Transcoder Settings

Plex Media Server Desktops & Laptops
1

Server Version#:1.16.0.1226
Player Version#: Web player

I just bought a monthly subscription to Plex Pass and have set up PMS on my desktop PC with an AMD Phenom 4 CPU. I really love what they’ve done with the guide, apps, and the DVR service. Really nice.

But…when running PMS on my PC, when watching live TV on the PC or on another PC or my Android tablet, CPU usage goes up to over 90% and even hitting 100% at times which causes live TV to buffer a lot. I’ve changed the transcoder settings a couple times to see if it would reduce the strain on the CPU but so far I’ve not had much success.

What should the optimal transcoder settings be to reduce CPU usage as much as possible and still have decent picture quality? My current settings are:

Transcoder quality: Automatic
Transcoder default throttle buffer: 10
Background transcoding x264 preset: Fast
Use hardware acceleration when available is checked
Maximum simultaneous video transcode: Unlimited

Short of getting a more powerful PC, is there anything else I can do besides changing the transcoder settings? Thanks for any and all help!

2

There is nothing you can do about it. Your CPU is quite old and doesn’t have plenty of computing power for this kind of task.
https://www.cpubenchmark.net/cpu.php?cpu=AMD+Phenom+II+X4+970&id=371

https://support.plex.tv/articles/201774043-what-kind-of-cpu-do-i-need-for-my-server/

3

Bummer. Well, I really appreciate the info. Seeing that chart comparing my CPU to others was a real eye-opener. What would you recommend as an ideal or at least sufficient CPU of those on that list to be able to run PMS adequately?

4

Read the second link.

5

So, after reading the article on what kind of CPU do I need for my server, the rough guideline says for transcoding a 1080p file the CPU should have a Passmark score of at least 2000. My AMD Phenom II X4 has a Passmark score of 4317. So should it not be capable of doing the transcoding the Plex server requires?

6

This 2000 passmark guideline is only valid if the source file uses the H.264 video codec and has no more than 10 Mbps bandwidth.

And only, if no subtitles need to get burned in, because that requires additional computing power.

7

Gotcha. So when recording broadcast television from an antenna, what video codec is used and how much bandwidth is typically used?

8

That depends totally on how live TV is broadcast in your area.
By default, the stream is recorded without changing it. Which means codec type and bitrate will stay as they are broadcasted.

If you activate ‘transcoding’ in the device settings of your DVR, this will be converted to H.264 + AAC for maximum compatibility.
But it also means that your server will be taxed by the conversion during the recording, so it needs to be fast enough or you’ll end up with faulty recordings.
Keep in mind that this may happen while your server is already under load by playback (s) (which in turn may involve transcoding as well). So the required processing capabilities need to be even more plentiful.
https://support.plex.tv/articles/225877347-live-tv-dvr/

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