Very slow transcoding TS-253A



I've had the QNAP TS-253A (still running 4.2 because some other apps I use don't work on 4.3) for almost two years and have maxed out the memory to 8GB. For the longest time, everything was fine. Now, when I am using the Plex mobile app while out and streaming from my NAS at home, the transcoding is taking a lot longer than it used to. This just started happening in the last week or so. It's to the point where I can't even watch a 720p 30-minute show without having to stop to buffer for minutes at a time every couple of minutes.

Is there any advice on what to check? I could be wrong, but I don't believe it's my upload bandwidth at home as nothing has changed with my plan. I am also streaming from the same places I have for years so I don't think it's my phone's network connection. I have set the transcode settings to Automatic and Very Fast in Plex.

And as of this moment, trying to stream will buffer very slow, then after a minute or two the video buffering will just reset and spin without doing anything.

Anyone else experiencing this, or have any ideas on what I can check or do? Any help would be appreciated!


Which remote device ? iOS ? Android ?


@moody_blue said:
Which remote device ? iOS ? Android ?

iPhone 6 Plus running iOS 10.3.1. I’ve been running this version of iOS for quite some time and the issues just started. I’d understand if as soon as I updated iOS it changed, but it went from fine to very slow on the same iOS version.


When I’m not using Direct Play at home (also trying to figure out how to make all downloads get converted to Direct Play format outside of this thread), the transcoding is also very slow there too, so maybe the problem is with the QNAP itself? It used to say it was at around 1.5 and now it’s saying around 0.5 (I can see this value in PlexPy).

Been running the same firmware on the QNAP for a long time as well. Could a Plex Media Server update on the QNAP have caused this, and is there any place I can get old versions of PMS to test out?


I feel stupid. Turns out, at the moment at least, that is was due to the type of file I was streaming. It was a .m4v file. After using Handbrake to change the container the transcoding is way faster.


For iDevices .m4v is always preferrable to .mkv. If you used Handbrake to reduce bitrate and/or change codec to H264 this explains why it works better now. For a “not so fast” NAS as the TS-253A you need to assure that when transcoding occurs H264 videos are limited to 10MBbs bitrate. If you use HW transcoding higher bitrates are possible but I have no sizing guidelines.

Other codecs (such as H265) have lower bitrates as the acceptable limit for the TS-253A.


The files were .m4v, but something must have been weird with them. Converting to .mp4 with H264 and AAC audio fixed everything right up.