v20 New Kodi subtitles renderer in Kodi 20 - TESTERS NEEDED
#1
We are working on a big change in the management of subtitles in Kodi 20
the main change is how the subtitles are rendered, now the rendering will be done by the LibAss library for most of subtitles format types
and this includes many other fixes and also includes new features

Here i mention the main changes:
  • Fix wrong subtitles positions in kodi windowed mode or when there is a too lower/higher resolution
  • Fix wrong proportion between font size points and pixels size (default font size is now 42 to match the wrong previous 28 value)
  • VPlayer subtitles: fix not displaying multiple lines
  • SAMI subtitles: fixed multilanguage support
  • Subtitles settings can now be changed while in playback without side effects
  • Add support to underline style
  • Add support to subtitle dynamic positioning by using subtitles tags (e.g. {\a4})
  • Add new subtitle setting "Override ASS / SSA subtitles styles"
All the changes are explained in details in the PR's:
https://github.com/xbmc/xbmc/pull/20010
https://github.com/xbmc/xbmc/pull/20169

Since there are many variables to test we need volunteers to test these changes,
what we want to know is not to have regressions compared to the regular version of Kodi

If you encounter problems with subtitles embedded in videos or by using external files,
please make a detailed report,
with attaching the Log with Kodi debugging enabled, and specify the type of subtitle used.

You can download the test builds from these links: ## links removed use nightly builds ##

UPDATE:
Now the PR is merged to the master branch
this means that to test these changes, you have to download and install the Kodi nightly builds
Dev-Maintainer of InputStream Adaptive add-on, Netflix add-on ▫ Skills Python, C#, VB.NET and a bit of C++
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#2
I have started to test this.  I am using the Winx64 nightly build of 20210928.  I will add replies as I test some different things.

1.  My issue #21008 is corrected using this build.  Local font files in userdata media/Fonts are searched and used as appropriate with no crash.
2.  I see my local font is appearing in settings/player/language/font to use for text subtitles.  I can select my local font and it is used in an external .srt subtitle.
3.  An old issue I had #15902 is corrected with this build.  See  screenshots of a videowindow control  placed in the home window.   In 19.2 subtitle is rendered outside of videowindow (bottom left) and not scaled

19.2 20210913 nightly
Image
20.0 20210928 nightly
Image

I did see something strange when using an external .ass subtitle  with an .iso movie -- no render issues but the event at 00:10:27 was displayed at 00:00:27.  (also true in 19.1 release and 18.9 release.)  I need to look into this more.

Will do more testing over coming days, but so far so good.

scott s.
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#3
good to know
thanks for the detailed report
if you can attach here or send me the ASS file on kodi Slack, so i can verify directly what happens if i am able reproduce it
Dev-Maintainer of InputStream Adaptive add-on, Netflix add-on ▫ Skills Python, C#, VB.NET and a bit of C++
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#4
Btw, the subtitles rework was already merged. So you can rely on current v20 nightlies for testing Smile
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#5
I am testing using "Sintel" from Blender.  The BD ISO file can be downloaded here: https://download.blender.org/durian/movi...Bluray.iso I am playing the iso by selecting "play main title: 0" from the video library Sintel entry. The iso contains PGS subs. Srt format subs may be downloaded from here:  https://download.blender.org/durian/subs/ I use subedit 3.6.2 to convert srt subs into ass. Here are a couple (RUS / zh-HanT aka ZHO):
Russian (CyrL)
Chinese (HanT)

During playback of the ISO the event at 00:10:21 plays at time 00:00:21 and then the next one at 00:00:26 (which happens to be the last in the sub file so haven't tested how other timestamps are handled).  I remuxed the movie into an mkv container, and the 2 ass subs both played at the correct times.

scott s.
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#6
OK so did a bunch of testing.  I'm not really familiar with ASS subs, mainly just SRT.  I tested external SRT and ASS subs, all passed.

1.  SRT subs.  Edited Settings/Player/language settings for size/style/color/opacity/background color/background opacity 
all were displayed correctly on the SRT subs.
2.  ASS subs.  Selected settings for override ass/ssa subtitle styles.  All worked as expected.
3.  ASS subs.  Tested with an attached font file.  Font was picked up and used (when style not overridden in settings).

Will do some testing with subs muxed in files next.   I would like to test with some external vtt, but I think we need another PR for that.  I can test with vtt muxed into mp4 (I don't think vtt in mkv works due to how mkvmerge labels vtt subs?)

scott s.
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#7
I justed tested the new subtitle renderer on one of the latest nightlies (Android version on a Shield 2019 Pro) and I found the following:
  • The subtitles seems to be rendered in a higher resolution, which looks better than in previous versions
  • To achieve the same size, the size setting needs to be increased (I went from 30 to 48)
  • A negative effect is that subtitles are rendered with a very thin black outline/shadow. This makes them harder to read on bright backgrounds
That last point is quite annoying, so I hope that can be fixed.

Made a couple of screen photos to illustrate. This is from a Dolby Vision MP4 with subtitle color set to Dark Grey, subtitle opacity set to 100% and background opacity set to 0%

Old method with regular outlines:

Image

New method with thin outlines:

Image
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#8
It's part of https://github.com/xbmc/xbmc/pull/20169 along with other (new) features
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#9
@enen92 Ok thanks, but that last PR is not yet in the nightlies is it? Because I don't see those extra options at the moment.
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#10
Nope, not yet. Just pointing out that your issue will eventually be fixed soon.
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#11
@enen92 Good to know, thanks!
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#12
I think I found a problem with RTL rendering.  I created a subrip srt subtitle with a long text string in Hebrew.  When rendered the text was split into 2 line.  The punctuation (periods) were correctly placed on the first line, but wrong on the second.

Image

First sub caption is the one I'm playing with
srt file here: sarozakeqa (paste)

scott s.
.
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#13
(2021-10-09, 00:33)enen92 Wrote: It's part of https://github.com/xbmc/xbmc/pull/20169 along with other (new) features
Sorry to quote you again, but I read something worrying in that PR:

Quote:Info about the Background type "Box":
The "Box" backgroud effect has some limitations due to LibAss rendering,
the font border size and border color cannot be set

If we will not get the option to increase the border size, the new subtitle rendering will become pretty useless for me.

As you can see from my pictures above, the font border is too thin at the moment and makes subtitles hard to read on bright backgrounds.

@CastagnaIT Any thoughts on this?
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#14
> If we will not get the option to increase the border size, the new subtitle rendering will become pretty useless for me.
> As you can see from my pictures above, the font border is too thin at the moment and makes subtitles hard to read on bright backgrounds

in the PR is clear explained that concern the background type box

<<< Info about the Background type "Box": >>>

in your screenshots you do not use the background type "box"
Dev-Maintainer of InputStream Adaptive add-on, Netflix add-on ▫ Skills Python, C#, VB.NET and a bit of C++
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#15
@CastagnaIT Ok sorry, the text is just a little confusing, because it talks about "font border size".

Does this mean the size of the thin black line around the characters (what is this called anyway? Outline size or something?) will be configurable in a later version?
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New Kodi subtitles renderer in Kodi 20 - TESTERS NEEDED0