‘thin’ and limited to whatever the device/hardware can directly support. If the client cannot handle a certain file type or codec, then the server will convert it (transcode) to a compatible format.
The load is on the SERVER.
5th rule = 4k content usually includes DTS or atmos/truehd. so your soundbar supports dts, that really doesn’t mean much, lossless truehd/atmos is the main problem, which means transcoding for systems which don’t support it.
6th rule = most smart tvs do not support the HD audio, which is why people always freak out when their new 4k tv plex app starts transcoding and buffering and bogging down their server.
if your tv/soundbar doesn’t support that truehd/atmos audio stream, then the SERVER will try to transcode it to a compatible ac3/dolbydigital audio stream.
in most cases, plex can transcode only the AUDIO (which is less load than transcoding both video and audio). However if subtitles are enabled, this can cause the video to be transcoded too, which obviously makes you to lose the 4k/hdr effects.
rule 7 = sure sounds like your covered, but the point is that hdmi cables DO matter, and if your cable is not new enough, then that will cause problems.
rule 8 = many smart tv only support 100mbit ethernet (or wifi), instead of 1gbit ethernet. some 4k content can exceed the 100mbit network speed, so this can cause buffering or audio/video drop outs. So even with a direct same network connection, it can still be too slow (limited by the client connection). Wifi is highly variable, it might work for some people and other people might have too much interference for good throughput.
the main point to understand, is transcoding 4k is extremely difficult computationally. You can throw powerful hardware at it in order to do, but you are better off avoiding when you can.
for remote users or non-4k local users, keeping a 1080/720 copy is the easiest solution.
the atmos receiver is what lets you direct play HD audio, like the lossless truehd/atmos, and the dts-hd ma 7.1 audio streams. Otherwise the audio will likely need to be converted by the server, or manually switched to a different audio stream (ie 5.1 DD/DTS or stereo) to avoid transcoding.
direct play is explained above, direct play means the server doesn’t need to convert anything.
unless you have like 200+ meg upload, you probably do not want to let any remote users try to direct play 4k.