From 783b56d54788f177881d68ae2ec7a7cb4bb38ac4 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Sun, 18 Apr 2004 01:35:53 +0000
Subject: Initial commit

git-svn-id: file:///home/lennart/svn/public/vfax/trunk@3 541b366f-4dd8-0310-ae39-b2612fd50714
---
 resample.c | 147 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 147 insertions(+)
 create mode 100644 resample.c

(limited to 'resample.c')

diff --git a/resample.c b/resample.c
new file mode 100644
index 0000000..ee9e540
--- /dev/null
+++ b/resample.c
@@ -0,0 +1,147 @@
+#include <stdio.h>
+#include <assert.h>
+#include <string.h>
+#include <math.h>
+#include <inttypes.h>
+
+#include "resample.h"
+#include "interpol.h"
+
+#define SINC_RADIUS 10
+
+struct resample_state {
+    float delta;
+
+    int sfreq, dfreq;
+    struct interpol_state interpol;
+};
+
+
+static int lcd(int a, int b) {
+    assert(a >= 1 && b >= 1);
+
+    while (a != b) {
+        while (a > b) {
+            a = a-b;
+        }
+
+        while (b > a) {
+            b = b-a;
+        }
+    }
+
+    return a;
+}
+
+void resample_init(struct resample_state *s) {
+    assert(s);
+    memset(s, 0, sizeof(struct resample_state));
+    s->sfreq = s->dfreq = -1;
+}
+
+void resample_done(struct resample_state *s) {
+    assert(s);
+    interpol_done(&s->interpol);
+}
+
+void resample_get(struct resample_state *s, float* sp, int *sl, float *dp, int *dl, int sfreq, int dfreq) {
+    int di;
+    float x = 0;
+
+    assert(s && sp && dp && sfreq > 0 && dfreq > 0);
+    assert(*sl > 0);
+    assert(*dl > 0);
+
+    if (sfreq != s->sfreq || dfreq != s->dfreq) {
+        interpol_done(&s->interpol);
+        interpol_init(&s->interpol, dfreq/lcd(sfreq,dfreq), SINC_RADIUS);
+        s->sfreq = sfreq;
+        s->dfreq = dfreq;
+    }
+
+    di = 0;
+    while (di < *dl) {
+        x = (float) di*sfreq/dfreq + s->delta;
+
+        if (x + SINC_RADIUS + 1 > *sl)
+            break;
+        
+        *(dp++) = interpol_get(&s->interpol, sp, *sl, x);
+        di++;
+    }
+    
+    *dl = di;
+
+    if (x >= SINC_RADIUS) {
+        *sl = (int) (x - SINC_RADIUS);
+        s->delta = x - *sl;
+    } else
+        *sl = 0;
+}
+
+#if (TEST == 7)
+
+#define BUFSIZE (10*1024)
+
+void sinbuf(float *buf, int l) {
+    static int i = 0;
+
+    for (; l > 0; l--, i = (i+1 == 100) ? 0 : i+1)
+        *(buf++) = sin(i*2*M_PI/100);
+}
+
+void convbuf(float *buf, int l) {
+    int16_t *p = (int16_t*) buf;
+    for (; l > 0; l--, p+=2) {
+        float v = ((float) *p + (float) *(p+1))/0x7FFF;
+        *(buf++) = (v < -1) ? -1 : ((v > 1) ? 1 : v);
+    }
+            
+}
+
+
+int main(int argc, char *argv[]) {
+    struct resample_state resample;
+    float inbuf[BUFSIZE];
+    int total_n_inbuf = 0;
+
+    if (argc > 1) {
+        stdin = fopen(argv[1], "r");
+        assert(stdin);
+    }
+
+    resample_init(&resample);
+    
+    while (!feof(stdin)) {
+        float outbuf[BUFSIZE];
+        int n_outbuf = sizeof(outbuf) / sizeof(float);
+        int n_inbuf, c;
+
+        fprintf(stderr, "LOOP!\n");
+
+        c = fread(inbuf + total_n_inbuf, sizeof(float), sizeof(inbuf)/sizeof(float) - total_n_inbuf, stdin);
+        convbuf(inbuf + total_n_inbuf, c);
+        n_inbuf = (total_n_inbuf += c);
+
+        
+        
+/*          sinbuf(inbuf + total_n_inbuf, sizeof(inbuf)/sizeof(float) - total_n_inbuf); */
+/*          n_inbuf = total_n_inbuf = sizeof(inbuf)/sizeof(float); *\/ */
+
+
+        resample_get(&resample, inbuf, &n_inbuf, outbuf, &n_outbuf, 44100, 8000);
+        
+        fwrite(outbuf, sizeof(float), n_outbuf, stdout);
+
+        if (n_inbuf) {
+            total_n_inbuf -= n_inbuf;
+            memmove(inbuf, inbuf + n_inbuf, total_n_inbuf*sizeof(float));
+        }
+    }
+
+    resample_done(&resample);
+    
+    return 0;
+}
+
+#endif
-- 
cgit