MKV with embedded ASS subtitles not rendering when there's fade effect

[Phreack 1]

On the latest Emby version, LG B8 with the latest firmware, sometimes MKV videos suddenly stopped showing any subtitles for a few seconds (embedded, ASS format) and I realized it was usually when signs were showing. I tracked it down and it looks like the problem occurs when the `fad()` effect was being applied.

A sample line looks like this

Dialogue: 0,0:00:50.61,0:00:56.28,volley-show-title-top,,0,0,0,,{\fad(600,1)}Haikyu!!

with the headers being

Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text

It works correctly when played on VLC and the web player. Could it be an issue with the library for parsing subtitles on WebOS? I'd rather not have fade as a quick fix and allow the subs to show since it sometimes skips dialogue when this happens.

Edited June 28, 2022 by Phreack
Formatting as code

[SamES 1004]

Yes, I've seen this issue before.  The fade() effect doesn't work well on LG (or Samsung) TV's.  Part of it is a limitation of the ass library that we use, but the TV's also have fairly limited processing power so app based animations aren't quite as smooth as you would get in a browser

[Phreack 1]

Is the library you mention open source? I could try and help out with it if possible as I can't seem to find a quick script or tool to remove all fade effects from the .ass subtitle quickly and I'd rather fix the problem than spend time working around it.

It's a big problem with shows that tend to have lots of fading signs - the spoken dialogue's subtitle is skipped for seconds at a time in many instances.

[SamES 1004]

It is open source, but there is a lot of work going on with it at the moment.  We need to wait for that to wrap up, then see we'll see if it still even works on your TV, and if it already fixes the issue.

[Phreack 1]

Could you tell me which library it is by any chance?

[Luke 40086]

Sometimes libjass and sometimes javascriptsubtitlesoctopus. It depends on the device.

[Phreack 1]

Got it, I'll go check if there's a way to work around the problem by ignoring effects in the meantime, thanks!

[Luke 40086]

Emby for LG TV's 1.0.37 has been released. Stay tuned to the blog for the release announcement.

Can you please try out the new update and let us know how it compares? Thanks !

[Phreack 1]

Hi! It's a bit better now in that the fad()'d effects don't just stop rendering of all subtitles on screen, instead only the text with fade effects isn't rendered. This helps because dialogue text doesn't tend to have fade effects and it's rendered now when something else is trying to fade, but things like translated sound effects (which typically have visual effects too like fade) are not rendered.

[nasobuko 2]

Hi! This keeps happening on my LG TV, (B9) when signs appear on many occasions they are not shown on Emby for LG (1.0.45), the subtitles do not appear either