tsmuxer + makemkv (subtitle)

[CAPRICORNX10X]

Hi, hello everyone.
I would be happy to solve a problem I noticed recently,

I usually create an mkv file in the following way:
1. I download srt subtitles, change size, font and color in tsmuxer and convert them to a pgs file (bluray) through tsmuxer.
2. Use BDSup2Sub to change the position of the subtitles
3. I download a uhd bluray movie, attach to it the pgs subtitles that I created and create again through tsmuxer a bdmv folder with the subtitles and the audio and video tracks that are relevant to me.
4. Use makemkv to convert bmdv to mkv.

This way when it comes to a full uhd bluray movie, the subtitles I converted through tsmuxer to pgs and changed the size, font color and position. Saved properly and as I wanted in the final mkv file.

The problem starts when I do it with an mkv file from the start.
Instead of downloading a full uhd bluray movie, I download an mkv movie. and converts it via tsmuxer to bmdv, so that I can use the subtitles I download as I want them to see.

In the end, after I create an mkv file again via makemkv, the subtitles do not appear properly. The location is right above, the size is smaller.

Really very strange...

[Woodstock]

Not sure this is a MakeMKV issue, since you're starting with a questionable source to begin with. MakeMKV is meant for converting legal source disks, not random created downloads.

[ArArdin]

It's indeed not a MakeMKV issue. I don't think importing mkv in tsMuxer for (any) subtitle conversion is a proper idea. Not in the last place because mkv's often aren't (UHD)BD compliant. IMO, both MakeMKV and tsMuxer aren't even called for here.

I think it's a better approach to handle your subtitle issue with dedicated subtitle software. Something like Subtitle Edit. Easy to use, it can directly export to blu-ray SUP after you've loaded the srt. Note that PGS subtitles on UHD discs are authored to 1920x1080 screensize, just like on full HD blu-rays. SE has a nice preview window which shows how your subs will come out when doing the settings. Set the correct framerate and use darker colors/grays for HDR video. Of course you can edit SE result with BDSup2Sub to change positions.

Once ready, mux the SUP file into the mkv using MKVToolNix

[Chetwood]

I can't think of any reason why SRTs shouldn't be more than fine on playback.

[ArArdin]

I'd agree srt often will suffice. By function at least. But "more than fine" may be overgraded. How srt will look on-screen, depends on the player's onboard bells and whistles to handling text-based subs. The format was basically developed as simple text only, without thought of any further artistical usage like position, font, color etc. Even today it's not uncommon to see "simple" italic tags in srt not being honoured.

PGS is an image-based, BD compliant format that's widely supported. Obvious key difference from srt is that not the player, but the creator determines how the subtitles will look, and where in video they are displayed. Being busy with PGS (and ASS for that matter) for many years, I think that exploiting the formats properties can yield subtitle display that absolutely adds to the intended video atmosphere. Where I'd advise caution to not exaggerate things.

Which immediately points out an underlying risk. When not caring about where/how subtitles will look, viewing pleasure will mercilessly be destroyed. An ancient patent on this seems to be painstakingly held by Warner Bros, btw. Already from early video-dvd days till current UHDBD times, their subs often look crafted by people badly needing a guide dog. Leaving the viewer in a sad crave for simple srt instead, I might add.

[Chetwood]

I'd agree srt often will suffice. By function at least. But "more than fine" may be overgraded. How srt will look on-screen, depends on the player's onboard bells and whistles to handling text-based subs. The format was basically developed as simple text only, without thought of any further artistical usage like position, font, color etc.

Of course, but since he bases his muxes on files that lack these attributes, I don't see any reason to convert them to bitmap. So far any player I've seen handles SRTs reasonable well, better than some players do with bitmaps.

[ArArdin]

...since he bases his muxes on files that lack these attributes, I don't see any reason to convert them to bitmap.

OP does, according to his initial post. He uses BDSup2Sub to change position after PGS has been created by tsMuxer. Which already has options for default H/V offsets. Not sure why, but as an example he may need to reposition just a few subtitles to avoid them interfering with burned in text or other specific video detail.
Maybe OP can provide with some feedback.