To render sheet music, simply add the string you’d like to render between the [abcjs] shortcode. If you’re not familiar with the proper syntax to use, ABCNotation.com has a good article that explains the basics. The string that is used in the shortcode is passed to the ABCjs library, which translates and renders it into an SVG element.
Here’s an example of ABC Notation in action. The first image shows the string while the second shows the rendered output.
ABC Notation is an excellent example of a plugin that might not have a large audience, but will come in handy to those who need it. I tested it on WordPress 4.2 beta 3 and didn’t encounter any issues. You can download it for free from the WordPress plugin directory.