This guide is designed to provide information on what is required to successfully run Plex Media Server on a NAS as well as whether or not it might be a good choice for you.
There are two very important things you need to first determine if you're interested in using a NAS with Plex:
- Do you plan to run your Plex Media Server on the NAS or only use it for storage?
- Will you need to transcode media for any of your Plex apps?
Let's expand on those questions and see what they really mean.
Do you plan to run your Plex Media Server on the NAS or only use it for storage?
If you just want to store your media on your NAS (but run Plex Media Server elsewhere), then there isn't really anything specific to Plex that needs to influence which NAS you buy. Find a brand you like that can hold the amount of storage you want and you're done.
If you want to run your server on the NAS itself, keep reading.
Will you need to transcode media for any of your Plex Apps?
Running your server on the NAS itself means you'll need to choose a NAS that meets a few basic criteria. It will need to:
- Be a brand and model with an x86 CPU and have a CPU fast enough to transcode the type of media you want to watch, on the types of clients you want to watch it on, or
- Be a supported ARM model
Note: ARM models generally do not support video transcoding at all.
For ARM models, the format of your media will need to 100% match the formats your clients can play. Without the transcoder, you may also run into issues when viewing your media remotely as you will only be able to stream the media at full bitrate, needing an internet connection with a high bandwidth.
Related Page: Plex Media Server > NAS Devices > NAS Compatibility List
Even Compatible Media May Need Transcoding
There are also situations where transcoding is required even if your media is otherwise compatible with your playback device. This can be the case when:
- Using Subtitles: For many Plex apps, subtitles have to be "burned in" to the video stream by the server. That requires transcoding to accomplish.
- Remote Access: When your Server is accessed from outside your home, it may not be possible to stream the content at the full quality. In these cases, the server has to transcode the content to a lower quality in order to be able to stream without buffering.
Related Page: How do I choose the right Streaming Quality in an App?
Transcoding and Media
Transcoding is the process of converting media from one format to another. For many other applications, when trying to play a media file that is in a format not supported by a given playback device, it will simply stop and say it cannot play it. However, with Plex it will still play, and that's due to the transcoder.
The Plex Media Server will analyze the media when it's added to your library and detect the format and details of the media such as encoding, bitrate, etc. When playing media on any device with Plex, the following process happens:
- Before a Plex app tries to play content, it requests the media information from the Server
- Using the media information together with the current settings (such as stream quality, Direct Play, and Direct Stream settings), the Plex app determines whether it can play the media directly (Direct Play) or whether it will need help from the Server.
- If the Plex app needs help, then the Server will automatically transcode the content as appropriate to a format that the Plex app can play.
- The media will then play in the Plex app, and continue playing as long as the CPU doing the transcoding is fast enough to transcode the media at a rate that is equal to or faster than it is being watched.
Your content is much more than just a file extension. Your media has some important properties:
- File container (mkv, mp4, avi, etc.)
- Video codec (H.264, divx, xvid, etc.)
- Audio codec (DTS, AC-3, AAC, MP3, etc.)
- Subtitle format (SRT, VOBSUB, PGS, etc.)
- And more
The combination of these things make up the "format" of your media and will determine how it can be played back. In order to get an idea about what sort of media you have, you'll need to be able to examine this information.
The "MediaInfo" application—particularly when used in the "Tree" or "Text" view to see details—can provide a wealth of information about your content.
Related Page: MediaInfo Download
Related Page: Troubleshooting > Media > Investigate Media Information and Formats
Is Your Content Supported?
If you wish to have your content play directly without transcoding, then you need to be sure that the device and Plex app you wish to use support your content. If you'll be using more than one Plex app, be sure that they all support your content.
Plex Media Player
The Plex media Player desktop application will typically always play content directly if you're using it with a local Plex Media Server. This app can play nearly any kind of content:
- mp4, mkv, avi, and other containers
- H.264, DivX, XviD, MPEG-2, and other video codecs
- MP3, AAC, AC-3, DTS, and other audio codecs
- SRT, ASS, VOBSUB, PGS, and other subtitle formats
Note that if you're trying to use Plex Media Player with a remote Server, you may still require transcoding if your network connection is not fast enough to support streaming the file in full quality.
Other Plex Apps
Capabilities of other Plex apps can vary greatly. They will largely depend on the operating system running the app (Android, iOS, Roku, Windows Phone, etc.) as well as the capabilities of the device hardware itself. Look at the specifications listed for the device on the device manufacturer's website.
Generally speaking, Plex apps use the default playback engine on the device, so what's listed on the manufacturer's site should correspond well with what can be Direct Played.
While there simply does not exist any kind of "universal format" that is compatible everywhere, the following is about as close as you'll get:
- Container: MP4
- Video Codec: H.264 (level 4.0)
- Audio Codec: AAC (2.0 audio)
- Total Bitrate: Less than 8Mbps (8000 Kbps)
CPUs and Transcoding
By now, you should know whether or not you'll need to be able to transcode your media. If you will need transcoding support and you plan to run your Plex Media Server on the NAS device, you'll want to choose a NAS that both supports transcoding and is powerful enough for your needs.
Remember, transcoding is not supported for nearly all ARM models.
CPU requirements for transcoding aren't set in stone. There is no single answer for what is required, because that will depend on the particular media in question, the Plex app being used, etc.
When transcoding content, generally the higher the resolution and the higher the bitrate, the more powerful CPU you'll need. There are some broad guidelines you can use to get an idea, though.
Related Page: What kind of CPU do I need for my Server?
CPUs in NAS
The CPUs used in most home or small-business NAS are not particularly powerful. Only some NAS will be capable of good performance when transcoding 720p type content. Very few NAS will be able to do so for 1080p type content.
The NAS Compatibility List should help you figure out which processor a particular NAS model has. You can also try doing a search for "NAS model xyz CPU type" on Google or similar (putting in the NAS model in which you're interested, of course) to determine what sort of CPU is used in a particular NAS device.
x86 vs ARM Processors
There are a couple of broad architectures of processors that you might find in your NAS:
- x86: This type of architecture is normally found in desktop or laptop computers. It's designed to be fast and run almost any kind of computer software. When included in NAS, though, the x86 processor versions used are usually slower and less powerful than a typical desktop computer.
- ARM: This kind of processor is more commonly found in a mobile phone or tablet. It's inexpensive and designed to be very energy-efficient and is typically not as powerful as a similar x86 processor.
Only x86-based processors are really capable of the sort of transcoding that Plex Media Server does. Even many x86-based systems may not be powerful enough to transcode content fast enough to be useful.