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--- alsa-lib-1.0.6-orig/src/pcm/pcm_rate.c 2004-08-09 08:31:41.000000000 +0200
+++ alsa-lib-1.0.6/src/pcm/pcm_rate.c 2004-09-05 22:46:17.947253031 +0200
@@ -45,7 +45,8 @@
#ifndef DOC_HIDDEN
/* LINEAR_DIV needs to be large enough to handle resampling from 192000 -> 8000 */
-#define LINEAR_DIV (1<<19)
+#define LINEAR_DIV_SHIFT 19
+#define LINEAR_DIV (1<<LINEAR_DIV_SHIFT)
enum rate_type {
RATE_TYPE_LINEAR, /* linear interpolation */
@@ -206,9 +207,12 @@
const char *src;
char *dst;
int src_step, dst_step;
+ int16_t old_sample = 0;
+ int16_t new_sample = 0;
+ int old_weight, new_weight;
sum = states->u.linear.sum;
//int16_t old_sample = states->u.linear.old_sample;
- pos = LINEAR_DIV/2; /* Start at 0.5 */
+ pos = LINEAR_DIV - get_increment; /* Force first sample to be copied */
states->u.linear.init = 0;
src = snd_pcm_channel_area_addr(src_area, src_offset);
dst = snd_pcm_channel_area_addr(dst_area, dst_offset);
@@ -223,11 +227,15 @@
#include "plugin_ops.h"
#undef GET16_END
after_get:
+ new_sample = sample;
src += src_step;
src_frames1++;
pos += get_increment;
if (pos >= LINEAR_DIV) {
pos -= LINEAR_DIV;
+ old_weight = (pos << (32 - LINEAR_DIV_SHIFT)) / (get_increment >> (LINEAR_DIV_SHIFT - 16));
+ new_weight = 0x10000 - old_weight;
+ sample = (old_sample * old_weight + new_sample * new_weight) >> 16;
goto *put;
#define PUT16_END after_put
#include "plugin_ops.h"
@@ -237,6 +245,7 @@
dst_frames1++;
assert(dst_frames1 <= dst_frames);
}
+ old_sample = new_sample;
}
states->u.linear.sum = sum;
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