Is there any free software tool or combination that allows me to identify the pitch of a recorded singing session?
The idea is to display some kind of graph with the current pitch in a time line along with markers for the standard notes (C3, C#3, D, etc). I don't need pitch correction and I don't need it to be done in real time, either.
I know that once there was a plugin for Rosegarden that did that, but it has gone missing.
Cheers, Luis Fernando
Not exactly what you are looking for, but the Singstar lookalike Ultrastar-NG at least does something like this. http://ultrastar-ng.sourceforge.net/
Checkout Audacity. It came out of a project to do musical pitch analysis.
I'm unaware of any software package that has this built in. If you're interested in writing something like this, you'll want to look at Discrete Fourier Transforms. This turns a time-series sample into a collection of frequencies. But this leaves you with no information about when the various frequencies occur, so you must do a windowed Fourier Transform, with windows of whatever time-resolution you want. Increasing the time resolution decreases the frequency resolution, however.
The simplest thing to do is to figure out the largest frequency component in any window and call that the frequency. But real music (a) has chords and (b) has overtones and undertones. In addition singing often has "tremolo", where the singer varies the actual pitch around the theoretical pitch the music is marked at.