Issues burning in ASS subtitles

[amateurgod 33]

Since updating to 4.8.11 when watching something with ASS subtitles while having the force burn in ASS subtitles option selected I will have to start playback twice before it starts transcoding. 

 

The first time I have to press play, and then it will just constantly show the spinning wheel but in the dashboard it will show it as playing via direct play. 

I then stop playback on the device and press play again and then it will start actually showing in dashboard as transcoding and burning in ASS subs. 

However in the logs both times it will show it as starting a transcode.

This has only been happening in 4.8.11 it worked fine in 4.8.10 

 

(Currently on mobile so unable to upload logs, however once at PC I will add them as a comment) 

[visproduction 286]

AG,

I would supsect the media has timeline metadata corruption.  If you start playback from the beginning the timeline can match up and playback, but stopping in the middle and starting again fails to work right away, possibly due to faulty timeline metadata or even variable bit rates not resolving quickly and the media now looks like it needs transcoding.  VBR encoded media tends to make this happen a lot especially if it is being played back remotely.   A way to check for this is to download a test video which was created with everything working properly and see if it plays back better.  You could also try to remux the video and repair the timeline and see if that helps.  To make a metaphor, you don't want to start repairing the engine, if it's bad fuel.  Find out what is really the culprit.

Having ASS subs that need burning is an added factor and it might be an Emby issue.  But maybe the ASS subs will work fine from a test video.  Perhaps having corrupt timeline metadata plus ASS subs and starting in the middle is the combo that triggers transcoding. If everything was correct in the media, perhaps direct play would continue to work.

https://www.handyrecovery.com/repair-video-file/
https://sample-videos.com/

Hope that helps.

Edited March 23 by visproduction

[amateurgod 33]

The media is being started from the beginning, the issue is I have to start it, then exit, then start it again for it to actually start transcoding and playing. 

[Luke 40145]

 

Hi there, let's look at an example. Please attach the information requested in how to report a media playback issue. Thanks!

 

[amateurgod 33]

Hi @Lukeso I couldn't find the correct log for it as it had been a couple days since I watched something with ASS subs, and when I tried to recreate the issue so I could get logs it was no longer happening. Not sure what's changed as I haven't made any changes to anything. 

 

I would also like to check is subtitle burn in still done by the CPU or is this able to be hardware accelerated, as I read in a thread from 2020 that a future Emby update would enable hardware acceleration for subtitle burn in too, however when I look at the logs the subtitle burn in is being done by the CPU and there is a line saying that hardware acceleration is disabled by a debug option but this only shows up when the transcode reason is to burn in subs, everything else is hardware accelerated 

[Luke 40145]

On 3/26/2025 at 7:36 PM, amateurgod said:

Hi @Lukeso I couldn't find the correct log for it as it had been a couple days since I watched something with ASS subs, and when I tried to recreate the issue so I could get logs it was no longer happening. Not sure what's changed as I haven't made any changes to anything. 

 

I would also like to check is subtitle burn in still done by the CPU or is this able to be hardware accelerated, as I read in a thread from 2020 that a future Emby update would enable hardware acceleration for subtitle burn in too, however when I look at the logs the subtitle burn in is being done by the CPU and there is a line saying that hardware acceleration is disabled by a debug option but this only shows up when the transcode reason is to burn in subs, everything else is hardware accelerated 

@amateurgodit is not fully done in hardware yet, although that doesn't mean that burning in subtitles will cause a software transcode.