11.3 Linked media

By default, pandoc will download media referenced from any <img>, <audio>, <video> or <source> element present in the generated EPUB, and include it in the EPUB container, yielding a completely self-contained EPUB. If you want to link to external media resources instead, use raw HTML in your source and add data-external="1" to the tag with the src attribute. For example:

<audio controls="1">
  <source src="https://example.com/music/toccata.mp3"
          data-external="1" type="audio/mpeg">
  </source>
</audio>

If the input format already is HTML then data-external="1" will work as expected for <img> elements. Similarly, for Markdown, external images can be declared with ![img](url){external=1}. Note that this only works for images; the other media elements have no native representation in pandoc’s AST and require the use of raw HTML.