Forced subtitles

[Ghitulescu]

There are millions of forced subtitle threads according to google, I have read a few hundred which I considered to be the most relevant, still found no true information about this. And yes I do not have the "bible".

The almost "copy/pasted" information goes like this - forced subtitles are those subtitles that appear when aliens speak

What I want to know is the way they really really work in a DVD player.

* For instance, assuming I am a German national, what forced subtitles are displayed, the English ones or the German ones? Similarly for French and other non English and/or non Alien nationals On which basis the player chooses which one to display? And in case of conflicting requirements and settings, which are the prevailing ones?
* Can they be fully inactivated? Can they be activated (by hand)? Taking for instance a WW2 movies, where German soldiers speaking German are forcibly subtitled: no use of English forced subtitles, unless one believes conspiracy theories

Thank you.

[rik1138]

That depends on how the 'forced' subtitles are programmed. There's two ways to do it, and each way works very differently:
The most common is for the 'forced' stream to actually be another subtitle track. So you might have, on an English movie with a Spanish and French dubbed audio track, these subtitle streams:
1- English
2- Spanish
3- French
4- Spanish
5- French

That usually means that subtitle track 4 and 5 are the 'forced' tracks that should be displayed when you have the Spanish or French dubbed audio selected. In authoring, we have to program it so that if a user selects the Spanish audio track, and he doesn't have any other subtitle specifically selected, we have to select and display track 4 (some studios will switch to track 4 regardless of previous subtitle selections, just depends on what they like).

You can surf them off (if the UOP isn't disabled), but usually if you select 'Off' in the menus, the programming will turn on track 4. If you surf the audio from English to Spanish while watching the video, you won't get the forced track, as the programming doesn't know you changed audio tracks (this is one reason why some studios lock out audio/subtitle surfing, so they can guarantee these settings get turned on correctly as you are forced to use the menus to change anything).

(In the world of Blu-ray, with Java based programming, you can actually monitor this and change the subtitles at any point. But not with HDMV programming).


The other way is to allow the player to do it with true forced subtitles. In this case, you will have 3 subtitle files: English, Spanish and French (+ all the appropriate .TIF/.PNGs).
In the Spanish and French subtitle file, some of the subtitles will actually be labelled as 'forced'.
The forced subtitle events are triggered if you have the subtitle stream selected, but not being displayed. This is the only practical use for selecting, say, Spanish but having the display flag set to off. Any subtitle in the Spanish stream that is labelled 'forced' will display automatically. So, in programming, when someone selects Spanish audio (and no previous subtitles are specifically selected), you would then change the subtitles to stream 2 (Spanish), but 'display subtitles' is turned off.
If _every_ subtitle stream on the disc has at least one forced subtitle, then you can't, technically, turn them off. The forced subtitles in whatever stream is selected will be displayed. This might be the case on a disc with a real 'alien' language (John Carter, for example). When the Aliens are speaking their language, a forced subtitle in either English, Spanish or French will be displayed, but it wouldn't be possible to turn them off completely if the disc was made with true forced subtitles.

Where this breaks (and why the studios usually prefer the first option) is that every player handles subtitles differently. On some, you just toggle through all the subtitles until 'Off' is seen to turn them off. At this point, the player usually has the first subtitle stream selected, but not displayed. Some players actually have a button for surfing subtitles, and a separate button to turn them off, those players would work perfectly. Still other players will always switch back to stream 1 if the subtitles are off no matter how you turned them off. Even if you program the disc to select stream 2, but display off, the player will revert to having stream 1 selected.

So, true forced subtitles can't be guaranteed to work perfectly in every player, so the first technique has become the industry standard used by most studios.

With regards to your question about which ones you get 'by default':
At disc start-up, these options can also be selected by programming (or the player) based on the language settings you put in the player. So, if you had a movie like John Carter, and you have told your player that you speak German, on disk startup you will likely get English audio and full German subtitles (if there's no dub), or German dub and the German forced subtitles. Studios usually read the Menu/Aud/Subtitle settings that you can control, or some will make you select a language on startup (this is based on the assumption that most people aren't smart enough to properly set up a DVD/Blu-ray player...) If you tell the player you like English audio, but German subtitles, then the programming will usually be set so you get the forced stream in German. (Of course, this all varies by studio, as they all have different specs for this stuff... So there really is no 'standard' that will be universal for every movie...)

In general, audio setting takes precedence. If you have the player set for German audio and French subtitles, you get the German audio if it exists. If not, you will get English audio and German subtitles, if they exist. If there's no German at all, you get English audio and French subtitles. If there's no French subtitles, you will get English audio and no subtitles. Usually you wouldn't get a French dub, as the subtitle selection will never override audio (but if it's a French movie, then French would likely be the fall-back instead of English). And again, the specifics are different for every studio...

There's the long, wordy explanation... Hopefully I remembered everything correctly. (And it actually makes sense.)

[Ghitulescu]

It does a lot of sense, most of this I knew it already, just that the details were missing from the picture and blurred the whole image considerably...

[Ghitulescu]

So, in fact, marking an entire subtitle track (not the individual subtitles wthin) as Forced does actually nothing. I mean it acts like a normal, user selectable (if UOP) one.

However, marking some subtitles as forced (FORCED _START) within a normal track has to be correctly interpreted by the player (provided the track has been selected - the rest depends on whether it was activated or not).

And the correct way of handling them is not to leave their selection at the user choice but to implement a true mechanism via VM commands (for DVD).