Create your text layer.
Create a 100% black solid layer
Create a 100% white solid layer, make sure it is above the black layer.
Precomp the two solid layers (cmd/control + shift + c) and jump into the comp.
Add a 'venetian blinds' effect to the white layer and delete the keyframes that automatically accompany it.
Set the 'Direction' to -90deg, 'transition ...
The Guitar Pro website doesn't list video as one of the output formats available within the software. So, you'll need to use screen capture software to record the animated tabs, then composite this over your instrument footage.
Alternatively, you could use hardware video mixing devices to combine the video feed of the tab playback with a live camera feed ...