[FFmpeg-trac] #9808(avcodec:new): Curly brace characters in WebVTT subtitle files not encoded correctly

[FFmpeg]

#9808: Curly brace characters in WebVTT subtitle files not encoded correctly
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             Reporter:  Gavin        |                    Owner:  (none)
  Llewellyn                          |
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:  avcodec
              Version:  unspecified  |               Resolution:
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Changes (by tfischer):

 * component:  undetermined => avcodec

Comment:

 I can confirm this bug. It happens when a WebVTT file is decoded in
 libavcodec/webvttdec.c, function webvtt_event_to_ass. See also line 40's
 comment "escape to avoid ASS markup conflicts".
 Although removing line 40 would "solve" this particular bug, it may
 introduce new problems in other areas of subtitle handling, esp. ASS
 markup.

 My proposed solution is to change function webvtt_encode_frame in
 libavcodec/webvttenc.c to "unescape" the two affected characters "{" and
 "}".

 I am going to attach a patch that implements this feature.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9808#comment:1>
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