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redesigned ddc, replaced delay lines with common buffer

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This commit is contained in:
Ahmet Inan 2012-09-14 22:05:41 +02:00
parent 1dc17ba23b
commit 13420ca857
7 changed files with 112 additions and 128 deletions
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48
decode.c
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@ -14,7 +14,7 @@ You should have received a copy of the CC0 Public Domain Dedication along with t
#include <time.h>
#include "pcm.h"
#include "ddc.h"
#include "delay.h"
#include "buffer.h"
#include "yuv.h"
#include "utils.h"
#include "img.h"
@ -289,23 +289,20 @@ int demodulate(struct pcm *pcm, float *cnt_freq, float *dat_freq, float *drate)
static float dstep;
static float complex cnt_last = -I;
static float complex dat_last = -I;
static float *cnt_amp;
static float *dat_amp;
static float complex *cnt_q;
static float complex *dat_q;
static struct ddc *cnt_ddc;
static struct ddc *dat_ddc;
static struct delay *cnt_delay;
static struct delay *dat_delay;
static short *buff;
static struct buffer *buffer;
static int cnt_delay;
static int dat_delay;
static short *pcm_buff;
static int init = 0;
if (!init) {
init = 1;
rate = rate_pcm(pcm);
channels = channels_pcm(pcm);
const float step = 1.0 / rate;
#if DN && UP
// 320 / 0.088 = 160 / 0.044 = 40000 / 11 = 3636.(36)~ pixels per second for Y, U and V
factor_L = 40000;
@ -331,18 +328,19 @@ int demodulate(struct pcm *pcm, float *cnt_freq, float *dat_freq, float *drate)
*drate = rate * (float)factor_L / (float)factor_M;
dstep = 1.0 / *drate;
fprintf(stderr, "using factor of %ld/%ld, working at %.2fhz\n", factor_L, factor_M, *drate);
cnt_amp = malloc(sizeof(float) * factor_M);
dat_amp = malloc(sizeof(float) * factor_M);
cnt_q = malloc(sizeof(float complex) * factor_L);
dat_q = malloc(sizeof(float complex) * factor_L);
// same factor to keep life simple and have accurate horizontal sync
cnt_ddc = alloc_ddc(1200.0, 200.0, step, cnt_taps, factor_L, factor_M, kaiser, 2.0);
dat_ddc = alloc_ddc(1900.0, 800.0, step, dat_taps, factor_L, factor_M, kaiser, 2.0);
cnt_ddc = alloc_ddc(factor_L, factor_M, 1200.0, 200.0, rate, cnt_taps, kaiser, 2.0);
dat_ddc = alloc_ddc(factor_L, factor_M, 1900.0, 800.0, rate, dat_taps, kaiser, 2.0);
// delay input by phase shift of other filter to synchronize outputs
cnt_delay = alloc_delay((dat_taps - 1) / (2 * factor_L));
dat_delay = alloc_delay((cnt_taps - 1) / (2 * factor_L));
cnt_delay = (dat_taps - 1) / (2 * factor_L);
dat_delay = (cnt_taps - 1) / (2 * factor_L);
buff = (short *)malloc(sizeof(short) * channels * factor_M);
pcm_buff = (short *)malloc(sizeof(short) * channels * factor_M);
// 0.1 second history + enough room for delay and taps
buffer = alloc_buffer(0.1 * rate + 2 * fmaxf(cnt_delay, dat_delay));
// start immediately below
out = factor_L;
@ -350,22 +348,20 @@ int demodulate(struct pcm *pcm, float *cnt_freq, float *dat_freq, float *drate)
if (out >= factor_L) {
out = 0;
if (!read_pcm(pcm, buff, factor_M)) {
if (!read_pcm(pcm, pcm_buff, factor_M)) {
init = 0;
free(buff);
free(pcm_buff);
free_ddc(cnt_ddc);
free_ddc(dat_ddc);
free(cnt_amp);
free(dat_amp);
free_buffer(buffer);
return 0;
}
for (int j = 0; j < factor_M; j++) {
float amp = (float)buff[j * channels] / 32767.0;
cnt_amp[j] = do_delay(cnt_delay, amp);
dat_amp[j] = do_delay(dat_delay, amp);
}
do_ddc(cnt_ddc, cnt_amp, cnt_q);
do_ddc(dat_ddc, dat_amp, dat_q);
float *buff = 0;
for (int j = 0; j < factor_M; j++)
buff = do_buffer(buffer, (float)pcm_buff[j * channels] / 32767.0);
do_ddc(cnt_ddc, buff + cnt_delay, cnt_q);
do_ddc(dat_ddc, buff + dat_delay, dat_q);
}
*cnt_freq = fclampf(1200.0 + cargf(cnt_q[out] * conjf(cnt_last)) / (2.0 * M_PI * dstep), 1100.0, 1300.0);