Subtitles Cause Video Not To Buffer?



I'm running Plex Media Server via OpenMediaVault on my RPi3. It plays all of my music fine across all platforms, though the Pi definitely struggles with transcoding my HEVC media obviously, unless I'm playing outside of my home network or on my phone. Then media streams fine. And for clarification, I'm aware that the Raspberry Pi is nowhere near capable of effectively transcoding HEVC media. I wanted to try out Plex and needed an excuse to use my Pi for something, and so this month long experiment was born.

Today I ran into an issue when trying to watch Kill la Kill. It does not even attempt to buffer if I have subtitles enabled. The format for these subtitles are "ASS". I know very little about how subtitles work, but a quick Google search revealed that they are "image based subtitles", as opposed to another format card "SRT" which uses text. Chuck uses subtitles in this format, however currently I cannot test if these subtitles work.

I read on a few posts from a couple of years ago that I can enable something called "burn in" for the subtitles in the settings. I did this, and though the video will buffer on Plex desktop it never plays. The video does not play on the Plex Android app nor does it play on the Plex add-on for Kodi. The add-on simply returns "Playback Failure". I read that Plex has some issues transcoding HEVC with this subtitle format specifically. I switched off WiFi on my phone and attempted to stream the media to no avail. Turning subtitles off resolves the issue.

Is the subtitle issue a result of my Pi simply not being able to transcode the HEVC media? It can barely keep up normally and having to carry subtitles with it must be straining on what little resources the device has. Worst case I can always set up another Plex server for my HEVC media and continue using my Pi for music, however I'd at least like to get the Pi to make an attempt at streaming the video. For the sake of the experiment (and at the risk of lighting everything around me on fire :p ).

Thanks in advance!


Burn in = transcoding

ASS = not picture-based, but capable of very elaborate formatting and effects - therefore very demanding on CPU resources too.

I’m aware that the Raspberry Pi is nowhere near capable of effectively transcoding HEVC media.

There, fixed that for you.


You might try to convert the subtitles off-line to a format called “TX3G.” It is a text based format stored in a stream separate from the video stream that plex supports on a number of players.

You never said what device your are using as client. I have to say that I have no experience with h.265.

And replace “I’m aware that the Raspberry Pi is nowhere near capable of effectively transcoding HEVC media” by “We are aware that none of the Raspberry Pis is capable of transcoding demanding video streams in real time.”