[FFmpeg-trac] #11566(ffmpeg:new): Arabic subtitles rendering artifact BUG

[FFmpeg]

#11566: Arabic subtitles rendering artifact BUG
------------------------------------+----------------------------------
             Reporter:  ellat       |                    Owner:  (none)
                 Type:  defect      |                   Status:  new
             Priority:  normal      |                Component:  ffmpeg
              Version:  git-master  |               Resolution:
             Keywords:  subtitles   |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
------------------------------------+----------------------------------
Description changed by ellat:

Old description:

> Summary of the bug:
> How to reproduce:
> Create the file a.srt:
>
> {{{
> 1
> 00:00:00,000 --> 00:00:15,000
> الأسد
> }}}
>
> Use a random input video and run this command to burn subtitles:
>
> `%./ffmpeg -i input_video.mp4 -vf
> subtitles=a.srt:force_style='FontName=Arial' out.mp4`
>
> A box outline will appear in the middle of the arabic word.
>
> {{{
> ffmpeg version N-119396-g48c0dba23b-20250430 Copyright (c) 2000-2025 the
> FFmpeg developers
> built with gcc 14.2.0 (crosstool-NG 1.27.0.18_7458341)
> }}}
>
> According to: https://bugs.kde.org/show_bug.cgi?id=502725
> this issue has existed for 2 years.

New description:

 Summary of the bug:
 How to reproduce:
 Create the file `sub.srt`:

 {{{
 1
 00:00:00,000 --> 00:00:15,000
 الأسد
 }}}

 Use a random input video and run this command to burn subtitles:

 `%./ffmpeg -i input_video.mp4 -vf
 subtitles=sub.srt:force_style='FontName=Arial' out.mp4`

 A box outline will appear in the middle of the arabic word.

 {{{
 ffmpeg version N-119396-g48c0dba23b-20250430 Copyright (c) 2000-2025 the
 FFmpeg developers
 built with gcc 14.2.0 (crosstool-NG 1.27.0.18_7458341)
 }}}

 According to: https://bugs.kde.org/show_bug.cgi?id=502725
 this issue has existed for 2 years.

--
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/11566#comment:1>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker