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Optimised intra prediction a bit -- removed a conditional branch and replaced

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some calls to ec_enc_uint() by calls to ec_enc_bits() (saves divisions)
This commit is contained in:
Jean-Marc Valin 2008-03-25 15:25:08 +11:00
parent b886ddc08c
commit 208ae6e33d
1 changed files with 28 additions and 13 deletions
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41
libcelt/vq.c
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@ -275,6 +275,9 @@ static const celt_word16_t pg[11] = {32767, 24576, 21299, 19661, 19661, 19661, 1
static const celt_word16_t pg[11] = {1.f, .75f, .65f, 0.6f, 0.6f, .6f, .55f, .55f, .5f, .5f, .5f};
#endif
#define MAX_INTRA 32
#define LOG_MAX_INTRA 5
void intra_prediction(celt_norm_t *x, celt_mask_t *W, int N, int K, celt_norm_t *Y, celt_norm_t *P, int B, int N0, ec_enc *enc)
{
int i,j;
@ -285,36 +288,45 @@ void intra_prediction(celt_norm_t *x, celt_mask_t *W, int N, int K, celt_norm_t
celt_word32_t E;
celt_word16_t pred_gain;
int max_pos = N0-N/B;
if (max_pos > 32)
max_pos = 32;
if (max_pos > MAX_INTRA)
max_pos = MAX_INTRA;
for (i=0;i<max_pos*B;i+=B)
{
celt_word32_t xy=0, yy=0;
celt_word32_t score;
/* If this doesn't generate a double-MAC on supported architectures,
complain to your compilor vendor */
for (j=0;j<N;j++)
{
xy = MAC16_16(xy, x[j], Y[i+N-j-1]);
yy = MAC16_16(yy, Y[i+N-j-1], Y[i+N-j-1]);
}
/* If you're really desperate for speed, just use xy as the score */
score = celt_div(MULT16_16(ROUND16(xy,14),ROUND16(xy,14)), ROUND16(yy,14));
if (score > best_score)
{
best_score = score;
best = i;
if (xy>0)
s = 1;
else
s = -1;
/* Store xy as the sign. We'll normalise it to +/- 1 later. */
s = ROUND16(xy,14);
}
}
if (s<0)
{
s = -1;
sign = 1;
else
} else {
s = 1;
sign = 0;
}
/*printf ("%d %d ", sign, best);*/
ec_enc_uint(enc,sign,2);
ec_enc_uint(enc,best/B,max_pos);
ec_enc_bits(enc,sign,1);
if (max_pos == MAX_INTRA)
ec_enc_bits(enc,best/B,LOG_MAX_INTRA);
else
ec_enc_uint(enc,best/B,max_pos);
/*printf ("%d %f\n", best, best_score);*/
if (K>10)
@ -353,16 +365,19 @@ void intra_unquant(celt_norm_t *x, int N, int K, celt_norm_t *Y, celt_norm_t *P,
celt_word32_t E;
celt_word16_t pred_gain;
int max_pos = N0-N/B;
if (max_pos > 32)
max_pos = 32;
if (max_pos > MAX_INTRA)
max_pos = MAX_INTRA;
sign = ec_dec_uint(dec, 2);
sign = ec_dec_bits(dec, 1);
if (sign == 0)
s = 1;
else
s = -1;
best = B*ec_dec_uint(dec, max_pos);
if (max_pos == MAX_INTRA)
best = B*ec_dec_bits(dec, LOG_MAX_INTRA);
else
best = B*ec_dec_uint(dec, max_pos);
/*printf ("%d %d ", sign, best);*/
if (K>10)