Having subs in 4k will not play and spike server cpu (only in roku)

Plex Players
1

I have reported this many times

Roku stopped supporting subs in 4k for some reason. Theres nothing i can do to fix it. I am tired of reporting this

2

Can you point me to that thread? No need for a new one.

3

Sadly all in reddit

But this is reproduced 100% of the time. Any 4k movie wont play once you load subs

4

Plex doesn’t officially support reports on Reddit so those may not get seen. If you can repost here I’d be glad to take a look.

What type of sub? Is the video direct playing or being transcoded? Is it every 4k video or have you found a pattern such as HDR10?

5

Finally we might be getting something

So

Any 4K movie wont play regardless if direct play or transcoded down once you load subs. This is observed in all roku devices from sticks to ultra.

Type of sub wont matter, srt or psg both wont play…i have tried on all other clients on same server and movies and they all play flawlessly except rokus
Shield
Apple
Ps5
Fire stick
Google chrome cast

This is strictly a bug in roku devices

6

I just tried playing a 4K video with PGS subtitles on my Roku TV. Video played back with subs just fine for me. Latest 7.0.9 version of the app.

Can you reproduce and get me the Roku logs?

7

I didnt wanna confuse you further but from every 10 tries it will randomly work and fail 9 times.

Heres the log
https://pastebin.com/VXBvCtKY

8

Just as another “works for me” datapoint with different variables, I’m currently watching 4K HEVC P5 Dolby Vision with SRT subs on a Roku TV.

9

That was removed from Pastebin.

10

Log posted in another site

11

Didnt try it with dv or roku tv incase this is an actual tv?

But i confirm that another friend of mine with roku stick just tried and he also cant load 4k movies with subs. Once he remove subs they work. Different server than mine

12

On the Roku, what Quality settings are configured at Settings → Video?

Local Quality should be Original.

13

It doesnt matter. At this example i used transcoding to 1080. But i assure u the same happen for original quality would happen

Also my server is nuc 11 i7 that transcodes 17 4k to 1080 with 75% cpu. So its not that

But one 4k in roku wont play

14

Your video is HDR10. Your logs show your Roku doesn’t support it, hence the transcode. Do you have the option enabled to tone map? If not, then you are getting a 10-bit h264 output and that won’t work on your Roku. What Roku model do you have? Do you know what your friend has?

15

Tone map enabled. Its the same for direct play (i produced this log in a tv that doesnt support 4k)

My friend hve streaming stick 4k

Also same thing happens with roku ultra

Also, the second i turn off subs it works fine (i wish i did that in the log lol)

16

Also the test now was done on streaming stick +

17

The subtitles are being burnt into the video. Burning subs is pretty darn CPU intensive - surprisingly so - much more so than simple transcoding.

The Roku can play SRT (sorry, typoed PGS originally) subs when there’s no transcoding involved, so this might be a consequence of the downscaling and/or tone-mapping, of the audio conversion, or of the Subtitle settings on the Roku.

You mentioned that the same problem exists with SRT subs? Can you confirm that?

18

I confirm same happens with srt (and example in log using srt as wel as psg)

19

Looks like a 3810X per the logs.

(I know the Shield can downscale and upscale and perform local HDR → SDR tone mapping, but I don’t think any Roku devices will do that. Do you know differently?)

20

But the same happens with direct play