ref: d54ff9dc3df4cd84b1b86c67b0d7da3b50d126d1
parent: 648e30bca6a58039a8d3ec6fa956e8124766c8a9
author: Dmitry Kovalev <dkovalev@google.com>
date: Tue Nov 5 12:41:56 EST 2013
Cleaning up vp9_quantize_b_c() function. Change-Id: I42c75530a8c9cff68480657f074131e6b60d9fca
--- a/vp9/encoder/vp9_quantize.c
+++ b/vp9/encoder/vp9_quantize.c
@@ -22,7 +22,7 @@
extern int enc_debug;
#endif
-void vp9_quantize_b_c(const int16_t *coeff_ptr, intptr_t n_coeffs,
+void vp9_quantize_b_c(const int16_t *coeff_ptr, intptr_t count,
int skip_block,
const int16_t *zbin_ptr, const int16_t *round_ptr,
const int16_t *quant_ptr, const int16_t *quant_shift_ptr,
@@ -30,58 +30,44 @@
const int16_t *dequant_ptr,
int zbin_oq_value, uint16_t *eob_ptr,
const int16_t *scan, const int16_t *iscan) {- int i, rc, eob;
- int zbins[2], nzbins[2], zbin;
- int x, y, z, sz;
- int zero_flag = n_coeffs;
+ int i, non_zero_count = count, eob = -1;
+ const int zbins[2] = { zbin_ptr[0] + zbin_oq_value,+ zbin_ptr[1] + zbin_oq_value };
+ const int nzbins[2] = { zbins[0] * -1,+ zbins[1] * -1 };
- vpx_memset(qcoeff_ptr, 0, n_coeffs*sizeof(int16_t));
- vpx_memset(dqcoeff_ptr, 0, n_coeffs*sizeof(int16_t));
+ vpx_memset(qcoeff_ptr, 0, count * sizeof(int16_t));
+ vpx_memset(dqcoeff_ptr, 0, count * sizeof(int16_t));
- eob = -1;
-
- // Base ZBIN
- zbins[0] = zbin_ptr[0] + zbin_oq_value;
- zbins[1] = zbin_ptr[1] + zbin_oq_value;
- nzbins[0] = zbins[0] * -1;
- nzbins[1] = zbins[1] * -1;
-
if (!skip_block) {// Pre-scan pass
- for (i = n_coeffs - 1; i >= 0; i--) {- rc = scan[i];
- z = coeff_ptr[rc];
+ for (i = count - 1; i >= 0; i--) {+ const int rc = scan[i];
+ const int coeff = coeff_ptr[rc];
- if (z < zbins[rc != 0] && z > nzbins[rc != 0]) {- zero_flag--;
- } else {+ if (coeff < zbins[rc != 0] && coeff > nzbins[rc != 0])
+ non_zero_count--;
+ else
break;
- }
}
// Quantization pass: All coefficients with index >= zero_flag are
// skippable. Note: zero_flag can be zero.
- for (i = 0; i < zero_flag; i++) {- rc = scan[i];
- z = coeff_ptr[rc];
+ for (i = 0; i < non_zero_count; i++) {+ const int rc = scan[i];
+ const int coeff = coeff_ptr[rc];
+ const int coeff_sign = (coeff >> 31);
+ const int abs_coeff = (coeff ^ coeff_sign) - coeff_sign;
- zbin = (zbins[rc != 0]);
+ if (abs_coeff >= zbins[rc != 0]) {+ int tmp = clamp(abs_coeff + round_ptr[rc != 0], INT16_MIN, INT16_MAX);
+ tmp = ((((tmp * quant_ptr[rc != 0]) >> 16) + tmp) *
+ quant_shift_ptr[rc != 0]) >> 16; // quantization
+ qcoeff_ptr[rc] = (tmp ^ coeff_sign) - coeff_sign;
+ dqcoeff_ptr[rc] = qcoeff_ptr[rc] * dequant_ptr[rc != 0];
- sz = (z >> 31); // sign of z
- x = (z ^ sz) - sz;
-
- if (x >= zbin) {- x += (round_ptr[rc != 0]);
- x = clamp(x, INT16_MIN, INT16_MAX);
- y = (((int)(((int)(x * quant_ptr[rc != 0]) >> 16) + x)) *
- quant_shift_ptr[rc != 0]) >> 16; // quantize (x)
- x = (y ^ sz) - sz; // get the sign back
- qcoeff_ptr[rc] = x; // write to destination
- dqcoeff_ptr[rc] = x * dequant_ptr[rc != 0]; // dequantized value
-
- if (y) {- eob = i; // last nonzero coeffs
- }
+ if (tmp)
+ eob = i;
}
}
}