I am thinking about recording some music instruction videos, and thought of a great way to demonstrate concepts. I would like to have an empty grand staff displayed on the screen, clefs, and an optional key signature, but no bar lines, and when I play midi notes on my synth, those notes appear on the staff, either as quarters, or wholes, or even without stems, depending on how I set it. When I release the keys on the synth, the notes would disappear, and you'd be back to the empty staff. This way I could play a chord, and as long as the chord was sounding, the notes being played are notated on screen. But there are no bars created, nothing is "written". Does that make sense? Is there any kind of program anyone knows of that will do that?

There is an iPad app called magic stave which might do most of what you want. If you have access to an iPad you could try the free version.

http://www.farnellcompute...magicstave/manual.html

Hope this helps,
ZT

Found this YouTube video of it. Don't know if you can disable the note scrolling...
https://youtu.be/KkmLJibePDM

Thanks! Interesting app, and he has some other cool ones too. But this won't do it. The scrolling can't be turned off, and I want the notes to disappear when I release the keys. Also, since this takes audio input, it won't do chords.

I thought it read MIDI input but I have just installed it and it doesn't :(
The paid version reads MIDI files but not MIDI from a keyboard.
 
I have just tried the following in Sonar Platinum which is almost there.
It works with chords too.
 
1. Create a new project
2. Insert a MIDI instrument e.g. piano
3. Select and area on the track, right click and select Staff View
4. Make the staff view as big as you like
5. Enable Step Record and check "Delete on Back Step"
6. Play a note on your keyboard and it will be displayed (whole notes give a nice clean display)
7. Now press Numpad 0 and the note will be deleted ready for your next note
8. Repeat 6 and 7 ad nauseam.
 
If you uncheck "Auto Advance" the position will stay where it is but unfortunately it won't delete the last note so the display gradually fills up with all the notes that have been played.
 
It may be possible to write some CAL to do exactly what you want behind this? Probably not though as I think it is more intended for performing actions on a MIDI track rather than monitoring events in realtime and acting on them.
 
ZT
 

If you remove the need to erase notes on the fly (while releasing keys), just about any notation program will do.
 
So rather than look for notation software that acts precisely as you describe (a longshot at best), I think you'd be better off rethinking your approach.  If you want the notes to "disappear", well, pretty much anything can be effected through editing. 
 
Just a thought.

A nice free notation program that starts with an empty score is MuseScore 2. 
https://musescore.org/
 
You can select a layout from a template, then pick key signature, time signature, number of measures, etc.  You can add just one measure if you wish.
 
You enter notes or chords from a MIDI keyboard by activating note input (keyboard "N").  The note length is selectable from the toolbar.  So for example, add a score with just one measure, and select whole notes.  Play a chord.  Chord appears on the score.  Play another chord, first chord disappears and is replaced by the new one!

MuseScore 2 example:
 

ZincTrumpet
I thought it read MIDI input but I have just installed it and it doesn't :(
The paid version reads MIDI files but not MIDI from a keyboard.
 
I have just tried the following in Sonar Platinum which is almost there.
It works with chords too.
 
1. Create a new project
2. Insert a MIDI instrument e.g. piano
3. Select and area on the track, right click and select Staff View
4. Make the staff view as big as you like
5. Enable Step Record and check "Delete on Back Step"
6. Play a note on your keyboard and it will be displayed (whole notes give a nice clean display)
7. Now press Numpad 0 and the note will be deleted ready for your next note
8. Repeat 6 and 7 ad nauseam.
 
If you uncheck "Auto Advance" the position will stay where it is but unfortunately it won't delete the last note so the display gradually fills up with all the notes that have been played.
 
It may be possible to write some CAL to do exactly what you want behind this? Probably not though as I think it is more intended for performing actions on a MIDI track rather than monitoring events in realtime and acting on them.
 
ZT
 

Hey, this almost works perfectly! I couldn't figure out the back step business, but simply Ctrl-Z to undo and then my custom rewind keystroke gets me right back. Awesome!

jkoseattle
 
Hey, this almost works perfectly! I couldn't figure out the back step business, but simply Ctrl-Z to undo and then my custom rewind keystroke gets me right back. Awesome!

Glad to help :)
ZT