# Unknown decoder 'aac\_lc' - when playing MKV from Roku
**URL:** https://forums.plex.tv/t/unknown-decoder-aac-lc-when-playing-mkv-from-roku/726459
**Category:** Plex Media Server
**Tags:** server-linux, roku
**Created:** [July 3, 2021, 11:42pm UTC](https://forums.plex.tv/t/unknown-decoder-aac-lc-when-playing-mkv-from-roku/726459 "2021-07-03T23:42:31Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@rbirkline](https://forums.plex.tv/u/rbirkline)
#### Post date: [July 3, 2021, 11:42pm UTC](https://forums.plex.tv/t/unknown-decoder-aac-lc-when-playing-mkv-from-roku/726459/1 "2021-07-03T23:42:31Z")
Server Version#: 1.23.2.4656
I have recently upgraded the plexserver on my Ubuntu server from 1.22.3.4523 to the newer 1.23.X.XXXX versions. I have tried each version as they come out with the version number 1.23.X but when playing MKV video files from a Roku I always get the following error.
```auto
[Transcoder] Unknown decoder 'aac_lc' in the logs.
```
If I revert back to the older 1.22.3.4523 version and the error stops and the video plays as normal. The error only shows when trying to access from a Roku device.
I like to keep my software up to date but this is preventing me from being able to update the plexserver.
Does anyone have some thoughts on how to address this. I have looked through older post related to this and tried it all, nothing seems to work.
---
### Author:  [@rbirkline](https://forums.plex.tv/u/rbirkline)
#### Post date: [July 29, 2021, 1:11am UTC](https://forums.plex.tv/t/unknown-decoder-aac-lc-when-playing-mkv-from-roku/726459/2 "2021-07-29T01:11:58Z")
Is anyone else having this issue? Even with the latest update the issue still exists.
---
### Author:  [@ChuckPa](https://forums.plex.tv/u/ChuckPa)
#### Post date: [July 29, 2021, 3:03am UTC](https://forums.plex.tv/t/unknown-decoder-aac-lc-when-playing-mkv-from-roku/726459/3 "2021-07-29T03:03:43Z")
1. Stop Plex
2. (presuming you run PMS as the default user `plex`)
3. `sudo chown -R plex:plex /var/lib/plexmediaserver`
4. Start Plex
5. Try again.
6. If still failing, Stop again
a. Terminal session
b. sudo bash
c cd /var/lib/plexmediaserver/Library/Application Support/Plex Media Server/Codecs
d. rm -rf \* (it will remove what is likely damaged)
e. Restart
f. It will require a few extra seconds to get each codec again (download) the first time it plays but the codec will be local after that.
---
### Author:  [@rbirkline](https://forums.plex.tv/u/rbirkline)
#### Post date: [July 29, 2021, 12:10pm UTC](https://forums.plex.tv/t/unknown-decoder-aac-lc-when-playing-mkv-from-roku/726459/4 "2021-07-29T12:10:35Z")
I tried all of that and it didn’t help. I just installed 1.23.6.4881-e2e58f321 that was updated yesterday and it appears to have fixed the issue.
---
### Author:  [@system](https://forums.plex.tv/u/system)
#### Post date: [October 27, 2021, 12:10pm UTC](https://forums.plex.tv/t/unknown-decoder-aac-lc-when-playing-mkv-from-roku/726459/5 "2021-10-27T12:10:59Z")
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