WCAG 2.1 Success Criterion 2.5.5 Target Size reads:

The size of the target for pointer inputs is at least 44 by 44 CSS pixels except when:

• Equivalent - The target is available through an equivalent link or control on the same page that is at least 44 by 44 CSS pixels;
• Inline - The target is in a sentence or block of text;
• User Agent Control - The size of the target is determined by the user agent and is not modified by the author;
• Essential - A particular presentation of the target is essential to the information being conveyed.

This is a Level AAA success criterion, but worth considering, particularly on mobile devices. Currently Able Player buttons have min-width set to 24px, so 44px would be considerably larger.