I finished migrating plex from synology to a new ugreen dxp4800plus and initially got everything working great. However once i started to watch videos with .ass subtitles resulting in transcoding i started to notice frequent artifacting/pixelation in the videos.
The more movement there is in the picture the more common the artifacting/pixelation becomes. Artifacting might be the wrong word to use, it looks more like it switches momentarely to a very low quality encode then back to the regular encode.
After a lot of debugging including trying to install a 100% clean plex on docker with no migration to rule out the migration being the cause i have run out of things to try.
It does not seem to affect the webplayer only the 2 tv’s that i have in the house (both samsungs from 2021)
Plex on my old synology DX720+ works perfectly i only wanted to upgrade to get more storage bays and a stronger cpu that can handle 4k transcodes with .ass subtitle burning which DXP4800PLUS handels without breaking a sweat.
It seems that with these low bitrate 1080p cartoons there are some wierd interactions.
The first and the root cause of this issue is that it incorrectly reports a bitrate of 2147483.6 which is also INT32 max value. This causes plex app to freak out asking for a lower quality encode to reduce the bitrate… like a LOT lower quality resulting in the pixelated mess from the first screenshot.
A workaround fix for this is to “Disable Bitrate Limiting” then the plex app wont freak out over the 2 Tbps bitrate and everything runs smoothly.
A second thing here is that 3.6 Mbps prevents you from being able to select anything more than 720p as the next down the list is 2.2 Mbps 720p blocking you from trying to transcode your 1080p AV1/HVEC to any resonable 1080p H264 stream other the original which has the 2 Tbps bitrate buggy thing.
I don’t think that it’s using hardware transcoding. Did you pass the gpu thru to the docker container?
On the settings -> transcoder screen do you see a gpu under “Hardware Transcoding Device,” at the bottom like here?
You can also see there that on the server dashboard is showing 10 Gbps which it obviously is not doing on an 1 Gbps lan connection. Something is being report incorrectly on the plex media server causing issues on the app that can be fixed by using the “Disable Bitrate Limiting”
Did some more testing after the “Disable Bitrate Limiting” fixed most of the issue but there is still an issue and i’m able to replicate it on the web player so it’s not an issue with the TV
on the ugreen nas with pentium gold 8505 cpu just as the scene changes to the door the picture is heavily pixelated but recovers to normal within a few seconds
While it didn’t make much sense to play with “Internet upload speed” and “Limit remote stream bitrate” considering i was having issues localy with the server, pc and tv on the same LAN… it did make a difference
Setting “Internet upload speed” to my current internet speed made no diference
Setting “Limit remote stream bitrate” from “Original (No Limit)” to “40 Mbps (4k)” seems to make the issue go away on local play
Now i wish there was a “60 Mbps (4k)” setting or an 8k setting since some 4k content excedes 40 Mbps making them unplayable in direct play if you dont have “Limit remote stream bitrate” on “Original (No Limit)”
Need to do more testing but seems like this could be a pick your poison scenario unless plex fixes the issue or adds more higher limit options
