fix in velocity calculation

diff --git a/ChangeLog b/ChangeLog
index 7c60b87..1708e2d 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2004-11-03  Eric A. Welsh <ewelsh@ccb.wustl.edu>
+
+       * timidity/playmidi.c: fix to correctly handle non-linear velocity
+         levels
+
 2004-10-27  TAMUKI Shoichi <tamuki@linet.gr.jp>
 
        * configure, autoconf/utils.m4, doc/{C,ja_JP.eucJP}/readme.dl,

diff --git a/timidity/playmidi.c b/timidity/playmidi.c
index aa8276c..d2cf273 100644 (file)
--- a/timidity/playmidi.c
+++ b/timidity/playmidi.c
@@ -84,8 +84,6 @@ int usleep(unsigned int useconds);
 #define DEFAULT_CHORUS_DELAY1          0.02
 #define DEFAULT_CHORUS_DELAY2          0.003
 #define CHORUS_OPPOSITE_THRESHOLD      32
-#define CHORUS_VELOCITY_TUNING1                0.7
-#define CHORUS_VELOCITY_TUNING2                0.6
 #define EOT_PRESEARCH_LEN              32
 #define SPEED_CHANGE_RATE              1.0594630943592953  /* 2^(1/12) */
 
@@ -1012,6 +1010,27 @@ static void recompute_amp(int v)
        else
                tempamp *= 1.35f;
 
+       /* Reduce amplitude for chorus partners.
+        * 2x voices -> 2x power -> sqrt(2)x amplitude.
+        * 1 / sqrt(2) = ~0.7071, which is very close to the old
+        * CHORUS_VELOCITY_TUNING1 value of 0.7.
+        *
+        * The previous amp scaling for the various digital effects should
+        * really be redone to split them into separate scalings for each
+        * effect, rather than a single scaling if any one of them is used
+        * (which is NOT correct).  As it is now, if partner chorus is the
+        * only effect in use, then it is reduced in volume twice and winds
+        * up too quiet.  Compare the output of "-EFreverb=0 -EFchorus=0",
+        * "-EFreverb=0 -EFchorus=2", "-EFreverb=4 -EFchorus=2", and
+        * "-EFreverb=4 -EFchorus=0" to see how the digital effect volumes
+        * are not scaled properly.  Idealy, all the resulting output should
+        * have the same volume, regardless of effects used.  This will
+        * require empirically determining the amount to scale for each
+        * individual effect.
+        */
+       if (voice[v].chorus_link != v)
+           tempamp *= 0.7071067811865f;
+
        /* NRPN - drum instrument tva level */
        if(ISDRUMCHANNEL(ch)) {
                if(channel[ch].drums[voice[v].note] != NULL) {
@@ -1514,9 +1533,8 @@ static int reduce_voice_CPU(void)
     {
        cut_notes++;
 
-       /* hack - double volume of chorus partner, fix pan */
+       /* fix pan */
        j = voice[lowest].chorus_link;
-       voice[j].velocity <<= 1;
        voice[j].panning = channel[voice[lowest].channel].panning;
        recompute_amp(j);
        apply_envelope_to_amp(j);
@@ -1715,9 +1733,8 @@ static int reduce_voice(void)
     {
        cut_notes++;
 
-       /* hack - double volume of chorus partner, fix pan */
+       /* fix pan */
        j = voice[lowest].chorus_link;
-       voice[j].velocity <<= 1;
        voice[j].panning = channel[voice[lowest].channel].panning;
        recompute_amp(j);
        apply_envelope_to_amp(j);
@@ -2471,18 +2488,16 @@ static void new_delay_voice(int v1, int level)
 static void new_chorus_voice(int v1, int level)
 {
     int v2, ch;
-    uint8 vol;
 
     if((v2 = find_free_voice()) == -1)
        return;
     ch = voice[v1].channel;
-    vol = voice[v1].velocity;
     voice[v2] = voice[v1];     /* copy all parameters */
 
-       /* NRPN Chorus Send Level of Drum */
-       if(ISDRUMCHANNEL(ch) && channel[ch].drums[voice[v1].note] != NULL) {
-               level *= (FLOAT_T)channel[ch].drums[voice[v1].note]->chorus_level / 127.0;
-       }
+    /* NRPN Chorus Send Level of Drum */
+    if(ISDRUMCHANNEL(ch) && channel[ch].drums[voice[v1].note] != NULL) {
+       level *= (FLOAT_T)channel[ch].drums[voice[v1].note]->chorus_level / 127.0;
+    }
 
     /* Choose lower voice index for base voice (v1) */
     if(v1 > v2)
@@ -2496,9 +2511,6 @@ static void new_chorus_voice(int v1, int level)
      * v2: Sub chorus voice (detuned)
      */
 
-    voice[v1].velocity = (uint8)(vol * CHORUS_VELOCITY_TUNING1);
-    voice[v2].velocity = (uint8)(vol * CHORUS_VELOCITY_TUNING2);
-
     /* Make doubled link v1 and v2 */
     voice[v1].chorus_link = v2;
     voice[v2].chorus_link = v1;
@@ -2546,8 +2558,8 @@ static void new_chorus_voice(int v1, int level)
        voice[v2].delay += (int)(play_mode->rate * delay);
     }
 
-       init_voice_pan_delay(v1);
-       init_voice_pan_delay(v2);
+    init_voice_pan_delay(v1);
+    init_voice_pan_delay(v2);
 
     recompute_amp(v1);
     apply_envelope_to_amp(v1);
@@ -2568,7 +2580,7 @@ static void new_chorus_voice(int v1, int level)
 static void new_chorus_voice_alternate(int v1, int level)
 {
     int v2, ch, panlevel;
-    uint8 vol, pan;
+    uint8 pan;
     double delay;
     double freq, frac;
     int note_adjusted;
@@ -2595,11 +2607,6 @@ static void new_chorus_voice_alternate(int v1, int level)
        v1 ^= v2;
     }
 
-    /* lower the volumes so that the two notes add to roughly the orig. vol */
-    vol = voice[v1].velocity;
-    voice[v1].velocity  = (uint8)(vol * CHORUS_VELOCITY_TUNING1);
-    voice[v2].velocity  = (uint8)(vol * CHORUS_VELOCITY_TUNING1);
-
     /* Make doubled link v1 and v2 */
     voice[v1].chorus_link = v2;
     voice[v2].chorus_link = v1;