#include <math.h>
#include <unistd.h>
#include <assert.h>
+#include <vector>
#include <algorithm>
#define LANCZOS_RADIUS 30
-#define LEN 813440
+#define BUFSIZE 4096
#define HYSTERESIS_LIMIT 1000
double sinc(double x)
}
#endif
-double interpolate(const short *in, double i)
+double interpolate(const std::vector<short> &pcm, double i)
{
- int lower = std::max(int(ceil(i - LANCZOS_RADIUS)), 0);
- int upper = std::min(int(floor(i + LANCZOS_RADIUS)), LEN - 1);
+ int lower = std::max<int>(ceil(i - LANCZOS_RADIUS), 0);
+ int upper = std::min<int>(floor(i + LANCZOS_RADIUS), pcm.size() - 1);
double sum = 0.0f;
for (int x = lower; x <= upper; ++x) {
- sum += in[x] * weight(i - x);
+ sum += pcm[x] * weight(i - x);
}
return sum;
}
-short in[LEN];
-
// between [x,x+1]
-double find_zerocrossing(int x)
+double find_zerocrossing(const std::vector<short> &pcm, int x)
{
- if (in[x] == 0) {
+ if (pcm[x] == 0) {
return x;
}
- if (in[x + 1] == 0) {
+ if (pcm[x + 1] == 0) {
return x + 1;
}
- assert(in[x + 1] > 0);
- assert(in[x] < 0);
+ assert(pcm[x + 1] > 0);
+ assert(pcm[x] < 0);
double lower = x;
double upper = x + 1;
while (upper - lower > 1e-6) {
double mid = 0.5f * (upper + lower);
- if (interpolate(in, mid) > 0) {
+ if (interpolate(pcm, mid) > 0) {
upper = mid;
} else {
lower = mid;
int main(int argc, char **argv)
{
- fread(in, LEN*2, 1, stdin);
+ std::vector<short> pcm;
+
+ while (!feof(stdin)) {
+ short buf[BUFSIZE];
+ ssize_t ret = fread(buf, 2, BUFSIZE, stdin);
+ if (ret >= 0) {
+ pcm.insert(pcm.end(), buf, buf + ret);
+ }
+ }
#if 0
for (int i = 0; i < LEN; ++i) {
int last_bit = -1;
double last_upflank = -1;
int last_max_level = 0;
- for (int i = 0; i < LEN; ++i) {
- int bit = (in[i] > 0) ? 1 : 0;
+ for (int i = 0; i < pcm.size(); ++i) {
+ int bit = (pcm[i] > 0) ? 1 : 0;
if (bit == 1 && last_bit == 0 && last_max_level > HYSTERESIS_LIMIT) {
// up-flank!
- double t = find_zerocrossing(i - 1) * (123156.0/44100.0);
+ double t = find_zerocrossing(pcm, i - 1) * (123156.0/44100.0);
if (last_upflank > 0) {
// fprintf(stderr, "length: %f (0x%x)\n", t - last_upflank, lrintf(t - last_upflank));
int len = lrintf(t - last_upflank);
last_upflank = t;
last_max_level = 0;
}
- last_max_level = std::max(last_max_level, abs(in[i]));
+ last_max_level = std::max(last_max_level, abs(pcm[i]));
last_bit = bit;
}
}