PDF: strong for viewing and printing
A music PDF is primarily a page presentation. It usually preserves how the score looks very well and is easy to share or print. A notation program, however, does not automatically know which graphic element represents a particular note, voice, or measure.
Turning a scan or PDF back into editable notation typically requires an optical music recognition step and then musical verification.
MusicXML: structured notation
MusicXML was designed for exchanging digital sheet music. It can represent pitches, durations, voices, meters, accidentals, articulations, and many layout details in structured form. That makes it a strong choice when notation needs to move between programs and remain editable.
MusicXML still does not promise pixel-identical engraving. Different programs can lay out the same musical content differently.
MIDI: performance and control data
MIDI does not store a recorded sound wave. It represents events such as note on/off, pitch, velocity, and controller information. A MIDI file can therefore be very flexible in a DAW or with virtual instruments.
For publication-ready notation, however, MIDI lacks many of the decisions required by engraving. An import may have to infer rhythm spelling, voices, and notation choices.
Which format fits which job?
- Viewing, sharing, or printing: usually PDF.
- Continuing to edit notation in another score program: preferably MusicXML.
- Performance data, virtual instruments, or a DAW workflow: often MIDI.
- Turning a scan into editable notation: OMR plus careful checking; automated conversion is not automatically correct.
Be careful with conversions
Any conversion can discard information or introduce interpretation. Keep the original file and compare the result with the visible or audible source before relying on it downstream.
If an existing file format needs to become a concrete playable result, the Intent-to-Playable workflow is the relevant next step.