[FFmpeg-trac] #10659(undetermined:new): Converting to ass subtitles results in overlap.

[FFmpeg]

#10659: Converting to ass subtitles results in overlap.
-------------------------------------+-------------------------------------
             Reporter:  typological  |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 When converting to ass subtitles from srt or vtt, there are some overlaps
 that weren't there, probably due to wrong rounding.

 How to reproduce:
 {{{
 % ffmpeg -i sub.srt sub.ass
 ffmpeg version n6.0 Copyright (c) 2000-2023 the FFmpeg developers
 built with gcc 13.2.1 (GCC) 20230801
 }}}

 sub.srt (input):
 {{{
 1
 00:00:29,566 --> 00:00:34,332
 test 1

 2
 00:00:34,333 --> 00:00:38,833
 test 2

 3
 00:00:38,833 --> 00:00:39,833
 test 3
 }}}

 sub.ass (actual output):
 {{{
 ...
 [Events]
 Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect,
 Text
 Dialogue: 0,0:00:29.57,0:00:34.34,Default,,0,0,0,,test 1
 Dialogue: 0,0:00:34.33,0:00:38.83,Default,,0,0,0,,test 2
 Dialogue: 0,0:00:38.83,0:00:39.83,Default,,0,0,0,,test 3
 }}}

 sub.ass (expected output):
 {{{
 ...
 [Events]
 Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect,
 Text
 Dialogue: 0,0:00:29.57,0:00:34.33,Default,,0,0,0,,test 1
 Dialogue: 0,0:00:34.33,0:00:38.83,Default,,0,0,0,,test 2
 Dialogue: 0,0:00:38.83,0:00:39.83,Default,,0,0,0,,test 3
 }}}

 (note the 34, that should've been 33, at the first Dialogue line)

 the same happens if I use sub.vtt as input with the command
 {{{
 ffmpeg -i sub.vtt sub.ass
 }}}

 with sub.vtt (input)
 {{{
 WEBVTT
 Kind: captions
 Language: en

 00:00:29.566 --> 00:00:34.332
 test 1

 00:00:34.333 --> 00:00:38.833
 test 2

 00:00:38.833 --> 00:00:39.833
 test 3
 }}}
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10659>
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