High CPU use with 1080p moives

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1
I notice a very high CPU usage (more than 80%) due to the process "Plex New Transcoder" while I'm streaming a 1080p to my appleTV with Plexconnect.
 
My config is the following: 
Mac mini Mid 2011 intel core i5 / 8gb of RAM / AMD Radeon 6630M 256MB / SSD 128GB / Mavericks (clean install)
AppleTV 3rd generation
Plex Media Server V.0.9.8.10.215 and Plexconnect 
Everything is connected trough Ethernet connection via a Time Capsule
 
Sometimes still with 1080p movies the CPU is used only at 50% and with others the image is fragmented...
 
Please find enclosed the Activity Monitor screen shot.
 
Thanks in advance for your help because currenlty I can't wtach 1080p movies due to the fans noise
2

Thats because the movie youre watching isnt supposed to run on an AppleTV natively and it has to transcode (maybe both video and audio) so it can run it, this needs high cpu (as Plex Server is always taking what it can take from a CPU). To avoid this its only possible to use a client which can natively run anything

3

This is how the new transcoder works i think. Use's as much CPU as possible to buffer the transcode.

I don't use plex connect but some clients allow you to try the 'old' transcoder.

4

What are your transcode settings set to in the PlexConnect GUI settings, do you have them at 40mbps and auto transcode?

EDIT: also are you using subs?

5

Try something for me. Play that 1080p movie straight on your machine and tell me what the CPU usage is. It’s probably about the same.





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6

Thanks for your quick feedback.

@f00b4r yes I'm using subs (French one) including in the mkv files and I'll tell you my PlexConnect GUI settings as soon as I'm back home.

@jdillinger should I play the movies with a player like vlc or the Plex server?

7

I definately doubt that it will have the same CPU usage when you play it over VLC :)

8

Play it with vlc





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9

If you mkv file was H264 content then it would likely be direct streamed (remuxed on the fly by the PMS to MP4 container natively playable by the ATV) with very little CPU overhead on your PMS.

As you are using subtitles the PMS is having to reencode the movie with burned in subs to 1080P (a lot of horsepower) - this may drop (depending on sub format used) in later versions of PlexConnect as we add a subtitles renderer but for now you have two options:

- Accept that your PMS will use a lot of CPU power

- Use something like iFlicks or Subler to remux the files and integrate the subs to an MP4 container that is natively playable by the ATV (they will then just get streamed to the ATV) - it will take about 5 mins a movie and you can batch ocnvert them.

10

What is still surprising for me is that I used exactly the same configuration before  with the only difference that I run PMS on a Macbook Pro early 11 without observe this high CPU usage...

11

It might be the type of subs in the file, whether they require full transcoding of the stream or not.

12

Please find bellow my ATVSettings.py code because I can't find the PlexConnect GUI

13
Additional test here with a iPad client less CPU power used with 8Mbps, 1080p setting and as soon as I increase the Mbps setting it increase dramatly the CPU power. 
 
How can I manage this setting for Plexconnect ?
14

Go into settings of Plexconnect on the ATV and look under the Transcoder menu items.

15

I changed but nothing happen even at very low quality…

16

Pleconnect working fine with HD 720p tv shows :smiley: I mean not CPU hard power

17

@ George Jolliffe: Should I use a previous version of plexconnect to avoid that? Because I used before My MBP for that (early 11) whitout meeting any issue...

@jdillinger: play 1080P movies with VLC  and no hard CPU power observed

18

@ George Jolliffe: Should I use a previous version of plexconnect to avoid that? Because I used before My MBP for that (early 11) whitout meeting any issue...

I'm sorry i don't have any experience with Plex Connect. My understanding of the current transcoder is that it will use all available CPU to buffer the transcode then slow down. This can have the unfortunate effect of making fans nosier than the old version. There is naturally the potential that you are using sub-optimal transcoder settings which are triggering unnecessary transcodes but i think others are better placed to try and help you with that issue.

19

Do you know when this way to transcode has been introduced? Because I'd like to find a old version of plex to try it.

20

In PlexConnect? I don't think we ever used the "old transcoder"...