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lavc/opus_celt: replace pow by exp2

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exp2 is faster.

It may be possible to optimize further; e.g the exponents seem to be
multiples of 0.25. This requires study though.

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
This commit is contained in:
Ganesh Ajjanagadde 2015-12-09 18:23:00 -05:00
parent 95b59bfb9d
commit 97d2c2d678
1 changed files with 2 additions and 2 deletions
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4
libavcodec/opus_celt.c
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@ -1677,7 +1677,7 @@ static void celt_denormalize(CeltContext *s, CeltFrame *frame, float *data)
for (i = s->startband; i < s->endband; i++) { for (i = s->startband; i < s->endband; i++) {
float *dst = data + (celt_freq_bands[i] << s->duration); float *dst = data + (celt_freq_bands[i] << s->duration);
float norm = pow(2, frame->energy[i] + celt_mean_energy[i]); float norm = exp2(frame->energy[i] + celt_mean_energy[i]);
for (j = 0; j < celt_freq_range[i] << s->duration; j++) for (j = 0; j < celt_freq_range[i] << s->duration; j++)
dst[j] *= norm; dst[j] *= norm;
@ -1857,7 +1857,7 @@ static void process_anticollapse(CeltContext *s, CeltFrame *frame, float *X)
/* r needs to be multiplied by 2 or 2*sqrt(2) depending on LM because /* r needs to be multiplied by 2 or 2*sqrt(2) depending on LM because
short blocks don't have the same energy as long */ short blocks don't have the same energy as long */
r = pow(2, 1 - Ediff); r = exp2(1 - Ediff);
if (s->duration == 3) if (s->duration == 3)
r *= M_SQRT2; r *= M_SQRT2;
r = FFMIN(thresh, r) * sqrt_1; r = FFMIN(thresh, r) * sqrt_1;