Thanks alot for the reply, but I’m already doing this to circumvent this problem. I’m just curious why this is happening and if there is a solution to this problem. If it should be possible to watch three streams in parallel with burning, I wonder why I am not able to watch a single one.
I also tried it with tonemapping turned off, but the problem still remains. (However, it seems that it buffers slightly less often). It is also happening on my second plex server (i7-7700 root server at Hetzner).
In my opinion this means that the bottleneck is caused by either burning in the subtitles or the data-transfer (after decoding the video it has to be transferred to the cpu for software image processing and then back to the gpu for encoding).
If this is true, it means that the only possible solution to this problem is to do the subtitle burning with the gpu (if that is possible at all). According to ffmpeg there is a filter that can be used to to image overlay with opencl, but I don’t know if it can be used to do an overlay of image-based subtitles. (FFmpeg Filters Documentation )
I believe that this is the same issue that is described here:
Thus, I think that a solution to this would help many of us who are struggling with 4K movies.
