From 1459271f3dab16fd88eb05387653a423ce866da9 Mon Sep 17 00:00:00 2001
From: Volker Fischer <corrados@users.noreply.github.com>
Date: Sat, 4 Jul 2009 13:58:21 +0000
Subject: [PATCH] added resample filter taps for ratio 3/4

---
 src/resample.cpp     |  2 +-
 src/resamplefilter.h | 24 ++++++++++++++++++++++++
 src/resamplefilter.m | 36 +++++++++++++++++++++++++++++-------
 3 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/src/resample.cpp b/src/resample.cpp
index c841c235..01015699 100755
--- a/src/resample.cpp
+++ b/src/resample.cpp
@@ -154,7 +154,7 @@ void CStereoAudioResample::Init ( const int iNewMonoInputBlockSize,
     iMonoOutputBlockSize  = (int) ( iNewMonoInputBlockSize * dRation );
 
     // set correct parameters
-    if ( iFrom == SND_CRD_SAMPLE_RATE ) // downsampling case
+    if ( iFrom >= iTo ) // downsampling case
     {
         switch ( iTo )
         {
diff --git a/src/resamplefilter.h b/src/resamplefilter.h
index 550680de..80996d3c 100644
--- a/src/resamplefilter.h
+++ b/src/resamplefilter.h
@@ -6,11 +6,14 @@
 #define _RESAMPLEFILTER_H_
 
 #define NUM_TAPS_PER_PHASE2          4
+#define NUM_TAPS_PER_PHASE4_3        4
 #define NUM_TAPS_PER_PHASE3_2        4
 #define NUM_TAPS_PER_PHASE12_7       4
 #define NUM_TAPS_PER_PHASE1          4
 #define INTERP_I_2                   2
 #define DECIM_D_2                    1
+#define INTERP_I_4_3                 4
+#define DECIM_D_4_3                  3
 #define INTERP_I_3_2                 3
 #define DECIM_D_3_2                  2
 #define INTERP_I_12_7                12
@@ -32,6 +35,27 @@ static float fResTaps2[INTERP_I_2 * DECIM_D_2 * NUM_TAPS_PER_PHASE2] = {
 };
 
 
+// Filter for ratio 4 / 3
+static float fResTaps4_3[INTERP_I_4_3 * DECIM_D_4_3 * NUM_TAPS_PER_PHASE4_3] = {
+	-0.00168001826454421440f,
+	-0.01144215502840437900f,
+	-0.02497303843128512500f,
+	-0.01659712409419326200f,
+	0.04986971950193624900f,
+	0.18653698120980966000f,
+	0.35284376758014113000f,
+	0.46867597265041389000f,
+	0.46867597265041389000f,
+	0.35284376758014113000f,
+	0.18653698120980966000f,
+	0.04986971950193624900f,
+	-0.01659712409419326200f,
+	-0.02497303843128512500f,
+	-0.01144215502840437900f,
+	-0.00168001826454421440f
+};
+
+
 // Filter for ratio 3 / 2
 static float fResTaps3_2[INTERP_I_3_2 * DECIM_D_3_2 * NUM_TAPS_PER_PHASE3_2] = {
 	-0.00236050848304511720f,
diff --git a/src/resamplefilter.m b/src/resamplefilter.m
index 33c48ebc..29482f5c 100755
--- a/src/resamplefilter.m
+++ b/src/resamplefilter.m
@@ -1,10 +1,10 @@
-%/******************************************************************************\
-% * Copyright (c) 2004-2009
-% *
-% * Author(s):
-% *	Volker Fischer
-% *
-%\******************************************************************************/
+% /****************************************************************************\
+%  * Copyright (c) 2004-2009
+%  *
+%  * Author(s):
+%  *	Volker Fischer
+%  *
+% \****************************************************************************/
 
 function resamplefilter()
 
@@ -12,6 +12,7 @@ function resamplefilter()
 GlobalNoTaps = 4; % use global value for all types
 
 NoTapsP2    = GlobalNoTaps; % 24 kHz
+NoTapsP4_3  = GlobalNoTaps; % 32 kHz <-> 24 kHz
 NoTapsP3_2  = GlobalNoTaps; % 32 kHz
 NoTapsP12_7 = GlobalNoTaps; % 28 kHz
 NoTapsP1    = GlobalNoTaps; % 48 kHz
@@ -26,6 +27,15 @@ D2 = 1;
 h2 = DesignFilter(NoTapsP2, I2);
 
 
+% Filter for ratio 4 / 3 -------------------------------------------------------
+% I and D
+I4_3 = 4;
+D4_3 = 3;
+
+% filter design
+h4_3 = DesignFilter(NoTapsP4_3, I4_3);
+
+
 % Filter for ratio 3 / 2 -------------------------------------------------------
 % I and D
 I3_2 = 3;
@@ -65,6 +75,9 @@ fprintf(fid, '#define _RESAMPLEFILTER_H_\n\n');
 fprintf(fid, '#define NUM_TAPS_PER_PHASE2          ');
 fprintf(fid, int2str(NoTapsP2));
 fprintf(fid, '\n');
+fprintf(fid, '#define NUM_TAPS_PER_PHASE4_3        ');
+fprintf(fid, int2str(NoTapsP4_3));
+fprintf(fid, '\n');
 fprintf(fid, '#define NUM_TAPS_PER_PHASE3_2        ');
 fprintf(fid, int2str(NoTapsP3_2));
 fprintf(fid, '\n');
@@ -80,6 +93,12 @@ fprintf(fid, '\n');
 fprintf(fid, '#define DECIM_D_2                    ');
 fprintf(fid, int2str(D2));
 fprintf(fid, '\n');
+fprintf(fid, '#define INTERP_I_4_3                 ');
+fprintf(fid, int2str(I4_3));
+fprintf(fid, '\n');
+fprintf(fid, '#define DECIM_D_4_3                  ');
+fprintf(fid, int2str(D4_3));
+fprintf(fid, '\n');
 fprintf(fid, '#define INTERP_I_3_2                 ');
 fprintf(fid, int2str(I3_2));
 fprintf(fid, '\n');
@@ -101,6 +120,9 @@ fprintf(fid, '\n\n');
 fprintf(fid, '\n// Filter for ratio 2\n');
 ExportFilterTaps(fid, 'fResTaps2[INTERP_I_2 * DECIM_D_2 * NUM_TAPS_PER_PHASE2]', h2);
 
+fprintf(fid, '\n// Filter for ratio 4 / 3\n');
+ExportFilterTaps(fid, 'fResTaps4_3[INTERP_I_4_3 * DECIM_D_4_3 * NUM_TAPS_PER_PHASE4_3]', h4_3);
+
 fprintf(fid, '\n// Filter for ratio 3 / 2\n');
 ExportFilterTaps(fid, 'fResTaps3_2[INTERP_I_3_2 * DECIM_D_3_2 * NUM_TAPS_PER_PHASE3_2]', h3_2);