LilyPond is a music engraving program, devoted to producing the highest-quality sheet music possible. It brings the aesthetics of traditionally engraved music to computer printouts. LilyPond is free software and part of the GNU Project.
Frescobaldi ~ LilyPond Sheet Music Editor
Frescobaldi is a free and open source LilyPond sheet music text editor.
ly2video ~ GNU LilyPond Files Into Video
ly2video is a Python script which converts music represented by a GNU LilyPond file into a video containing a horizontally scrolling music staff which is synchronized with a MIDI-generated audio rendering of the music.
It is also possible to synchronize the video of the scrolling music notation with a previously recorded audio track of the same music, such as a live performance, even when the audio uses tempo rubato or is not precisely metronomic.