Changes 16 point idct

This commit changes the inverse 16 point dct to use the same algorithm
as the one for 32 point idct. In fact, now 16 point dct uses the exact
version of the souce code for even portion of the 32 point idct.

Tests showed current implementation has significant better accuracy
than the previous version. With this implementation and the minor bug
fix on forward 16 point dct, encoding tests showed about 0.2% better
compression of CIF set, test results on std-hd setting pending.

Change-Id: I68224b60c816ba03434e9f08bee147c7e344fb63

diff --git a/vp9/common/vp9_idctllm.c b/vp9/common/vp9_idctllm.c
index e45eb06ec50097e8dab86cf9268e0c91cd8a190c..770f3077a020a0a8029129dc3dc86a09c34568dd 100644 (file)
--- a/vp9/common/vp9_idctllm.c
+++ b/vp9/common/vp9_idctllm.c
@@ -33,6 +33,50 @@ static const int cospi8sqrt2minus1 = 20091;
 static const int sinpi8sqrt2      = 35468;
 static const int rounding = 0;
 
+// Constants and Macros used by 16 and 32 point idct functions
+#define DCT_CONST_BITS 14
+#define DCT_CONST_ROUNDING  (1 << (DCT_CONST_BITS - 1))
+// Constants are 16384 * cos(kPi/64) where k = 1 to 31.
+// Note: sin(kPi/64) = cos((32-k)Pi/64)
+static const int cospi_1_64  = 16364;
+static const int cospi_2_64  = 16305;
+static const int cospi_3_64  = 16207;
+static const int cospi_4_64  = 16069;
+static const int cospi_5_64  = 15893;
+static const int cospi_6_64  = 15679;
+static const int cospi_7_64  = 15426;
+static const int cospi_8_64  = 15137;
+static const int cospi_9_64  = 14811;
+static const int cospi_10_64 = 14449;
+static const int cospi_11_64 = 14053;
+static const int cospi_12_64 = 13623;
+static const int cospi_13_64 = 13160;
+static const int cospi_14_64 = 12665;
+static const int cospi_15_64 = 12140;
+static const int cospi_16_64 = 11585;
+static const int cospi_17_64 = 11003;
+static const int cospi_18_64 = 10394;
+static const int cospi_19_64 = 9760;
+static const int cospi_20_64 = 9102;
+static const int cospi_21_64 = 8423;
+static const int cospi_22_64 = 7723;
+static const int cospi_23_64 = 7005;
+static const int cospi_24_64 = 6270;
+static const int cospi_25_64 = 5520;
+static const int cospi_26_64 = 4756;
+static const int cospi_27_64 = 3981;
+static const int cospi_28_64 = 3196;
+static const int cospi_29_64 = 2404;
+static const int cospi_30_64 = 1606;
+static const int cospi_31_64 = 804;
+
+static int16_t dct_const_round_shift(int input) {
+  int rv = (input + DCT_CONST_ROUNDING) >> DCT_CONST_BITS;
+  assert((rv <= INT16_MAX) && (rv >= INT16_MIN));
+  return (int16_t)rv;
+}
+
+
 static const int16_t idct_i4[16] = {
   8192,  10703,  8192,   4433,
   8192,   4433, -8192, -10703,
@@ -1147,206 +1191,168 @@ void vp9_short_idct16x16_c(int16_t *input, int16_t *output, int pitch) {
 
 #else
 
-#define INITIAL_SHIFT 2
-#define INITIAL_ROUNDING (1 << (INITIAL_SHIFT - 1))
-#define RIGHT_SHIFT 14
-#define RIGHT_ROUNDING (1 << (RIGHT_SHIFT - 1))
-
-static const int16_t C1 = 16305;
-static const int16_t C2 = 16069;
-static const int16_t C3 = 15679;
-static const int16_t C4 = 15137;
-static const int16_t C5 = 14449;
-static const int16_t C6 = 13623;
-static const int16_t C7 = 12665;
-static const int16_t C8 = 11585;
-static const int16_t C9 = 10394;
-static const int16_t C10 = 9102;
-static const int16_t C11 = 7723;
-static const int16_t C12 = 6270;
-static const int16_t C13 = 4756;
-static const int16_t C14 = 3196;
-static const int16_t C15 = 1606;
-
-static void butterfly_16x16_idct_1d(int16_t input[16], int16_t output[16],
-                                    int last_shift_bits) {
-  int16_t step[16];
-  int intermediate[16];
+void idct16_1d(int16_t *input, int16_t *output) {
+  int16_t step1[16], step2[16];
   int temp1, temp2;
 
-  int step1_shift = RIGHT_SHIFT + INITIAL_SHIFT;
-  int step1_rounding = 1 << (step1_shift - 1);
-  int last_rounding = 0;
-
-  if (last_shift_bits > 0)
-    last_rounding = 1 << (last_shift_bits - 1);
-
-  // step 1 and 2
-  step[ 0] = (input[0] + input[8] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-  step[ 1] = (input[0] - input[8] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-
-  temp1 = input[4] * C12;
-  temp2 = input[12] * C4;
-  temp1 = (temp1 - temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-  temp1  *= C8;
-  step[ 2] = (2 * (temp1) + step1_rounding) >> step1_shift;
-
-  temp1 = input[4] * C4;
-  temp2 = input[12] * C12;
-  temp1 = (temp1 + temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-  temp1 *= C8;
-  step[ 3] = (2 * (temp1) + step1_rounding) >> step1_shift;
-
-  temp1 = input[2] * C8;
-  temp1 = (2 * (temp1) +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-  temp2 = input[6] + input[10];
-  step[ 4] = (temp1 + temp2 + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-  step[ 5] = (temp1 - temp2 + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-
-  temp1 = input[14] * C8;
-  temp1 = (2 * (temp1) +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-  temp2 = input[6] - input[10];
-  step[ 6] = (temp2 - temp1 + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-  step[ 7] = (temp2 + temp1 + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-
-  // for odd input
-  temp1 = input[3] * C12;
-  temp2 = input[13] * C4;
-  temp1 = (temp1 + temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-  temp1 *= C8;
-  intermediate[ 8] = (2 * (temp1) +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = input[3] * C4;
-  temp2 = input[13] * C12;
-  temp2 = (temp2 - temp1 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-  temp2 *= C8;
-  intermediate[ 9] = (2 * (temp2) +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  intermediate[10] = (2 * (input[9] * C8) + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-  intermediate[11] = input[15] - input[1];
-  intermediate[12] = input[15] + input[1];
-  intermediate[13] = (2 * (input[7] * C8) + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = input[11] * C12;
-  temp2 = input[5] * C4;
-  temp2 = (temp2 - temp1 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-  temp2 *= C8;
-  intermediate[14] = (2 * (temp2) +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = input[11] * C4;
-  temp2 = input[5] * C12;
-  temp1 = (temp1 + temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-  temp1 *= C8;
-  intermediate[15] = (2 * (temp1) +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  step[ 8] = (intermediate[ 8] + intermediate[14] + INITIAL_ROUNDING)
-      >> INITIAL_SHIFT;
-  step[ 9] = (intermediate[ 9] + intermediate[15] + INITIAL_ROUNDING)
-      >> INITIAL_SHIFT;
-  step[10] = (intermediate[10] + intermediate[11] + INITIAL_ROUNDING)
-      >> INITIAL_SHIFT;
-  step[11] = (intermediate[10] - intermediate[11] + INITIAL_ROUNDING)
-      >> INITIAL_SHIFT;
-  step[12] = (intermediate[12] + intermediate[13] + INITIAL_ROUNDING)
-      >> INITIAL_SHIFT;
-  step[13] = (intermediate[12] - intermediate[13] + INITIAL_ROUNDING)
-      >> INITIAL_SHIFT;
-  step[14] = (intermediate[ 8] - intermediate[14] + INITIAL_ROUNDING)
-      >> INITIAL_SHIFT;
-  step[15] = (intermediate[ 9] - intermediate[15] + INITIAL_ROUNDING)
-      >> INITIAL_SHIFT;
-
-  // step 3
-  output[0] = step[ 0] + step[ 3];
-  output[1] = step[ 1] + step[ 2];
-  output[2] = step[ 1] - step[ 2];
-  output[3] = step[ 0] - step[ 3];
-
-  temp1 = step[ 4] * C14;
-  temp2 = step[ 7] * C2;
-  output[4] =  (temp1 - temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = step[ 4] * C2;
-  temp2 = step[ 7] * C14;
-  output[7] =  (temp1 + temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = step[ 5] * C10;
-  temp2 = step[ 6] * C6;
-  output[5] =  (temp1 - temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = step[ 5] * C6;
-  temp2 = step[ 6] * C10;
-  output[6] =  (temp1 + temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  output[8] = step[ 8] + step[11];
-  output[9] = step[ 9] + step[10];
-  output[10] = step[ 9] - step[10];
-  output[11] = step[ 8] - step[11];
-  output[12] = step[12] + step[15];
-  output[13] = step[13] + step[14];
-  output[14] = step[13] - step[14];
-  output[15] = step[12] - step[15];
-
-  // output 4
-  step[ 0] = output[0] + output[7];
-  step[ 1] = output[1] + output[6];
-  step[ 2] = output[2] + output[5];
-  step[ 3] = output[3] + output[4];
-  step[ 4] = output[3] - output[4];
-  step[ 5] = output[2] - output[5];
-  step[ 6] = output[1] - output[6];
-  step[ 7] = output[0] - output[7];
-
-  temp1 = output[8] * C7;
-  temp2 = output[15] * C9;
-  step[ 8] = (temp1 - temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = output[9] * C11;
-  temp2 = output[14] * C5;
-  step[ 9] = (temp1 + temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = output[10] * C3;
-  temp2 = output[13] * C13;
-  step[10] = (temp1 - temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = output[11] * C15;
-  temp2 = output[12] * C1;
-  step[11] = (temp1 + temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = output[11] * C1;
-  temp2 = output[12] * C15;
-  step[12] = (temp2 - temp1 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = output[10] * C13;
-  temp2 = output[13] * C3;
-  step[13] = (temp1 + temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = output[9] * C5;
-  temp2 = output[14] * C11;
-  step[14] = (temp2 - temp1 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  temp1 = output[8] * C9;
-  temp2 = output[15] * C7;
-  step[15] = (temp1 + temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-  // step 5
-  output[0] = (step[0] + step[15] + last_rounding) >> last_shift_bits;
-  output[1] = (step[1] + step[14] + last_rounding) >> last_shift_bits;
-  output[2] = (step[2] + step[13] + last_rounding) >> last_shift_bits;
-  output[3] = (step[3] + step[12] + last_rounding) >> last_shift_bits;
-  output[4] = (step[4] + step[11] + last_rounding) >> last_shift_bits;
-  output[5] = (step[5] + step[10] + last_rounding) >> last_shift_bits;
-  output[6] = (step[6] + step[ 9] + last_rounding) >> last_shift_bits;
-  output[7] = (step[7] + step[ 8] + last_rounding) >> last_shift_bits;
-
-  output[15] = (step[0] - step[15] + last_rounding) >> last_shift_bits;
-  output[14] = (step[1] - step[14] + last_rounding) >> last_shift_bits;
-  output[13] = (step[2] - step[13] + last_rounding) >> last_shift_bits;
-  output[12] = (step[3] - step[12] + last_rounding) >> last_shift_bits;
-  output[11] = (step[4] - step[11] + last_rounding) >> last_shift_bits;
-  output[10] = (step[5] - step[10] + last_rounding) >> last_shift_bits;
-  output[9] = (step[6] - step[ 9] + last_rounding) >> last_shift_bits;
-  output[8] = (step[7] - step[ 8] + last_rounding) >> last_shift_bits;
+  // stage 1
+  step1[0] = input[0/2];
+  step1[1] = input[16/2];
+  step1[2] = input[8/2];
+  step1[3] = input[24/2];
+  step1[4] = input[4/2];
+  step1[5] = input[20/2];
+  step1[6] = input[12/2];
+  step1[7] = input[28/2];
+  step1[8] = input[2/2];
+  step1[9] = input[18/2];
+  step1[10] = input[10/2];
+  step1[11] = input[26/2];
+  step1[12] = input[6/2];
+  step1[13] = input[22/2];
+  step1[14] = input[14/2];
+  step1[15] = input[30/2];
+
+  // stage 2
+  step2[0] = step1[0];
+  step2[1] = step1[1];
+  step2[2] = step1[2];
+  step2[3] = step1[3];
+  step2[4] = step1[4];
+  step2[5] = step1[5];
+  step2[6] = step1[6];
+  step2[7] = step1[7];
+
+  temp1 = step1[8] * cospi_30_64 - step1[15] * cospi_2_64;
+  temp2 = step1[8] * cospi_2_64 + step1[15] * cospi_30_64;
+  step2[8] = dct_const_round_shift(temp1);
+  step2[15] = dct_const_round_shift(temp2);
+
+  temp1 = step1[9] * cospi_14_64 - step1[14] * cospi_18_64;
+  temp2 = step1[9] * cospi_18_64 + step1[14] * cospi_14_64;
+  step2[9] = dct_const_round_shift(temp1);
+  step2[14] = dct_const_round_shift(temp2);
+
+  temp1 = step1[10] * cospi_22_64 - step1[13] * cospi_10_64;
+  temp2 = step1[10] * cospi_10_64 + step1[13] * cospi_22_64;
+  step2[10] = dct_const_round_shift(temp1);
+  step2[13] = dct_const_round_shift(temp2);
+
+  temp1 = step1[11] * cospi_6_64 - step1[12] * cospi_26_64;
+  temp2 = step1[11] * cospi_26_64 + step1[12] * cospi_6_64;
+  step2[11] = dct_const_round_shift(temp1);
+  step2[12] = dct_const_round_shift(temp2);
+
+  // stage 3
+  step1[0] = step2[0];
+  step1[1] = step2[1];
+  step1[2] = step2[2];
+  step1[3] = step2[3];
+
+  temp1 = step2[4] * cospi_28_64 - step2[7] * cospi_4_64;
+  temp2 = step2[4] * cospi_4_64 + step2[7] * cospi_28_64;
+  step1[4] = dct_const_round_shift(temp1);
+  step1[7] = dct_const_round_shift(temp2);
+  temp1 = step2[5] * cospi_12_64 - step2[6] * cospi_20_64;
+  temp2 = step2[5] * cospi_20_64 + step2[6] * cospi_12_64;
+  step1[5] = dct_const_round_shift(temp1);
+  step1[6] = dct_const_round_shift(temp2);
+
+  step1[8] = step2[8] + step2[9];
+  step1[9] = step2[8] - step2[9];
+  step1[10] = -step2[10] + step2[11];
+  step1[11] = step2[10] + step2[11];
+  step1[12] = step2[12] + step2[13];
+  step1[13] = step2[12] - step2[13];
+  step1[14] = -step2[14] + step2[15];
+  step1[15] = step2[14] + step2[15];
+
+  temp1 = (step1[0] + step1[1]) * cospi_16_64;
+  temp2 = (step1[0] - step1[1]) * cospi_16_64;
+  step2[0] = dct_const_round_shift(temp1);
+  step2[1] = dct_const_round_shift(temp2);
+  temp1 = step1[2] * cospi_24_64 - step1[3] * cospi_8_64;
+  temp2 = step1[2] * cospi_8_64 + step1[3] * cospi_24_64;
+  step2[2] = dct_const_round_shift(temp1);
+  step2[3] = dct_const_round_shift(temp2);
+  step2[4] = step1[4] + step1[5];
+  step2[5] = step1[4] - step1[5];
+  step2[6] = -step1[6] + step1[7];
+  step2[7] = step1[6] + step1[7];
+
+  step2[8] = step1[8];
+  step2[15] = step1[15];
+  temp1 = -step1[9] * cospi_8_64 + step1[14] * cospi_24_64;
+  temp2 = step1[9] * cospi_24_64 + step1[14] * cospi_8_64;
+  step2[9] = dct_const_round_shift(temp1);
+  step2[14] = dct_const_round_shift(temp2);
+  temp1 = -step1[10] * cospi_24_64 - step1[13] * cospi_8_64;
+  temp2 = -step1[10] * cospi_8_64 + step1[13] * cospi_24_64;
+  step2[10] = dct_const_round_shift(temp1);
+  step2[13] = dct_const_round_shift(temp2);
+  step2[11] = step1[11];
+  step2[12] = step1[12];
+
+  // stage 5
+  step1[0] = step2[0] + step2[3];
+  step1[1] = step2[1] + step2[2];
+  step1[2] = step2[1] - step2[2];
+  step1[3] = step2[0] - step2[3];
+  step1[4] = step2[4];
+  temp1 = (step2[6] - step2[5]) * cospi_16_64;
+  temp2 = (step2[5] + step2[6]) * cospi_16_64;
+  step1[5] = dct_const_round_shift(temp1);
+  step1[6] = dct_const_round_shift(temp2);
+  step1[7] = step2[7];
+
+  step1[8] = step2[8] + step2[11];
+  step1[9] = step2[9] + step2[10];
+  step1[10] = step2[9] - step2[10];
+  step1[11] = step2[8] - step2[11];
+  step1[12] = -step2[12] + step2[15];
+  step1[13] = -step2[13] + step2[14];
+  step1[14] = step2[13] + step2[14];
+  step1[15] = step2[12] + step2[15];
+
+  // stage 6
+  step2[0] = step1[0] + step1[7];
+  step2[1] = step1[1] + step1[6];
+  step2[2] = step1[2] + step1[5];
+  step2[3] = step1[3] + step1[4];
+  step2[4] = step1[3] - step1[4];
+  step2[5] = step1[2] - step1[5];
+  step2[6] = step1[1] - step1[6];
+  step2[7] = step1[0] - step1[7];
+  step2[8] = step1[8];
+  step2[9] = step1[9];
+  temp1 = (-step1[10] + step1[13]) * cospi_16_64;
+  temp2 = (step1[10] + step1[13]) * cospi_16_64;
+  step2[10] = dct_const_round_shift(temp1);
+  step2[13] = dct_const_round_shift(temp2);
+  temp1 = (-step1[11] + step1[12]) * cospi_16_64;
+  temp2 = (step1[11] + step1[12]) * cospi_16_64;
+  step2[11] = dct_const_round_shift(temp1);
+  step2[12] = dct_const_round_shift(temp2);
+  step2[14] = step1[14];
+  step2[15] = step1[15];
+
+  // stage 7
+  output[0] = step2[0] + step2[15];
+  output[1] = step2[1] + step2[14];
+  output[2] = step2[2] + step2[13];
+  output[3] = step2[3] + step2[12];
+  output[4] = step2[4] + step2[11];
+  output[5] = step2[5] + step2[10];
+  output[6] = step2[6] + step2[9];
+  output[7] = step2[7] + step2[8];
+  output[8] = step2[7] - step2[8];
+  output[9] = step2[6] - step2[9];
+  output[10] = step2[5] - step2[10];
+  output[11] = step2[4] - step2[11];
+  output[12] = step2[3] - step2[12];
+  output[13] = step2[2] - step2[13];
+  output[14] = step2[1] - step2[14];
+  output[15] = step2[0] - step2[15];
 }
 
 void vp9_short_idct16x16_c(int16_t *input, int16_t *output, int pitch) {
@@ -1358,7 +1364,7 @@ void vp9_short_idct16x16_c(int16_t *input, int16_t *output, int pitch) {
 
   // First transform rows
   for (i = 0; i < 16; ++i) {
-    butterfly_16x16_idct_1d(input, outptr, 0);
+    idct16_1d(input, outptr);
     input += short_pitch;
     outptr += 16;
   }
@@ -1367,140 +1373,12 @@ void vp9_short_idct16x16_c(int16_t *input, int16_t *output, int pitch) {
   for (i = 0; i < 16; ++i) {
     for (j = 0; j < 16; ++j)
       temp_in[j] = out[j * 16 + i];
-    butterfly_16x16_idct_1d(temp_in, temp_out, 3);
+    idct16_1d(temp_in, temp_out);
     for (j = 0; j < 16; ++j)
-        output[j * 16 + i] = temp_out[j];
+        output[j * 16 + i] = (temp_out[j] + 32) >> 6;
     }
 }
 
-/* The following function is called when we know the maximum number of non-zero
- * dct coefficients is less or equal 10.
- */
-static void butterfly_16x16_idct10_1d(int16_t input[16], int16_t output[16],
-                                      int last_shift_bits) {
-    int16_t step[16] = {0};
-    int intermediate[16] = {0};
-    int temp1, temp2;
-    int last_rounding = 0;
-
-    if (last_shift_bits > 0)
-      last_rounding = 1 << (last_shift_bits - 1);
-
-    // step 1 and 2
-    step[ 0] = (input[0] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-    step[ 1] = (input[0] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-
-    temp1 = (2 * (input[2] * C8) + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-    step[ 4] = (temp1 + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-    step[ 5] = (temp1 + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-
-    // for odd input
-    temp1 = (input[3] * C12 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-    temp1 *= C8;
-    intermediate[ 8] = (2 * (temp1) + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    temp1 = (-input[3] * C4 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-    temp1 *= C8;
-    intermediate[ 9] = (2 * (temp1) + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    step[ 8] = (intermediate[ 8] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-    step[ 9] = (intermediate[ 9] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-    step[10] = (-input[1] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-    step[11] = (input[1] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-    step[12] = (input[1] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-    step[13] = (input[1] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-    step[14] = (intermediate[ 8] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-    step[15] = (intermediate[ 9] + INITIAL_ROUNDING) >> INITIAL_SHIFT;
-
-    // step 3
-    output[0] = step[ 0];
-    output[1] = step[ 1];
-    output[2] = step[ 1];
-    output[3] = step[ 0];
-
-    temp1 = step[ 4] * C14;
-    output[4] =  (temp1 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    temp1 = step[ 4] * C2;
-    output[7] =  (temp1 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    temp1 = step[ 5] * C10;
-    output[5] =  (temp1 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    temp1 = step[ 5] * C6;
-    output[6] =  (temp1 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    output[8] = step[ 8] + step[11];
-    output[9] = step[ 9] + step[10];
-    output[10] = step[ 9] - step[10];
-    output[11] = step[ 8] - step[11];
-    output[12] = step[12] + step[15];
-    output[13] = step[13] + step[14];
-    output[14] = step[13] - step[14];
-    output[15] = step[12] - step[15];
-
-    // output 4
-    step[ 0] = output[0] + output[7];
-    step[ 1] = output[1] + output[6];
-    step[ 2] = output[2] + output[5];
-    step[ 3] = output[3] + output[4];
-    step[ 4] = output[3] - output[4];
-    step[ 5] = output[2] - output[5];
-    step[ 6] = output[1] - output[6];
-    step[ 7] = output[0] - output[7];
-
-    temp1 = output[8] * C7;
-    temp2 = output[15] * C9;
-    step[ 8] = (temp1 - temp2 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    temp1 = output[9] * C11;
-    temp2 = output[14] * C5;
-    step[ 9] = (temp1 + temp2 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    temp1 = output[10] * C3;
-    temp2 = output[13] * C13;
-    step[10] = (temp1 - temp2 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    temp1 = output[11] * C15;
-    temp2 = output[12] * C1;
-    step[11] = (temp1 + temp2 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    temp1 = output[11] * C1;
-    temp2 = output[12] * C15;
-    step[12] = (temp2 - temp1 + RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    temp1 = output[10] * C13;
-    temp2 = output[13] * C3;
-    step[13] = (temp1 + temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    temp1 = output[9] * C5;
-    temp2 = output[14] * C11;
-    step[14] = (temp2 - temp1 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    temp1 = output[8] * C9;
-    temp2 = output[15] * C7;
-    step[15] = (temp1 + temp2 +   RIGHT_ROUNDING) >> RIGHT_SHIFT;
-
-    // step 5
-    output[0] = (step[0] + step[15] + last_rounding) >> last_shift_bits;
-    output[1] = (step[1] + step[14] + last_rounding) >> last_shift_bits;
-    output[2] = (step[2] + step[13] + last_rounding) >> last_shift_bits;
-    output[3] = (step[3] + step[12] + last_rounding) >> last_shift_bits;
-    output[4] = (step[4] + step[11] + last_rounding) >> last_shift_bits;
-    output[5] = (step[5] + step[10] + last_rounding) >> last_shift_bits;
-    output[6] = (step[6] + step[ 9] + last_rounding) >> last_shift_bits;
-    output[7] = (step[7] + step[ 8] + last_rounding) >> last_shift_bits;
-
-    output[15] = (step[0] - step[15] + last_rounding) >> last_shift_bits;
-    output[14] = (step[1] - step[14] + last_rounding) >> last_shift_bits;
-    output[13] = (step[2] - step[13] + last_rounding) >> last_shift_bits;
-    output[12] = (step[3] - step[12] + last_rounding) >> last_shift_bits;
-    output[11] = (step[4] - step[11] + last_rounding) >> last_shift_bits;
-    output[10] = (step[5] - step[10] + last_rounding) >> last_shift_bits;
-    output[9] = (step[6] - step[ 9] + last_rounding) >> last_shift_bits;
-    output[8] = (step[7] - step[ 8] + last_rounding) >> last_shift_bits;
-}
-
 void vp9_short_idct10_16x16_c(int16_t *input, int16_t *output, int pitch) {
     int16_t out[16 * 16];
     int16_t *outptr = &out[0];
@@ -1513,7 +1391,7 @@ void vp9_short_idct10_16x16_c(int16_t *input, int16_t *output, int pitch) {
      */
     vpx_memset(out, 0, sizeof(out));
     for (i = 0; i < 4; ++i) {
-      butterfly_16x16_idct10_1d(input, outptr, 0);
+      idct16_1d(input, outptr);
       input += short_pitch;
       outptr += 16;
     }
@@ -1522,60 +1400,25 @@ void vp9_short_idct10_16x16_c(int16_t *input, int16_t *output, int pitch) {
     for (i = 0; i < 16; ++i) {
       for (j = 0; j < 16; ++j)
         temp_in[j] = out[j*16 + i];
-      butterfly_16x16_idct10_1d(temp_in, temp_out, 3);
+      idct16_1d(temp_in, temp_out);
       for (j = 0; j < 16; ++j)
-        output[j*16 + i] = temp_out[j];
+        output[j*16 + i] = (temp_out[j] + 32) >> 6;
     }
 }
-#undef INITIAL_SHIFT
-#undef INITIAL_ROUNDING
-#undef RIGHT_SHIFT
-#undef RIGHT_ROUNDING
-#endif
 
-#if !CONFIG_DWTDCTHYBRID
-#define DCT_CONST_BITS 14
-#define DCT_CONST_ROUNDING  (1 << (DCT_CONST_BITS - 1))
-// Constants are 16384 * cos(kPi/64) where k = 1 to 31.
-// Note: sin(kPi/64) = cos((32-k)Pi/64)
-static const int cospi_1_64  = 16364;
-static const int cospi_2_64  = 16305;
-static const int cospi_3_64  = 16207;
-static const int cospi_4_64  = 16069;
-static const int cospi_5_64  = 15893;
-static const int cospi_6_64  = 15679;
-static const int cospi_7_64  = 15426;
-static const int cospi_8_64  = 15137;
-static const int cospi_9_64  = 14811;
-static const int cospi_10_64 = 14449;
-static const int cospi_11_64 = 14053;
-static const int cospi_12_64 = 13623;
-static const int cospi_13_64 = 13160;
-static const int cospi_14_64 = 12665;
-static const int cospi_15_64 = 12140;
-static const int cospi_16_64 = 11585;
-static const int cospi_17_64 = 11003;
-static const int cospi_18_64 = 10394;
-static const int cospi_19_64 = 9760;
-static const int cospi_20_64 = 9102;
-static const int cospi_21_64 = 8423;
-static const int cospi_22_64 = 7723;
-static const int cospi_23_64 = 7005;
-static const int cospi_24_64 = 6270;
-static const int cospi_25_64 = 5520;
-static const int cospi_26_64 = 4756;
-static const int cospi_27_64 = 3981;
-static const int cospi_28_64 = 3196;
-static const int cospi_29_64 = 2404;
-static const int cospi_30_64 = 1606;
-static const int cospi_31_64 = 804;
 
-static int16_t dct_const_round_shift(int input) {
-  int rv = (input + DCT_CONST_ROUNDING) >> DCT_CONST_BITS;
-  assert((rv <= INT16_MAX) && (rv >= INT16_MIN));
-  return (int16_t)rv;
+void vp9_short_idct1_16x16_c(int16_t *input, int16_t *output) {
+  int tmp;
+  int16_t out;
+  tmp = input[0] * cospi_16_64;
+  out = dct_const_round_shift(tmp);
+  tmp = out * cospi_16_64;
+  out = dct_const_round_shift(tmp);
+  *output = (out + 32) >> 6;
 }
+#endif
 
+#if !CONFIG_DWTDCTHYBRID
 void idct32_1d(int16_t *input, int16_t *output) {
   int16_t step1[32], step2[32];
   int temp1, temp2;

diff --git a/vp9/common/vp9_rtcd_defs.sh b/vp9/common/vp9_rtcd_defs.sh
index 39af2080ac6d1187581c316a58314b8773a317e1..6e6034a2dff1fb6dd14e37fbdbdd0c4b49d8bc90 100644 (file)
--- a/vp9/common/vp9_rtcd_defs.sh
+++ b/vp9/common/vp9_rtcd_defs.sh
@@ -398,6 +398,10 @@ specialize vp9_short_idct16x16
 prototype void vp9_short_idct10_16x16 "int16_t *input, int16_t *output, int pitch"
 specialize vp9_short_idct10_16x16
 
+prototype void vp9_short_idct1_16x16 "int16_t *input, int16_t *output"
+specialize vp9_short_idct1_16x16
+
+
 prototype void vp9_short_idct32x32 "int16_t *input, int16_t *output, int pitch"
 specialize vp9_short_idct32x32
 

diff --git a/vp9/decoder/vp9_dequantize.c b/vp9/decoder/vp9_dequantize.c
index 354d2bd3657a3aa084c6371f19c9d18f1986e010..dc26ab882238dc0e9073a69600ddb3605f38c61b 100644 (file)
--- a/vp9/decoder/vp9_dequantize.c
+++ b/vp9/decoder/vp9_dequantize.c
@@ -300,14 +300,11 @@ void vp9_dequant_idct_add_16x16_c(int16_t *input, const int16_t *dq,
     vp9_copy_mem16x16(pred, pitch, dest, stride);
   } else if (eob == 1) {
     /* DC only DCT coefficient. */
+    int16_t in = input[0] * dq[0];
     int16_t out;
-
     /* Note: the idct1 will need to be modified accordingly whenever
      * vp9_short_idct16x16_c() is modified. */
-    out = (input[0] * dq[0] + 2) >> 2;
-    out = (out + 2) >> 2;
-    out = (out + 4) >> 3;
-
+    vp9_short_idct1_16x16_c(&in, &out);
     input[0] = 0;
 
     add_constant_residual(out, pred, pitch, dest, stride, 16, 16);