Server Version#: 1.43.0.10492
Player Version#: 9.4 Build 12
The latest Roku update (9.4 Build 12) is till having trouble. The subtitles are out of sync (way off on timing) and displayed in the ugly black-box format. Shows played through the same server, but with different Plex apps (Samsung TV, Fire TV, web browser player) all display in a much better looking, non-black-box font, and sequenced properly with the show dialog.
Follow-up: It appears that the issue is related to subtitles handed off to the Roku to display. Changing the subtitle transcode setting from Automatic to Always gave me the behavior and look that I prefer and had become accustomed to.
Thanks for the initial report and the follow up. I’ll let the engineers know about your experience.
@SunCat There is a fix for the subtitle sync issue on the latest PMS beta.
If you’re able to check out the beta and report back, that would be great. Totally understandable if you’d prefer to wait until it’s in a production release.
Another team member mentioned that you can go to Settings > Accessibility > Caption style in the Roku system settings (not app settings) to adjust how non-burned subtitles look.
Thanks @Atomatth. The transcoding appears to work fine so I’m not sure a PMS change would help here, and I seem to be running the latest version (1.43.0.10492) available for Ubuntu. It’s the change in the client behavior where the subtitles were being handed over to the Roku instead of being burned in that appears to be the issue here.
Thanks for the info on changing the Roku settings. That helps in making the subtitles look better, but the passed-through subtitles are still ahead of the actual dialog/action.
Changing the client subtitle handling from Automatic to Always (so that the server burns in the subtitles when they are enabled) fixes both the timing issue and gives me the look I prefer.
I’d love to blame the Roku for this one, but the Plex app is the only one showing this subtitle behavior (all of my other apps display perfectly synced subtitles when enabled).
If it helps any, I’m testing on a Roku Ultra LT device running SW version 15.1. The source video I am currently testing with is a Handbrake converted .ts stream that was captured from an HDHomeRun tuner. The output container is m4v with MOV_TEXT subtitles:
Codec H264
Bitrate 696 kbps
Bit Depth 8
Chroma Location left
Chroma Subsampling 4:2:0
Coded Height 480
Coded Width 864
Color Primaries bt709
Color Range tv
Color Space bt709
Color Trc bt709
Frame Rate 29.97 fps
Height 480
Level 3.1
Profile high
Ref Frames 4
Scan Type progressive
Stream Identifier 1
Width 854
Display Title 480p (H.264)
Extended Display Title 480p (H.264)
Codec AC3
Channels 6
Bitrate 384 kbps
Language English
Language Tag en
Audio Channel Layout 5.1(side)
Sampling Rate 48000 Hz
Stream Identifier 2
Display Title English (AC3 5.1)
Extended Display Title English (AC3 5.1)
Codec MOV_TEXT
Language English
Language Tag en
Stream Identifier 3
Display Title English (MOV_TEXT)
Extended Display Title English (MOV_TEXT)
@Atomatth : My bad. It seems that I need to actually “save” the change to the beta channel before the beta versions become visible 
I updated to 1.43.1.10540 and the sync issues are no more. Silly me for thinking it was at the client side 
Thank you very much for the quick response to my post. You may close this one down as being resolved in the latest release candidate.
Thanks again. -Kevin (AKA: SunCat)
Glad to hear! Have a great weekend!
This also happens on an older Apple TV, with the same workaround.
