swr: Implement Noise shaping dither

The following variants are implemented: lipshitz noise shaping dither shibata noise shaping dither low shibata noise shaping dither high shibata noise shaping dither f-weighted noise shaping dither modified-e-weighted noise shaping dither improved-e-weighted noise shaping dither Data tables taken from SOX Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2013-01-09 18:03:49 +01:00 · 2013-01-09 18:03:49 +01:00 · 82742294b7
parent 5b69c07d12
commit 82742294b7
6 changed files with 368 additions and 18 deletions
--- a/libswresample/dither.c
+++ b/libswresample/dither.c
@ -21,6 +21,8 @@
 #include "libavutil/avassert.h"
 #include "swresample_internal.h"

+#include "noise_shaping_data.c"
+
 void swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt) {
    double scale = 0;
 #define TMP_EXTRA 2
@ -41,19 +43,37 @@ void swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSa

    scale *= s->dither_scale;

+    s->ns_pos = 0;
+    s->ns_scale   =   scale;
+    s->ns_scale_1 = 1/scale;
+    memset(s->ns_errors, 0, sizeof(s->ns_errors));
+    for (i=0; filters[i].coefs; i++) {
+        const filter_t *f = &filters[i];
+        if (fabs(s->out_sample_rate - f->rate) / f->rate <= .05 && f->name == s->dither_method) {
+            int j;
+            s->ns_taps = f->len;
+            for (j=0; j<f->len; j++)
+                s->ns_coeffs[j] = f->coefs[j];
+            break;
+        }
+    }
+    if (!filters[i].coefs && s->dither_method > SWR_DITHER_NS) {
+        av_log(s, AV_LOG_WARNING, "Requested noise shaping dither not available at this sampling rate, using triangular hp dither\n");
+        s->dither_method = SWR_DITHER_TRIANGULAR_HIGHPASS;
+    }
+
    for(i=0; i<len + TMP_EXTRA; i++){
        double v;
        seed = seed* 1664525 + 1013904223;

        switch(s->dither_method){
            case SWR_DITHER_RECTANGULAR: v= ((double)seed) / UINT_MAX - 0.5; break;
-            case SWR_DITHER_TRIANGULAR :
-            case SWR_DITHER_TRIANGULAR_HIGHPASS :
+            default:
+                av_assert0(s->dither_method < SWR_DITHER_NB);
                v = ((double)seed) / UINT_MAX;
                seed = seed*1664525 + 1013904223;
                v-= ((double)seed) / UINT_MAX;
                break;
-            default: av_assert0(0);
        }
        tmp[i] = v;
    }
@ -62,14 +82,13 @@ void swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSa
        double v;

        switch(s->dither_method){
-            case SWR_DITHER_RECTANGULAR:
-            case SWR_DITHER_TRIANGULAR :
+            default:
+                av_assert0(s->dither_method < SWR_DITHER_NB);
                v = tmp[i];
                break;
            case SWR_DITHER_TRIANGULAR_HIGHPASS :
                v = (- tmp[i] + 2*tmp[i+1] - tmp[i+2]) / sqrt(6);
                break;
-            default: av_assert0(0);
        }

        v*= scale;
@ -85,3 +104,19 @@ void swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSa

    av_free(tmp);
 }
+
+#define TEMPLATE_DITHER_S16
+#include "dither_template.c"
+#undef TEMPLATE_DITHER_S16
+
+#define TEMPLATE_DITHER_S32
+#include "dither_template.c"
+#undef TEMPLATE_DITHER_S32
+
+#define TEMPLATE_DITHER_FLT
+#include "dither_template.c"
+#undef TEMPLATE_DITHER_FLT
+
+#define TEMPLATE_DITHER_DBL
+#include "dither_template.c"
+#undef TEMPLATE_DITHER_DBL
--- a/libswresample/dither_template.c
+++ b/libswresample/dither_template.c
@ -0,0 +1,53 @@
+
+#if defined(TEMPLATE_DITHER_DBL)
+#    define RENAME(N) N ## _double
+#    define DELEM  double
+#    define CLIP(v)
+
+#elif defined(TEMPLATE_DITHER_FLT)
+#    define RENAME(N) N ## _float
+#    define DELEM  float
+#    define CLIP(v)
+
+#elif defined(TEMPLATE_DITHER_S32)
+#    define RENAME(N) N ## _int32
+#    define DELEM  int32_t
+#    define CLIP(v) v = FFMAX(FFMIN(v, INT32_MAX), INT32_MIN)
+
+#elif defined(TEMPLATE_DITHER_S16)
+#    define RENAME(N) N ## _int16
+#    define DELEM  int16_t
+#    define CLIP(v) v = FFMAX(FFMIN(v, INT16_MAX), INT16_MIN)
+
+#else
+ERROR
+#endif
+
+void RENAME(swri_noise_shaping)(SwrContext *s, AudioData *srcs, AudioData *noises, int count){
+    int i, j, pos, ch;
+    int taps  = s->ns_taps;
+    float S   = s->ns_scale;
+    float S_1 = s->ns_scale_1;
+
+    for (ch=0; ch<srcs->ch_count; ch++) {
+        const float *noise = ((const float *)noises->ch[ch]) + s->dither_pos;
+        DELEM *data = (DELEM*)srcs->ch[ch];
+        pos  = s->ns_pos;
+        for (i=0; i<count; i++) {
+            double d1, d = data[i];
+            for(j=0; j<taps; j++)
+                d -= s->ns_coeffs[j] * s->ns_errors[ch][pos + j];
+            pos = pos ? pos - 1 : pos - 1 + taps;
+            d1 = rint((d + noise[i]) * S_1)*S;
+            s->ns_errors[ch][pos + taps] = s->ns_errors[ch][pos] = d1 - d;
+            CLIP(d1);
+            data[i] = d1;
+        }
+    }
+
+    s->ns_pos = pos;
+}
+
+#undef RENAME
+#undef DELEM
+#undef CLIP
--- a/libswresample/noise_shaping_data.c
+++ b/libswresample/noise_shaping_data.c
@ -0,0 +1,223 @@
+/* Effect: dither/noise-shape   Copyright (c) 2008-9 robs@users.sourceforge.net
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+typedef struct {
+  int  rate;
+  enum {fir, iir} type;
+  size_t len;
+  int gain_cB; /* Chosen so clips are few if any, but not guaranteed none. */
+  double const * coefs;
+  enum SwrDitherType name;
+} filter_t;
+
+static double const lip44[] = {2.033, -2.165, 1.959, -1.590, .6149};
+static double const fwe44[] = {
+  2.412, -3.370, 3.937, -4.174, 3.353, -2.205, 1.281, -.569, .0847};
+static double const mew44[] = {
+  1.662, -1.263, .4827, -.2913, .1268, -.1124, .03252, -.01265, -.03524};
+static double const iew44[] = {
+  2.847, -4.685, 6.214, -7.184, 6.639, -5.032, 3.263, -1.632, .4191};
+static double const ges44[] = {
+  2.2061, -.4706, -.2534, -.6214, 1.0587, .0676, -.6054, -.2738};
+static double const ges48[] = {
+  2.2374, -.7339, -.1251, -.6033, .903, .0116, -.5853, -.2571};
+
+static double const shi48[] = {
+  2.8720729351043701172,  -5.0413231849670410156,   6.2442994117736816406,
+  -5.8483986854553222656, 3.7067542076110839844,  -1.0495119094848632812,
+  -1.1830236911773681641,   2.1126792430877685547, -1.9094531536102294922,
+  0.99913084506988525391, -0.17090806365013122559, -0.32615602016448974609,
+  0.39127644896507263184, -0.26876461505889892578,  0.097676105797290802002,
+  -0.023473845794796943665,
+};
+static double const shi44[] = {
+  2.6773197650909423828,  -4.8308925628662109375,   6.570110321044921875,
+  -7.4572014808654785156, 6.7263274192810058594,  -4.8481650352478027344,
+  2.0412089824676513672,   0.7006359100341796875, -2.9537565708160400391,
+  4.0800385475158691406,  -4.1845216751098632812,   3.3311812877655029297,
+  -2.1179926395416259766,   0.879302978515625,      -0.031759146600961685181,
+  -0.42382788658142089844, 0.47882103919982910156, -0.35490813851356506348,
+  0.17496839165687561035, -0.060908168554306030273,
+};
+static double const shi38[] = {
+  1.6335992813110351562,  -2.2615492343902587891,   2.4077029228210449219,
+  -2.6341717243194580078, 2.1440362930297851562,  -1.8153258562088012695,
+  1.0816224813461303711,  -0.70302653312683105469, 0.15991993248462677002,
+  0.041549518704414367676, -0.29416576027870178223,  0.2518316805362701416,
+  -0.27766478061676025391,  0.15785403549671173096, -0.10165894031524658203,
+  0.016833892092108726501,
+};
+static double const shi32[] =
+{ /* dmaker 32000: bestmax=4.99659 (inverted) */
+0.82118552923202515,
+-1.0063692331314087,
+0.62341964244842529,
+-1.0447187423706055,
+0.64532512426376343,
+-0.87615132331848145,
+0.52219754457473755,
+-0.67434263229370117,
+0.44954317808151245,
+-0.52557498216629028,
+0.34567299485206604,
+-0.39618203043937683,
+0.26791760325431824,
+-0.28936097025871277,
+0.1883765310049057,
+-0.19097308814525604,
+0.10431359708309174,
+-0.10633844882249832,
+0.046832218766212463,
+-0.039653312414884567,
+};
+static double const shi22[] =
+{ /* dmaker 22050: bestmax=5.77762 (inverted) */
+0.056581053882837296,
+-0.56956905126571655,
+-0.40727734565734863,
+-0.33870288729667664,
+-0.29810553789138794,
+-0.19039161503314972,
+-0.16510021686553955,
+-0.13468159735202789,
+-0.096633769571781158,
+-0.081049129366874695,
+-0.064953058958053589,
+-0.054459091275930405,
+-0.043378707021474838,
+-0.03660014271736145,
+-0.026256965473294258,
+-0.018786206841468811,
+-0.013387725688517094,
+-0.0090983230620622635,
+-0.0026585909072309732,
+-0.00042083300650119781,
+};
+static double const shi16[] =
+{ /* dmaker 16000: bestmax=5.97128 (inverted) */
+-0.37251132726669312,
+-0.81423574686050415,
+-0.55010956525802612,
+-0.47405767440795898,
+-0.32624706625938416,
+-0.3161766529083252,
+-0.2286367267370224,
+-0.22916607558727264,
+-0.19565616548061371,
+-0.18160104751586914,
+-0.15423151850700378,
+-0.14104481041431427,
+-0.11844276636838913,
+-0.097583092749118805,
+-0.076493598520755768,
+-0.068106919527053833,
+-0.041881654411554337,
+-0.036922425031661987,
+-0.019364040344953537,
+-0.014994367957115173,
+};
+static double const shi11[] =
+{ /* dmaker 11025: bestmax=5.9406 (inverted) */
+-0.9264228343963623,
+-0.98695987462997437,
+-0.631156325340271,
+-0.51966935396194458,
+-0.39738872647285461,
+-0.35679301619529724,
+-0.29720726609230042,
+-0.26310476660728455,
+-0.21719355881214142,
+-0.18561814725399017,
+-0.15404847264289856,
+-0.12687471508979797,
+-0.10339745879173279,
+-0.083688631653785706,
+-0.05875682458281517,
+-0.046893671154975891,
+-0.027950936928391457,
+-0.020740609616041183,
+-0.009366452693939209,
+-0.0060260160826146603,
+};
+static double const shi08[] =
+{ /* dmaker 8000: bestmax=5.56234 (inverted) */
+-1.202863335609436,
+-0.94103097915649414,
+-0.67878556251525879,
+-0.57650017738342285,
+-0.50004476308822632,
+-0.44349345564842224,
+-0.37833768129348755,
+-0.34028723835945129,
+-0.29413089156150818,
+-0.24994957447052002,
+-0.21715600788593292,
+-0.18792112171649933,
+-0.15268312394618988,
+-0.12135542929172516,
+-0.099610626697540283,
+-0.075273610651493073,
+-0.048787496984004974,
+-0.042586319148540497,
+-0.028991291299462318,
+-0.011869125068187714,
+};
+static double const shl48[] = {
+  2.3925774097442626953,  -3.4350297451019287109,   3.1853709220886230469,
+  -1.8117271661758422852, -0.20124770700931549072,  1.4759907722473144531,
+  -1.7210904359817504883,   0.97746700048446655273, -0.13790138065814971924,
+  -0.38185903429985046387,  0.27421241998672485352,  0.066584214568138122559,
+  -0.35223302245140075684,  0.37672343850135803223, -0.23964276909828186035,
+  0.068674825131893157959,
+};
+static double const shl44[] = {
+  2.0833916664123535156,  -3.0418450832366943359,   3.2047898769378662109,
+  -2.7571926116943359375, 1.4978630542755126953,  -0.3427594602108001709,
+  -0.71733748912811279297,  1.0737057924270629883, -1.0225815773010253906,
+  0.56649994850158691406, -0.20968692004680633545, -0.065378531813621520996,
+  0.10322438180446624756, -0.067442022264003753662, -0.00495197344571352005,
+};
+static double const shh44[] = {
+   3.0259189605712890625, -6.0268716812133789062,   9.195003509521484375,
+   -11.824929237365722656, 12.767142295837402344, -11.917946815490722656,
+   9.1739168167114257812,  -5.3712320327758789062, 1.1393624544143676758,
+   2.4484779834747314453,  -4.9719839096069335938,   6.0392003059387207031,
+   -5.9359521865844726562,  4.903278350830078125,   -3.5527443885803222656,
+   2.1909697055816650391, -1.1672389507293701172,  0.4903914332389831543,
+   -0.16519790887832641602,  0.023217858746647834778,
+};
+
+static const filter_t filters[] = {
+  {44100, fir,  5, 210, lip44,          SWR_DITHER_NS_LIPSHITZ},
+  {46000, fir,  9, 276, fwe44,          SWR_DITHER_NS_F_WEIGHTED},
+  {46000, fir,  9, 160, mew44,          SWR_DITHER_NS_MODIFIED_E_WEIGHTED},
+  {46000, fir,  9, 321, iew44,          SWR_DITHER_NS_IMPROVED_E_WEIGHTED},
+//   {48000, iir,  4, 220, ges48, SWR_DITHER_NS_GESEMANN},
+//   {44100, iir,  4, 230, ges44, SWR_DITHER_NS_GESEMANN},
+  {48000, fir, 16, 301, shi48,          SWR_DITHER_NS_SHIBATA},
+  {44100, fir, 20, 333, shi44,          SWR_DITHER_NS_SHIBATA},
+  {37800, fir, 16, 240, shi38,          SWR_DITHER_NS_SHIBATA},
+  {32000, fir, 20, 240/*TBD*/, shi32,   SWR_DITHER_NS_SHIBATA},
+  {22050, fir, 20, 240/*TBD*/, shi22,   SWR_DITHER_NS_SHIBATA},
+  {16000, fir, 20, 240/*TBD*/, shi16,   SWR_DITHER_NS_SHIBATA},
+  {11025, fir, 20, 240/*TBD*/, shi11,   SWR_DITHER_NS_SHIBATA},
+  { 8000, fir, 20, 240/*TBD*/, shi08,   SWR_DITHER_NS_SHIBATA},
+  {48000, fir, 16, 250, shl48,          SWR_DITHER_NS_LOW_SHIBATA},
+  {44100, fir, 15, 250, shl44,          SWR_DITHER_NS_LOW_SHIBATA},
+  {44100, fir, 20, 383, shh44,          SWR_DITHER_NS_HIGH_SHIBATA},
+  {    0, fir,  0,   0,  NULL,          SWR_DITHER_NONE},
+};
--- a/libswresample/swresample.c
+++ b/libswresample/swresample.c
@ -78,7 +78,14 @@ static const AVOption options[]={
 {"dither_method"        , "set dither method"           , OFFSET(dither_method  ), AV_OPT_TYPE_INT  , {.i64=0                     }, 0      , SWR_DITHER_NB-1, PARAM, "dither_method"},
 {"rectangular"          , "select rectangular dither"   , 0                      , AV_OPT_TYPE_CONST, {.i64=SWR_DITHER_RECTANGULAR}, INT_MIN, INT_MAX   , PARAM, "dither_method"},
 {"triangular"           , "select triangular dither"    , 0                      , AV_OPT_TYPE_CONST, {.i64=SWR_DITHER_TRIANGULAR }, INT_MIN, INT_MAX   , PARAM, "dither_method"},
-{"triangular_hp"        , "select triangular dither with high pass" , 0                 , AV_OPT_TYPE_CONST, {.i64=SWR_DITHER_TRIANGULAR_HIGHPASS }, INT_MIN, INT_MAX, PARAM, "dither_method"},
+{"triangular_hp"        , "select triangular dither with high pass" , 0          , AV_OPT_TYPE_CONST, {.i64=SWR_DITHER_TRIANGULAR_HIGHPASS }, INT_MIN, INT_MAX, PARAM, "dither_method"},
+{"lipshitz"             , "select lipshitz noise shaping dither" , 0             , AV_OPT_TYPE_CONST, {.i64=SWR_DITHER_NS_LIPSHITZ}, INT_MIN, INT_MAX, PARAM, "dither_method"},
+{"shibata"              , "select shibata noise shaping dither" , 0              , AV_OPT_TYPE_CONST, {.i64=SWR_DITHER_NS_SHIBATA }, INT_MIN, INT_MAX, PARAM, "dither_method"},
+{"low_shibata"          , "select low shibata noise shaping dither" , 0          , AV_OPT_TYPE_CONST, {.i64=SWR_DITHER_NS_LOW_SHIBATA }, INT_MIN, INT_MAX, PARAM, "dither_method"},
+{"high_shibata"         , "select high shibata noise shaping dither" , 0         , AV_OPT_TYPE_CONST, {.i64=SWR_DITHER_NS_HIGH_SHIBATA }, INT_MIN, INT_MAX, PARAM, "dither_method"},
+{"f_weighted"           , "select f-weighted noise shaping dither" , 0           , AV_OPT_TYPE_CONST, {.i64=SWR_DITHER_NS_F_WEIGHTED }, INT_MIN, INT_MAX, PARAM, "dither_method"},
+{"modified_e_weighted"  , "select modified-e-weighted noise shaping dither" , 0  , AV_OPT_TYPE_CONST, {.i64=SWR_DITHER_NS_MODIFIED_E_WEIGHTED }, INT_MIN, INT_MAX, PARAM, "dither_method"},
+{"improved_e_weighted"  , "select improved-e-weighted noise shaping dither" , 0  , AV_OPT_TYPE_CONST, {.i64=SWR_DITHER_NS_IMPROVED_E_WEIGHTED }, INT_MIN, INT_MAX, PARAM, "dither_method"},

 {"filter_size"          , "set swr resampling filter size", OFFSET(filter_size)  , AV_OPT_TYPE_INT  , {.i64=32                    }, 0      , INT_MAX   , PARAM },
 {"phase_shift"          , "set swr resampling phase shift", OFFSET(phase_shift)  , AV_OPT_TYPE_INT  , {.i64=10                    }, 0      , 30        , PARAM },
@ -637,7 +644,7 @@ static int swr_convert_internal(struct SwrContext *s, AudioData *out, int out_co

    if(preout != out && out_count){
        if(s->dither_method){
-            int ch;
+            int ch, len1;
            int dither_count= FFMAX(out_count, 1<<16);
            av_assert0(preout != in);

@ -651,19 +658,28 @@ static int swr_convert_internal(struct SwrContext *s, AudioData *out, int out_co
            if(s->dither_pos + out_count > s->dither.count)
                s->dither_pos = 0;

-            if (s->mix_2_1_simd) {
-                int len1= out_count&~15;
-                int off = len1 * preout->bps;
+            if (s->dither_method < SWR_DITHER_NS){
+                if (s->mix_2_1_simd) {
+                    int len1= out_count&~15;
+                    int off = len1 * preout->bps;

-                if(len1)
+                    if(len1)
+                        for(ch=0; ch<preout->ch_count; ch++)
+                            s->mix_2_1_simd(preout->ch[ch], preout->ch[ch], s->dither.ch[ch] + s->dither.bps * s->dither_pos, s->native_one, 0, 0, len1);
+                    if(out_count != len1)
+                        for(ch=0; ch<preout->ch_count; ch++)
+                            s->mix_2_1_f(preout->ch[ch] + off, preout->ch[ch] + off, s->dither.ch[ch] + s->dither.bps * s->dither_pos + off + len1, s->native_one, 0, 0, out_count - len1);
+                } else {
                    for(ch=0; ch<preout->ch_count; ch++)
-                        s->mix_2_1_simd(preout->ch[ch], preout->ch[ch], s->dither.ch[ch] + s->dither.bps * s->dither_pos, s->native_one, 0, 0, len1);
-                if(out_count != len1)
-                    for(ch=0; ch<preout->ch_count; ch++)
-                        s->mix_2_1_f(preout->ch[ch] + off, preout->ch[ch] + off, s->dither.ch[ch] + s->dither.bps * s->dither_pos + off + len1, s->native_one, 0, 0, out_count - len1);
+                        s->mix_2_1_f(preout->ch[ch], preout->ch[ch], s->dither.ch[ch] + s->dither.bps * s->dither_pos, s->native_one, 0, 0, out_count);
+                }
            } else {
-                for(ch=0; ch<preout->ch_count; ch++)
-                    s->mix_2_1_f(preout->ch[ch], preout->ch[ch], s->dither.ch[ch] + s->dither.bps * s->dither_pos, s->native_one, 0, 0, out_count);
+                switch(s->int_sample_fmt) {
+                case AV_SAMPLE_FMT_S16P :swri_noise_shaping_int16(s, preout, &s->dither, out_count); break;
+                case AV_SAMPLE_FMT_S32P :swri_noise_shaping_int32(s, preout, &s->dither, out_count); break;
+                case AV_SAMPLE_FMT_FLTP :swri_noise_shaping_float(s, preout, &s->dither, out_count); break;
+                case AV_SAMPLE_FMT_DBLP :swri_noise_shaping_double(s,preout, &s->dither, out_count); break;
+                }
            }
            s->dither_pos += out_count;
        }
--- a/libswresample/swresample.h
+++ b/libswresample/swresample.h
@ -111,6 +111,15 @@ enum SwrDitherType {
    SWR_DITHER_RECTANGULAR,
    SWR_DITHER_TRIANGULAR,
    SWR_DITHER_TRIANGULAR_HIGHPASS,
+
+    SWR_DITHER_NS = 64,         ///< not part of API/ABI
+    SWR_DITHER_NS_LIPSHITZ,
+    SWR_DITHER_NS_F_WEIGHTED,
+    SWR_DITHER_NS_MODIFIED_E_WEIGHTED,
+    SWR_DITHER_NS_IMPROVED_E_WEIGHTED,
+    SWR_DITHER_NS_SHIBATA,
+    SWR_DITHER_NS_LOW_SHIBATA,
+    SWR_DITHER_NS_HIGH_SHIBATA,
    SWR_DITHER_NB,              ///< not part of API/ABI
 };

--- a/libswresample/swresample_internal.h
+++ b/libswresample/swresample_internal.h
@ -27,6 +27,8 @@

 #define SQRT3_2      1.22474487139158904909  /* sqrt(3/2) */

+#define NS_TAPS 20
+
 #if ARCH_X86_64
 typedef int64_t integer;
 #else
@ -71,6 +73,13 @@ struct SwrContext {
    enum SwrDitherType dither_method;
    int dither_pos;
    float dither_scale;
+    int ns_taps;                                    ///< Noise shaping dither taps
+    float ns_scale;                                 ///< Noise shaping dither scale
+    float ns_scale_1;                               ///< Noise shaping dither scale^-1
+    int ns_pos;                                     ///< Noise shaping dither position
+    float ns_coeffs[NS_TAPS];                       ///< Noise shaping filter coefficients
+    float ns_errors[SWR_CH_MAX][2*NS_TAPS];
+
    int filter_size;                                /**< length of each FIR filter in the resampling filterbank relative to the cutoff frequency */
    int phase_shift;                                /**< log2 of the number of entries in the resampling polyphase filterbank */
    int linear_interp;                              /**< if 1 then the resampling FIR filter will be linearly interpolated */
@ -152,6 +161,11 @@ int swri_resample_int32(struct ResampleContext *c, int32_t *dst, const int32_t *
 int swri_resample_float(struct ResampleContext *c, float   *dst, const float   *src, int *consumed, int src_size, int dst_size, int update_ctx);
 int swri_resample_double(struct ResampleContext *c,double  *dst, const double  *src, int *consumed, int src_size, int dst_size, int update_ctx);

+void swri_noise_shaping_int16 (SwrContext *s, AudioData *srcs, AudioData *noises, int count);
+void swri_noise_shaping_int32 (SwrContext *s, AudioData *srcs, AudioData *noises, int count);
+void swri_noise_shaping_float (SwrContext *s, AudioData *srcs, AudioData *noises, int count);
+void swri_noise_shaping_double(SwrContext *s, AudioData *srcs, AudioData *noises, int count);
+
 int swri_rematrix_init(SwrContext *s);
 void swri_rematrix_free(SwrContext *s);
 int swri_rematrix(SwrContext *s, AudioData *out, AudioData *in, int len, int mustcopy);