shithub: libvpx

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optmized rounding for transforms

the changes are still temporary, the final transforms, especially
inverse ones should take in account both accuracy, complexity, and
sign-bias, which should be decided at a later time.

Change-Id: I116b0c70b25f5ee324ae5713d4564f5d0aa27151

--- a/vp8/common/idctllm.c

+++ b/vp8/common/idctllm.c

@@ -396,7 +396,8 @@

     {

         for (j = 0; j < TX_DIM; j++)

         {

-             X[i * TX_DIM + j] = (int)(coefs[i * TX_DIM + j]+2)>>2;

+             X[i * TX_DIM + j] = (int)(coefs[i * TX_DIM + j]+1

+                                    + (coefs[i * TX_DIM + j]<0))>>2;

         }

     }

   for (i = 0; i < 8; i++)

@@ -487,7 +488,7 @@

        op[i] = 0;

    }

-   op[0] = (ip[0] + ip[1] + ip[4] + ip[8])>>1;

+   op[0] = (ip[0] + ip[1] + ip[4] + ip[8] + 1)>>1;

    op[1] = (ip[0] - ip[1] + ip[4] - ip[8])>>1;

    op[4] = (ip[0] + ip[1] - ip[4] - ip[8])>>1;

    op[8] = (ip[0] - ip[1] - ip[4] + ip[8])>>1;

--- a/vp8/encoder/dct.c

+++ b/vp8/encoder/dct.c

@@ -120,7 +120,7 @@

        op1[i] = 0;

    }

-   op1[0]=(ip1[0] + ip1[1] + ip1[4] + ip1[8])>>1;

+   op1[0]=(ip1[0] + ip1[1] + ip1[4] + ip1[8] + 1)>>1;

    op1[1]=(ip1[0] - ip1[1] + ip1[4] - ip1[8])>>1;

    op1[4]=(ip1[0] + ip1[1] - ip1[4] - ip1[8])>>1;

    op1[8]=(ip1[0] - ip1[1] - ip1[4] + ip1[8])>>1;