Fix IT sample global volume and sample vibrato.

* IT sample global volume was being ignored in sample mode due to
  QUIRK_INSVOL not being enabled. QUIRK_INSVOL is now unconditionally
  enabled for IT modules.
* IT sample global volume was being ignored in instrument mode for
  IT 1.x modules due to QUIRK_INSVOL not being enabled for IT 1.x
  modules. QUIRK_INSVOL is now unconditionally enabled for IT modules.
* Fixed an incorrect bitshift on IT sample vibrato depth that resulted
  in IT sample vibrato being very weak.
* Sample vibrato rate is now rounded instead of truncated. The LFO
  period size should probably eventually be expanded instead.

src/loaders/it_load.c

@@ -750,6 +750,7 @@ static int load_it_sample(struct module_data *m, int i, int start,
 
 	if (sample_mode) {
 		/* Create an instrument for each sample */
+		mod->xxi[i].vol = 64;
 		mod->xxi[i].sub[0].vol = ish.vol;
 		mod->xxi[i].sub[0].pan = 0x80;
 		mod->xxi[i].sub[0].sid = i;
@@ -782,7 +783,7 @@ static int load_it_sample(struct module_data *m, int i, int start,
 				sub->vol = ish.vol;
 				sub->gvl = ish.gvl;
 				sub->vra = ish.vis;	/* sample to sub-instrument vibrato */
-				sub->vde = ish.vid >> 1;
+				sub->vde = ish.vid << 1;
 				sub->vwf = ish.vit;
 				sub->vsw = (0xff - ish.vir) >> 1;
 
@@ -1090,10 +1091,6 @@ static int it_load(struct module_data *m, HIO_HANDLE *f, const int start)
 		m->period_type = PERIOD_LINEAR;
 	}
 
-	if (!sample_mode && ifh.cmwt >= 0x200) {
-		m->quirk |= QUIRK_INSVOL;
-	}
-
 	for (i = 0; i < 64; i++) {
 		struct xmp_channel *xxc = &mod->xxc[i];
 
@@ -1328,7 +1325,7 @@ static int it_load(struct module_data *m, HIO_HANDLE *f, const int start)
 
 	/* Format quirks */
 
-	m->quirk |= QUIRKS_IT | QUIRK_ARPMEM;
+	m->quirk |= QUIRKS_IT | QUIRK_ARPMEM | QUIRK_INSVOL;
 
 	if (ifh.flags & IT_LINK_GXX) {
 		m->quirk |= QUIRK_PRENV;

src/read_event.c

@@ -143,8 +143,11 @@ static void set_effect_defaults(struct context_data *ctx, int note,
 		} */
 #endif
 
+		/* TODO: should probably expand the LFO period size instead
+		 * of reducing the vibrato rate precision here.
+		 */
 		libxmp_lfo_set_depth(&xc->insvib.lfo, sub->vde);
-		libxmp_lfo_set_rate(&xc->insvib.lfo, sub->vra >> 2);
+		libxmp_lfo_set_rate(&xc->insvib.lfo, (sub->vra + 2) >> 2);
 		libxmp_lfo_set_waveform(&xc->insvib.lfo, sub->vwf);
 		xc->insvib.sweep = sub->vsw;