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2026.02.13

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sshlien
2026-02-13 11:24:24 -05:00
parent 0bbb7519cb
commit b662440d20
3 changed files with 194 additions and 12 deletions
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3
doc/CHANGES
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@@ -15667,4 +15667,7 @@ accidental_size prior to adding it to the pitchvalue.
pitchvalue += microtoneshift*accidental_size; /* [SS] 2025.02.16 */
February 13 2026
midistats: added new option -keystability.

27
doc/midistats.1
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@@ -1,4 +1,4 @@
.TH MIDISTATS 1 "26 November 2025"
.TH MIDISTATS 1 "13 February 2026"
.SH NAME
\fBmidistats\fP \- program to summarize the statistical properties of a midi file
.SH SYNOPSIS
@@ -323,6 +323,31 @@ splits the two 4-bit values with a period. Thus 33 = (2*16 + 1).
.br
Returns the pitch class distribution for the entire midi file.
.PP
-keystability
.br
Seqments the midi file into 8 beat units (probably 2 bars), and
for each segment it uses Craig Sapp's algorithm to determine the
key signature based on the distribution of the pitch classes.
It returns the number of sharps (positive number) or the number
of flats (negative number) for that key signature. For example,
the key of G major or E minor would be represented by the value
1.
.br
The list of sharp/flats is returned in the line
.br
localkeysf 0 0 0 0 0 1 0 0 0 0 0 0 3 0 0 0 0 0 -1 -5 -5 -5 -5
.br
For example, in the above sequence (ABBA/Money, Money, Money.7.mid)
the key signature starts in A minor but switches to Bb minor in the
last 8 bars.
.br
Beware of enharmonic keys. For example,
B Major (5#) and Cb Major (7b) contain the same notes.
Similarly F# Major (6#) and Gb Major (6b), and
C# Major (7#) and Db Major (5b), and all the
minor key equivalents.
.PP
-nseqfor n
.br

176
midistats.c
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@@ -17,7 +17,7 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#define VERSION "1.01 November 26 2025 midistats"
#define VERSION "1.02 February 08 2026 midistats"
/* midistrats.c is a descendent of midi2abc.c which was becoming to
large. The object of the program is to extract statistical characterisitic
@@ -97,6 +97,7 @@ int maintrack;
int format; /* MIDI file type */
int debug;
int noOutput;
int keystabilityAnalysis;
int pulseanalysis;
int percanalysis;
int percpattern;
@@ -108,6 +109,7 @@ int corestats;
int chordthreshold; /* number of maximum number of pulses separating note */
int beatsPerBar = 4; /* 4/4 time */
int divisionsPerBar;
int divisionsPer4Bar;
int unitDivision;
int maximumPulse;
int lastBeat;
@@ -127,6 +129,7 @@ int tempocount=0; /* number of tempo indications in MIDI file */
int stats = 0; /* flag - gather and print statistics */
int keystabilityAnalysis = 0;
int pulseanalysis = 0;
int percanalysis = 0;
int percpattern = 0;
@@ -225,6 +228,7 @@ int trkactivity[40]; /* [SS] 2023-10-25 */
int progactivity[128]; /* [SS] 2018-02-02 */
int pitchclass_activity[12]; /* [SS] 2018-02-02 */
int chanpitchhistogram[204]; /* [SS] 2023-09-13 */
int local_pitchclass_activity[12]; /* [SS] 2026-02-08 */
/* [SS] 2017-11-01 */
@@ -476,6 +480,7 @@ void stats_header (int format, int ntrks, int ldivision)
halfdivision = ldivision/2;
quietLimit = ldivision*8;
divisionsPerBar = division*beatsPerBar;
divisionsPer4Bar = divisionsPerBar*4;
unitDivision = divisionsPerBar/24;
lasttrack = ntrks; /* [SS] 2023-10-25 */
if (noOutput == 0) printf("ntrks %d\n",ntrks);
@@ -1182,6 +1187,8 @@ void load_header (int format, int ntrks, int ldivision)
int i;
division = ldivision;
halfdivision = ldivision/2;
divisionsPerBar = division*beatsPerBar;
divisionsPer4Bar = divisionsPerBar*4;
lasttrack = ntrks;
for (i=0;i<17;i++) channel_active[i] = 0; /* for counting number of channels*/
}
@@ -1489,6 +1496,35 @@ for (i = 0; i <lastEvent; i++) {
}
}
int localKeyMatch ();
void reset_local_pitchclass_activity (int barIndex);
void localPitchClassAnalysis () {
int i;
int channel;
int pitch;
int bar4Index, lastbar4Index;
int sf;
printf("localkeysf ");
lastbar4Index = 0;
for (i=0;i<12;i++) local_pitchclass_activity[i] = 0;
for (i = 0; i < lastEvent; i++) {
channel = midievents[i].channel;
if (channel == 9) continue;
bar4Index = midievents[i].onsetTime/divisionsPer4Bar;
if (bar4Index != lastbar4Index) {
sf = localKeyMatch();
reset_local_pitchclass_activity(lastbar4Index);
printf(" %d",sf);
lastbar4Index = bar4Index;
}
pitch = midievents[i].pitch;
local_pitchclass_activity[pitch % 12]++;
}
printf("\n");
}
void pitchClassAnalysis () {
int i;
int channel;
@@ -1502,6 +1538,17 @@ for (i = 0; i < lastEvent; i++) {
}
}
void reset_local_pitchclass_activity (int barIndex) {
int i;
int sf;
float dist[12];
float maxdiscrepancy;
float dif;
//printf("%d\t",barIndex);
for (i=0;i<12;i++) local_pitchclass_activity[i] = 0;
}
void output_perc_pattern (int i) {
int left,right;
left = i/16;
@@ -1570,7 +1617,16 @@ static char *majmin[] = {"maj", "min"};
/* number of sharps or flats for major keys in keylist */
static int maj2sf[] = {0, 7, 2, -3, 4, -1, 6, 1, -4, 3, -2, 5};
static int min2sf[] = {-3, 4, -1, -6, -4, 3, -4 -2, -7, 0, -5, 2};
static int min2sf[] = {-3, 4, -1, -6, 1, -4, 3, -2, -7, 0, -5, 2};
void verify_arrays () {
int i;
for (i == 0; i <11; i++) {
printf("%d %s %d %d\n",i, keylist[i], maj2sf[i], min2sf[i]);
}
}
void keymatch () {
int i;
@@ -1598,14 +1654,6 @@ for (i=0;i<12;i++) {
for (i=0;i<12;i++) {
hist[i] = (float) pitchhistogram[i]/(float) total;
}
fnorm = 0.0;
for (i=0;i<12;i++) {
fnorm = hist[i]*hist[i] + fnorm;
}
fnorm = sqrt(fnorm);
for (i=0;i<12;i++) {
hist[i] = hist[i]/fnorm;
}
for (i=0;i<12;i++) {
c2M += ssMj[i]*ssMj[i];
@@ -1651,6 +1699,100 @@ printf("\nrmin ");
for (r=0;r<12;r++) printf("%7.3f",rmin[r]);
}
/********
int index2sf (int index, int bestMode) {
int sf;
if (bestMode == 0) sf = maj2sf[index];
else sf = min2sf[index];
printf("\t\t%s%s %d %d\t",keylist[index],majmin[bestMode],bestMode,sf);
return sf;
}
********/
int localKeyMatch () {
int i;
int r;
int k;
float c2M,c2m,h2,hM,hm;
float rmaj[12],rmin[12];
float best;
float fnorm;
float total;
float hist[12];
int bestIndex,bestMode;
int sf; /* number of flats or sharps (flats negative) */
for (i=0;i<12;i++) {
hist[i] = (float) local_pitchclass_activity[i];
}
fnorm = 0.0;
for (i=0;i<11;i++) fnorm += hist[i];
for (i=0;i<12;i++) hist[i] = hist[i]/fnorm;
c2M = 0.0;
c2m = 0.0;
h2 = 0.0;
best = 0.0;
bestIndex = 0;
bestMode = -1;
total =0;
fnorm = 0.0;
for (i=0;i<12;i++) {
fnorm = hist[i] + fnorm;
}
//fnorm = sqrt(fnorm);
for (i=0;i<12;i++) {
hist[i] = hist[i]/fnorm;
}
for (i=0;i<12;i++) {
c2M += ssMj[i]*ssMj[i];
c2m += ssMn[i]*ssMn[i];
h2 += hist[i]*hist[i];
}
if (h2 < 0.0001) {
printf("zero histogram\n");
return 0;
}
for (r=0;r<12;r++) {
hM = 0.0;
hm = 0.0;
for (i=0;i<12;i++) {
k = (i - r) % 12;
if (k < 0) k = k + 12;
hM += hist[i]*ssMj[k];
hm += hist[i]*ssMn[k];
}
rmaj[r] = hM/sqrt(h2*c2M);
rmin[r] = hm/sqrt(h2*c2m);
}
for (r=0;r<12;r++) {
if(rmaj[r] > best) {
best = rmaj[r];
bestIndex = r;
bestMode = 0;
}
if(rmin[r] > best) {
best = rmin[r];
bestIndex = r;
bestMode = 1;
}
}
if (bestMode == 0) sf = maj2sf[bestIndex];
else sf = min2sf[bestIndex];
//printf("\nkey %s%s %d %f",keylist[bestIndex],majmin[bestMode],sf,best);
//printf("hist:\t");
//for (r=0;r<12;r++) printf("%5.2f",hist[r]);
//printf("\nrmaj ");
//for (r=0;r<12;r++) printf("%7.3f",rmaj[r]);
//printf("\nrmin ");
//for (r=0;r<12;r++) printf("%7.3f",rmin[r]);
return sf;
}
void percsummary () {
int i;
@@ -1815,6 +1957,13 @@ int argc;
stats = 1;
}
arg = getarg("-keystability",argc,argv);
if (arg != -1) {
keystabilityAnalysis = 1;
stats = 0;
}
arg = getarg("-pulseanalysis",argc,argv);
if (arg != -1) {
pulseanalysis = 1;
@@ -1909,6 +2058,7 @@ int argc;
printf("midistats filename <options>\n");
printf(" -corestats\n");
printf(" -CSV\n");
printf(" -keystability\n");
printf(" -pulseanalysis\n");
printf(" -panal\n");
printf(" -ppat\n");
@@ -1983,6 +2133,9 @@ if (pitchclassanalysis) {
pitchClassAnalysis();
outputPitchClassHistogram();
}
if (keystabilityAnalysis) {
localPitchClassAnalysis();
}
}
@@ -1994,10 +2147,11 @@ int argc;
FILE *efopen();
int arg;
// verify_arrays();
arg = process_command_line_arguments(argc,argv);
if(stats == 1) midistats(argc,argv);
if(pulseanalysis || corestats || percanalysis ||\
percpatternfor || percpattern || percpatternhist ||\
pitchclassanalysis || nseqfor || nseqdistinct) loadEvents();
pitchclassanalysis || nseqfor || nseqdistinct || keystabilityAnalysis) loadEvents();
return 0;
}