--- /dev/null
+libdir = $(libdir)/gst
+
+lib_LTLIBRARIES = libresample.la
+
+if HAVE_CPU_I386
+ARCHCFLAGS = -march=i486
+else
+if HAVE_CPU_PPC
+ARCHCFLAGS = -Wa,-m7400
+else
+ARCHCFLAGS =
+endif
+endif
+
+libresample_la_SOURCES = dtos.c functable.c resample.c resample.h
+libresample_la_LIBADD = $(GST_LIBS)
+libresample_la_CFLAGS = $(GST_CFLAGS) -ffast-math $(ARCHCFLAGS)
+
+noinst_HEADERS = resample.h
+
+#check_PROGRAMS = test
+#test_SOURCES = test.c
+#test_LDADD = libresample.la
+
+
+
--- /dev/null
+
+This is a snapshot of my current work developing an audio
+resampling library. While working on this library, I started
+writing lots of general purpose functions that should really
+be part of a larger library. Rather than have a constantly
+changing library, and since the current code is capable, I
+decided to freeze this codebase for use with gstreamer, and
+move active development of the code elsewhere.
+
+The algorithm used is based on Shannon's theorem, which says
+that you can recreate an input signal from equidistant samples
+using a sin(x)/x filter; thus, you can create new samples from
+the regenerated input signal. Since sin(x)/x is expensive to
+evaluate, an interpolated lookup table is used. Also, a
+windowing function (1-x^2)^2 is used, which aids the convergence
+of sin(x)/x for lower frequencies at the expense of higher.
+
+There is one tunable parameter, which is the filter length.
+Longer filter lengths are obviously slower, but more accurate.
+There's not much reason to use a filter length longer than 64,
+since other approximations start to dominate. Filter lengths
+as short as 8 are audially acceptable, but should not be
+considered for serious work.
+
+Performance: A PowerPC G4 at 400 Mhz can resample 2 audio
+channels at almost 10x speed with a filter length of 64, without
+using Altivec extensions. (My goal was 10x speed, which I almost
+reached. Maybe later.)
+
+Limitations: Currently only supports streams in the form of
+interleaved signed 16-bit samples.
+
+The test.c program is a simple regression test. It creates a
+test input pattern (1 sec at 48 khz) that is a frequency ramp
+from 0 to 24000 hz, and then converts it to 44100 hz using a
+filter length of 64. It then compares the result to the same
+pattern generated at 44100 hz, and outputs the result to the
+file "out".
+
+A graph of the correct output should have field 2 and field 4
+almost equal (plus/minus 1) up to about sample 40000 (which
+corresponds to 20 khz), and then field 2 should be close to 0
+above that. Running the test program will print to stdout
+something like the following:
+
+ time 0.112526
+ average error 10k=0.4105 22k=639.34
+
+The average error is RMS error over the range [0-10khz] and
+[0-22khz], and is expressed in sample values, for an input
+amplitude of 16000. Note that RMS errors below 1.0 can't
+really be compared, but basically this shows that below
+10 khz, the resampler is nearly perfect. Most of the error
+is concentrated above 20 khz.
+
+If the average error is significantly larger after modifying
+the code, it's probably not good.
+
+
+
+dave...
+
--- /dev/null
+/* Resampling library
+ * Copyright (C) <2001> David A. Schleef <ds@schleef.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#include <string.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+//#include <ml.h>
+#include <resample.h>
+
+
+
+#define short_to_double_table
+//#define short_to_double_altivec
+#define short_to_double_unroll
+
+#ifdef short_to_double_table
+static float ints_high[256];
+static float ints_low[256];
+
+void conv_double_short_table(double *dest, short *src, int n)
+{
+ static int init = 0;
+ int i;
+ unsigned int idx;
+ if(!init){
+ for(i=0;i<256;i++){
+ ints_high[i]=256.0*((i<128)?i:i-256);
+ ints_low[i]=i;
+ }
+ init = 1;
+ }
+
+ if(n&1){
+ idx = (unsigned short)*src++;
+ *dest++ = ints_high[(idx>>8)] + ints_low[(idx&0xff)];
+ n-=1;
+ }
+ for(i=0;i<n;i+=2){
+ idx = (unsigned short)*src++;
+ *dest++ = ints_high[(idx>>8)] + ints_low[(idx&0xff)];
+ idx = (unsigned short)*src++;
+ *dest++ = ints_high[(idx>>8)] + ints_low[(idx&0xff)];
+ }
+}
+
+#endif
+
+#ifdef short_to_double_unroll
+void conv_double_short_unroll(double *dest, short *src, int n)
+{
+ if(n&1){
+ *dest++ = *src++;
+ n--;
+ }
+ if(n&2){
+ *dest++ = *src++;
+ *dest++ = *src++;
+ n-=2;
+ }
+ while(n>0){
+ *dest++ = *src++;
+ *dest++ = *src++;
+ *dest++ = *src++;
+ *dest++ = *src++;
+ n-=4;
+ }
+}
+#endif
+
+void conv_double_short_ref(double *dest, short *src, int n)
+{
+ int i;
+ for(i=0;i<n;i++){
+ dest[i]=src[i];
+ }
+}
+
+#ifdef HAVE_CPU_PPC
+#if 0
+static union { int i[4]; float f[4]; } av_tmp __attribute__ ((__aligned__ (16)));
+
+void conv_double_short_altivec(double *dest, short *src, int n)
+{
+ int i;
+
+ for(i=0;i<n;i+=4){
+ av_tmp.i[0] = src[0];
+ av_tmp.i[1] = src[1];
+ av_tmp.i[2] = src[2];
+ av_tmp.i[3] = src[3];
+
+ asm(
+ " lvx 0,0,%0\n"
+ " vcfsx 1,0,0\n"
+ " stvx 1,0,%0\n"
+ : : "r" (&av_tmp)
+ );
+
+ dest[0]=av_tmp.f[0];
+ dest[1]=av_tmp.f[1];
+ dest[2]=av_tmp.f[2];
+ dest[3]=av_tmp.f[3];
+ src += 4;
+ dest += 4;
+ }
+}
+#endif
+#endif
+
+
+
+/* double to short */
+
+void conv_short_double_ref(short *dest, double *src, int n)
+{
+ int i;
+ double x;
+
+ for(i=0;i<n;i++){
+ x = *src++;
+ if(x<-32768.0)x=-32768.0;
+ if(x>32767.0)x=32767.0;
+ *dest++ = rint(x);
+ }
+}
+
+#ifdef HAVE_CPU_PPC
+void conv_short_double_ppcasm(short *dest, double *src, int n)
+{
+ int tmp[2];
+ double min = -32768.0;
+ double max = 32767.0;
+ double ftmp0, ftmp1;
+
+ asm __volatile__(
+ "\taddic. %3,%3,-8\n"
+ "\taddic. %6,%6,-2\n"
+ "loop:\n"
+ "\tlfdu %0,8(%3)\n"
+ "\tfsub %1,%0,%4\n"
+ "\tfsel %0,%1,%0,%4\n"
+ "\tfsub %1,%0,%5\n"
+ "\tfsel %0,%1,%5,%0\n"
+ "\tfctiw %1,%0\n"
+ "\taddic. 5,5,-1\n"
+ "\tstfd %1,0(%2)\n"
+ "\tlhz 9,6(%2)\n"
+ "\tsthu 9,2(%6)\n"
+ "\tbne loop\n"
+ : "=&f" (ftmp0), "=&f" (ftmp1)
+ : "b" (tmp), "r" (src), "f" (min), "f" (max), "r" (dest)
+ : "r9", "r5" );
+
+}
+#endif
+
+
+void conv_double_short_dstr(double *dest, short *src, int n, int dstr)
+{
+ int i;
+ void *d = dest;
+ for(i=0;i<n;i++){
+ (*(double *)d)=*src++;
+ d += dstr;
+ }
+}
+
+void conv_short_double_sstr(short *dest, double *src, int n, int sstr)
+{
+ int i;
+ double x;
+ void *s = src;
+
+ for(i=0;i<n;i++){
+ x = *(double *)s;
+ if(x<-32768.0)x=-32768.0;
+ if(x>32767.0)x=32767.0;
+ *dest++ = rint(x);
+ s += sstr;
+ }
+}
+
--- /dev/null
+/* Resampling library
+ * Copyright (C) <2001> David A. Schleef <ds@schleef.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#include <string.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <resample.h>
+
+
+
+double functable_sinc(void *p,double x)
+{
+ if(x==0)return 1;
+ return sin(x)/x;
+}
+
+double functable_dsinc(void *p,double x)
+{
+ if(x==0)return 0;
+ return cos(x)/x - sin(x)/(x*x);
+}
+
+double functable_window_boxcar(void *p,double x)
+{
+ if(x<-1 || x>1)return 0;
+ return 1;
+}
+
+double functable_window_dboxcar(void *p,double x)
+{
+ return 0;
+}
+
+double functable_window_std(void *p,double x)
+{
+ if(x<-1 || x>1)return 0;
+ return (1-x*x)*(1-x*x);
+}
+
+double functable_window_dstd(void *p,double x)
+{
+ if(x<-1 || x>1)return 0;
+ return -4*x*(1-x*x);
+}
+
+
+
+void functable_init(functable_t *t)
+{
+ int i;
+ double x;
+
+ t->fx = malloc(sizeof(double)*(t->len+1));
+ t->fdx = malloc(sizeof(double)*(t->len+1));
+
+ t->invoffset = 1.0 / t->offset;
+
+ for(i=0;i<t->len+1;i++){
+ x = t->start + t->offset * i;
+ x *= t->scale;
+
+ t->fx[i] = t->func_x(t->priv,x);
+ t->fdx[i] = t->scale * t->func_dx(t->priv,x);
+ }
+ if(t->func2_x){
+ double f1x,f1dx;
+ double f2x,f2dx;
+
+ for(i=0;i<t->len+1;i++){
+ x = t->start + t->offset * i;
+ x *= t->scale2;
+
+ f2x = t->func2_x(t->priv,x);
+ f2dx = t->scale2 * t->func2_dx(t->priv,x);
+
+ f1x = t->fx[i];
+ f1dx = t->fdx[i];
+
+ t->fx[i] = f1x * f2x;
+ t->fdx[i] = f1x * f2dx + f1dx * f2x;
+ }
+ }
+}
+
+double functable_eval(functable_t *t,double x)
+{
+ int i;
+ double f0, f1, w0, w1;
+ double x2, x3;
+ double w;
+
+ if(x<t->start || x>(t->start+(t->len+1)*t->offset)){
+ printf("x out of range %g\n",x);
+ }
+ x -= t->start;
+ x /= t->offset;
+ i = floor(x);
+ x -= i;
+
+ x2 = x * x;
+ x3 = x2 * x;
+
+ f1 = 3 * x2 - 2 * x3;
+ f0 = 1 - f1;
+ w0 = (x - 2 * x2 + x3) * t->offset;
+ w1 = (-x2 + x3) * t->offset;
+
+ //printf("i=%d x=%g f0=%g f1=%g w0=%g w1=%g\n",i,x,f0,f1,w0,w1);
+
+ w = t->fx[i] * f0 + t->fx[i + 1] * f1 +
+ t->fdx[i] * w0 + t->fdx[i + 1] * w1;
+
+ //w = t->fx[i] * (1-x) + t->fx[i+1] * x;
+
+ return w;
+}
+
+
+double functable_fir(functable_t *t, double x, int n, double *data, int len)
+{
+ int i,j;
+ double f0, f1, w0, w1;
+ double x2, x3;
+ double w;
+ double sum;
+
+ x -= t->start;
+ x /= t->offset;
+ i = floor(x);
+ x -= i;
+
+ x2 = x * x;
+ x3 = x2 * x;
+
+ f1 = 3 * x2 - 2 * x3;
+ f0 = 1 - f1;
+ w0 = (x - 2 * x2 + x3) * t->offset;
+ w1 = (-x2 + x3) * t->offset;
+
+ sum = 0;
+ for(j=0;j<len;j++){
+ w = t->fx[i] * f0 + t->fx[i + 1] * f1 +
+ t->fdx[i] * w0 + t->fdx[i + 1] * w1;
+ sum += data[j*2] * w;
+ i += n;
+ }
+
+ return sum;
+}
+
+void functable_fir2(functable_t *t, double *r0, double *r1, double x,
+ int n, double *data, int len)
+{
+ int i,j;
+ double f0, f1, w0, w1;
+ double x2, x3;
+ double w;
+ double sum0, sum1;
+ double floor_x;
+
+ x -= t->start;
+ x *= t->invoffset;
+ floor_x = floor(x);
+ i = floor_x;
+ x -= floor_x;
+
+ x2 = x * x;
+ x3 = x2 * x;
+
+ f1 = 3 * x2 - 2 * x3;
+ f0 = 1 - f1;
+ w0 = (x - 2 * x2 + x3) * t->offset;
+ w1 = (-x2 + x3) * t->offset;
+
+ sum0 = 0;
+ sum1 = 0;
+ for(j=0;j<len;j++){
+ w = t->fx[i] * f0 + t->fx[i + 1] * f1 +
+ t->fdx[i] * w0 + t->fdx[i + 1] * w1;
+ sum0 += data[j*2] * w;
+ sum1 += data[j*2+1] * w;
+ i += n;
+
+#define unroll2
+#define unroll3
+#define unroll4
+#ifdef unroll2
+ j++;
+
+ w = t->fx[i] * f0 + t->fx[i + 1] * f1 +
+ t->fdx[i] * w0 + t->fdx[i + 1] * w1;
+ sum0 += data[j*2] * w;
+ sum1 += data[j*2+1] * w;
+ i += n;
+#endif
+#ifdef unroll3
+ j++;
+
+ w = t->fx[i] * f0 + t->fx[i + 1] * f1 +
+ t->fdx[i] * w0 + t->fdx[i + 1] * w1;
+ sum0 += data[j*2] * w;
+ sum1 += data[j*2+1] * w;
+ i += n;
+#endif
+#ifdef unroll4
+ j++;
+
+ w = t->fx[i] * f0 + t->fx[i + 1] * f1 +
+ t->fdx[i] * w0 + t->fdx[i + 1] * w1;
+ sum0 += data[j*2] * w;
+ sum1 += data[j*2+1] * w;
+ i += n;
+#endif
+ }
+
+ *r0 = sum0;
+ *r1 = sum1;
+}
+
+
+
+#ifdef unused
+void functable_fir2_altivec(functable_t *t, float *r0, float *r1,
+ double x, int n, float *data, int len)
+{
+ int i,j;
+ double f0, f1, w0, w1;
+ double x2, x3;
+ double w;
+ double sum0, sum1;
+ double floor_x;
+
+ x -= t->start;
+ x *= t->invoffset;
+ floor_x = floor(x);
+ i = floor_x;
+ x -= floor_x;
+
+ x2 = x * x;
+ x3 = x2 * x;
+
+ f1 = 3 * x2 - 2 * x3;
+ f0 = 1 - f1;
+ w0 = (x - 2 * x2 + x3) * t->offset;
+ w1 = (-x2 + x3) * t->offset;
+
+ sum0 = 0;
+ sum1 = 0;
+ for(j=0;j<len;j++){
+ // t->fx, t->fdx needs to be multiplexed by n
+ // we need 5 consecutive floats, which fit into 2 vecs
+ // load v0, t->fx[i]
+ // load v1, t->fx[i+n]
+ // v2 = v0 (not correct)
+ // v3 = (v0>>32) || (v1<<3*32) (not correct)
+ //
+ // load v4, t->dfx[i]
+ // load v5, t->dfx[i+n]
+ // v6 = v4 (not correct)
+ // v7 = (v4>>32) || (v5<<3*32) (not correct)
+ //
+ // v8 = splat(f0)
+ // v9 = splat(f1)
+ // v10 = splat(w0)
+ // v11 = splat(w1)
+ //
+ // v12 = v2 * v8
+ // v12 += v3 * v9
+ // v12 += v6 * v10
+ // v12 += v7 * v11
+
+ w = t->fx[i] * f0 + t->fx[i + 1] * f1 +
+ t->fdx[i] * w0 + t->fdx[i + 1] * w1;
+
+ // v13 = data[j*2]
+ // v14 = data[j*2+4]
+ // v15 = deinterlace_high(v13,v14)
+ // v16 = deinterlace_low(v13,v14)
+ // (sum0) v17 += multsum(v13,v15)
+ // (sum1) v18 += multsum(v14,v16)
+
+ sum0 += data[j*2] * w;
+ sum1 += data[j*2+1] * w;
+ i += n;
+
+ }
+
+ *r0 = sum0;
+ *r1 = sum1;
+}
+#endif
+
--- /dev/null
+/* Resampling library
+ * Copyright (C) <2001> David A. Schleef <ds@schleef.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#include <string.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <resample.h>
+
+inline double sinc(double x)
+{
+ if(x==0)return 1;
+ return sin(x) / x;
+}
+
+inline double window_func(double x)
+{
+ x = 1 - x*x;
+ return x*x;
+}
+
+signed short double_to_s16(double x)
+{
+ if(x<-32768){
+ printf("clipped\n");
+ return -32768;
+ }
+ if(x>32767){
+ printf("clipped\n");
+ return -32767;
+ }
+ return rint(x);
+}
+
+signed short double_to_s16_ppcasm(double x)
+{
+ if(x<-32768){
+ return -32768;
+ }
+ if(x>32767){
+ return -32767;
+ }
+ return rint(x);
+}
+
+static void resample_sinc_ft(resample_t * r);
+
+void resample_init(resample_t * r)
+{
+ r->i_start = 0;
+ if(r->filter_length&1){
+ r->o_start = 0;
+ }else{
+ r->o_start = r->o_inc * 0.5;
+ }
+
+ memset(r->acc, 0, sizeof(r->acc));
+
+ resample_reinit(r);
+}
+
+void resample_reinit(resample_t * r)
+{
+ /* i_inc is the number of samples that the output increments for
+ * each input sample. o_inc is the opposite. */
+ r->i_inc = (double) r->o_rate / r->i_rate;
+ r->o_inc = (double) r->i_rate / r->o_rate;
+
+ r->halftaps = (r->filter_length - 1.0) * 0.5;
+
+ switch (r->method) {
+ default:
+ case RESAMPLE_NEAREST:
+ r->scale = resample_nearest;
+ break;
+ case RESAMPLE_BILINEAR:
+ r->scale = resample_bilinear;
+ break;
+ case RESAMPLE_SINC_SLOW:
+ r->scale = resample_sinc;
+ break;
+ case RESAMPLE_SINC:
+ r->scale = resample_sinc_ft;
+ break;
+ }
+}
+
+/*
+ * Prepare to be confused.
+ *
+ * We keep a "timebase" that is based on output samples. The zero
+ * of the timebase cooresponds to the next output sample that will
+ * be written.
+ *
+ * i_start is the "time" that corresponds to the first input sample
+ * in an incoming buffer. Since the output depends on input samples
+ * ahead in time, i_start will tend to be around halftaps.
+ *
+ * i_start_buf is the time of the first sample in the temporary
+ * buffer.
+ */
+void resample_scale(resample_t * r, void *i_buf, unsigned int i_size)
+{
+ int o_size;
+
+ r->i_buf = i_buf;
+
+ r->i_samples = i_size / 2 / r->channels;
+
+ r->i_start_buf = r->i_start - r->filter_length * r->i_inc;
+
+ /* i_start is the offset (in a given output sample) that is the
+ * beginning of the current input buffer */
+ r->i_end = r->i_start + r->i_inc * r->i_samples;
+
+ r->o_samples = floor(r->i_end - r->halftaps * r->i_inc);
+
+ o_size = r->o_samples * r->channels * 2;
+ r->o_buf = r->get_buffer(r->priv, o_size);
+
+ if(r->verbose){
+ printf("resample_scale: i_buf=%p i_size=%d\n",
+ i_buf,i_size);
+ printf("resample_scale: i_samples=%d o_samples=%d i_inc=%g o_buf=%p\n",
+ r->i_samples, r->o_samples, r->i_inc, r->o_buf);
+ printf("resample_scale: i_start=%g i_end=%g o_start=%g\n",
+ r->i_start, r->i_end, r->o_start);
+ }
+
+ if ((r->filter_length + r->i_samples)*2*2 > r->buffer_len) {
+ int size = (r->filter_length + r->i_samples) * sizeof(double) * 2;
+
+ if(r->verbose){
+ printf("resample temp buffer size=%d\n",size);
+ }
+ if(r->buffer)free(r->buffer);
+ r->buffer_len = size;
+ r->buffer = malloc(size);
+ memset(r->buffer, 0, size);
+ }
+
+ if(r->channels==2){
+ conv_double_short(
+ r->buffer + r->filter_length * sizeof(double) * 2,
+ r->i_buf, r->i_samples * 2);
+ }else{
+ conv_double_short_dstr(
+ r->buffer + r->filter_length * sizeof(double) * 2,
+ r->i_buf, r->i_samples, sizeof(double) * 2);
+ }
+
+ r->scale(r);
+
+ memcpy(r->buffer,
+ r->buffer + r->i_samples * sizeof(double) * 2,
+ r->filter_length * sizeof(double) * 2);
+
+ /* updating times */
+ r->i_start += r->i_samples * r->i_inc;
+ r->o_start += r->o_samples * r->o_inc - r->i_samples;
+
+ /* adjusting timebase zero */
+ r->i_start -= r->o_samples;
+}
+
+void resample_nearest(resample_t * r)
+{
+ signed short *i_ptr, *o_ptr;
+ int i_count = 0;
+ double a;
+ int i;
+
+ i_ptr = (signed short *) r->i_buf;
+ o_ptr = (signed short *) r->o_buf;
+
+ a = r->o_start;
+ i_count = 0;
+#define SCALE_LOOP(COPY,INC) \
+ for (i = 0; i < r->o_samples; i++) { \
+ COPY; \
+ a += r->o_inc; \
+ while (a >= 1) { \
+ a -= 1; \
+ i_ptr+=INC; \
+ i_count++; \
+ } \
+ o_ptr+=INC; \
+ }
+
+ switch (r->channels) {
+ case 1:
+ SCALE_LOOP(o_ptr[0] = i_ptr[0], 1);
+ break;
+ case 2:
+ SCALE_LOOP(o_ptr[0] = i_ptr[0];
+ o_ptr[1] = i_ptr[1], 2);
+ break;
+ default:
+ {
+ int n, n_chan = r->channels;
+
+ SCALE_LOOP(for (n = 0; n < n_chan; n++) o_ptr[n] =
+ i_ptr[n], n_chan);
+ }
+ }
+ if (i_count != r->i_samples) {
+ printf("handled %d in samples (expected %d)\n", i_count,
+ r->i_samples);
+ }
+}
+
+void resample_bilinear(resample_t * r)
+{
+ signed short *i_ptr, *o_ptr;
+ int o_count = 0;
+ double b;
+ int i;
+ double acc0, acc1;
+
+ i_ptr = (signed short *) r->i_buf;
+ o_ptr = (signed short *) r->o_buf;
+
+ acc0 = r->acc[0];
+ acc1 = r->acc[1];
+ b = r->i_start;
+ for (i = 0; i < r->i_samples; i++) {
+ b += r->i_inc;
+ //printf("in %d\n",i_ptr[0]);
+ if(b>=2){
+ printf("not expecting b>=2\n");
+ }
+ if (b >= 1) {
+ acc0 += (1.0 - (b-r->i_inc)) * i_ptr[0];
+ acc1 += (1.0 - (b-r->i_inc)) * i_ptr[1];
+
+ o_ptr[0] = rint(acc0);
+ //printf("out %d\n",o_ptr[0]);
+ o_ptr[1] = rint(acc1);
+ o_ptr += 2;
+ o_count++;
+
+ b -= 1.0;
+
+ acc0 = b * i_ptr[0];
+ acc1 = b * i_ptr[1];
+ } else {
+ acc0 += i_ptr[0] * r->i_inc;
+ acc1 += i_ptr[1] * r->i_inc;
+ }
+ i_ptr += 2;
+ }
+ r->acc[0] = acc0;
+ r->acc[1] = acc1;
+
+ if (o_count != r->o_samples) {
+ printf("handled %d out samples (expected %d)\n", o_count,
+ r->o_samples);
+ }
+}
+
+void resample_sinc_slow(resample_t * r)
+{
+ signed short *i_ptr, *o_ptr;
+ int i, j;
+ double c0, c1;
+ double a;
+ int start;
+ double center;
+ double weight;
+
+ if (!r->buffer) {
+ int size = r->filter_length * 2 * r->channels;
+
+ printf("resample temp buffer\n");
+ r->buffer = malloc(size);
+ memset(r->buffer, 0, size);
+ }
+
+ i_ptr = (signed short *) r->i_buf;
+ o_ptr = (signed short *) r->o_buf;
+
+ a = r->i_start;
+#define GETBUF(index,chan) (((index)<0) \
+ ? ((short *)(r->buffer))[((index)+r->filter_length)*2+(chan)] \
+ : i_ptr[(index)*2+(chan)])
+ {
+ double sinx, cosx, sind, cosd;
+ double x, d;
+ double t;
+
+ for (i = 0; i < r->o_samples; i++) {
+ start = floor(a) - r->filter_length;
+ center = a - r->halftaps;
+ x = M_PI * (start - center) * r->o_inc;
+ sinx = sin(M_PI * (start - center) * r->o_inc);
+ cosx = cos(M_PI * (start - center) * r->o_inc);
+ d = M_PI * r->o_inc;
+ sind = sin(M_PI * r->o_inc);
+ cosd = cos(M_PI * r->o_inc);
+ c0 = 0;
+ c1 = 0;
+ for (j = 0; j < r->filter_length; j++) {
+ weight = (x==0)?1:(sinx/x);
+//printf("j %d sin %g cos %g\n",j,sinx,cosx);
+//printf("j %d sin %g x %g sinc %g\n",j,sinx,x,weight);
+ c0 += weight * GETBUF((start + j), 0);
+ c1 += weight * GETBUF((start + j), 1);
+ t = cosx * cosd - sinx * sind;
+ sinx = cosx * sind + sinx * cosd;
+ cosx = t;
+ x += d;
+ }
+ o_ptr[0] = rint(c0);
+ o_ptr[1] = rint(c1);
+ o_ptr += 2;
+ a += r->o_inc;
+ }
+ }
+
+ memcpy(r->buffer,
+ i_ptr + (r->i_samples - r->filter_length) * r->channels,
+ r->filter_length * 2 * r->channels);
+}
+
+void resample_sinc(resample_t * r)
+{
+ double *ptr;
+ signed short *o_ptr;
+ int i, j;
+ double c0, c1;
+ double a;
+ int start;
+ double center;
+ double weight;
+ double x0, x, d;
+ double scale;
+
+ ptr = (double *) r->buffer;
+ o_ptr = (signed short *) r->o_buf;
+
+ /* scale provides a cutoff frequency for the low
+ * pass filter aspects of sinc(). scale=M_PI
+ * will cut off at the input frequency, which is
+ * good for up-sampling, but will cause aliasing
+ * for downsampling. Downsampling needs to be
+ * cut off at o_rate, thus scale=M_PI*r->i_inc. */
+ /* actually, it needs to be M_PI*r->i_inc*r->i_inc.
+ * Need to research why. */
+ scale = M_PI*r->i_inc;
+ for (i = 0; i < r->o_samples; i++) {
+ a = r->o_start + i * r->o_inc;
+ start = floor(a - r->halftaps);
+//printf("%d: a=%g start=%d end=%d\n",i,a,start,start+r->filter_length-1);
+ center = a;
+ //x = M_PI * (start - center) * r->o_inc;
+ //d = M_PI * r->o_inc;
+ //x = (start - center) * r->o_inc;
+ x0 = (start - center) * r->o_inc;
+ d = r->o_inc;
+ c0 = 0;
+ c1 = 0;
+ for (j = 0; j < r->filter_length; j++) {
+ x = x0 + d * j;
+ weight = sinc(x*scale*r->i_inc)*scale/M_PI;
+ weight *= window_func(x/r->halftaps*r->i_inc);
+ c0 += weight * ptr[(start + j + r->filter_length)*2 + 0];
+ c1 += weight * ptr[(start + j + r->filter_length)*2 + 1];
+ }
+ o_ptr[0] = double_to_s16(c0);
+ o_ptr[1] = double_to_s16(c1);
+ o_ptr += 2;
+ }
+}
+
+
+
+
+/*
+ * Resampling audio is best done using a sinc() filter.
+ *
+ *
+ * out[t] = Sum( in[t'] * sinc((t-t')/delta_t), all t')
+ *
+ * The immediate problem with this algorithm is that it involves a
+ * sum over an infinite number of input samples, both in the past
+ * and future. Note that even though sinc(x) is bounded by 1/x,
+ * and thus decays to 0 for large x, since sum(x,{x=0,1..,n}) diverges
+ * as log(n), we need to be careful about convergence. This is
+ * typically done by using a windowing function, which also makes
+ * the sum over a finite number of input samples.
+ *
+ * The next problem is computational: sinc(), and especially
+ * sinc() multiplied by a non-trivial windowing function is expensive
+ * to calculate, and also difficult to find SIMD optimizations. Since
+ * the time increment on input and output is different, it is not
+ * possible to use a FIR filter, because the taps would have to be
+ * recalculated for every t.
+ *
+ * To get around the expense of calculating sinc() for every point,
+ * we pre-calculate sinc() at a number of points, and then interpolate
+ * for the values we want in calculations. The interpolation method
+ * chosen is bi-cubic, which requires both the evalated function and
+ * its derivative at every pre-sampled point. Also, if the sampled
+ * points are spaced commensurate with the input delta_t, we notice
+ * that the interpolating weights are the same for every input point.
+ * This decreases the number of operations to 4 multiplies and 4 adds
+ * for each tap, regardless of the complexity of the filtering function.
+ *
+ * At this point, it is possible to rearrange the problem as the sum
+ * of 4 properly weghted FIR filters. Typical SIMD computation units
+ * are highly optimized for FIR filters, making long filter lengths
+ * reasonable.
+ */
+
+static functable_t *ft;
+
+double out_tmp[10000];
+
+static void resample_sinc_ft(resample_t * r)
+{
+ double *ptr;
+ signed short *o_ptr;
+ int i;
+ //int j;
+ double c0, c1;
+ //double a;
+ double start_f, start_x;
+ int start;
+ double center;
+ //double weight;
+ double x, d;
+ double scale;
+ int n = 4;
+
+ scale = r->i_inc; // cutoff at 22050
+ //scale = 1.0; // cutoff at 24000
+ //scale = r->i_inc * 0.5; // cutoff at 11025
+
+ if(!ft){
+ ft = malloc(sizeof(*ft));
+ memset(ft,0,sizeof(*ft));
+
+ ft->len = (r->filter_length + 2) * n;
+ ft->offset = 1.0 / n;
+ ft->start = - ft->len * 0.5 * ft->offset;
+
+ ft->func_x = functable_sinc;
+ ft->func_dx = functable_dsinc;
+ ft->scale = M_PI * scale;
+
+ ft->func2_x = functable_window_std;
+ ft->func2_dx = functable_window_dstd;
+ ft->scale2 = 1.0 / r->halftaps;
+
+ functable_init(ft);
+
+ //printf("len=%d offset=%g start=%g\n",ft->len,ft->offset,ft->start);
+ }
+
+ ptr = r->buffer;
+ o_ptr = (signed short *) r->o_buf;
+
+ center = r->o_start;
+ start_x = center - r->halftaps;
+ start_f = floor(start_x);
+ start_x -= start_f;
+ start = start_f;
+ for (i = 0; i < r->o_samples; i++) {
+ //start_f = floor(center - r->halftaps);
+//printf("%d: a=%g start=%d end=%d\n",i,a,start,start+r->filter_length-1);
+ x = start_f - center;
+ d = 1;
+ c0 = 0;
+ c1 = 0;
+//#define slow
+#ifdef slow
+ for (j = 0; j < r->filter_length; j++) {
+ weight = functable_eval(ft,x)*scale;
+ //weight = sinc(M_PI * scale * x)*scale*r->i_inc;
+ //weight *= window_func(x / r->halftaps);
+ c0 += weight * ptr[(start + j + r->filter_length)*2 + 0];
+ c1 += weight * ptr[(start + j + r->filter_length)*2 + 1];
+ x += d;
+ }
+#else
+ functable_fir2(ft,
+ &c0,&c1,
+ x, n,
+ ptr+(start + r->filter_length)*2,
+ r->filter_length);
+ c0 *= scale;
+ c1 *= scale;
+#endif
+
+ out_tmp[2 * i + 0] = c0;
+ out_tmp[2 * i + 1] = c1;
+ center += r->o_inc;
+ start_x += r->o_inc;
+ while(start_x>=1.0){
+ start_f++;
+ start_x -= 1.0;
+ start++;
+ }
+ }
+
+ if(r->channels==2){
+ conv_short_double(r->o_buf,out_tmp,2 * r->o_samples);
+ }else{
+ conv_short_double_sstr(r->o_buf,out_tmp,r->o_samples,2 * sizeof(double));
+ }
+}
+
--- /dev/null
+/* Resampling library
+ * Copyright (C) <2001> David Schleef <ds@schleef.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#ifndef __RESAMPLE_H__
+#define __RESAMPLE_H__
+
+#include <config.h>
+
+typedef struct resample_s resample_t;
+
+struct resample_s {
+ /* parameters */
+
+ int method;
+ int channels;
+ int verbose;
+
+ int filter_length;
+
+ double i_rate;
+ double o_rate;
+
+ void *priv;
+
+ void *(*get_buffer)(void *priv, unsigned int size);
+
+ /* internal parameters */
+
+ double halftaps;
+
+ /* filter state */
+
+ void *buffer;
+ int buffer_len;
+
+ double i_start;
+ double o_start;
+
+ double i_start_buf;
+ double i_end_buf;
+
+ double i_inc;
+ double o_inc;
+
+ double i_end;
+ double o_end;
+
+ int i_samples;
+ int o_samples;
+
+ void *i_buf, *o_buf;
+
+ double acc[10];
+
+ /* methods */
+ void (*scale)(resample_t *r);
+
+ double ack;
+};
+
+enum{
+ RESAMPLE_NEAREST = 0,
+ RESAMPLE_BILINEAR,
+ RESAMPLE_SINC_SLOW,
+ RESAMPLE_SINC,
+};
+
+void resample_init(resample_t *r);
+void resample_reinit(resample_t *r);
+
+void resample_scale(resample_t *r, void *i_buf, unsigned int size);
+
+void resample_nearest(resample_t *r);
+void resample_bilinear(resample_t *r);
+void resample_sinc(resample_t *r);
+void resample_sinc_slow(resample_t *r);
+
+
+typedef struct functable_s functable_t;
+struct functable_s {
+ double start;
+ double offset;
+ int len;
+
+ double invoffset;
+
+ double scale;
+ double scale2;
+
+ double (*func_x)(void *,double x);
+ double (*func_dx)(void *,double x);
+
+ double (*func2_x)(void *,double x);
+ double (*func2_dx)(void *,double x);
+
+ double *fx;
+ double *fdx;
+
+ void *priv;
+};
+
+void functable_init(functable_t *t);
+double functable_eval(functable_t *t,double x);
+
+double functable_fir(functable_t *t,double x0,int n,double *data,int len);
+void functable_fir2(functable_t *t,double *r0, double *r1, double x0,
+ int n,double *data,int len);
+
+double functable_sinc(void *p, double x);
+double functable_dsinc(void *p, double x);
+double functable_window_std(void *p, double x);
+double functable_window_dstd(void *p, double x);
+double functable_window_boxcar(void *p, double x);
+double functable_window_dboxcar(void *p, double x);
+
+/* math lib stuff */
+
+void conv_double_short_table(double *dest, short *src, int n);
+void conv_double_short_unroll(double *dest, short *src, int n);
+void conv_double_short_ref(double *dest, short *src, int n);
+#ifdef HAVE_CPU_PPC
+void conv_double_short_altivec(double *dest, short *src, int n);
+#endif
+
+void conv_short_double_ref(short *dest, double *src, int n);
+#ifdef HAVE_CPU_PPC
+void conv_short_double_ppcasm(short *dest, double *src, int n);
+#endif
+
+#ifdef HAVE_CPU_PPC
+#define conv_double_short conv_double_short_table
+#define conv_short_double conv_short_double_ppcasm
+#else
+#define conv_double_short conv_double_short_ref
+#define conv_short_double conv_short_double_ref
+#endif
+
+void conv_double_short_dstr(double *dest, short *src, int n, int dstr);
+void conv_short_double_sstr(short *dest, double *src, int n, int dstr);
+
+#endif /* __RESAMPLE_H__ */
+
--- /dev/null
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <sys/time.h>
+
+#include <resample.h>
+
+#define AMP 16000
+#define I_RATE 48000
+#define O_RATE 44100
+//#define O_RATE 24000
+
+//#define test_func(x) 1
+//#define test_func(x) sin(2*M_PI*(x)*10)
+//#define test_func(x) sin(2*M_PI*(x)*(x)*1000)
+#define test_func(x) sin(2*M_PI*(x)*(x)*12000)
+
+short i_buf[I_RATE*2*2];
+short o_buf[O_RATE*2*2];
+
+static int i_offset;
+static int o_offset;
+
+FILE *out;
+
+void test_res1(void);
+void test_res2(void);
+void test_res3(void);
+void test_res4(void);
+void test_res5(void);
+void test_res6(void);
+void test_res7(void);
+
+int main(int argc,char *argv[])
+{
+ out = fopen("out","w");
+
+ test_res7();
+
+ return 0;
+}
+
+void *get_buffer(void *priv, unsigned int size)
+{
+ void *ret;
+ ret = ((void *)o_buf) + o_offset;
+ o_offset += size;
+ return ret;
+}
+
+struct timeval start_time;
+void start_timer(void)
+{
+ gettimeofday(&start_time,NULL);
+ //printf("start %ld.%06ld\n",start_time.tv_sec,start_time.tv_usec);
+}
+
+void end_timer(void)
+{
+ struct timeval end_time;
+ double diff;
+
+ gettimeofday(&end_time,NULL);
+ //printf("end %ld.%06ld\n",end_time.tv_sec,end_time.tv_usec);
+ diff = (end_time.tv_sec - start_time.tv_sec) +
+ 1e-6*(end_time.tv_usec - start_time.tv_usec);
+
+ printf("time %g\n",diff);
+
+}
+
+void test_res1(void)
+{
+ resample_t *r;
+ int i;
+ double sum10k,sum22k;
+ double f;
+ int n10k,n22k;
+ double x;
+
+ for(i=0;i<I_RATE;i++){
+ i_buf[i*2+0] = rint(AMP * test_func((double)i/I_RATE));
+ //i_buf[i*2+1] = rint(AMP * test_func((double)i/I_RATE));
+ i_buf[i*2+1] = (i<1000)?AMP:0;
+ }
+
+ r = malloc(sizeof(resample_t));
+ memset(r,0,sizeof(resample_t));
+
+ r->i_rate = I_RATE;
+ r->o_rate = O_RATE;
+ //r->method = RESAMPLE_SINC_SLOW;
+ r->method = RESAMPLE_SINC;
+ r->channels = 2;
+ //r->verbose = 1;
+ r->filter_length = 64;
+ r->get_buffer = get_buffer;
+
+ resample_init(r);
+
+ start_timer();
+#define blocked
+#ifdef blocked
+ for(i=0;i+256<I_RATE;i+=256){
+ resample_scale(r,i_buf+i*2,256*2*2);
+ }
+ if(I_RATE-i){
+ resample_scale(r,i_buf+i*2,(I_RATE-i)*2*2);
+ }
+#else
+ resample_scale(r,i_buf,I_RATE*2*2);
+#endif
+ end_timer();
+
+ for(i=0;i<O_RATE;i++){
+ f = AMP*test_func((double)i/O_RATE);
+ //f = rint(AMP*test_func((double)i/O_RATE));
+ fprintf(out,"%d %d %d %g %g\n",i,
+ o_buf[2*i+0],o_buf[2*i+1],
+ f,o_buf[2*i+0]-f);
+ }
+
+ sum10k=0;
+ sum22k=0;
+ n10k=0;
+ n22k=0;
+ for(i=0;i<O_RATE;i++){
+ f = AMP*test_func((double)i/O_RATE);
+ //f = rint(AMP*test_func((double)i/O_RATE));
+ x = o_buf[2*i+0]-f;
+ if(((0.5*i)/O_RATE*I_RATE)<10000){
+ sum10k += x*x;
+ n10k++;
+ }
+ if(((0.5*i)/O_RATE*I_RATE)<22050){
+ sum22k += x*x;
+ n22k++;
+ }
+ }
+ printf("average error 10k=%g 22k=%g\n",
+ sqrt(sum10k/n10k),
+ sqrt(sum22k/n22k));
+}
+
+
+void test_res2(void)
+{
+ functable_t *t;
+ int i;
+ double x;
+ double f1,f2;
+
+ t = malloc(sizeof(*t));
+ memset(t,0,sizeof(*t));
+
+ t->start = -50.0;
+ t->offset = 1;
+ t->len = 100;
+
+ t->func_x = functable_sinc;
+ t->func_dx = functable_dsinc;
+
+ functable_init(t);
+
+ for(i=0;i<1000;i++){
+ x = -50.0 + 0.1 * i;
+ f1 = functable_sinc(NULL,x);
+ f2 = functable_eval(t,x);
+ fprintf(out,"%d %g %g %g\n",i,f1,f2,f1-f2);
+ }
+}
+
+void test_res3(void)
+{
+ functable_t *t;
+ int i;
+ double x;
+ double f1,f2;
+ int n = 1;
+
+ t = malloc(sizeof(*t));
+ memset(t,0,sizeof(*t));
+
+ t->start = -50.0;
+ t->offset = 1.0 / n;
+ t->len = 100 * n;
+
+ t->func_x = functable_sinc;
+ t->func_dx = functable_dsinc;
+
+ t->func2_x = functable_window_std;
+ t->func2_dx = functable_window_dstd;
+
+ t->scale = 1.0;
+ t->scale2 = 1.0 / (M_PI * 16);
+
+ functable_init(t);
+
+ for(i=0;i<1000 * n;i++){
+ x = -50.0 + 0.1/n * i;
+ f1 = functable_sinc(NULL,t->scale * x) *
+ functable_window_std(NULL,t->scale2 * x);
+ f2 = functable_eval(t,x);
+ fprintf(out,"%d %g %g %g\n",i,f1,f2,f2-f1);
+ }
+}
+
+double sinc_poly(double x)
+{
+#define INV3FAC 1.66666666666666666e-1
+#define INV5FAC 8.33333333333333333e-3
+#define INV7FAC 1.984126984e-4
+#define INV9FAC 2.755731922e-6
+#define INV11FAC 2.505210839e-8
+ double x2 = x * x;
+
+ return 1
+ - x2 * INV3FAC
+ + x2 * x2 * INV5FAC
+ - x2 * x2 * x2 * INV7FAC;
+ //+ x2 * x2 * x2 * x2 * INV9FAC
+ //- x2 * x2 * x2 * x2 * x2 * INV11FAC;
+}
+
+void test_res4(void)
+{
+ int i;
+ double x,f1,f2;
+
+ for(i=1;i<100;i++){
+ x = 0.01 * i;
+ f1 = 1 - sin(x)/x;
+ f2 = 1 - sinc_poly(x);
+
+ fprintf(out,"%g %.20g %.20g %.20g\n",x,f1,f2,f2-f1);
+ }
+}
+
+
+void test_res5(void)
+{
+ int i;
+ double sum;
+
+ start_timer();
+ sum = 0;
+ for(i=0;i<I_RATE;i++){
+ sum += i_buf[i*2];
+ }
+ end_timer();
+ i_buf[0] = sum;
+}
+
+
+void short_to_double(double *d,short *x) { *d = *x; }
+void short_to_float(float *f,short *x) { *f = *x; }
+void float_to_double(double *f,float *x) { *f = *x; }
+void double_to_short(short *f,double *x) { *f = *x; }
+
+double res6_tmp[1000];
+
+void test_res6(void)
+{
+ int i;
+
+ for(i=0;i<I_RATE;i++){
+ i_buf[i] = rint(AMP * test_func((double)i/I_RATE));
+ }
+
+ conv_double_short_ref(res6_tmp,i_buf,1000);
+ for(i=0;i<1000;i++){
+ res6_tmp[i] *= 3.0;
+ }
+ conv_short_double_ppcasm(o_buf,res6_tmp,1000);
+
+ for(i=0;i<1000;i++){
+ fprintf(out,"%d %d %g %d\n",i,i_buf[i],res6_tmp[i],o_buf[i]);
+ }
+}
+
+void test_res7(void)
+{
+ resample_t *r;
+ int i;
+ double sum10k,sum22k;
+ double f;
+ int n10k,n22k;
+ double x;
+
+ for(i=0;i<I_RATE;i++){
+ i_buf[i] = rint(AMP * test_func((double)i/I_RATE));
+ }
+
+ r = malloc(sizeof(resample_t));
+ memset(r,0,sizeof(resample_t));
+
+ r->i_rate = I_RATE;
+ r->o_rate = O_RATE;
+ //r->method = RESAMPLE_SINC_SLOW;
+ r->method = RESAMPLE_SINC;
+ r->channels = 1;
+ //r->verbose = 1;
+ r->filter_length = 64;
+ r->get_buffer = get_buffer;
+
+ resample_init(r);
+
+ start_timer();
+#define blocked
+#ifdef blocked
+ for(i=0;i+256<I_RATE;i+=256){
+ resample_scale(r,i_buf+i,256*2);
+ }
+ if(I_RATE-i){
+ resample_scale(r,i_buf+i,(I_RATE-i)*2);
+ }
+#else
+ resample_scale(r,i_buf,I_RATE*2);
+#endif
+ end_timer();
+
+ for(i=0;i<O_RATE;i++){
+ f = AMP*test_func((double)i/O_RATE);
+ //f = rint(AMP*test_func((double)i/O_RATE));
+ fprintf(out,"%d %d %d %g %g\n",i,
+ o_buf[i],0,
+ f,o_buf[i]-f);
+ }
+
+ sum10k=0;
+ sum22k=0;
+ n10k=0;
+ n22k=0;
+ for(i=0;i<O_RATE;i++){
+ f = AMP*test_func((double)i/O_RATE);
+ //f = rint(AMP*test_func((double)i/O_RATE));
+ x = o_buf[i]-f;
+ if(((0.5*i)/O_RATE*I_RATE)<10000){
+ sum10k += x*x;
+ n10k++;
+ }
+ if(((0.5*i)/O_RATE*I_RATE)<22050){
+ sum22k += x*x;
+ n22k++;
+ }
+ }
+ printf("average error 10k=%g 22k=%g\n",
+ sqrt(sum10k/n10k),
+ sqrt(sum22k/n22k));
+}
+
projects / platform / upstream / gstreamer.git / commitdiff