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Forced Subtitles

Posted: Tue Mar 05, 2024 8:34 pm
by fivestarplus
I can't get forced subtitles to work. I have searched this forum for solutions and have tried MKVToolNix and still no subtitles during play back. Please correct me if I am wrong. From what I have read MakeMKV can recognize subtitles but does not know where to put them so they are placed into a separate audio stream. I have added the "f" force flag to both the default and the second audio subtitles. I have tried MKVToolNix Header Editor. Still no subtitles during play back. I am getting subtitles for the entire movie even when I select forced subtitles only. I only want the subtitles when foreign language is used. My (LG) DVD player has the alternate BD-RE-WH16NS60 firmware version 1.02 patch for MT1959. I have tried muItiple players (VLC, PowerDVD 23, Media Player, PlayerFab). It seems like that I always get the message "Forced subtitles track #5 turned out to be empty and was removed from output file" even when I know there are forced subtitles. A lot of the potential solutions on this forum are older and I am hoping that there is a better way. What am I doing wrong?

Re: Forced Subtitles

Posted: Tue Mar 05, 2024 11:21 pm
by dcoke22
On a disc, for a given subtitle track, there's just a single stream of subtitles. Some of those individual subtitles in that stream might be marked as forced. If MakeMKV encounters some of these subtitles marked forced when it is ripping a movie, it copies these out into their own subtitle track. If MakeMKV does NOT encounter any of these subtitles marked forced, then at the end of the rip it deletes the empty subtitle track it had created so as to be ready in case some forced subtitles were encountered. This is the source of message like: "Forced subtitles track #5 turned out to be empty and was removed from output file"

Not all movies with forced subtitles use the model where there's a single stream of subtitles with some entries marked forced. Lots of movies just have a separate subtitle track that is only the forced subtitles. That subtitle track might not be marked or labeled as forced. The MKVToolNix tools come in handy in this case to mark these tracks as appropriate.

The tool MediaInfo can show you lots of details about a .mkv file, often including the number of elements in a subtitle track. For example:

Code: Select all

Text
ID                                       : 8
ID in the original source medium         : 4608 (0x1200)
Format                                   : PGS
Codec ID                                 : S_HDMV/PGS
Codec ID/Info                            : Picture based subtitle format used on BDs/HD-DVDs
Duration                                 : 1 h 34 min
Bit rate                                 : 53.1 kb/s
Frame rate                               : 0.614 FPS
Count of elements                        : 3476
Stream size                              : 35.9 MiB (0%)
Title                                    : SDH Subtitles
Language                                 : English
Default                                  : No
Forced                                   : No
Original source medium                   : Blu-ray
In that example, the count of elements is 3476, indicating it probably contains more than just some forced subtitles. After watching it for a couple of minutes, it was clear that those were SDH Subtitles and I used the MKVToolNix tools to label them as such.

Generally speaking, if you rip all the subtitle tracks for a title that are of the language you're interested in, you can figure out which track is which after the fact by a combination of the count of elements and just watching a few minutes with the subtitles on.

Typically when I have a movie with a forced subtitle track, I name it 'Forced Subtitles' and set both the forced flag and the default flag to true (with the MKVToolNix tools). Most of the time the players I use do the right thing in this scenario, but not always. Sometimes Plex has to be explicitly told to show the forced track, but typically only once. But each player behaves in its own special way. Only zero or one subtitle track should be marked as forced and/or default. It doesn't make sense for two or more subtitle tracks to be default or forced.

Re: Forced Subtitles

Posted: Wed Mar 06, 2024 11:28 am
by fivestarplus
I have MakeMKV set up to only select the English audio tracks. Most of my movies in addition to the audio track have 2 sets of subtitles like below.

Subtitles PGS English
Subtitles PGS English (forced only) marked as default
...
Subtitles PGS English
Subtiles PGS English (forced only)

In MakeMKV, I add the force flag to the one marked as default and create the MKV file. This has not been working when I play the movie to check for subtitles. I have also removed the default flag and made the 2nd (forced only) file as default and forced. This also does not work.

I have just recently begun to use MakeMKV and most of my movies so far have worked well. It's the ones with the subtitles that I have trouble with. I have gone through this forum and have looked at MKVToolNix Header Editor, MediaInfo, OpenFilesView and Subtitle Edit. With Subtitle Edit, I can export the subtitles to .SRT file. I'm just learning all of these products, so I am no expert and probably doing something wrong.

It may be the player that I am using to check for subtitles. I just tried MPC-BE and it is working with that player. I will check my other movies and see if this is consistent behaviour with using MPC-BE.

Re: Forced Subtitles

Posted: Wed Mar 06, 2024 2:56 pm
by dcoke22
It is probably the case that none of the subtitles are marked as forced in either subtitle track. That would be why no subtitles end up in subtitle track MakeMKV labels as forced only.

For clarity, when I say 'subtitles marked as forced in a subtitle track' I'm referring to something the author of the disc would do when they create the disc. This is distinctly separate from the action of setting the forced flag on a track in a .mkv file.

In the example you've shown, I would guess that the first subtitle track is whatever the normal subtitles are. I would guess the second subtitle track contains only the forced subtitles. I would also guess that none of the subtitles are marked as forced in the stream so MakeMKV will NOT put any subtitles into the track it labels as forced only.

I would guess you'd need to rip both subtitle tracks, determine which contains only the forced subtitles, and mark/label it as such using the MKVToolNix tools.

As a side note, MakeMKV has a feature where you can make a decrypted backup of a disc. This copies everything on the disc to a folder on your storage. You can then open this backup with MakeMKV and create .mkv files from it instead of from the disc directly. This allows you to make .mkv files as fast as your storage will go which is undoubtedly way faster than reading from the optical disc and makes this kind of experimentation faster.