user6356: I have a video in webm format, and two files in webVTT format, chapters and subtitles.
Is it possible to embed this two webVTT file in the webm in order to get only one file ?
webm is a derivative of Matroska, so it's certainly possible. The real question is they will be handled by a program like VLC ?
Thanks in advance !

user3295: Edit: It seems that WebM now supports VTT subtitles. See the link below for detailed information.
If you want to add subtitles to a video on a web page, have a look at the HTML5 'track' element. It allows adding subtitles without muxing them into the video container. More details here: https://developer.mozilla.org/en-US/docs/Web/Apps/Fundamentals/Audio_and_video_delivery/Adding_captions_and_subtitles_to_HTML5_video
WebM doesn't support subtitles nor chapters right now so you won't be able to embed them without creating a WebM file that is out of specs.
You will probably want to remux your video into mkv and then convert your VTT subtitles to SRT and mux these into your mkv aswell.
From http://www.webmproject.org/docs/container/

Initial WebM release does not support subtitles.
WHATWG / W3C RFC will release guidance on subtitles and other overlays in HTML5  in the near future. WebM intends to follow
  that guidance. Ref: WebVTT.


6356: <p>I have a video in webm format, and two files in webVTT format, chapters and subtitles.</p>

<p>Is it possible to embed this two webVTT file in the webm in order to get only one file ?
webm is a derivative of Matroska, so it's certainly possible. The real question is they will be handled by a program like VLC ?</p>

<p>Thanks in advance !</p>
 3295: <p>Edit: It seems that WebM now supports VTT subtitles. See the link below for detailed information.
If you want to add subtitles to a video on a web page, have a look at the HTML5 'track' element. It allows adding subtitles without muxing them into the video container. More details here: <a href="https://developer.mozilla.org/en-US/docs/Web/Apps/Fundamentals/Audio_and_video_delivery/Adding_captions_and_subtitles_to_HTML5_video" rel="nofollow noreferrer">https://developer.mozilla.org/en-US/docs/Web/Apps/Fundamentals/Audio_and_video_delivery/Adding_captions_and_subtitles_to_HTML5_video</a></p>

<p>WebM doesn't support subtitles nor chapters right now so you won't be able to embed them without creating a WebM file that is out of specs.
You will probably want to remux your video into mkv and then convert your VTT subtitles to SRT and mux these into your mkv aswell.</p>

<p>From <a href="http://www.webmproject.org/docs/container/" rel="nofollow noreferrer">http://www.webmproject.org/docs/container/</a></p>

<blockquote>
  <p>Initial WebM release does not support subtitles.</p>
  
  <p>WHATWG / W3C RFC will release guidance on subtitles and other overlays in HTML5  in the near future. WebM intends to follow
  that guidance. Ref: WebVTT.</p>
</blockquote>
