title: How to make words in ASS subtitles appear one at a time?
body: <p>I am trying to burn subtitles into a video such that they appear in a word-by-word fashion instead of all at once.</p>
  
  <p>What I mean by this is, a word will appear, then another word will appear next to it, and so on. Eventually the line will clear, then repeat.</p>
  
  <p>Example:</p>
  
  <p><a href="https://i.stack.imgur.com/75L3J.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/75L3J.gif" alt="A video shows a person speaking about chess. Subtitles at the bottom of the screen say “winning”. Moments later, the subtitles change to “winning a”, then “winning a piece”, later “winning a piece now” and so on. Each consecutive word instantly appears in whole, but each word only appears when the speaker says it."></a></p>
  
  <p>I thought I could create an <a href="https://www.matroska.org/technical/specs/subtitles/ssa.html" rel="nofollow noreferrer">Advanced Substation Alpha</a> file where subtitles share the same end-time but differing start times, however FFMPEG doesn't seem to cope very well when rendering the file:</p>
  
  <pre><code>[Script Info]
  ; Script generated by FFmpeg/Lavc57.107.100
  ScriptType: v4.00+
  PlayResX: 384
  PlayResY: 288
  
  [V4+ Styles]
  Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
  Style: Default,Arial,16,&amp;Hffffff,&amp;Hffffff,&amp;H0,&amp;H0,0,0,0,0,100,100,0,0,1,1,0,2,10,10,10,0
  
  [Events]
  Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
  Dialogue: 0,0:00:00.00,0:00:03.46,Default,,0,0,0,,I'm
  Dialogue: 0,0:00:01.00,0:00:03.46,Default,,0,0,0,,a
  Dialogue: 0,0:00:01.50,0:00:03.46,Default,,0,0,0,,subtitle
  </code></pre>
  
  <p>The idea being that <code>I'm</code> would appear, then 1 second later <code>a</code> would show up next to it followed by <code>subtitle</code> a half second later</p>