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af_scaletempo: don't use a window for offset search 

This might seem counter intuitive at first, but we want to change the
sound in total as little as possible, not only the middle part of the
overlap.

This also removes the loop unrolling from the integer path to keep it as
close to the float path as possible. The difference in performance is
fairly small and if such an optimization is deemed desirable in the
future it should be implemented for both float and integer
This commit is contained in:
Christoph Heinrich 2023-09-29 20:30:41 +02:00 committed by Kacper Michajłow
parent 2287804739
commit 3f6874f4d7
1 changed files with 8 additions and 65 deletions
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73
audio/filter/af_scaletempo.c
View File

@ -88,8 +88,6 @@ struct priv {
// best overlap
int frames_search;
int num_channels;
void *buf_pre_corr;
void *table_window;
int (*best_overlap_offset)(struct priv *s);
};
@ -136,27 +134,19 @@ static bool fill_queue(struct priv *s)
return bytes_needed == 0;
}
#define UNROLL_PADDING (4 * 4)
static int best_overlap_offset_float(struct priv *s)
{
float best_corr = INT_MIN;
int best_off = 0;
float *pw = s->table_window;
float *po = s->buf_overlap;
po += s->num_channels;
float *ppc = s->buf_pre_corr;
for (int i = s->num_channels; i < s->samples_overlap; i++)
*ppc++ = *pw++ **po++;
float *search_start = (float *)s->buf_queue + s->num_channels;
for (int off = 0; off < s->frames_search; off++) {
float corr = 0;
float *ps = search_start;
ppc = s->buf_pre_corr;
float *po = s->buf_overlap;
po += s->num_channels;
for (int i = s->num_channels; i < s->samples_overlap; i++)
corr += *ppc++ **ps++;
corr += *po++ * *ps++;
if (corr > best_corr) {
best_corr = corr;
best_off = off;
@ -172,28 +162,14 @@ static int best_overlap_offset_s16(struct priv *s)
int64_t best_corr = INT64_MIN;
int best_off = 0;
int32_t *pw = s->table_window;
int16_t *po = s->buf_overlap;
po += s->num_channels;
int32_t *ppc = s->buf_pre_corr;
for (long i = s->num_channels; i < s->samples_overlap; i++)
*ppc++ = (*pw++ **po++) >> 15;
int16_t *search_start = (int16_t *)s->buf_queue + s->num_channels;
for (int off = 0; off < s->frames_search; off++) {
int64_t corr = 0;
int16_t *ps = search_start;
ppc = s->buf_pre_corr;
ppc += s->samples_overlap - s->num_channels;
ps += s->samples_overlap - s->num_channels;
long i = -(s->samples_overlap - s->num_channels);
do {
corr += ppc[i + 0] * (int64_t)ps[i + 0];
corr += ppc[i + 1] * (int64_t)ps[i + 1];
corr += ppc[i + 2] * (int64_t)ps[i + 2];
corr += ppc[i + 3] * (int64_t)ps[i + 3];
i += 4;
} while (i < 0);
int16_t *po = s->buf_overlap;
po += s->num_channels;
for (int i = s->num_channels; i < s->samples_overlap; i++)
corr += *po++ * (int32_t)*ps++;
if (corr > best_corr) {
best_corr = corr;
best_off = off;
@ -449,39 +425,8 @@ static bool reinit(struct mp_filter *f)
s->best_overlap_offset = NULL;
else {
if (use_int) {
int64_t t = frames_overlap;
int32_t n = 8589934588LL / (t * t); // 4 * (2^31 - 1) / t^2
s->buf_pre_corr = realloc(s->buf_pre_corr,
s->bytes_overlap * 2 + UNROLL_PADDING);
s->table_window = realloc(s->table_window,
s->bytes_overlap * 2 - nch * bps * 2);
if (!s->buf_pre_corr || !s->table_window) {
MP_FATAL(f, "Out of memory\n");
return false;
}
memset((char *)s->buf_pre_corr + s->bytes_overlap * 2, 0,
UNROLL_PADDING);
int32_t *pw = s->table_window;
for (int i = 1; i < frames_overlap; i++) {
int32_t v = (i * (t - i) * n) >> 15;
for (int j = 0; j < nch; j++)
*pw++ = v;
}
s->best_overlap_offset = best_overlap_offset_s16;
} else {
s->buf_pre_corr = realloc(s->buf_pre_corr, s->bytes_overlap);
s->table_window = realloc(s->table_window,
s->bytes_overlap - nch * bps);
if (!s->buf_pre_corr || !s->table_window) {
MP_FATAL(f, "Out of memory\n");
return false;
}
float *pw = s->table_window;
for (int i = 1; i < frames_overlap; i++) {
float v = i * (frames_overlap - i);
for (int j = 0; j < nch; j++)
*pw++ = v;
}
s->best_overlap_offset = best_overlap_offset_float;
}
}
@ -491,7 +436,7 @@ static bool reinit(struct mp_filter *f)
s->bytes_queue = (s->frames_search + s->frames_stride + frames_overlap)
* bps * nch;
s->buf_queue = realloc(s->buf_queue, s->bytes_queue + UNROLL_PADDING);
s->buf_queue = realloc(s->buf_queue, s->bytes_queue);
if (!s->buf_queue) {
MP_FATAL(f, "Out of memory\n");
return false;
@ -553,9 +498,7 @@ static void af_scaletempo_destroy(struct mp_filter *f)
struct priv *s = f->priv;
free(s->buf_queue);
free(s->buf_overlap);
free(s->buf_pre_corr);
free(s->table_blend);
free(s->table_window);
TA_FREEP(&s->in);
mp_filter_free_children(f);
}