Forced Subtitles are not meant to be played primarily, but additionally [Wrong subtitle choosing behaviour]

[RokeWayne 5]

Hi, together.

Since a while I wanted to report some - in my humble opinion - wrong subtitle choosing behaviour in the emby player, at least on web, android and firetv-app. Maybe it could even be a server issue - I'm not sure, where this behaviour ultimately comes from.

Lets start with my understanding, what standard and forced subtitle flags mean (cause different understanding could cause trouble when discussing) and please feel free to correct me, if I'm wrong:

• When a subtitle track is flagged "standard" in a media file, in most cases it means that a player should automatically select this track to show/play on your screen while playing your media. If you'd imagine watching an film or an anime with foreign dubs, the subtitle in your preferred language should/could be flagged "standard, so that you never have to actively select it with additional interactions in your player.
• When a subtitle track is flagged "forced", in my humble opinion (and how its typically implemented on film BDs and DVDs and on some subbed animes) the subtitle should be played "additionally" to the currently selected subtitle track, either "off", "standard" or whichever track is actually selected to play/show.
• When a subtitle track isn't flagged at all, the subtitle track should not be selected by the video player at all and is only used by discretion of the user.
• Forced and Standard flag on a subtitle track CAN be mixed together. If deselected from the user, a video player should anyways show whatever is in this track. Mostly used for foreign signs in films and animes.

Now to my point, why I'm making the distinctions:

My Emby players, either on my phone or on my fireTV stick - but also the webplayer, so maybe its an server issue? -  always choose forced flagged subtitle tracks over any "standard" track which completely disrupts any watch or binging session, because its saved for every file/episode, so just manually correcting it for an episode is no help, because the next one starts with the wrong subtitle all again. It's even worse, when you don't use the subtitle configuration on the emby server, but try to use the audio and subtitle track config in your files, so rewatching a series results in the same wrong subtitle selection.

An example from an episode of an anime:

Thats how my subtitle options look in relevant casesright after starting playback and how it looks on the mkv-metadata config of the specific file:

For your help the translation:
Aus = off
Ja = yes
Nein = no
"Erzwungen" / "Anzeige erzwingen" = "forced", here in this case "S&S" stands for "Songs & Signs", cause its an anime

Starting this file locally on my pc with "vlc" or "media player classic" or starting it with kodi as a backend works perfectly fine: The Dialog subtititle track gets choosed, which is the important point here and depending of the player capabilites the forced subtitles additionally show up.
But playing it over emby or emby apps always results in playing the "signs and songs" subtitle track and forcing the user to interact with the player.

Could you look into this topic for the future?

Regarding my expectations here: It's not a huge issue when watching films, and since I'm mostly using Kodi on my FireTV stick, the issue arises not that often. But occasionally I watch my stoff when commuting, and in these occassions I regularly notice the wrongly choosed subtitles.
Anyway I don't expect you to rush here. Check, if the actual implementation is how you intended it and if you think that point could be corrected, do it whenever it works out for you guys.

Keep up the nice work.

Kind regards from a happy Lifetime license user
Roke

PS: I tried to find any related topics, but didn't see any. Feel free to move the topic or close it, if the point was already adressed elsewhere.

[GrimReaper 4739]

What Subtitle mode is selected in your user Settings? 

[RokeWayne 5]

3 minutes ago, GrimReaper said:

What Subtitle mode is selected in your user Settings? 

Hi.

Thank your for the fast reply.

Please tell me, if you want me to set emby on english so the screenshots are easier to read...

Thats my config in my user preferences:

[GrimReaper 4739]

18 minutes ago, RokeWayne said:

Please tell me, if you want me to set emby on english so the screenshots are easier to read.

No need, thanks, screenshots are enough. 

You might want to enable "Gewahlte Untertitel merken", as that should enable subsequent episodes subtitles to be selected same as last selected subs was. 

On 12/18/2023 at 5:18 AM, Luke said:

This will be in Emby Server 4.8.

How it Works:

• This requires that you enable remembering audio and subtitle track selections. this is enabled by default.
• The server will first check if you've previously played the video file, just like before, and if it has then it will use your previous track selections
• If not, then it will look at your last played episode of the same series and attempt to use the same audio and subtitle selections. Essentially it will take the languages of the tracks and put these languages at the front of the language priority list.

That might or might not work in your scenario as those are same language tracks, give it a spin and see how does it compare. 

That is only possible workaround, though, to go back to your original issue, guess Emby still prefers embedded Forced over Default tag when Default Subtitle mode is enabled (which still makes no sense to me just as it didn't back then):

 

[RokeWayne 5]

4 minutes ago, GrimReaper said:

You might want to enable "Gewahlte Untertitel merken", as that should enable subsequent episodes subtitles to be selected same as last selected subs was. 

Well, thats a short sighted workaround imho. It only works within a series or film - and the same irregularity shows up on the next series or the next film, where you have that subtitle constellation. Take someone with a big library and the subtitle problem shows up any second day.

4 minutes ago, GrimReaper said:

That might or might not work in your scenario as those are same language tracks, give it a spin and see how does it compare. 

I'll test it out, but I don't think it resolves the problem around the actual implementation thinking that the "default" and "forced" flags in a file work on the same plane of priority for showing up... In my humble opinion the "forced" subtitles should always show up (like in my topic title "additionally"), whichever subtitle track is chosen. Thats how it works on BDs and how its presumed in most media files with different subtitles track that don't have overlapping content.

4 minutes ago, GrimReaper said:

That is only possible workaround, though, to go back to your original issue, guess Emby still prefers embedded Forced over Default tag when Default Subtitle mode is enabled (which still makes no sense to me just as it didn't back then):

 

It seems that way. I don't want to discredit Luke in that old Thread, but I think he was wrong then and its still wrong in the actual implementation. Albeit the topic then was somehting slightly different regarding that someone wanted a higher priority for external subs, so maybe the discussion couldn't focus on the technicalities of the flags being misused contrary to the technical standard.

But yes, you are right: From a technical standpoint choosing BETWEEN forced and default and taking any of these two as the "winner" just doesn't correspond with the technicalities of video files, because then it would've been as simple as having a priority number in a subtitle track. But in reality they are two different flags (like shown in mkvtoolnix) that HAVE TO cover different aspects of video playback.

I'm just wondering why nobody else is complaining about this issue... I could only imagine, that most users don't use the native emby apps, but Kodi or other frontends, where the player takes over the playback and utilizes the correct subtitle behaviour. And therefore the few cases where it gets noticed, it gets ignored or forgotten...

[RokeWayne 5]

Tested allowing to save the subtitle settings per episode. When watching an episode, setting manually the playback to "default" subtitle track and then switching to the next episode, it defaults back to the "wrong" forced subtitle track in the playback of the next episode. So even with the idea as a workaround it doesnt work at all, because I'd need to manually set the track every ****ing time the next episode comes up.

I wonder how that would even work, if between two episodes the order of the subtitle or the descriptions of the subtitle track would chnage... Which reverts the siutation back to where my report started: Forced subtitles should not be considered when choosing the subtitle in the playback, but ideally played/showed additionally to whichever subtitle track is chosen by "default" flag or if no subtitle track is shown by lack of "default" flag.

[ebr 16169]

3 hours ago, RokeWayne said:

When a subtitle track is flagged "standard" in a media file, in most cases it means that a player should automatically select this track to show/play on your screen while playing your media. If you'd imagine watching an film or an anime with foreign dubs, the subtitle in your preferred language should/could be flagged "standard, so that you never have to actively select it with additional interactions in your player.

Hi.  I'm not aware of "standard" as a subtitle flag.  Do you mean Default?

3 hours ago, RokeWayne said:

When a subtitle track is flagged "forced", in my humble opinion (and how its typically implemented on film BDs and DVDs and on some subbed animes) the subtitle should be played "additionally" to the currently selected subtitle track,

This is not correct.  Only one subtitle track is displayed at any given time and a "forced" flag will usually take priority - meaning that is the one that will be selected depending on language settings.  A subtitle marked "forced" is usually a track that shows subtitles only for portions of the video where the spoken language doesn't match the primary language of the film.

[RokeWayne 5]

9 hours ago, ebr said:

Hi.  I'm not aware of "standard" as a subtitle flag.  Do you mean Default?

Yes, sorry. In German a lot of Tools translate default to "Standard", and since that word at least exists in the English vocabulary I apparently make that translation error in my head. I'll try to use the correct term from here on.

9 hours ago, ebr said:

This is not correct.  Only one subtitle track is displayed at any given time and a "forced" flag will usually take priority - meaning that is the one that will be selected depending on language settings.  A subtitle marked "forced" is usually a track that shows subtitles only for portions of the video where the spoken language doesn't match the primary language of the film.

Well, sorry for my bad choice of words: For any given moment you are correct that only 1 track is displayed, but over the course of the video it adds to the count of (different) subtitles that were shown.

I think choosing a sub track at the beginning of playback (or even before when showing properties of the media) and thinking that state is permanent is already a step in the wrong direction. I would say, that subtitle tracks need to dynamically switch during playback: Start always with default, if existing, or without subtitles, when no default track is existend, but when there is a forced track with subtitle lines, show them only at the defined timestamps. I'd presume, they (forced subtitles) would have to be additionally loaded into memory for a dynamic check of the timestamps.

Lets take my configured anime file from above for a short hypothetical comparison:

How it works in the current implementation by chosing "forced" tracks over all other tracks just by existing (imho the wrong way):

1. Presume there are two sub tracks (e.g. my file from above), one with the default flag (Dialog subtitles) and one with the forced flag (signs and songs). Also they don't overlap in regards of timestamps of the subtitles.
2. Emby currently chooses the "forced" flagged subtitle track before the playback
3. When starting the playback, lets assume some sort of Intro or story recap before an opening song/jingle. This goes from 00:00 until 00:30. During this time the forced subtitle track doesn't contain subtitle lines and nothing gets shown, but an user would expect the dialog to be subtitled.The default track contains dialog subtitles but by not getting chosen from the start, now an user would swap the subtitle track to the "default" one (or otherwise the user can't enjoy the media).
4. Now the opening song starts at 00:30 and goes until 02:00 of playback. Emby afaik currently doesn't swap dynamically to the forced subtitle track and in this case doesnt show the lines from the forced subtitle track during the song, so therefore the user would need to manually swap again back to the forced sub track if he wishes to see the song subtitles. I usually don't swap back, because I can live without the song subtitles, as long as i can chill and can avoid any additional interactions.
5. after that opening song the dialog lines in the main part of the episode are shown,  but only because the user swapped manually to default in 3
6. If any signs would be existent in the anime (with corresponding lines in the forced track), they dont get shown, also because of the manual swap to default in 3
7. when the end song plays, the forced track contains sub lines, but they are not shown
8. If there is a preview at the end after the ending song, lines are only shown because of the manual swap in 3
9. the file/playback ends and some subtitles were never shown. If the manual swap didn't occur in three, the whole episode would not have shown any dialog lines.

Now to how it should work In my mind and how it does on media player like "vlc" or "media player classic" (imho the right way):

1. same prerequsites as above
2. Emby now should choose the "default" flagged subtitle track, if existing, when showing the file/media properties
3. When starting the playback, lets again assume some sort of Intro or story recap before an opening song/jingle. This goes from 00:00 until 00:30. In that time the default track contains subtitles that would be shown, because of the default flag being correctly chosen. Also during this time the forced subtitle track doesn't contain subtitle lines.
4. Now the opening song starts at 00:30 and goes until 02:00 of playback. During this time the default subtitle track does not contain any subtitle to be shown, but the forced track does. the player should change temporarily to the forced subtiitle track for the duration of this opening (or have them in memory, cause they are "forced") and show forced subtitles.
5. after that opening the chosen subtitle track should be reverted from forced to the "default" one, because it would not contain any lines to be shown, but default does.
6. If any signs are shown in the anime, I'd expect the forced sub track to contain lines, therefore i would expect a display of these forced lines, and after that a swap back to the default track to be able to continuing showing the dialog lines
7. when the end song play the same change of tracks should happen like I explained in point 4.
8. If there is a preview at the end after the ending song, back to default like in point 5
9. the file ends and all subtitles were shown in the right moment of playback and no user interactions were necessary

If no track with the default flag exists, that would be the only case, where emby can choose the forced track from start to end and the playback of the subtitles would bare the correct/expected results, because choosing the forced track from the beginning causes the same result as if the forced lines would be dynamically shown, so here no complex swapping has to occur.

Maybe - and its a big maybe, because i don't know how emby tries to handle subtitles internally-  the correct way would not be about choosing a track at the beginning and trying to swap dynamically, but loading all subtitle lines of flagged tracks into memory and showing them accordingly to any given timestamps.

 

Edited May 23, 2025 by RokeWayne

[RokeWayne 5]

17 minutes ago, RokeWayne said:

Maybe - and its a big maybe, because i don't know how emby tries to handle subtitles internally-  the correct way would not be about choosing a track at the beginning and trying to swap dynamically, but loading all subtitle lines of flagged tracks into memory and showing them accordingly to any given timestamps.

 

And if the user manually changes the active subtitle track (default) to any other given track, the default lines in memory would have to be replaced by the lines from the newly chosen subtitle track - all while forced lines would still have to stay in memory and be shown.

[ebr 16169]

18 hours ago, RokeWayne said:

I think choosing a sub track at the beginning of playback (or even before when showing properties of the media) and thinking that state is permanent is already a step in the wrong direction. I would say, that subtitle tracks need to dynamically switch during playback

Hi.  That is simply not how any player I'm aware of operates.  You choose one and only one sub track and that is the one that is shown until you turn it off or change it.

Now, the contents of the different tracks may make it appear like multiple are being shown, but that isn't what is happening.

[RokeWayne 5]

I'm pretty sure, that subtitles on optical discs like dvds and BluRays work exactly that way that I described (in regards, which subtitles are shown, not how the subtitle display is implemented; that I can't know)

Here are two points, why the "default" and "forced" flag never could mean the same...

1) Heres the definition, what forced subtitles are (I know about AI hallucinations, but here its coherent with what i know about the flags, since I mux a lot of files):

2)

On 5/23/2025 at 8:13 PM, ebr said:

You choose one and only one sub track and that is the one that is shown until you turn it off or change it.

If you exclude the "forced" flag from the equation, thats exactly how it works with the default flag, if it exists or with manually chosen subtitles. But then, if the "forced" flag would only be considered to work like any other subtitle track (like its actually implemented in emby and its apps), there would be no need for the "forced" flag to be saved separately in a file. Heck, there would be no need for the "forced" flag at all - it would simply be sufficient to have either a "default" or a "forced" flag, but not both. And I'm not talking how a media file is muxed by an user, I'm talking about the technical capabilities of the mp4 and mkv container...

See here the two columns, when a mkv file is opened in mkvtoolnix...
you can see, that forced and default are stored separately - which wouldn't be necessary if only lines from one subtitle track have to be shown.

On 5/22/2025 at 12:49 PM, RokeWayne said:

For your help the translation:
Aus = off
Ja = yes
Nein = no
"Erzwungen" / "Anzeige erzwingen" = "forced", here in this case "S&S" stands for "Songs & Signs", cause its an anime

"Standardspur" is translated with "default track" and ">>Anzeige erzwingen<<-schalter" is literally translated with "forced display flag". Both columns exist separately, which they wouldn't have to be if both "forced" and "default" flag would both influence the same aspect in subtitle display. Therefore they have to influence the subtitle display during playback in a different way. 

And from my understanding, and also regarding that definition that ai displayed it has to be summarized this way:

The "default" flag, if existent in a media file, has to regarded to when playback starts and its correspondent subtitle track should be intially chosen and displayed. If no track with "default flag" is existent in a file, no "regular" subtitles have to be shown (excluding for the behaviour in the next sentence).
If a "forced" subtitle track exists, its lines have to be shown during playback, whichever regular subtitle track is actually automatically or manually chosen from the other tracks (the non-forced flagged ones).

If you agree here, then - as much as it hurts me to say - the actual implementation in emby is not the technically right way to handle those flags and its subtitle mechanisms would have to be reevaluated in the server and in the player apps.

Please be advised, that our discussion should focus on which behaviour during playback would be correct, not about the technically right way how to implement the wanted behaviour.
Since I don't have any development knowhow in players, our discussion would quickly divert from the point that I was trying to make.

Kind regards
Roke

 

 

[RokeWayne 5]

On 5/23/2025 at 8:13 PM, ebr said:

Hi.  That is simply not how any player I'm aware of operates.  You choose one and only one sub track and that is the one that is shown until you turn it off or change it.

Now, the contents of the different tracks may make it appear like multiple are being shown, but that isn't what is happening.

I'm pretty sure, that I have never seen an optical hint by players, when displaying forced subtitles, because the subtitle track configuration is not changed at all and would confuse users more than it helps. The Subtitles from tracks with the "forced" flag are simply shown automatically, like i said "additionally" to whichever subtitle configuration is currently active.

I can tell you by digging into some of my anime files and also occasionally muxing them, that thats exactly what vlc, kodi and media player classic from the k-lite package do, when displaying subtitles. Take any file with both tracks flagged "default" and "forced" and usually they take the "default" one for displaying, while also showing the lines from the "forced" track.

[pwhodges 2012]

It is clear that (a) there is no authority which defines the handling of forced subtitles, and (b) different media suppliers, streaming platforms, and players handle them differently.

Historically (early DVD) forced subtitles started as individual flagged lines within a single subtitle stream which were shown even if the rest of the stream was turned off - and DVD ripping programs would make two files from the one subtitle stream to enable selection of complete (including the forced lines) or just the forced subtitles.

Netflix rules require that all forced subtitle contents must be included in the main subtitle files, so that they are still shown when another subtitle stream is selected; it is assumed that only one subtitle stream is used at a time.

Some streaming platforms expect forced subtitles to be burned in to the video - that at least forces them to be shown!  I've even seen a requirement that they are all capitals.

Basically, the use of a forced flag is a snare and a delusion - it is as easy to simply select the subtitle stream you want, or to set it as default so that it plays automatically.

An additional confusion is caused by the fact that Handbrake (at least when using the GUI) automatically adds the forced flag when you select the default flag.  This creates a situation, for instance, in which some programs - MPV in my experience - won't play the subtitles correctly if there is more than one subtitle stream and one has both default and forced flags.

My policy is therefore to remove all forced flags, because they create unwanted issues and add no value.

Paul

[RokeWayne 5]

Hi, Paul.

Thanks for discussing with us and contributing to the topic.

5 hours ago, pwhodges said:

It is clear that (a) there is no authority which defines the handling of forced subtitles, and (b) different media suppliers, streaming platforms, and players handle them differently.

Historically (early DVD) forced subtitles started as individual flagged lines within a single subtitle stream which were shown even if the rest of the stream was turned off - and DVD ripping programs would make two files from the one subtitle stream to enable selection of complete (including the forced lines) or just the forced subtitles.

Netflix rules require that all forced subtitle contents must be included in the main subtitle files, so that they are still shown when another subtitle stream is selected; it is assumed that only one subtitle stream is used at a time.

Some streaming platforms expect forced subtitles to be burned in to the video - that at least forces them to be shown!  I've even seen a requirement that they are all capitals.

Well you are right in your points. All the more reasons to contribute to emby trying it to handle it in the right way.

5 hours ago, pwhodges said:

Basically, the use of a forced flag is a snare and a delusion - it is as easy to simply select the subtitle stream you want, or to set it as default so that it plays automatically.

Well, here starts the problem: By emby choosing the "forced" flag over the default flag and most media having the subtitle track with a "forced" flag having only a fraction of the subtitles in it (like in my example up above) , it enforces the user having to manually interact with the player at the start of the playback of every file/episode/film.

Take into account, how many files an emby user could have on its server and it quickly becomes a substantial annoyance. For me still not annoying enough to stop using emby, but enough to at least wanting to start a conversation.

5 hours ago, pwhodges said:

An additional confusion is caused by the fact that Handbrake (at least when using the GUI) automatically adds the forced flag when you select the default flag.  This creates a situation, for instance, in which some programs - MPV in my experience - won't play the subtitles correctly if there is more than one subtitle stream and one has both default and forced flags.

My policy is therefore to remove all forced flags, because they create unwanted issues and add no value.

Its okay that you do, and even better if it solves the problems in your media collection. 

To me instead, changing my files to not have the "forced" flags would mean, that I
1) need to manually edit subtitiles on thousands of files, where I would need to migrate the lines of "forced" tracks into the "default" ones (that is needed because in animes the tracks don't overlap, therefore the forced track is not included in the default one - refer to my example above)(with the tool Subtitle Edit) AND 
2) then deleting the forced track with miktoolnix on the same thousand of files.
That would be substantial work that additionally solves the problem only for me. Other users would still run into the same problem.
Also it would feel like taking a problem and only solving the symptoms, not the root cause.

That's why I wanted emby to handle the "default" and "forced" flag differently, because it would help in n users, where as a personal invest in changing someones own files helps only 1 user.
Interestingly enough my suggestion would not have any impact on your viewing experience, since you allegedly don't use the "forced" flag.


 

[ebr 16169]

21 minutes ago, RokeWayne said:

By emby choosing the "forced" flag over the default flag

That is going to depend on your specific "Subtitle handling" setting as well as the language tags for the tracks in question.

[RokeWayne 5]

37 minutes ago, ebr said:

That is going to depend on your specific "Subtitle handling" setting as well as the language tags for the tracks in question.

Sorry: By emby choosing the "forced" flag over the default flag ... in the default subtitle mode.
But we are starting to split hairs now ^^

[pwhodges 2012]

2 hours ago, RokeWayne said:

I would need to migrate the lines of "forced" tracks into the "default" ones (that is needed because in animes the tracks don't overlap, therefore the forced track is not included in the default one

I have a large collection of anime, and I can't recall a single case in which the main subs (usually default, because the default audio is usually Japanese) don't include the content of forced subs (in the cases where they are present, which is by no means a given).

Oh, and there is a GUI for doing bulk edits of the flags without rewriting the whole file, in mkv files at least, so the forced flag is rather easily removed.

Paul

Edited May 26, 2025 by pwhodges

[RokeWayne 5]

On 5/26/2025 at 6:47 PM, pwhodges said:

I have a large collection of anime, and I can't recall a single case in which the main subs (usually default, because the default audio is usually Japanese) don't include the content of forced subs (in the cases where they are present, which is by no means a given).

There is at least the example, that i provided above - and I know I have tons more of them in my collection. I presume, it depends where you get your files from.

[RokeWayne 5]

@pwhodges:
But anyways:
Even IF your point (that forced subtiltle tracks would be included in the default ones) were always true (which I acknowledge happens), that would still prove my point, that emby choosing primarily the forced subtitle over an existent default flagged subtitle track when starting the playback still results in the wrong subtitle display (when having "DEFAULT" as subtitle mode). Which then forces an imho unncessary user interaction.

You cutting the forced flags out of files is just a workaround for programs that choose the wrong priority for subtitle tracks.

 

So my actual wish for the different cases would be to have this implementation:

Check if a file has a forced-flagged subtitle track
If yes
    Check if the file has a default-flagged subtitle track
    If yes
        Set subtitle playback track to default subtitle track
    If no
        Set subtitle playback track to forced-flagged subtitle track
    If-End
If no (regarding the forced flag track)
    Check if the file has a default-flagged subtitle track
    If yes
        Set subtitle playback track to default subtitle track
    If no
        Set subtitle playback track to "null" (no subtitles shown at all)
If-End

This implementation would regard the subtitle tracks in this order:

default flagged track > forced flagged track > no subtitle shown

This would create a better experience for everyone independently of forced flag tracks being included in default flagged tracks.

And for you, @pwhodges, it would cut off the necessity to remove the forced-flag tracks of your files.