Verovio Humdrum Viewer
Verovio Humdrum Viewer is an online musical data editor. The primary function of the website is for viewing and editing music in the Humdrum data format, but also music can be loaded and edited in the MusicXML, MEI, MuseData, and EsAC data formats. The editor is semi-graphical: some elements such as pitch, beaming, slurs, articulations can be changed graphically, while other elements such as lyrics, adding music, changing rhythms, can only be done by editing the digital score in the text editor. The editor also allows simple MIDI playback within the web browser, and generation of PDFs. After preparing music in the editor, the Humdrum Notation Plugin is useful to display the music notation on your own website.
Online scores
The VHV editor also has built-in musical data which can be accessed through the "Scores" menu. Here is an example of a score loaded from the Mozart piano sonatas entry in the menu:
Here is a direct link to the score in the VHV editor: http://verovio.humdrum.org/?file=mozart/sonatas/sonata13-1.krn . This particular score comes from a Github repository for the Mozart sonatas and is loaded directly in to the VHV editor.
Data processing in VHV editor
Try adding the line:
!!!filter: transpose -k c
to the digital score. This will transpose the music from B-flat major to C major:
Or extract the first seven measures from the score with the line:
!!!filter: myank -m 0-7
"myank" means "measure yank", which is a filter to extract measures from a score. And "-m 0-7" means to extract from measure 0 (the pickup measure through measure 7).
Rendering library
VHV uses verovio (on Github) to convert the digital score into graphical notation (in the SVG format).