I've found and patched two problems with the pitch bend
tuning code:
1) The pitch isn't always rounded to the nearest equally
tempered value, so the result looks strange in a sequencer,
and artifacts caused by the pitch bends are more severe.
2) The tuning is rounded to cents before the pitch bends
are calculated. It may not be a big deal, but there's no
need for it, and the code's simpler calculating the bends
directly.
I don't think either of these are registered issues. As
I'm new with Git, the two issues are mixed in the two
patches. Problem (1) is fixed in get_semitone_pitch().
It's just a question of rounding off the result.
Everything else is for problem (2).
Graham
>From d402cd356203205f4863ad35f67ae23ff3422a03 Mon Sep 17 00:00:00 2001
From: Graham Breed <gbr...@gmail.com>
Date: Fri, 24 Jun 2011 00:12:52 +0100
Subject: [PATCH 1/2] Pitch bends of full precision centered on zero.
---
configure.in | 2 +-
lily/midi-item.cc | 13 ++++---------
2 files changed, 5 insertions(+), 10 deletions(-)
diff --git a/configure.in b/configure.in
index cf0178f..1ea0428 100644
--- a/configure.in
+++ b/configure.in
@@ -140,7 +140,7 @@ STEPMAKE_PYTHON_DEVEL(REQUIRED)
STEPMAKE_PATH_PROG(GHOSTSCRIPT, gs, OPTIONAL, 8.60)
-STEPMAKE_PATH_PROG(FONTFORGE, fontforge, REQUIRED, 20100501)
+STEPMAKE_PATH_PROG(FONTFORGE, fontforge, REQUIRED, 20090923)
STEPMAKE_PATH_PROG(FONTFORGE, fontforge, OPTIONAL, 20110222)
STEPMAKE_PATH_PROG(T1ASM, t1asm, REQUIRED)
diff --git a/lily/midi-item.cc b/lily/midi-item.cc
index 1fcb259..bbc4691 100644
--- a/lily/midi-item.cc
+++ b/lily/midi-item.cc
@@ -28,10 +28,8 @@
#include "string-convert.hh"
#include "warn.hh"
-#define PITCH_WHEEL_TOP 0x3FFF
#define PITCH_WHEEL_CENTER 0x2000
-#define PITCH_WHEEL_BOTTOM 0x0000
-#define PITCH_WHEEL_RANGE (PITCH_WHEEL_TOP - PITCH_WHEEL_BOTTOM)
+#define PITCH_WHEEL_SEMITONE 0X1000
Midi_item *
Midi_item::get_midi (Audio_item *a)
@@ -193,14 +191,14 @@ Midi_note::get_fine_tuning () const
+ audio_->transposing_.tone_pitch ()) * Rational (2);
tune -= Rational (get_semitone_pitch ());
- tune *= 100;
+ tune *= PITCH_WHEEL_SEMITONE;
return (int) double (tune);
}
int
Midi_note::get_semitone_pitch () const
{
- return int (double ((audio_->pitch_.tone_pitch ()
+ return int (0.5 + double ((audio_->pitch_.tone_pitch ()
+ audio_->transposing_.tone_pitch ()) * Rational (2)));
}
@@ -214,10 +212,7 @@ Midi_note::to_string () const
// print warning if fine tuning was needed, HJJ
if (get_fine_tuning () != 0)
{
- finetune = PITCH_WHEEL_CENTER;
- // Move pitch wheel to a shifted position.
- // The pitch wheel range (of 4 semitones) is multiplied by the cents.
- finetune += (PITCH_WHEEL_RANGE *get_fine_tuning ()) / (4 * 100);
+ finetune = PITCH_WHEEL_CENTER + get_fine_tuning();
str += ::to_string ((char) (0xE0 + channel_));
str += ::to_string ((char) (finetune & 0x7F));
--
1.7.0.4
>From 888b2f2ab042e0cd966f53a21e027a1d385ac818 Mon Sep 17 00:00:00 2001
From: Graham Breed <gbr...@gmail.com>
Date: Fri, 24 Jun 2011 18:05:38 +0100
Subject: [PATCH 2/2] Small pitch bends correct and tested.
Pitch bends are not rounded to cents.
---
lily/midi-item.cc | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/lily/midi-item.cc b/lily/midi-item.cc
index bbc4691..02bdd7a 100644
--- a/lily/midi-item.cc
+++ b/lily/midi-item.cc
@@ -198,8 +198,9 @@ Midi_note::get_fine_tuning () const
int
Midi_note::get_semitone_pitch () const
{
- return int (0.5 + double ((audio_->pitch_.tone_pitch ()
- + audio_->transposing_.tone_pitch ()) * Rational (2)));
+ double tune = double ((audio_->pitch_.tone_pitch ()
+ + audio_->transposing_.tone_pitch ()) * Rational (2));
+ return (tune > 0)? int (tune + 0.5): int(tune - 0.5);
}
string
--
1.7.0.4
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