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lpc: use levinson for the first pass of multipass cholesky 

Levinson is faster, and cholesky is only needed if we want to apply different
weights to different samples, which doesn't happen on the first pass.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
This commit is contained in:
Loren Merritt 2013-06-16 00:53:47 +00:00 committed by Luca Barbato
parent b545179fdf
commit c93ccf5a4c
1 changed files with 16 additions and 13 deletions
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29
libavcodec/lpc.c
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@ -176,7 +176,7 @@ int ff_lpc_calc_coefs(LPCContext *s,
double autoc[MAX_LPC_ORDER+1];
double ref[MAX_LPC_ORDER];
double lpc[MAX_LPC_ORDER][MAX_LPC_ORDER];
int i, j, pass;
int i, j, pass = 0;
int opt_order;
assert(max_order >= MIN_LPC_ORDER && max_order <= MAX_LPC_ORDER &&
@ -189,7 +189,7 @@ int ff_lpc_calc_coefs(LPCContext *s,
ff_lpc_init(s, blocksize, max_order, lpc_type);
}
if (lpc_type == FF_LPC_TYPE_LEVINSON) {
if (lpc_type == FF_LPC_TYPE_LEVINSON || (lpc_type == FF_LPC_TYPE_CHOLESKY && lpc_passes > 1)) {
s->lpc_apply_welch_window(samples, blocksize, s->windowed_samples);
s->lpc_compute_autocorr(s->windowed_samples, blocksize, max_order, autoc);
@ -198,13 +198,20 @@ int ff_lpc_calc_coefs(LPCContext *s,
for(i=0; i<max_order; i++)
ref[i] = fabs(lpc[i][i]);
} else if (lpc_type == FF_LPC_TYPE_CHOLESKY) {
pass++;
}
if (lpc_type == FF_LPC_TYPE_CHOLESKY) {
LLSModel m[2];
LOCAL_ALIGNED(32, double, var, [FFALIGN(MAX_LPC_ORDER+1,4)]);
double av_uninit(weight);
memset(var, 0, FFALIGN(MAX_LPC_ORDER+1,4)*sizeof(*var));
for(pass=0; pass<lpc_passes; pass++){
for(j=0; j<max_order; j++)
m[0].coeff[max_order-1][j] = -lpc[max_order-1][j];
for(; pass<lpc_passes; pass++){
avpriv_init_lls(&m[pass&1], max_order);
weight=0;
@ -259,15 +266,11 @@ av_cold int ff_lpc_init(LPCContext *s, int blocksize, int max_order,
s->max_order = max_order;
s->lpc_type = lpc_type;
if (lpc_type == FF_LPC_TYPE_LEVINSON) {
s->windowed_buffer = av_mallocz((blocksize + 2 + FFALIGN(max_order, 4)) *
sizeof(*s->windowed_samples));
if (!s->windowed_buffer)
return AVERROR(ENOMEM);
s->windowed_samples = s->windowed_buffer + FFALIGN(max_order, 4);
} else {
s->windowed_samples = NULL;
}
s->windowed_buffer = av_mallocz((blocksize + 2 + FFALIGN(max_order, 4)) *
sizeof(*s->windowed_samples));
if (!s->windowed_buffer)
return AVERROR(ENOMEM);
s->windowed_samples = s->windowed_buffer + FFALIGN(max_order, 4);
s->lpc_apply_welch_window = lpc_apply_welch_window_c;
s->lpc_compute_autocorr = lpc_compute_autocorr_c;