Google Chromecast/Streamer 4K - Video Stutter with ASS subtitles

[Luckyy 0]

Hello!

I have a problem when I watch a video with ASS subtitles: my video stutters from time to time (mainly where there are a lot of effects in the subtitles).

My config is:
TV: Google Streamer 4K (on my LG TV 4K)
Android version: 14
Emby TV app version: 2.1.23g
Emby app version: 3.4.74

I uploaded 2 debug log files (one per Emby app).
My actions were:
- My user (named "Lucky") had one web session to set the debug logs
- He had one other session on my Android TV where he launched a movie with some ASS subtitles
    - On the Android TV session, from 00:00:15 into the movie to the end of the session, there is stuttering.

I use a specific ASS subtitle (that I just trimmed and shifted from an original subtitle that caused the stuttering) to force create the stuttering from 00:00:15 to 00:01:45 in any video file.
I uploaded the ASS file with the logs.
The ASS subtitle file is basically a karaoke to force the stutter to be easily visible, but I also get this without karaoke at some moments in my videos where it's more difficult to reproduce for logs.

As soon as I turn off the ASS subtitles, the video doesn't stutter anymore (and it begins stuttering again as soon as I turn them on).

Between the Emby TV app and the usual Emby app, the stuttering was much worse on the usual Emby app.
In the usual Emby app, the stuttering slowed the video playback and made 1 minute 45 of the video last 3 minutes in reality (while it lasts approximately 1 minute 45 for the Emby TV app).

I noticed that my Emby server does not transcode the video when there are ASS subtitles but I don't know how to force the transcoding.
I'm currently watching Emby back on my LG WebOS, which forces the transcode, so I don't have the issue here.

I couldn't try on a 1080p TV, so I don't know if that affects the issue.
However, the problem persisted when I tried on a Google Chromecast 4K (Android version 12); it was even worse on the Google Chromecast than on the Google Streamer.
And the problem also persisted when I tried it on the TV of a friend, which is a Samsung 4K.

I also tried on my android tablet and phone (which are Android 16 and have Emby app version 3.4.74), and I didn't see the problem there.


Thanks.

embyserver-63892746284_tv.emby.embyatv_2.1.23g.txt embyserver-63892746562_com.mb.android_3.4.74.txt make_emby_tv_stutter_from_00-00-15_to_00-01-45_subtitle.ass

[Luke 41257]

Hi, we are looking into this. Thanks for reporting.

[btw_01 0]

Just wanted to pipe in, I am experiencing this on an Onn 4K Plus, with subtitles for an anime episode. No problems on Google Pixel 7 or my PC. Let me know if you want anything else. 

embyserver.txt

[visproduction 308]

Does the .ass file need to have the actual  [Fonts] embedded in the file.  I've seen other .ass files have a section with these fonts.
 

Quote

[Fonts]
fontname: Spork_0.ttf
!!%!!!!2!1!!"!!12E:5478^-#E!!%VQ!!!!(%>%259!FQ!E!!",*!!!!#B(5%^4.P9S>!!!3XQ!!!(S
2V.61LD`O0Y!!%N-!!!!-%^4,T+&O,LF!!!"G!!!!&:D<7&QA?9>;!!!!Z!!!!&C9X:U)!!B!HE!!!4U
...

The .ass file listed above does not have [Fonts] section and it lists Ghandi, French Canon roman and FOT-ManyoGyosho Std E.  Where does it get the fonts.  Is the TV app or browser OS suppose to have them?  I am not sure how that works.  Maybe the fonts listing is suppose to have embedded fonts somewhere in the .ass file.  Maybe if all these files come from a blu-ray, the fonts are in the blu-ray file lists that were never copied and made available to the embedded .ass, so can that be why there is no subtitles?