Plex does not playback anything

Plex Media Server NAS & Devices
,
1

Server Version#: 1.19.1.2645
Player Version#: 4.22.3

I tried playing various types of content, right now everything gives me an error
“Conversion failed. The transcoder exited due to an error”.
I tried looking at the downloaded logs, and I can see something like:
[FFMPEG] - Error loading external lib: /config/Library/Application Support/Plex Media Server/Codecs/99c90e0-3095-linux-x86_64/libhevc_decoder.so: failed to map segment from shared object

Quick gooling, hints into permissions issue between OpenMediaVault, and plex docker volume mapping.

History of my setup:
Followed the OMV 5 instructions, using the plugin etc.
Docker env values set as follows:
|PUID|1000|
|PGID|100|
|VERSION|docker|
|UMASK_SET|022|

I created a new user in OMV, and it is set as uid=1000, gid=100, and that is what I set for plex, I don’t use that user otherwise.

There is admin user in /etc/passwd:
admin:x:998:100:openmediavault
I dont know, perhaps I should set it to this?

I did not mount a special drive for transcoding, opting to let it use the system drive for now (SSD).
I did, however create a special mount for plex config, for ease of future reinstall:
/srv/dev-disk-by-label-NAS/Media/config/plex mounted to /config in docker, when going inside the docker container, this is what I see (until the last dir is removed after some time):

root@nas:/config/Library/Application Support/Plex Media Server/Codecs/99c90e0-3095-linux-x86_64# ll
total 8468
drwxr-sr-x 2 abc users 4096 Apr 9 15:14 ./
drwxr-sr-x 3 abc users 4096 Apr 9 15:14 …/
-rw-r–r-- 1 abc users 265440 Apr 9 15:13 libaac_encoder.so
-rw-r–r-- 1 abc users 175024 Apr 9 15:13 libac3_decoder.so
-rw-r–r-- 1 abc users 1948720 Apr 9 15:13 libh264_decoder.so
-rw-r–r-- 1 abc users 1559600 Apr 9 15:13 libhevc_decoder.so
-rw-r–r-- 1 abc users 1888600 Apr 9 15:14 liblibx264_encoder.so
-rw-r–r-- 1 abc users 860848 Apr 9 15:14 libmpeg4_decoder.so
-rw-r–r-- 1 abc users 664968 Apr 9 15:13 libmsmpeg4v3_decoder.so
-rw-r–r-- 1 abc users 1283896 Apr 9 15:13 libvc1_decoder.so

I was able to touch and create a file… as well as delete it inside the directory so I dont think it is permission issues.

Transcode dir is set to /tmp/transcode and quality to “Make my CPU hurt” (Ideally I would like to stream original quality as much as possible).

I also tried disabling the transcoding, and then when trying to playback 1080p, I get “This server is not powerful enough to convert video.”

CPU of the server is i3-2100Plex Media Server Logs_2020-04-10_05-59-51.zip (3.3 MB)

2

Chances are quite good that the disk labeled /srv/dev-disk-by-label-NAS is mounted noxec. Look in your /etc/fstab to see if this is so.

Since the transcoders are downloaded to and run from that disk, they will never work if the disk is mounted noexec.

If none of your media will play directly and must be transcoded, none of it will play in the above scenario.

Also, the directory /srv/dev-disk-by-label-NAS/Media/config/plex must be readable and writable by the user that the docker runs as. Is it?

Check the log for the plex container for any possible problems.

Instructions for how to properly make the changes to mount disks exec in Openmediavault are available in their user forum. Look / ask there.

https://forum.openmediavault.org/

3

Thank you for the quick response! do you mean inside the container mount, or the host OMV?
mount output in docker:

/dev/sdb1 on /photos type ext4 (rw,noexec,relatime,jqfmt=vfsv0,usrjquota=aquota.user,grpjquota=aquota.group)
/dev/sdb1 on /kids type ext4 (rw,noexec,relatime,jqfmt=vfsv0,usrjquota=aquota.user,grpjquota=aquota.group)
/dev/sdb1 on /russian type ext4 (rw,noexec,relatime,jqfmt=vfsv0,usrjquota=aquota.user,grpjquota=aquota.group)
/dev/sdb1 on /tv type ext4 (rw,noexec,relatime,jqfmt=vfsv0,usrjquota=aquota.user,grpjquota=aquota.group)
/dev/sdb1 on /movies type ext4 (rw,noexec,relatime,jqfmt=vfsv0,usrjquota=aquota.user,grpjquota=aquota.group)
/dev/sdb1 on /config type ext4 (rw,noexec,relatime,jqfmt=vfsv0,usrjquota=aquota.user,grpjquota=aquota.group)

And on OMV:
/dev/sdb1 on /srv/dev-disk-by-label-NAS type ext4 (rw,noexec,relatime,jqfmt=vfsv0,usrjquota=aquota.user,grpjquota=aquota.group)

I will fix this on OMV side later today, busy right now… but why doesnt it play anything with transcoding totally disabled?
I tested even 4K 2160p files directly from CIFS share on the TV using VLC, and it plays just fine…

4

Your mount point in OMV has the noexec capability set. This will not allow the transcoders to run. Fix this.

You will have to investigate for yourself if your media files will play directly in whatever client applications you are using or not, and if not they must be transcoded.

If your files will not play directly and must be transcoded by Plex they are not going to play until you make the changes needed to allow the transcoders within Plex to execute. It’s as simple as that.

VLC is a very capable player. It will play all my h265 files, and some others too, directly without transcoding. However since my ROKU box will not play h265, the files must be transcoded by Plex. Since my transcoding setup isn’t broken like yours is, …they play just fine on ROKU.

5

Does transcoding means I would get less than original quality?

6

In the first place it means you have a player that for some reason won’t play the video with all its streams in its original form. In some cases it’s sufficient for Plex to put the streams as-is in a different container (“envelope”) – that won’t touch the content of your file. If that doesn’t work / isn’t sufficient, Plex will decode the files on the server and re-encode them to meet the parameters given by the client. Such parameters / restrictions can be things like video resolution, bitrate, codecs, amount of audio channels, supported subtitle formats… Common restrictions are e.g. audio or video formats not supported by a device (e.g. DTS or Atmos Audio, occasionally older devices don’t support H265 etc.)

Typically, transcodes will impact the video quality. In some cases that’s more visible than in others.

Keep in mind… one “restriction” causing a transcode can also be your own choice of video quality (e.g. if you set it to a lower bitrate to “squeeze” through your router’s internet upload bandwidth).

7

Tha solved it, thanks!
I dont understand though, why Plex doesnt play anything at all, without transcoding enabled! even simple 480p does not work, while my screen is plenty enough for that…
I tested in the web player so I dont have to run upstairs to test on the 4k tv and run back to the PC.

8

The web player is the most restricted. It can only rely on the resources made available through the browser.
If you want to test on your computer… use Plex for Windows or Plex Media Player instead. Those support a significantly wider range of codecs and formats.

9

I tried disabling it again, this time using the Plex for Windows instead.
I get error:

Not enough CPU for conversion of this item.

Why, if now I use the correct player?

10

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