PGS Subtitles MakeMKV & Handbrake

[kfreeb]

Handbrake now supports PGS subtitles, and as a result there is a thread, (currently going on) in the Handbrake forum, (HB) about Make MKV, (MMKV) not properly decoding Blu-ray subtitles, when exporting only forced subtitles. Here is the link: https://forum.handbrake.fr/viewtopic.ph ... 25#p111452

Here's the issue Mike. When using the forced subtitle option to burn-in the subtitles for shows like Avatar and the Navi language, it has been found that if you use MMKVs forced subtitle export check box, (leaving unchecked the outset checkbox) the resulting PGS subtitle track has no clear subtitles, (used to turn off any given subtitle at the proper time) they remain on screen till the next forced sub comes along.

However, if you rip the Blu-ray disk using the "Decrypted Back Up" option in MMKV, then encode using Handbrake, selecting forced subtitles/burn-in and the appropriate PGS subtitle track, the clear subtitles are present.

Something is being changed, (in the PGS subtitle track) when you extract only the movie with only force subtitles, leaving all of the clear subtitles missing from the final MKV, PGS subtitle track.

Could you please see why this is happing?

[Chetwood]

I don't use Handbrake but there appears to be something off with MakeMKV's forced sub recognition. I always rip main movie only with DVDFab to HDD keeping all English and German streams (I always check forced only too). Then I use MakeMKV and remux again with MKVToolnix (since WDTV does not support uncompressed PGS subs). My recent rips turned out like this:

• MakeMKV extracted 2 forced sub streams which are identical (only four items translating signs). Each of which is marked as forced in BDSUP2SUB. But when I add the MKV to MKVToolnix only one stream is flagged as forced?
• MakeMKV extracted 2 forced sub streams which are not identical. The second stream consist of one only 1 (!) item which actually is present as item 6 (of 13) in the first forced stream.
• MakeMKV extracts a stream with very few items, none of which are flagged as forced.

Mike, if you want I can pm you what discs I'm talking about in case you wanna try and reproduce this. Since I'm in Region B/2 and A/1 discs might be authored differently. BTW, how about an advanced option that while converting to MKV would also extract all sub streams simultaneously so we could identify them with BDSUP2SUB? Having to skip through the movie to find 20 or so items is a PITA. Thanks.

[mike admin]

There was a bug about not keeping non-forced "clear subtitle" command after forced subtitle, that was fixed around 1.6.8 or so. The data from post at handbrake suggest that similar bug is still present or you do have a file from old MakeMKV. Please make an MKV file from this disc (referenced at https://forum.handbrake.fr/viewtopic.ph ... 25#p111452 ) that has all subtitle streams (don't check forced), then extract all subtitle streams from MKV with mkvextract and send them to support@makemkv.com .

Also, in addition to keeping "clear subtitle", MakeMKV always tries to set "duration" of subtitle frame properly, as mentioned in the same post.

[kfreeb]

There was a bug about not keeping non-forced "clear subtitle" command after forced subtitle, that was fixed around 1.6.8 or so. The data from post at handbrake suggest that similar bug is still present or you do have a file from old MakeMKV. Please make an MKV file from this disc (referenced at https://forum.handbrake.fr/viewtopic.ph ... 25#p111452 ) that has all subtitle streams (don't check forced), then extract all subtitle streams from MKV with mkvextract and send them to support@makemkv.com .

Also, in addition to keeping "clear subtitle", MakeMKV always tries to set "duration" of subtitle frame properly, as mentioned in the same post.

Hi Mike, thanks for replying.

The MKV file referenced above, containg the forced subtitle extract was created with MMKV ver. 1.7.4.

I want to get this right, so what I'm going to do is send two english PGS subtitle tracks, one with all subs intact, one with forced only. They will be properly labeled as to which is which.

This issue seems to only show up, when extracting just forced subtitles as part of the MKV file. It is this type of file that seems to be missing the clear subtitles, as you can see by the log that HB creates, (forced subtitle log: https://forum.handbrake.fr/viewtopic.ph ... 25#p111452) were as the log from the decrypted backup, (one down/below the forced log, containing all english subs) shows the clear subtitles being present.

I have MKV Tools 3.0, (for the Macinthosh) which creates a sup file extraction of the PGS track, MKV extract is not supported in the version of MKV Toolnix that I have, (MKV Toolnix 4.3.0.) This feature seems to only be available in the PC version of MKV Toolnix. I can't run PC software, I'm Mac only.

Or I guess I could delete all tracks in the MKV file, (except for the PGS track and remux it again into an MKV file, will that work for you?

[Romansh]

Also, in addition to keeping "clear subtitle", MakeMKV always tries to set "duration" of subtitle frame properly, as mentioned in the same post.

libavformat currently ignores the MKV block durations for subtitle tracks (and therefore, so does HandBrake). We'd have to patch it to get the durations.


Also: https://forum.handbrake.fr/viewtopic.ph ... 50#p111517

Unfortunately there wasn't enough logging in the build I provided to kfreeb to be sure of it, but it appears that there is a sequence of 3 subtitles:

1) forced subtitle

2) regular subtitle

3) clear subtitle

Currently, in forced-only extraction mode, HandBrake will only include subtitles 1 and 3, and skip subtitle 2. My first idea was to move subtitle 3, changing its start time to match that of subtitle 2. But it doesn't cover the following scenario:

1) forced subtitle

2) regular subtitle

3) forced subtitle

This is a theoretical scenario as we haven't seen it yet in actual sources, but we figured it might occur. Here, subtitle 3 can't simply be moved, as it isn't empty and would start too early.

So what HandBrake will now do (in forced-only extraction mode) is, when it finds a regular subtitle after a forced subtitle, it will convert it to a clear subtitle (in the presentation segment, setting the number of composition objects to 0 and removing them - the rest of the subtitle is unmodified), so that applications relying on said subtitles rather than container-level durations can clear the subtitle on time. FWIW.

[Chetwood]

Please make an MKV file from this disc (referenced at https://forum.handbrake.fr/viewtopic.ph ... 25#p111452 ) that has all subtitle streams (don't check forced), then extract all subtitle streams from MKV with mkvextract and send them to support@makemkv.com

Mmh, am I blind? I've checked the thread at the Handbrake forums but I don't know what disc you are referring to. Or do mean, everyone who had trouble with forced subs on some of their ripped discs should send those in? BTW, the examples I gave above where all done with MakeMKV Win 1.7.4.

[Smithcraft]

Avatar.

https://forum.handbrake.fr/viewtopic.ph ... 50#p111350

SC

[Chetwood]

Thanks, thats what I figured but I couldn't remember encountering any "clear" subtitles when ripping this one. I'm also not entirely sure what you guys mean by "clear"

[kfreeb]

Thanks, thats what I figured but I couldn't remember encountering any "clear" subtitles when ripping this one. I'm also not entirely sure what you guys mean by "clear"

As I understand it, looking a Romansh's post above, there are three types of subtitles present in a PGS subtitle track, (regular, forced & clear.) Unlike a dvd subtitle, where it has a duration set by timecode, and then is removed, PGS subtitles use something similar, also driven by the time code, actually places a subtitle that has no text in it, "clear" transparent, forcing the previous subtitle to be replaced, by one that has nothing in it, making the previous text vanish. It has the same effect as the way DVD subs work, but using additional subs to clear off previous subtitles.

PGS subs are usually a series of PNG images, containing text, and are transparent except for the text, which overlays any image it is merged with, allowing the movie image to show through, except where the text overlays. So in essence, once a PGS subtitle has been introduced in a movie, there is always a subtitle image, (PNG) overlaying the movie image all the way to the end of the movie, even if doesn't contains any text, (transparent) and can't be see. Which is the purpose of a "clear" subtitle.

[Chetwood]

Having an emtpy image overlaying instead of simply turning off the previous image by its timecode sounds a bit weird to me but would explain one phenomenon I forgot to add to my list above. The forced only stream extracted from Sherlock Holmes, Games of Shadows has some empty items in between.

[kfreeb]

There you GO.

More proof of how PGS subs work!

[Chetwood]

Apparently, but I tink it's strange that it starts with some clear items. This is the stream extracted as forced only by MakeMKV:

Code: Select all

01  00:00:00:000  clear
02  00:01:10:880  clear
03  00:01:55:120  clear
04  00:05:32:040  clear
05  00:14:26:280  clear
06  00:16:23:000  clear
07  00:26:14:360
08  00:26:15:640
09  00:26:18:120
10  00:26:20:320
11  00:26:22:640
12  00:27:44:240  clear
13  00:38:15:960  clear
14  00:40:58:280  clear
15  00:44:09:440  clear
16  00:54:40:240
17  00:56:48:920
18  00:57:20:800
19  01:00:58:400
20  01:01:02:640
21  01:01:12:240
22  01:07:58:480
23  01:08:03:760
24  01:13:16:920  clear
25  01:15:46:520  clear
26  01:21:35:480  clear
27  01:24:18:880  clear
28  01:26:50:800  clear
29  01:47:45:760
30  01:47:47:520
31  01:47:57:640
32  01:53:31:840  clear
33  01:57:32:920  clear
34  02:08:40:320

None of these items is flagged as forced according to BDSUP2SUB but items 7-11 definitely are cause they are translating the letter that Holmes hands to Sim.

[kfreeb]

Apparently, but I tink it's strange that it starts with some clear items. This is the stream extracted as forced only by MakeMKV:

None of these items is flagged as forced according to BDSUP2SUB but items 7-11 definitely are cause they are translating the letter that Holmes hands to Sim.

This is the issue that we currently have with Make MKV, the way it extracts PGS subtitles when checking the forced only box, (it's screwed up) it is not translating them correctly. To work around this limitation, I have been extracting all subs, then checking forced only in handbrake to burn-in just the forced ones, which for the most part seems to work fairly well.

When you extract all of the subs, Make MKV seems to extract all subs correctly, (regular, forced & clear) which you can then pick forced only in HB. You should see what Avatar does, (when extracting forced only in MMKV) there are no clear subs, allowing subs to stay on screen for several minutes at a time, till the next forced sub replaces it. However, when extracting all subs, then all three kinds of subs are there, (allowing for the correct duration of subs on screen.)

[Chetwood]

This is the issue that we currently have with Make MKV

Yeah, well, seems to be rather new cause AFAIR I never had clear subtitles before in forced only streams. BTW, I've also just realized that MakeMKV flags forced only streams as forced rather than default and forced but I guess standalones only rely on the former?

[voip-ninja]

Guys,

I've just stumbled again across this thread as I discovered that recent Handbrake builds now support forced subtitles. What I was trying to figure out is what the best approach is if I want to preserve the original PGS subtitle track (all subs) as well as have forced subtitles working.

Currently I rip the main and forced selections with MakeMKV and then I use MKVMerge to go in and mark the forced track as "forced" (using the forced flag) and this seems to have worked very well as I get forced subs to come on automatically when playing back these titles but can also select the full subtitle track if desired.

Would this work similarly with Handbrake? I rip just the full subtitle track in MakeMKV and then using Handbrake I select that track two times, once as a "regular" subtitle track and the 2nd time with "forced only" or am I mixed up on this?

Thanks.

(This question now comes up as I have purchased and am ripping True Blood Season 4 and True Blood almost always has forced subs in some episodes... I always re-encode these with Handbrake to 720P to save space and normally have to do a filthy merge afterwards in MKVMerge to get everything right, it would be great if Handbrake could do it in one clean step).