[Audacity-devel] NoteTrack, MIDI, Alignment, etc.

[Roger D. <rb...@cs...>]

I committed a number of changes yesterday. I think my goal of adding 
MIDI-to-Audio alignment is about met (and boy was this *much* more work 
than I expected). Some remaining issues are:

1) I modified TrackArtist.cpp around line 5520 for a track not to 
require the current Focus in order to draw the highlight. This fixes a 
display problem and seems to work, but makes me a little nervous since 
Leland wrote this condition in conjunction with some accessibility code, 
and we haven't heard any comments from him about this.

2) Tracks are fully redrawn when sliders move. This gives bad 
performance for audio and even worse performance for Note tracks. I 
would be happy to spend some time and optimize this, but, as discussed, 
it risks introducing some subtle bugs. I got the sense that people would 
be happier to put this off until later.

3) I can't figure out the Unix build system. I added autoconf files for 
portmidi and libscorealign (some review by someone who really knows how 
to do this is in order), but I could not get the main configure and make 
files in src and lib-src to work properly. I believe on Linux everything 
still builds OK without EXPERIMENTAL_MIDI_OUT (requiring portmidi) or 
EXPERIMENTAL_SCOREALIGN (requiring libscorealign), but if you enable 
these, you have to make some changes to link in these libraries.

4) Effects. I implemented pitch changing and time stretching effects for 
Note Tracks, but you cannot currently apply the effect to a Note Track 
alone because effects expect to operate on a Wave track. I suggested we 
enable effects if ANY type of track has a selection. This means that 
some effects will do nothing. Are there any objections?

5) Documentation for Score Alignment. I'm not sure what form is most 
useful. I will write a description of the "Synchronize MIDI with Audio" 
command and its dialog box on a web page and post a URL to here for 
comment unless I hear a different suggestion.

6) Edgar and I have been looking at some Audacity Unicode vs XLISP Ascii 
problems and I believe with minor changes, Nyquist effects could handle 
non-ascii file names and perhaps some other non-ascii strings. XLISP can 
already open non-ascii-named files, so it seems to be just a matter of 
translating strings (or not) between dialogs and XLISP. This seems like 
a good thing to fix for 2.0 if the changes are minor.

7) Should there be an effect called "SAL prompt..." that allows SAL 
syntax expressions? I think this would be simple, and given that the 
latest Nyquist documentation is oriented toward SAL, it might reduce the 
learning curve substantially. I'd be willing to do something immediately 
for 2.0, but if the feeling is this would be a new feature we should 
hold off on, I'll wait.

8) I know the plan is to hold off on putting Midi output and score 
alignment into 2.0, but I hope to make an alpha version available with 
this stuff enabled, and people can and do build their own from the SVN head.

Finally, since I've taken so much of your time already, I want to say 
what a great thing Audacity is for computing and music. Recently, I've 
come to appreciate both the extent of Audacity's impact on the world and 
the insane amount of work that goes into fixing, porting, maintaining, 
and improving the code. Every developer should be extremely proud.

-Roger