Question regarding (SSA/ASS) subtitles

[justmeyep 5]

Hello,

first of all thank you for your work on emby? I have a quick question regarding the subtitle support.

I know (from here) that Emby supports the SSA and ASS format. My primary concern is the playback using the web app.

From what I have gathered, when using the web app, it will try to extract embedded subtitles from the MKV and display them. But this takes some time once for every subtitle.

Does it make a difference if the .SSA/.ASS is available separately, next to the media file? Will it be faster? Are they getting converted to something different or can they be played directly by the browser?

Does it matter that the media container itself doesn't support these subtitles? (E.g. when using Firefox, it doesn't support MKV. So it will be remuxed. Does this have an effect on the (embedded/external) SSA/ASS subtitles?)

I hope I have worded it correctly and you might be able to answer my question.

[Abobader 3464]

Hello justmeyep,

** This is an auto reply **

Please wait for someone from staff support or our members to reply to you.

It's recommended to provide more info, as it explain in this thread:

Thank you.

Emby Team

[Luke 42078]

Hi, yes external will be faster and will avoid the whole extraction process.

[pwhodges 2012]

External ASS/SSA subtitles are unusual, and even when they exist hardly ever have any fonts they require embedded in them.  The usual arrangement is that they are alongside the video and audio in an MKV file which has the fonts included as attachments.  Emby 4.8 (currently in beta) is very good at embedding these subtitles into the video (which requires transcoding, of course) with the full ASS functionality, even for karaoke over opening and closing songs in anime, so they are fully usable in the web client or on the Roku, for instance.

(Even when ASS subs are included in an MKV, it is sadly common that whoever prepared the file didn't include the fonts as attachments, so sometimes I have to go hunting and add them to the files myself.)

Paul

[justmeyep 5]

First of all, thank you both for clearing things up a little for me.

 

@pwhodgesMy biggest concern with subtitles as of right now is that the (I guess) extraction of these subtitles takes quite some time on my hardware unfortunately.

It can be pretty irritating, especially with e.g. anime movies which  have a long runtime. Due to the hardware 'burning in' the subtitles into the video is also not really a viable option.

I thought about building a workflow, which will extract the embedded SSA/ASS subtitles of the MKV and place it next to the media file.

From what I have understood, this would improve the experience while still allowing the original subtitle functionality. Is this correct?

Or does the beta improve the handling in such a way that this shouldn't be an issue anymore?

 

[pwhodges 2012]

My hardware is fine with the transcoding, so I can't really comment on problems with more limited equipment.  But simple extraction of subs to text shouldn't be a big issue.  Note that when Emby extracts subtitles to be delivered as text, they are passed on in a more basic form than SSA/ASS subs - at least in pre 4.8 versions of Emby (tbh, I have been contentedly using the latest facilities for so long, I can't remember the details of how it was before...).  So, simple subtitles in ASS format may have nothing significant to lose, and will be fine - but more elaborate anime subs with a lot of karaoke effects, fancy fonts and positioning for signs, and even movement to follow a panned sign will be pretty screwed up.  This is why having them fully rendered on the server and burned in is such a worthwhile advance - so long as your hardware can cope with it.

But I don't think that putting the ASS subs next to the video in their original form will help - the kind of clients which can't handle them embedded in MKV probably can't render them anyway (and there's the fonts issue I mentioned before).

To get the full effect of full-on ASS subs, you need either to use a client which can handle the MKV file as it stands, or to have hardware which will let you burn the subs in at the server in real time.  Of course, you could use HandBrake to make a version of the file with the subs rendered and burnt in in advance...

Paul

[Luke 42078]

1 hour ago, pwhodges said:

My hardware is fine with the transcoding, so I can't really comment on problems with more limited equipment.  But simple extraction of subs to text shouldn't be a big issue.  Note that when Emby extracts subtitles to be delivered as text, they are passed on in a more basic form than SSA/ASS subs - at least in pre 4.8 versions of Emby (tbh, I have been contentedly using the latest facilities for so long, I can't remember the details of how it was before...).  So, simple subtitles in ASS format may have nothing significant to lose, and will be fine - but more elaborate anime subs with a lot of karaoke effects, fancy fonts and positioning for signs, and even movement to follow a panned sign will be pretty screwed up.  This is why having them fully rendered on the server and burned in is such a worthwhile advance - so long as your hardware can cope with it.

But I don't think that putting the ASS subs next to the video in their original form will help - the kind of clients which can't handle them embedded in MKV probably can't render them anyway (and there's the fonts issue I mentioned before).

To get the full effect of full-on ASS subs, you need either to use a client which can handle the MKV file as it stands, or to have hardware which will let you burn the subs in at the server in real time.  Of course, you could use HandBrake to make a version of the file with the subs rendered and burnt in in advance...

Paul

Actually one part of this isn’t true. Having them external next to the video will help by eliminating the need for an up front extraction which can sometimes take a bit of time.

[pwhodges 2012]

Thanks for the correction - I have always imagined the process being carried out in parallel with streaming.  I could explain my reasoning, but I can also now see a serious flaw in it!

Paul

[justmeyep 5]

I tried it with some external ASS subtitles now and it does help quite a lot when the system is under load. I'm now trying to build a workflow which will extract them out of the file and place them next to it.

Emby does the extraction only on playback. Maybe it makes sense to offer an option which will do this before so you can see them quicker when starting playback on a file that hasn't been watched before?

Would you consider such a feature request?
But anyways, thanks again to both of you!

[Luke 42078]

On 5/21/2023 at 3:20 PM, justmeyep said:

I tried it with some external ASS subtitles now and it does help quite a lot when the system is under load. I'm now trying to build a workflow which will extract them out of the file and place them next to it.

Emby does the extraction only on playback. Maybe it makes sense to offer an option which will do this before so you can see them quicker when starting playback on a file that hasn't been watched before?

Would you consider such a feature request?
But anyways, thanks again to both of you!

HI, yes this idea has come up before and is certainly possible for future updates.