shithub: libvpx

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Iadst transforms to use internal low precision

Change-Id: I266777d40c300bc53b45b205144520b85b0d6e58
(cherry picked from commit a1b726117f5470f227bc90cd030b7d25045dc510)

--- a/vp9/common/vp9_idct.c

+++ b/vp9/common/vp9_idct.c

@@ -276,10 +276,10 @@

 static void iadst4(const tran_low_t *input, tran_low_t *output) {

   tran_high_t s0, s1, s2, s3, s4, s5, s6, s7;

-  tran_high_t x0 = input[0];

-  tran_high_t x1 = input[1];

-  tran_high_t x2 = input[2];

-  tran_high_t x3 = input[3];

+  tran_low_t x0 = input[0];

+  tran_low_t x1 = input[1];

+  tran_low_t x2 = input[2];

+  tran_low_t x3 = input[3];

   if (!(x0 | x1 | x2 | x3)) {

     output[0] = output[1] = output[2] = output[3] = 0;

@@ -295,24 +295,19 @@

   s6 = sinpi_4_9 * x3;

   s7 = x0 - x2 + x3;

-  x0 = s0 + s3 + s5;

-  x1 = s1 - s4 - s6;

-  x2 = sinpi_3_9 * s7;

-  x3 = s2;

+  s0 = s0 + s3 + s5;

+  s1 = s1 - s4 - s6;

+  s3 = s2;

+  s2 = sinpi_3_9 * s7;

-  s0 = x0 + x3;

-  s1 = x1 + x3;

-  s2 = x2;

-  s3 = x0 + x1 - x3;

-

   // 1-D transform scaling factor is sqrt(2).

   // The overall dynamic range is 14b (input) + 14b (multiplication scaling)

   // + 1b (addition) = 29b.

   // Hence the output bit depth is 15b.

-  output[0] = WRAPLOW(dct_const_round_shift(s0), 8);

-  output[1] = WRAPLOW(dct_const_round_shift(s1), 8);

+  output[0] = WRAPLOW(dct_const_round_shift(s0 + s3), 8);

+  output[1] = WRAPLOW(dct_const_round_shift(s1 + s3), 8);

   output[2] = WRAPLOW(dct_const_round_shift(s2), 8);

-  output[3] = WRAPLOW(dct_const_round_shift(s3), 8);

+  output[3] = WRAPLOW(dct_const_round_shift(s0 + s1 - s3), 8);

 }

 void vp9_iht4x4_16_add_c(const tran_low_t *input, uint8_t *dest, int stride,

@@ -1702,10 +1697,10 @@

 static void highbd_iadst4(const tran_low_t *input, tran_low_t *output, int bd) {

   tran_high_t s0, s1, s2, s3, s4, s5, s6, s7;

-  tran_high_t x0 = input[0];

-  tran_high_t x1 = input[1];

-  tran_high_t x2 = input[2];

-  tran_high_t x3 = input[3];

+  tran_low_t x0 = input[0];

+  tran_low_t x1 = input[1];

+  tran_low_t x2 = input[2];

+  tran_low_t x3 = input[3];

   (void) bd;

   if (!(x0 | x1 | x2 | x3)) {

@@ -1720,26 +1715,21 @@

   s4 = sinpi_1_9 * x2;

   s5 = sinpi_2_9 * x3;

   s6 = sinpi_4_9 * x3;

-  s7 = x0 - x2 + x3;

+  s7 = (tran_high_t)(x0 - x2 + x3);

-  x0 = s0 + s3 + s5;

-  x1 = s1 - s4 - s6;

-  x2 = sinpi_3_9 * s7;

-  x3 = s2;

+  s0 = s0 + s3 + s5;

+  s1 = s1 - s4 - s6;

+  s3 = s2;

+  s2 = sinpi_3_9 * s7;

-  s0 = x0 + x3;

-  s1 = x1 + x3;

-  s2 = x2;

-  s3 = x0 + x1 - x3;

-

   // 1-D transform scaling factor is sqrt(2).

   // The overall dynamic range is 14b (input) + 14b (multiplication scaling)

   // + 1b (addition) = 29b.

   // Hence the output bit depth is 15b.

-  output[0] = WRAPLOW(dct_const_round_shift(s0), bd);

-  output[1] = WRAPLOW(dct_const_round_shift(s1), bd);

+  output[0] = WRAPLOW(dct_const_round_shift(s0 + s3), bd);

+  output[1] = WRAPLOW(dct_const_round_shift(s1 + s3), bd);

   output[2] = WRAPLOW(dct_const_round_shift(s2), bd);

-  output[3] = WRAPLOW(dct_const_round_shift(s3), bd);

+  output[3] = WRAPLOW(dct_const_round_shift(s0 + s1 - s3), bd);

 }

 void vp9_highbd_iht4x4_16_add_c(const tran_low_t *input, uint8_t *dest8,

@@ -1779,14 +1769,14 @@

 static void highbd_iadst8(const tran_low_t *input, tran_low_t *output, int bd) {

   tran_high_t s0, s1, s2, s3, s4, s5, s6, s7;

-  tran_high_t x0 = input[7];

-  tran_high_t x1 = input[0];

-  tran_high_t x2 = input[5];

-  tran_high_t x3 = input[2];

-  tran_high_t x4 = input[3];

-  tran_high_t x5 = input[4];

-  tran_high_t x6 = input[1];

-  tran_high_t x7 = input[6];

+  tran_low_t x0 = input[7];

+  tran_low_t x1 = input[0];

+  tran_low_t x2 = input[5];

+  tran_low_t x3 = input[2];

+  tran_low_t x4 = input[3];

+  tran_low_t x5 = input[4];

+  tran_low_t x6 = input[1];

+  tran_low_t x7 = input[6];

   (void) bd;

   if (!(x0 | x1 | x2 | x3 | x4 | x5 | x6 | x7)) {

@@ -2113,22 +2103,22 @@

   tran_high_t s0, s1, s2, s3, s4, s5, s6, s7, s8;

   tran_high_t s9, s10, s11, s12, s13, s14, s15;

-  tran_high_t x0 = input[15];

-  tran_high_t x1 = input[0];

-  tran_high_t x2 = input[13];

-  tran_high_t x3 = input[2];

-  tran_high_t x4 = input[11];

-  tran_high_t x5 = input[4];

-  tran_high_t x6 = input[9];

-  tran_high_t x7 = input[6];

-  tran_high_t x8 = input[7];

-  tran_high_t x9 = input[8];

-  tran_high_t x10 = input[5];

-  tran_high_t x11 = input[10];

-  tran_high_t x12 = input[3];

-  tran_high_t x13 = input[12];

-  tran_high_t x14 = input[1];

-  tran_high_t x15 = input[14];

+  tran_low_t x0 = input[15];

+  tran_low_t x1 = input[0];

+  tran_low_t x2 = input[13];

+  tran_low_t x3 = input[2];

+  tran_low_t x4 = input[11];

+  tran_low_t x5 = input[4];

+  tran_low_t x6 = input[9];

+  tran_low_t x7 = input[6];

+  tran_low_t x8 = input[7];

+  tran_low_t x9 = input[8];

+  tran_low_t x10 = input[5];

+  tran_low_t x11 = input[10];

+  tran_low_t x12 = input[3];

+  tran_low_t x13 = input[12];

+  tran_low_t x14 = input[1];

+  tran_low_t x15 = input[14];

   (void) bd;

   if (!(x0 | x1 | x2 | x3 | x4 | x5 | x6 | x7 | x8