Dropped frames caused by subtitle rendering

Yes. It plays without issue on Windows 10 PC via VLC, Nvidia Shield via Emby, and Dune D1.

You have an NFS mount to what looks like a NAS and I also see a large number of Emby-related error messages.

So does the file play fine when locally attaached on the Vero4K?

I put the file on a thumb drive directly attached to the Vero. No difference—file plays fine except for the stutter when the subtitles are first rendered on the screen.

Can anyone else confirm they do not have this issue on the Vero 4K+ when playing an mkv version of Avatar with the “decorative” forced pgs subtitles?

Thanks for the help.

I can confirm that I have this issue with Avatar, and also with every other subtitle when first subs appear on the screen as before in v17, and now in v18.

Here is a log with stutter on first subtitle appear. https://paste.osmc.tv/atodobemay

I can confirm I have the same skipped frame subtitle problem with Avatar and 18.1, though it’s significantly better than 17.X.

I can confirm the issue… frames dropped the first time the subtitles are rendered… after the first time, it will not happen again in the same video… but the issue will always reappear on the next video.

Thanks for the report, will look in to this.

Thx Sam :slight_smile:

I think the problem is not only about subtitles but about osd in generell. For example, the first time I use my hotkey for codec info, there will also be a significant frame drop. This is not that huge of a problem because that osd will cover most of the screen anyway and you know that this is happening.

With subtitles though it quite a problem because it kills the immersion in that moment.

Anyway just wanted to add that it seems to be not limited to subtitles only, might help identifying the problem.

Those with the player process info I also experience - I don’t really use subtitles. This is kind of the same as in v17, but a lot less… Would be interesting to know what team Kodi did to make it better. But obviously it’s not completely gone yet.

I really don‘t mind the frame drops when opening an osd window… my action itself gets me out of immersion because I want to get some info or want to change a settings.

On subtitles however it is a different beast. Especially when an unexpected forced subtitle (with forced flag) pops up… before you realize that there is something to read, you will rather notice the dropped frames first… it is really irritating, unexpected dropped frames are always kind of annoying.

This is occurring because when you request to bring up these windows, time is taken away from the render thread.

A couple of things that might be possible here:

  • Preloading these windows / assets
  • Increasing render thread priority so subtitle dialogue etc takes a little longer to appear but doesn’t drop frames.

Well the dropped frames issue on subtitles is new since the Kodi 18 update.

Anyway, I try out your suggestions… How to I increase render thread priority? Advanced settings I suppose?

We’ve seen the subtitle issue on v17 as well… Mostly with PGS subtitles.

Never noticed it before but I only use SRT subtitles. I am pretty sure there was no frame drop with SRT in Kodi 17, at least for me.

Was hopeful the issue was fixed in Leia, obviously not…

Same deal on Kodi 18 as before. Avatar is a good test because it uses 1920x1080 PGS subtitles for the forced ones and some scenes where they are used have nice slow and steady movement where you can see it easily. The testclip I linked September '18 still demonstrates the problem in Leia. Basically there has been no improvement in Kodi 18 compared to Kodi 17 as far as I can tell in regards to playback on the Vero.

I don’t think VideoPlayer moved far enough with v18 as expected. So some of the old Kodi limitations still exist.

I’ll try and work around them

I will do some testing tomorrow with „dirty regions“ in advancedsettings, While I was using the libreelec box until the sync issue was fixed, I did alot of testing on other small issues and had some promising result with one particular setting. So I am hoping to get the same effect on the Vero 4k.

I’ve never seen this issue before until the other night when I was watching the first Avengers movie with my children.
There were a couple dropped frames right before the first subtitles were displayed.
That brought me here where I found this thread.
Interesting read.
Unfortunately I was unable to duplicate the issue.
Every attempt after the initial veiwing played smoothly, even with statistics on screen.

I watch a ton of 1080p Remux, Web-DL and encodes mostly with muxed in srt subtitles and never had this issue. Would be interesting to know what triggers it. Maybe only PGS maybe 4k ? Or some sort of combination of it