/* downsample.c -- linear interpolation to a lower sample rate */
/* CHANGE LOG
* --------------------------------------------------------------------
* 28Apr03 dm changes for portability and fix compiler warnings
*/
#include "stdio.h"
#ifndef mips
#include "stdlib.h"
#endif
#include "xlisp.h"
#include "sound.h"
#include "falloc.h"
#include "cext.h"
#include "downsample.h"
void down_free(snd_susp_type a_susp);
typedef struct down_susp_struct {
snd_susp_node susp;
boolean started;
long terminate_cnt;
boolean logically_stopped;
sound_type s;
long s_cnt;
sample_block_values_type s_ptr;
/* support for interpolation of s */
sample_type s_x1_sample;
double s_pHaSe;
double s_pHaSe_iNcR;
/* support for ramp between samples of s */
double output_per_s;
long s_n;
} down_susp_node, *down_susp_type;
void down_i_fetch(snd_susp_type a_susp, snd_list_type snd_list)
{
down_susp_type susp = (down_susp_type) a_susp;
int cnt = 0; /* how many samples computed */
sample_type s_x2_sample;
int togo;
int n;
sample_block_type out;
register sample_block_values_type out_ptr;
register sample_block_values_type out_ptr_reg;
register double s_pHaSe_iNcR_rEg = susp->s_pHaSe_iNcR;
register double s_pHaSe_ReG;
register sample_type s_x1_sample_reg;
falloc_sample_block(out, "down_i_fetch");
out_ptr = out->samples;
snd_list->block = out;
/* make sure sounds are primed with first values */
if (!susp->started) {
susp->started = true;
susp_check_term_log_samples(s, s_ptr, s_cnt);
susp->s_x1_sample = susp_fetch_sample(s, s_ptr, s_cnt);
}
susp_check_term_log_samples(s, s_ptr, s_cnt);
s_x2_sample = susp_current_sample(s, s_ptr);
/* initially, s_x1_sample and s_x2_samples will be the first 2 samples
* and phase will be zero, so interpolation between these two will yield
* s_x1_sample. */
while (cnt < max_sample_block_len) { /* outer loop */
/* first compute how many samples to generate in inner loop: */
/* don't overflow the output sample block: */
togo = max_sample_block_len - cnt;
/* don't run past terminate time */
if (susp->terminate_cnt != UNKNOWN &&
susp->terminate_cnt <= susp->susp.current + cnt + togo) {
togo = susp->terminate_cnt - (susp->susp.current + cnt);
if (togo <= 0) {
togo = 0;
break;
}
}
/* don't run past logical stop time */
if (!susp->logically_stopped && susp->susp.log_stop_cnt != UNKNOWN) {
int to_stop = susp->susp.log_stop_cnt - (susp->susp.current + cnt);
/* break if to_stop == 0 (we're at the logical stop)
* AND cnt > 0 (we're not at the beginning of the
* output block).
*/
if (to_stop < togo) {
if (to_stop == 0) {
if (cnt) {
togo = 0;
break;
} else /* keep togo as is: since cnt == 0, we
* can set the logical stop flag on this
* output block
*/
susp->logically_stopped = true;
} else /* limit togo so we can start a new
* block at the LST
*/
togo = to_stop;
}
}
n = togo;
s_pHaSe_ReG = susp->s_pHaSe;
s_x1_sample_reg = susp->s_x1_sample;
out_ptr_reg = out_ptr;
if (n) do {
while (s_pHaSe_ReG >= 1.0) {
if (s_pHaSe_ReG < 2) { /* quick, just take one sample */
s_x1_sample_reg = s_x2_sample;
/* pick up next sample as s_x2_sample: */
susp->s_ptr++;
susp_took(s_cnt, 1);
s_pHaSe_ReG -= 1.0;
} else { /* jump over as much input as possible */
int take = (int) s_pHaSe_ReG; /* rounds down */
take--; /* leave s_pHaSe_ReG > 1 so we stay in loop */
/* next iteration will set s_x1_sample_reg */
if (take > susp->s_cnt) take = susp->s_cnt;
susp->s_ptr += take;
susp_took(s_cnt, take);
s_pHaSe_ReG -= take;
}
/* derived from susp_check_term_log_samples_break, but with
a goto instead of a break */
if (susp->s_cnt == 0) {
susp_get_samples(s, s_ptr, s_cnt);
terminate_test(s_ptr, s, susp->s_cnt);
/* see if newly discovered logical stop time: */
logical_stop_test(s, susp->s_cnt);
if ((susp->terminate_cnt != UNKNOWN &&
susp->terminate_cnt <
susp->susp.current + cnt + togo) ||
(!susp->logically_stopped &&
susp->susp.log_stop_cnt != UNKNOWN &&
susp->susp.log_stop_cnt <
susp->susp.current + cnt + togo)) {
/* Because we are down sampling, we could have just
computed an output at sample N and be working on
sample N+1, but then the next input sample is
logically stopped. Bad because we cannot back up
and undo sample N to put it in the next block with
a logical stop flag set. Our only choice is to "fix"
the logical stop time to be on the next sample. */
if (susp->terminate_cnt != UNKNOWN &&
susp->terminate_cnt < susp->susp.current + togo - n) {
susp->terminate_cnt = susp->susp.current + togo - n;
}
if (susp->susp.log_stop_cnt != UNKNOWN &&
susp->susp.log_stop_cnt <
susp->susp.current + togo - n) {
susp->susp.log_stop_cnt = susp->susp.current + togo - n;
}
goto breakout;
}
}
s_x2_sample = susp_current_sample(s, s_ptr);
}
*out_ptr_reg++ = (sample_type)
(s_x1_sample_reg * (1 - s_pHaSe_ReG) +
s_x2_sample * s_pHaSe_ReG);
s_pHaSe_ReG += s_pHaSe_iNcR_rEg;
} while (--n); /* inner loop */
breakout:
togo -= n;
susp->s_pHaSe = s_pHaSe_ReG;
susp->s_x1_sample = s_x1_sample_reg;
out_ptr += togo;
cnt += togo;
} /* outer loop */
/* test for termination */
if (togo == 0 && cnt == 0) {
snd_list_terminate(snd_list);
} else {
snd_list->block_len = cnt;
susp->susp.current += cnt;
}
/* test for logical stop */
if (susp->logically_stopped) {
snd_list->logically_stopped = true;
} else if (susp->susp.log_stop_cnt == susp->susp.current) {
susp->logically_stopped = true;
}
} /* down_i_fetch */
void down_toss_fetch(snd_susp_type a_susp, snd_list_type snd_list)
{
down_susp_type susp = (down_susp_type) a_susp;
long final_count = MIN(susp->susp.current + max_sample_block_len,
susp->susp.toss_cnt);
time_type final_time = susp->susp.t0 + final_count / susp->susp.sr;
long n;
/* fetch samples from s up to final_time for this block of zeros */
while (((long) ((final_time - susp->s->t0) * susp->s->sr + 0.5)) >=
susp->s->current)
susp_get_samples(s, s_ptr, s_cnt);
/* convert to normal processing when we hit final_count */
/* we want each signal positioned at final_time */
if (final_count == susp->susp.toss_cnt) {
n = ROUNDBIG((final_time - susp->s->t0) * susp->s->sr -
(susp->s->current - susp->s_cnt));
susp->s_ptr += n;
susp_took(s_cnt, n);
susp->susp.fetch = susp->susp.keep_fetch;
}
snd_list->block_len = (short) (final_count - susp->susp.current);
susp->susp.current = final_count;
snd_list->u.next = snd_list_create((snd_susp_type) susp);
snd_list->block = internal_zero_block;
}
void down_mark(snd_susp_type a_susp)
{
down_susp_type susp = (down_susp_type) a_susp;
sound_xlmark(susp->s);
}
void down_free(snd_susp_type a_susp)
{
down_susp_type susp = (down_susp_type) a_susp;
sound_unref(susp->s);
ffree_generic(susp, sizeof(down_susp_node), "down_free");
}
void down_print_tree(snd_susp_type a_susp, int n)
{
down_susp_type susp = (down_susp_type) a_susp;
indent(n);
stdputstr("s:");
sound_print_tree_1(susp->s, n);
}
sound_type snd_make_down(rate_type sr, sound_type s)
{
register down_susp_type susp;
/* sr specified as input parameter */
time_type t0 = s->t0;
sample_type scale_factor = 1.0F;
time_type t0_min = t0;
if (s->sr < sr) {
sound_unref(s);
xlfail("snd-down: output sample rate must be lower than input");
}
falloc_generic(susp, down_susp_node, "snd_make_down");
susp->susp.fetch = down_i_fetch;
susp->terminate_cnt = UNKNOWN;
/* handle unequal start times, if any */
if (t0 < s->t0) sound_prepend_zeros(s, t0);
/* minimum start time over all inputs: */
t0_min = min(s->t0, t0);
/* how many samples to toss before t0: */
susp->susp.toss_cnt = (long) ((t0 - t0_min) * sr + 0.5);
if (susp->susp.toss_cnt > 0) {
susp->susp.keep_fetch = susp->susp.fetch;
susp->susp.fetch = down_toss_fetch;
}
/* initialize susp state */
susp->susp.free = down_free;
susp->susp.sr = sr;
susp->susp.t0 = t0;
susp->susp.mark = down_mark;
susp->susp.print_tree = down_print_tree;
susp->susp.name = "down";
susp->logically_stopped = false;
susp->susp.log_stop_cnt = logical_stop_cnt_cvt(s);
susp->started = false;
susp->susp.current = 0;
susp->s = s;
susp->s_cnt = 0;
susp->s_pHaSe = 0.0;
susp->s_pHaSe_iNcR = s->sr / sr;
susp->s_n = 0;
susp->output_per_s = sr / s->sr;
return sound_create((snd_susp_type)susp, t0, sr, scale_factor);
}
sound_type snd_down(rate_type sr, sound_type s)
{
sound_type s_copy = sound_copy(s);
return snd_make_down(sr, s_copy);
}