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aacdec: 4% faster main profile decoding. 

Originally committed as revision 24474 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Alex Converse 2010-07-24 02:41:47 +00:00
parent 51ffd3a62f
commit 70c99adb48
1 changed files with 7 additions and 4 deletions
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11
libavcodec/aacdec.c
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@ -1231,7 +1231,8 @@ static av_always_inline float flt16_trunc(float pf)
return pun.f;
}
static av_always_inline void predict(AACContext *ac, PredictorState *ps, float *coef,
static av_always_inline void predict(PredictorState *ps, float *coef,
float sf_scale, float inv_sf_scale,
int output_enable)
{
const float a = 0.953125; // 61.0 / 64
@ -1245,9 +1246,9 @@ static av_always_inline void predict(AACContext *ac, PredictorState *ps, float *
pv = flt16_round(k1 * ps->r0 + k2 * ps->r1);
if (output_enable)
*coef += pv * ac->sf_scale;
*coef += pv * sf_scale;
e0 = *coef / ac->sf_scale;
e0 = *coef * inv_sf_scale;
e1 = e0 - k1 * ps->r0;
ps->cor1 = flt16_trunc(alpha * ps->cor1 + ps->r1 * e1);
@ -1265,6 +1266,7 @@ static av_always_inline void predict(AACContext *ac, PredictorState *ps, float *
static void apply_prediction(AACContext *ac, SingleChannelElement *sce)
{
int sfb, k;
float sf_scale = ac->sf_scale, inv_sf_scale = 1 / ac->sf_scale;
if (!sce->ics.predictor_initialized) {
reset_all_predictors(sce->predictor_state);
@ -1274,7 +1276,8 @@ static void apply_prediction(AACContext *ac, SingleChannelElement *sce)
if (sce->ics.window_sequence[0] != EIGHT_SHORT_SEQUENCE) {
for (sfb = 0; sfb < ff_aac_pred_sfb_max[ac->m4ac.sampling_index]; sfb++) {
for (k = sce->ics.swb_offset[sfb]; k < sce->ics.swb_offset[sfb + 1]; k++) {
predict(ac, &sce->predictor_state[k], &sce->coeffs[k],
predict(&sce->predictor_state[k], &sce->coeffs[k],
sf_scale, inv_sf_scale,
sce->ics.predictor_present && sce->ics.prediction_used[sfb]);
}
}