The Tor Browser: media/libvpx/vp9/encoder/vp9_dct.c@b8a032363ba2 (annotated)

media/libvpx/vp9/encoder/vp9_dct.c@b8a032363ba2 (annotated)

media/libvpx/vp9/encoder/vp9_dct.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include <assert.h>
 #include <math.h>
 #include "./vpx_config.h"
 #include "./vp9_rtcd.h"
 #include "vp9/common/vp9_blockd.h"
 #include "vp9/common/vp9_idct.h"
 #include "vp9/common/vp9_systemdependent.h"
 #include "vp9/encoder/vp9_dct.h"
 static INLINE int fdct_round_shift(int input) {
   int rv = ROUND_POWER_OF_TWO(input, DCT_CONST_BITS);
   assert(INT16_MIN <= rv && rv <= INT16_MAX);
   return rv;
 }
 static void fdct4(const int16_t *input, int16_t *output) {
   int16_t step[4];
   int temp1, temp2;
   step[0] = input[0] + input[3];
   step[1] = input[1] + input[2];
   step[2] = input[1] - input[2];
   step[3] = input[0] - input[3];
   temp1 = (step[0] + step[1]) * cospi_16_64;
   temp2 = (step[0] - step[1]) * cospi_16_64;
   output[0] = fdct_round_shift(temp1);
   output[2] = fdct_round_shift(temp2);
   temp1 = step[2] * cospi_24_64 + step[3] * cospi_8_64;
   temp2 = -step[2] * cospi_8_64 + step[3] * cospi_24_64;
   output[1] = fdct_round_shift(temp1);
   output[3] = fdct_round_shift(temp2);
 }
 void vp9_fdct4x4_c(const int16_t *input, int16_t *output, int stride) {
   // The 2D transform is done with two passes which are actually pretty
   // similar. In the first one, we transform the columns and transpose
   // the results. In the second one, we transform the rows. To achieve that,
   // as the first pass results are transposed, we tranpose the columns (that
   // is the transposed rows) and transpose the results (so that it goes back
   // in normal/row positions).
   int pass;
   // We need an intermediate buffer between passes.
   int16_t intermediate[4 * 4];
   const int16_t *in = input;
   int16_t *out = intermediate;
   // Do the two transform/transpose passes
   for (pass = 0; pass < 2; ++pass) {
     /*canbe16*/ int input[4];
     /*canbe16*/ int step[4];
     /*needs32*/ int temp1, temp2;
     int i;
     for (i = 0; i < 4; ++i) {
       // Load inputs.
       if (0 == pass) {
         input[0] = in[0 * stride] * 16;
         input[1] = in[1 * stride] * 16;
         input[2] = in[2 * stride] * 16;
         input[3] = in[3 * stride] * 16;
         if (i == 0 && input[0]) {
           input[0] += 1;
         }
       } else {
         input[0] = in[0 * 4];
         input[1] = in[1 * 4];
         input[2] = in[2 * 4];
         input[3] = in[3 * 4];
       }
       // Transform.
       step[0] = input[0] + input[3];
       step[1] = input[1] + input[2];
       step[2] = input[1] - input[2];
       step[3] = input[0] - input[3];
       temp1 = (step[0] + step[1]) * cospi_16_64;
       temp2 = (step[0] - step[1]) * cospi_16_64;
       out[0] = fdct_round_shift(temp1);
       out[2] = fdct_round_shift(temp2);
       temp1 = step[2] * cospi_24_64 + step[3] * cospi_8_64;
       temp2 = -step[2] * cospi_8_64 + step[3] * cospi_24_64;
       out[1] = fdct_round_shift(temp1);
       out[3] = fdct_round_shift(temp2);
       // Do next column (which is a transposed row in second/horizontal pass)
       in++;
       out += 4;
     }
     // Setup in/out for next pass.
     in = intermediate;
     out = output;
   }
   {
     int i, j;
     for (i = 0; i < 4; ++i) {
       for (j = 0; j < 4; ++j)
         output[j + i * 4] = (output[j + i * 4] + 1) >> 2;
     }
   }
 }
 static void fadst4(const int16_t *input, int16_t *output) {
   int x0, x1, x2, x3;
   int s0, s1, s2, s3, s4, s5, s6, s7;
   x0 = input[0];
   x1 = input[1];
   x2 = input[2];
   x3 = input[3];
   if (!(x0 | x1 | x2 | x3)) {
     output[0] = output[1] = output[2] = output[3] = 0;
     return;
   }
   s0 = sinpi_1_9 * x0;
   s1 = sinpi_4_9 * x0;
   s2 = sinpi_2_9 * x1;
   s3 = sinpi_1_9 * x1;
   s4 = sinpi_3_9 * x2;
   s5 = sinpi_4_9 * x3;
   s6 = sinpi_2_9 * x3;
   s7 = x0 + x1 - x3;
   x0 = s0 + s2 + s5;
   x1 = sinpi_3_9 * s7;
   x2 = s1 - s3 + s6;
   x3 = s4;
   s0 = x0 + x3;
   s1 = x1;
   s2 = x2 - x3;
   s3 = x2 - x0 + x3;
   // 1-D transform scaling factor is sqrt(2).
   output[0] = fdct_round_shift(s0);
   output[1] = fdct_round_shift(s1);
   output[2] = fdct_round_shift(s2);
   output[3] = fdct_round_shift(s3);
 }
 static const transform_2d FHT_4[] = {
   { fdct4,  fdct4  },  // DCT_DCT  = 0
   { fadst4, fdct4  },  // ADST_DCT = 1
   { fdct4,  fadst4 },  // DCT_ADST = 2
   { fadst4, fadst4 }   // ADST_ADST = 3
 };
 void vp9_short_fht4x4_c(const int16_t *input, int16_t *output,
                         int stride, int tx_type) {
   int16_t out[4 * 4];
   int16_t *outptr = &out[0];
   int i, j;
   int16_t temp_in[4], temp_out[4];
   const transform_2d ht = FHT_4[tx_type];
   // Columns
   for (i = 0; i < 4; ++i) {
     for (j = 0; j < 4; ++j)
       temp_in[j] = input[j * stride + i] * 16;
     if (i == 0 && temp_in[0])
       temp_in[0] += 1;
     ht.cols(temp_in, temp_out);
     for (j = 0; j < 4; ++j)
       outptr[j * 4 + i] = temp_out[j];
   }
   // Rows
   for (i = 0; i < 4; ++i) {
     for (j = 0; j < 4; ++j)
       temp_in[j] = out[j + i * 4];
     ht.rows(temp_in, temp_out);
     for (j = 0; j < 4; ++j)
       output[j + i * 4] = (temp_out[j] + 1) >> 2;
   }
 }
 static void fdct8(const int16_t *input, int16_t *output) {
   /*canbe16*/ int s0, s1, s2, s3, s4, s5, s6, s7;
   /*needs32*/ int t0, t1, t2, t3;
   /*canbe16*/ int x0, x1, x2, x3;
   // stage 1
   s0 = input[0] + input[7];
   s1 = input[1] + input[6];
   s2 = input[2] + input[5];
   s3 = input[3] + input[4];
   s4 = input[3] - input[4];
   s5 = input[2] - input[5];
   s6 = input[1] - input[6];
   s7 = input[0] - input[7];
   // fdct4(step, step);
   x0 = s0 + s3;
   x1 = s1 + s2;
   x2 = s1 - s2;
   x3 = s0 - s3;
   t0 = (x0 + x1) * cospi_16_64;
   t1 = (x0 - x1) * cospi_16_64;
   t2 =  x2 * cospi_24_64 + x3 *  cospi_8_64;
   t3 = -x2 * cospi_8_64  + x3 * cospi_24_64;
   output[0] = fdct_round_shift(t0);
   output[2] = fdct_round_shift(t2);
   output[4] = fdct_round_shift(t1);
   output[6] = fdct_round_shift(t3);
   // Stage 2
   t0 = (s6 - s5) * cospi_16_64;
   t1 = (s6 + s5) * cospi_16_64;
   t2 = fdct_round_shift(t0);
   t3 = fdct_round_shift(t1);
   // Stage 3
   x0 = s4 + t2;
   x1 = s4 - t2;
   x2 = s7 - t3;
   x3 = s7 + t3;
   // Stage 4
   t0 = x0 * cospi_28_64 + x3 *   cospi_4_64;
   t1 = x1 * cospi_12_64 + x2 *  cospi_20_64;
   t2 = x2 * cospi_12_64 + x1 * -cospi_20_64;
   t3 = x3 * cospi_28_64 + x0 *  -cospi_4_64;
   output[1] = fdct_round_shift(t0);
   output[3] = fdct_round_shift(t2);
   output[5] = fdct_round_shift(t1);
   output[7] = fdct_round_shift(t3);
 }
 void vp9_fdct8x8_c(const int16_t *input, int16_t *final_output, int stride) {
   int i, j;
   int16_t intermediate[64];
   // Transform columns
   {
     int16_t *output = intermediate;
     /*canbe16*/ int s0, s1, s2, s3, s4, s5, s6, s7;
     /*needs32*/ int t0, t1, t2, t3;
     /*canbe16*/ int x0, x1, x2, x3;
     int i;
     for (i = 0; i < 8; i++) {
       // stage 1
       s0 = (input[0 * stride] + input[7 * stride]) * 4;
       s1 = (input[1 * stride] + input[6 * stride]) * 4;
       s2 = (input[2 * stride] + input[5 * stride]) * 4;
       s3 = (input[3 * stride] + input[4 * stride]) * 4;
       s4 = (input[3 * stride] - input[4 * stride]) * 4;
       s5 = (input[2 * stride] - input[5 * stride]) * 4;
       s6 = (input[1 * stride] - input[6 * stride]) * 4;
       s7 = (input[0 * stride] - input[7 * stride]) * 4;
       // fdct4(step, step);
       x0 = s0 + s3;
       x1 = s1 + s2;
       x2 = s1 - s2;
       x3 = s0 - s3;
       t0 = (x0 + x1) * cospi_16_64;
       t1 = (x0 - x1) * cospi_16_64;
       t2 =  x2 * cospi_24_64 + x3 *  cospi_8_64;
       t3 = -x2 * cospi_8_64  + x3 * cospi_24_64;
       output[0 * 8] = fdct_round_shift(t0);
       output[2 * 8] = fdct_round_shift(t2);
       output[4 * 8] = fdct_round_shift(t1);
       output[6 * 8] = fdct_round_shift(t3);
       // Stage 2
       t0 = (s6 - s5) * cospi_16_64;
       t1 = (s6 + s5) * cospi_16_64;
       t2 = fdct_round_shift(t0);
       t3 = fdct_round_shift(t1);
       // Stage 3
       x0 = s4 + t2;
       x1 = s4 - t2;
       x2 = s7 - t3;
       x3 = s7 + t3;
       // Stage 4
       t0 = x0 * cospi_28_64 + x3 *   cospi_4_64;
       t1 = x1 * cospi_12_64 + x2 *  cospi_20_64;
       t2 = x2 * cospi_12_64 + x1 * -cospi_20_64;
       t3 = x3 * cospi_28_64 + x0 *  -cospi_4_64;
       output[1 * 8] = fdct_round_shift(t0);
       output[3 * 8] = fdct_round_shift(t2);
       output[5 * 8] = fdct_round_shift(t1);
       output[7 * 8] = fdct_round_shift(t3);
       input++;
       output++;
     }
   }
   // Rows
   for (i = 0; i < 8; ++i) {
     fdct8(&intermediate[i * 8], &final_output[i * 8]);
     for (j = 0; j < 8; ++j)
       final_output[j + i * 8] /= 2;
   }
 }
 void vp9_fdct16x16_c(const int16_t *input, int16_t *output, int stride) {
   // The 2D transform is done with two passes which are actually pretty
   // similar. In the first one, we transform the columns and transpose
   // the results. In the second one, we transform the rows. To achieve that,
   // as the first pass results are transposed, we tranpose the columns (that
   // is the transposed rows) and transpose the results (so that it goes back
   // in normal/row positions).
   int pass;
   // We need an intermediate buffer between passes.
   int16_t intermediate[256];
   const int16_t *in = input;
   int16_t *out = intermediate;
   // Do the two transform/transpose passes
   for (pass = 0; pass < 2; ++pass) {
     /*canbe16*/ int step1[8];
     /*canbe16*/ int step2[8];
     /*canbe16*/ int step3[8];
     /*canbe16*/ int input[8];
     /*needs32*/ int temp1, temp2;
     int i;
     for (i = 0; i < 16; i++) {
       if (0 == pass) {
         // Calculate input for the first 8 results.
         input[0] = (in[0 * stride] + in[15 * stride]) * 4;
         input[1] = (in[1 * stride] + in[14 * stride]) * 4;
         input[2] = (in[2 * stride] + in[13 * stride]) * 4;
         input[3] = (in[3 * stride] + in[12 * stride]) * 4;
         input[4] = (in[4 * stride] + in[11 * stride]) * 4;
         input[5] = (in[5 * stride] + in[10 * stride]) * 4;
         input[6] = (in[6 * stride] + in[ 9 * stride]) * 4;
         input[7] = (in[7 * stride] + in[ 8 * stride]) * 4;
         // Calculate input for the next 8 results.
         step1[0] = (in[7 * stride] - in[ 8 * stride]) * 4;
         step1[1] = (in[6 * stride] - in[ 9 * stride]) * 4;
         step1[2] = (in[5 * stride] - in[10 * stride]) * 4;
         step1[3] = (in[4 * stride] - in[11 * stride]) * 4;
         step1[4] = (in[3 * stride] - in[12 * stride]) * 4;
         step1[5] = (in[2 * stride] - in[13 * stride]) * 4;
         step1[6] = (in[1 * stride] - in[14 * stride]) * 4;
         step1[7] = (in[0 * stride] - in[15 * stride]) * 4;
       } else {
         // Calculate input for the first 8 results.
         input[0] = ((in[0 * 16] + 1) >> 2) + ((in[15 * 16] + 1) >> 2);
         input[1] = ((in[1 * 16] + 1) >> 2) + ((in[14 * 16] + 1) >> 2);
         input[2] = ((in[2 * 16] + 1) >> 2) + ((in[13 * 16] + 1) >> 2);
         input[3] = ((in[3 * 16] + 1) >> 2) + ((in[12 * 16] + 1) >> 2);
         input[4] = ((in[4 * 16] + 1) >> 2) + ((in[11 * 16] + 1) >> 2);
         input[5] = ((in[5 * 16] + 1) >> 2) + ((in[10 * 16] + 1) >> 2);
         input[6] = ((in[6 * 16] + 1) >> 2) + ((in[ 9 * 16] + 1) >> 2);
         input[7] = ((in[7 * 16] + 1) >> 2) + ((in[ 8 * 16] + 1) >> 2);
         // Calculate input for the next 8 results.
         step1[0] = ((in[7 * 16] + 1) >> 2) - ((in[ 8 * 16] + 1) >> 2);
         step1[1] = ((in[6 * 16] + 1) >> 2) - ((in[ 9 * 16] + 1) >> 2);
         step1[2] = ((in[5 * 16] + 1) >> 2) - ((in[10 * 16] + 1) >> 2);
         step1[3] = ((in[4 * 16] + 1) >> 2) - ((in[11 * 16] + 1) >> 2);
         step1[4] = ((in[3 * 16] + 1) >> 2) - ((in[12 * 16] + 1) >> 2);
         step1[5] = ((in[2 * 16] + 1) >> 2) - ((in[13 * 16] + 1) >> 2);
         step1[6] = ((in[1 * 16] + 1) >> 2) - ((in[14 * 16] + 1) >> 2);
         step1[7] = ((in[0 * 16] + 1) >> 2) - ((in[15 * 16] + 1) >> 2);
       }
       // Work on the first eight values; fdct8(input, even_results);
       {
         /*canbe16*/ int s0, s1, s2, s3, s4, s5, s6, s7;
         /*needs32*/ int t0, t1, t2, t3;
         /*canbe16*/ int x0, x1, x2, x3;
         // stage 1
         s0 = input[0] + input[7];
         s1 = input[1] + input[6];
         s2 = input[2] + input[5];
         s3 = input[3] + input[4];
         s4 = input[3] - input[4];
         s5 = input[2] - input[5];
         s6 = input[1] - input[6];
         s7 = input[0] - input[7];
         // fdct4(step, step);
         x0 = s0 + s3;
         x1 = s1 + s2;
         x2 = s1 - s2;
         x3 = s0 - s3;
         t0 = (x0 + x1) * cospi_16_64;
         t1 = (x0 - x1) * cospi_16_64;
         t2 = x3 * cospi_8_64  + x2 * cospi_24_64;
         t3 = x3 * cospi_24_64 - x2 * cospi_8_64;
         out[0] = fdct_round_shift(t0);
         out[4] = fdct_round_shift(t2);
         out[8] = fdct_round_shift(t1);
         out[12] = fdct_round_shift(t3);
         // Stage 2
         t0 = (s6 - s5) * cospi_16_64;
         t1 = (s6 + s5) * cospi_16_64;
         t2 = fdct_round_shift(t0);
         t3 = fdct_round_shift(t1);
         // Stage 3
         x0 = s4 + t2;
         x1 = s4 - t2;
         x2 = s7 - t3;
         x3 = s7 + t3;
         // Stage 4
         t0 = x0 * cospi_28_64 + x3 *   cospi_4_64;
         t1 = x1 * cospi_12_64 + x2 *  cospi_20_64;
         t2 = x2 * cospi_12_64 + x1 * -cospi_20_64;
         t3 = x3 * cospi_28_64 + x0 *  -cospi_4_64;
         out[2] = fdct_round_shift(t0);
         out[6] = fdct_round_shift(t2);
         out[10] = fdct_round_shift(t1);
         out[14] = fdct_round_shift(t3);
       }
       // Work on the next eight values; step1 -> odd_results
       {
         // step 2
         temp1 = (step1[5] - step1[2]) * cospi_16_64;
         temp2 = (step1[4] - step1[3]) * cospi_16_64;
         step2[2] = fdct_round_shift(temp1);
         step2[3] = fdct_round_shift(temp2);
         temp1 = (step1[4] + step1[3]) * cospi_16_64;
         temp2 = (step1[5] + step1[2]) * cospi_16_64;
         step2[4] = fdct_round_shift(temp1);
         step2[5] = fdct_round_shift(temp2);
         // step 3
         step3[0] = step1[0] + step2[3];
         step3[1] = step1[1] + step2[2];
         step3[2] = step1[1] - step2[2];
         step3[3] = step1[0] - step2[3];
         step3[4] = step1[7] - step2[4];
         step3[5] = step1[6] - step2[5];
         step3[6] = step1[6] + step2[5];
         step3[7] = step1[7] + step2[4];
         // step 4
         temp1 = step3[1] *  -cospi_8_64 + step3[6] * cospi_24_64;
         temp2 = step3[2] * -cospi_24_64 - step3[5] *  cospi_8_64;
         step2[1] = fdct_round_shift(temp1);
         step2[2] = fdct_round_shift(temp2);
         temp1 = step3[2] * -cospi_8_64 + step3[5] * cospi_24_64;
         temp2 = step3[1] * cospi_24_64 + step3[6] *  cospi_8_64;
         step2[5] = fdct_round_shift(temp1);
         step2[6] = fdct_round_shift(temp2);
         // step 5
         step1[0] = step3[0] + step2[1];
         step1[1] = step3[0] - step2[1];
         step1[2] = step3[3] - step2[2];
         step1[3] = step3[3] + step2[2];
         step1[4] = step3[4] + step2[5];
         step1[5] = step3[4] - step2[5];
         step1[6] = step3[7] - step2[6];
         step1[7] = step3[7] + step2[6];
         // step 6
         temp1 = step1[0] * cospi_30_64 + step1[7] *  cospi_2_64;
         temp2 = step1[1] * cospi_14_64 + step1[6] * cospi_18_64;
         out[1] = fdct_round_shift(temp1);
         out[9] = fdct_round_shift(temp2);
         temp1 = step1[2] * cospi_22_64 + step1[5] * cospi_10_64;
         temp2 = step1[3] *  cospi_6_64 + step1[4] * cospi_26_64;
         out[5] = fdct_round_shift(temp1);
         out[13] = fdct_round_shift(temp2);
         temp1 = step1[3] * -cospi_26_64 + step1[4] *  cospi_6_64;
         temp2 = step1[2] * -cospi_10_64 + step1[5] * cospi_22_64;
         out[3] = fdct_round_shift(temp1);
         out[11] = fdct_round_shift(temp2);
         temp1 = step1[1] * -cospi_18_64 + step1[6] * cospi_14_64;
         temp2 = step1[0] *  -cospi_2_64 + step1[7] * cospi_30_64;
         out[7] = fdct_round_shift(temp1);
         out[15] = fdct_round_shift(temp2);
       }
       // Do next column (which is a transposed row in second/horizontal pass)
       in++;
       out += 16;
     }
     // Setup in/out for next pass.
     in = intermediate;
     out = output;
   }
 }
 static void fadst8(const int16_t *input, int16_t *output) {
   int s0, s1, s2, s3, s4, s5, s6, s7;
   int x0 = input[7];
   int x1 = input[0];
   int x2 = input[5];
   int x3 = input[2];
   int x4 = input[3];
   int x5 = input[4];
   int x6 = input[1];
   int x7 = input[6];
   // stage 1
   s0 = cospi_2_64  * x0 + cospi_30_64 * x1;
   s1 = cospi_30_64 * x0 - cospi_2_64  * x1;
   s2 = cospi_10_64 * x2 + cospi_22_64 * x3;
   s3 = cospi_22_64 * x2 - cospi_10_64 * x3;
   s4 = cospi_18_64 * x4 + cospi_14_64 * x5;
   s5 = cospi_14_64 * x4 - cospi_18_64 * x5;
   s6 = cospi_26_64 * x6 + cospi_6_64  * x7;
   s7 = cospi_6_64  * x6 - cospi_26_64 * x7;
   x0 = fdct_round_shift(s0 + s4);
   x1 = fdct_round_shift(s1 + s5);
   x2 = fdct_round_shift(s2 + s6);
   x3 = fdct_round_shift(s3 + s7);
   x4 = fdct_round_shift(s0 - s4);
   x5 = fdct_round_shift(s1 - s5);
   x6 = fdct_round_shift(s2 - s6);
   x7 = fdct_round_shift(s3 - s7);
   // stage 2
   s0 = x0;
   s1 = x1;
   s2 = x2;
   s3 = x3;
   s4 = cospi_8_64  * x4 + cospi_24_64 * x5;
   s5 = cospi_24_64 * x4 - cospi_8_64  * x5;
   s6 = - cospi_24_64 * x6 + cospi_8_64  * x7;
   s7 =   cospi_8_64  * x6 + cospi_24_64 * x7;
   x0 = s0 + s2;
   x1 = s1 + s3;
   x2 = s0 - s2;
   x3 = s1 - s3;
   x4 = fdct_round_shift(s4 + s6);
   x5 = fdct_round_shift(s5 + s7);
   x6 = fdct_round_shift(s4 - s6);
   x7 = fdct_round_shift(s5 - s7);
   // stage 3
   s2 = cospi_16_64 * (x2 + x3);
   s3 = cospi_16_64 * (x2 - x3);
   s6 = cospi_16_64 * (x6 + x7);
   s7 = cospi_16_64 * (x6 - x7);
   x2 = fdct_round_shift(s2);
   x3 = fdct_round_shift(s3);
   x6 = fdct_round_shift(s6);
   x7 = fdct_round_shift(s7);
   output[0] =   x0;
   output[1] = - x4;
   output[2] =   x6;
   output[3] = - x2;
   output[4] =   x3;
   output[5] = - x7;
   output[6] =   x5;
   output[7] = - x1;
 }
 static const transform_2d FHT_8[] = {
   { fdct8,  fdct8  },  // DCT_DCT  = 0
   { fadst8, fdct8  },  // ADST_DCT = 1
   { fdct8,  fadst8 },  // DCT_ADST = 2
   { fadst8, fadst8 }   // ADST_ADST = 3
 };
 void vp9_short_fht8x8_c(const int16_t *input, int16_t *output,
                         int stride, int tx_type) {
   int16_t out[64];
   int16_t *outptr = &out[0];
   int i, j;
   int16_t temp_in[8], temp_out[8];
   const transform_2d ht = FHT_8[tx_type];
   // Columns
   for (i = 0; i < 8; ++i) {
     for (j = 0; j < 8; ++j)
       temp_in[j] = input[j * stride + i] * 4;
     ht.cols(temp_in, temp_out);
     for (j = 0; j < 8; ++j)
       outptr[j * 8 + i] = temp_out[j];
   }
   // Rows
   for (i = 0; i < 8; ++i) {
     for (j = 0; j < 8; ++j)
       temp_in[j] = out[j + i * 8];
     ht.rows(temp_in, temp_out);
     for (j = 0; j < 8; ++j)
       output[j + i * 8] = (temp_out[j] + (temp_out[j] < 0)) >> 1;
   }
 }
 /* 4-point reversible, orthonormal Walsh-Hadamard in 3.5 adds, 0.5 shifts per
    pixel. */
 void vp9_fwht4x4_c(const int16_t *input, int16_t *output, int stride) {
   int i;
   int a1, b1, c1, d1, e1;
   const int16_t *ip = input;
   int16_t *op = output;
   for (i = 0; i < 4; i++) {
     a1 = ip[0 * stride];
     b1 = ip[1 * stride];
     c1 = ip[2 * stride];
     d1 = ip[3 * stride];
     a1 += b1;
     d1 = d1 - c1;
     e1 = (a1 - d1) >> 1;
     b1 = e1 - b1;
     c1 = e1 - c1;
     a1 -= c1;
     d1 += b1;
     op[0] = a1;
     op[4] = c1;
     op[8] = d1;
     op[12] = b1;
     ip++;
     op++;
   }
   ip = output;
   op = output;
   for (i = 0; i < 4; i++) {
     a1 = ip[0];
     b1 = ip[1];
     c1 = ip[2];
     d1 = ip[3];
     a1 += b1;
     d1 -= c1;
     e1 = (a1 - d1) >> 1;
     b1 = e1 - b1;
     c1 = e1 - c1;
     a1 -= c1;
     d1 += b1;
     op[0] = a1 * UNIT_QUANT_FACTOR;
     op[1] = c1 * UNIT_QUANT_FACTOR;
     op[2] = d1 * UNIT_QUANT_FACTOR;
     op[3] = b1 * UNIT_QUANT_FACTOR;
     ip += 4;
     op += 4;
   }
 }
 // Rewrote to use same algorithm as others.
 static void fdct16(const int16_t in[16], int16_t out[16]) {
   /*canbe16*/ int step1[8];
   /*canbe16*/ int step2[8];
   /*canbe16*/ int step3[8];
   /*canbe16*/ int input[8];
   /*needs32*/ int temp1, temp2;
   // step 1
   input[0] = in[0] + in[15];
   input[1] = in[1] + in[14];
   input[2] = in[2] + in[13];
   input[3] = in[3] + in[12];
   input[4] = in[4] + in[11];
   input[5] = in[5] + in[10];
   input[6] = in[6] + in[ 9];
   input[7] = in[7] + in[ 8];
   step1[0] = in[7] - in[ 8];
   step1[1] = in[6] - in[ 9];
   step1[2] = in[5] - in[10];
   step1[3] = in[4] - in[11];
   step1[4] = in[3] - in[12];
   step1[5] = in[2] - in[13];
   step1[6] = in[1] - in[14];
   step1[7] = in[0] - in[15];
   // fdct8(step, step);
   {
     /*canbe16*/ int s0, s1, s2, s3, s4, s5, s6, s7;
     /*needs32*/ int t0, t1, t2, t3;
     /*canbe16*/ int x0, x1, x2, x3;
     // stage 1
     s0 = input[0] + input[7];
     s1 = input[1] + input[6];
     s2 = input[2] + input[5];
     s3 = input[3] + input[4];
     s4 = input[3] - input[4];
     s5 = input[2] - input[5];
     s6 = input[1] - input[6];
     s7 = input[0] - input[7];
     // fdct4(step, step);
     x0 = s0 + s3;
     x1 = s1 + s2;
     x2 = s1 - s2;
     x3 = s0 - s3;
     t0 = (x0 + x1) * cospi_16_64;
     t1 = (x0 - x1) * cospi_16_64;
     t2 = x3 * cospi_8_64  + x2 * cospi_24_64;
     t3 = x3 * cospi_24_64 - x2 * cospi_8_64;
     out[0] = fdct_round_shift(t0);
     out[4] = fdct_round_shift(t2);
     out[8] = fdct_round_shift(t1);
     out[12] = fdct_round_shift(t3);
     // Stage 2
     t0 = (s6 - s5) * cospi_16_64;
     t1 = (s6 + s5) * cospi_16_64;
     t2 = fdct_round_shift(t0);
     t3 = fdct_round_shift(t1);
     // Stage 3
     x0 = s4 + t2;
     x1 = s4 - t2;
     x2 = s7 - t3;
     x3 = s7 + t3;
     // Stage 4
     t0 = x0 * cospi_28_64 + x3 *   cospi_4_64;
     t1 = x1 * cospi_12_64 + x2 *  cospi_20_64;
     t2 = x2 * cospi_12_64 + x1 * -cospi_20_64;
     t3 = x3 * cospi_28_64 + x0 *  -cospi_4_64;
     out[2] = fdct_round_shift(t0);
     out[6] = fdct_round_shift(t2);
     out[10] = fdct_round_shift(t1);
     out[14] = fdct_round_shift(t3);
   }
   // step 2
   temp1 = (step1[5] - step1[2]) * cospi_16_64;
   temp2 = (step1[4] - step1[3]) * cospi_16_64;
   step2[2] = fdct_round_shift(temp1);
   step2[3] = fdct_round_shift(temp2);
   temp1 = (step1[4] + step1[3]) * cospi_16_64;
   temp2 = (step1[5] + step1[2]) * cospi_16_64;
   step2[4] = fdct_round_shift(temp1);
   step2[5] = fdct_round_shift(temp2);
   // step 3
   step3[0] = step1[0] + step2[3];
   step3[1] = step1[1] + step2[2];
   step3[2] = step1[1] - step2[2];
   step3[3] = step1[0] - step2[3];
   step3[4] = step1[7] - step2[4];
   step3[5] = step1[6] - step2[5];
   step3[6] = step1[6] + step2[5];
   step3[7] = step1[7] + step2[4];
   // step 4
   temp1 = step3[1] *  -cospi_8_64 + step3[6] * cospi_24_64;
   temp2 = step3[2] * -cospi_24_64 - step3[5] *  cospi_8_64;
   step2[1] = fdct_round_shift(temp1);
   step2[2] = fdct_round_shift(temp2);
   temp1 = step3[2] * -cospi_8_64 + step3[5] * cospi_24_64;
   temp2 = step3[1] * cospi_24_64 + step3[6] *  cospi_8_64;
   step2[5] = fdct_round_shift(temp1);
   step2[6] = fdct_round_shift(temp2);
   // step 5
   step1[0] = step3[0] + step2[1];
   step1[1] = step3[0] - step2[1];
   step1[2] = step3[3] - step2[2];
   step1[3] = step3[3] + step2[2];
   step1[4] = step3[4] + step2[5];
   step1[5] = step3[4] - step2[5];
   step1[6] = step3[7] - step2[6];
   step1[7] = step3[7] + step2[6];
   // step 6
   temp1 = step1[0] * cospi_30_64 + step1[7] *  cospi_2_64;
   temp2 = step1[1] * cospi_14_64 + step1[6] * cospi_18_64;
   out[1] = fdct_round_shift(temp1);
   out[9] = fdct_round_shift(temp2);
   temp1 = step1[2] * cospi_22_64 + step1[5] * cospi_10_64;
   temp2 = step1[3] *  cospi_6_64 + step1[4] * cospi_26_64;
   out[5] = fdct_round_shift(temp1);
   out[13] = fdct_round_shift(temp2);
   temp1 = step1[3] * -cospi_26_64 + step1[4] *  cospi_6_64;
   temp2 = step1[2] * -cospi_10_64 + step1[5] * cospi_22_64;
   out[3] = fdct_round_shift(temp1);
   out[11] = fdct_round_shift(temp2);
   temp1 = step1[1] * -cospi_18_64 + step1[6] * cospi_14_64;
   temp2 = step1[0] *  -cospi_2_64 + step1[7] * cospi_30_64;
   out[7] = fdct_round_shift(temp1);
   out[15] = fdct_round_shift(temp2);
 }
 static void fadst16(const int16_t *input, int16_t *output) {
   int s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14, s15;
   int x0 = input[15];
   int x1 = input[0];
   int x2 = input[13];
   int x3 = input[2];
   int x4 = input[11];
   int x5 = input[4];
   int x6 = input[9];
   int x7 = input[6];
   int x8 = input[7];
   int x9 = input[8];
   int x10 = input[5];
   int x11 = input[10];
   int x12 = input[3];
   int x13 = input[12];
   int x14 = input[1];
   int x15 = input[14];
   // stage 1
   s0 = x0 * cospi_1_64  + x1 * cospi_31_64;
   s1 = x0 * cospi_31_64 - x1 * cospi_1_64;
   s2 = x2 * cospi_5_64  + x3 * cospi_27_64;
   s3 = x2 * cospi_27_64 - x3 * cospi_5_64;
   s4 = x4 * cospi_9_64  + x5 * cospi_23_64;
   s5 = x4 * cospi_23_64 - x5 * cospi_9_64;
   s6 = x6 * cospi_13_64 + x7 * cospi_19_64;
   s7 = x6 * cospi_19_64 - x7 * cospi_13_64;
   s8 = x8 * cospi_17_64 + x9 * cospi_15_64;
   s9 = x8 * cospi_15_64 - x9 * cospi_17_64;
   s10 = x10 * cospi_21_64 + x11 * cospi_11_64;
   s11 = x10 * cospi_11_64 - x11 * cospi_21_64;
   s12 = x12 * cospi_25_64 + x13 * cospi_7_64;
   s13 = x12 * cospi_7_64  - x13 * cospi_25_64;
   s14 = x14 * cospi_29_64 + x15 * cospi_3_64;
   s15 = x14 * cospi_3_64  - x15 * cospi_29_64;
   x0 = fdct_round_shift(s0 + s8);
   x1 = fdct_round_shift(s1 + s9);
   x2 = fdct_round_shift(s2 + s10);
   x3 = fdct_round_shift(s3 + s11);
   x4 = fdct_round_shift(s4 + s12);
   x5 = fdct_round_shift(s5 + s13);
   x6 = fdct_round_shift(s6 + s14);
   x7 = fdct_round_shift(s7 + s15);
   x8  = fdct_round_shift(s0 - s8);
   x9  = fdct_round_shift(s1 - s9);
   x10 = fdct_round_shift(s2 - s10);
   x11 = fdct_round_shift(s3 - s11);
   x12 = fdct_round_shift(s4 - s12);
   x13 = fdct_round_shift(s5 - s13);
   x14 = fdct_round_shift(s6 - s14);
   x15 = fdct_round_shift(s7 - s15);
   // stage 2
   s0 = x0;
   s1 = x1;
   s2 = x2;
   s3 = x3;
   s4 = x4;
   s5 = x5;
   s6 = x6;
   s7 = x7;
   s8 =    x8 * cospi_4_64   + x9 * cospi_28_64;
   s9 =    x8 * cospi_28_64  - x9 * cospi_4_64;
   s10 =   x10 * cospi_20_64 + x11 * cospi_12_64;
   s11 =   x10 * cospi_12_64 - x11 * cospi_20_64;
   s12 = - x12 * cospi_28_64 + x13 * cospi_4_64;
   s13 =   x12 * cospi_4_64  + x13 * cospi_28_64;
   s14 = - x14 * cospi_12_64 + x15 * cospi_20_64;
   s15 =   x14 * cospi_20_64 + x15 * cospi_12_64;
   x0 = s0 + s4;
   x1 = s1 + s5;
   x2 = s2 + s6;
   x3 = s3 + s7;
   x4 = s0 - s4;
   x5 = s1 - s5;
   x6 = s2 - s6;
   x7 = s3 - s7;
   x8 = fdct_round_shift(s8 + s12);
   x9 = fdct_round_shift(s9 + s13);
   x10 = fdct_round_shift(s10 + s14);
   x11 = fdct_round_shift(s11 + s15);
   x12 = fdct_round_shift(s8 - s12);
   x13 = fdct_round_shift(s9 - s13);
   x14 = fdct_round_shift(s10 - s14);
   x15 = fdct_round_shift(s11 - s15);
   // stage 3
   s0 = x0;
   s1 = x1;
   s2 = x2;
   s3 = x3;
   s4 = x4 * cospi_8_64  + x5 * cospi_24_64;
   s5 = x4 * cospi_24_64 - x5 * cospi_8_64;
   s6 = - x6 * cospi_24_64 + x7 * cospi_8_64;
   s7 =   x6 * cospi_8_64  + x7 * cospi_24_64;
   s8 = x8;
   s9 = x9;
   s10 = x10;
   s11 = x11;
   s12 = x12 * cospi_8_64  + x13 * cospi_24_64;
   s13 = x12 * cospi_24_64 - x13 * cospi_8_64;
   s14 = - x14 * cospi_24_64 + x15 * cospi_8_64;
   s15 =   x14 * cospi_8_64  + x15 * cospi_24_64;
   x0 = s0 + s2;
   x1 = s1 + s3;
   x2 = s0 - s2;
   x3 = s1 - s3;
   x4 = fdct_round_shift(s4 + s6);
   x5 = fdct_round_shift(s5 + s7);
   x6 = fdct_round_shift(s4 - s6);
   x7 = fdct_round_shift(s5 - s7);
   x8 = s8 + s10;
   x9 = s9 + s11;
   x10 = s8 - s10;
   x11 = s9 - s11;
   x12 = fdct_round_shift(s12 + s14);
   x13 = fdct_round_shift(s13 + s15);
   x14 = fdct_round_shift(s12 - s14);
   x15 = fdct_round_shift(s13 - s15);
   // stage 4
   s2 = (- cospi_16_64) * (x2 + x3);
   s3 = cospi_16_64 * (x2 - x3);
   s6 = cospi_16_64 * (x6 + x7);
   s7 = cospi_16_64 * (- x6 + x7);
   s10 = cospi_16_64 * (x10 + x11);
   s11 = cospi_16_64 * (- x10 + x11);
   s14 = (- cospi_16_64) * (x14 + x15);
   s15 = cospi_16_64 * (x14 - x15);
   x2 = fdct_round_shift(s2);
   x3 = fdct_round_shift(s3);
   x6 = fdct_round_shift(s6);
   x7 = fdct_round_shift(s7);
   x10 = fdct_round_shift(s10);
   x11 = fdct_round_shift(s11);
   x14 = fdct_round_shift(s14);
   x15 = fdct_round_shift(s15);
   output[0] = x0;
   output[1] = - x8;
   output[2] = x12;
   output[3] = - x4;
   output[4] = x6;
   output[5] = x14;
   output[6] = x10;
   output[7] = x2;
   output[8] = x3;
   output[9] =  x11;
   output[10] = x15;
   output[11] = x7;
   output[12] = x5;
   output[13] = - x13;
   output[14] = x9;
   output[15] = - x1;
 }
 static const transform_2d FHT_16[] = {
   { fdct16,  fdct16  },  // DCT_DCT  = 0
   { fadst16, fdct16  },  // ADST_DCT = 1
   { fdct16,  fadst16 },  // DCT_ADST = 2
   { fadst16, fadst16 }   // ADST_ADST = 3
 };
 void vp9_short_fht16x16_c(const int16_t *input, int16_t *output,
                           int stride, int tx_type) {
   int16_t out[256];
   int16_t *outptr = &out[0];
   int i, j;
   int16_t temp_in[16], temp_out[16];
   const transform_2d ht = FHT_16[tx_type];
   // Columns
   for (i = 0; i < 16; ++i) {
     for (j = 0; j < 16; ++j)
       temp_in[j] = input[j * stride + i] * 4;
     ht.cols(temp_in, temp_out);
     for (j = 0; j < 16; ++j)
       outptr[j * 16 + i] = (temp_out[j] + 1 + (temp_out[j] < 0)) >> 2;
 //      outptr[j * 16 + i] = (temp_out[j] + 1 + (temp_out[j] > 0)) >> 2;
   }
   // Rows
   for (i = 0; i < 16; ++i) {
     for (j = 0; j < 16; ++j)
       temp_in[j] = out[j + i * 16];
     ht.rows(temp_in, temp_out);
     for (j = 0; j < 16; ++j)
       output[j + i * 16] = temp_out[j];
   }
 }
 static INLINE int dct_32_round(int input) {
   int rv = ROUND_POWER_OF_TWO(input, DCT_CONST_BITS);
   assert(-131072 <= rv && rv <= 131071);
   return rv;
 }
 static INLINE int half_round_shift(int input) {
   int rv = (input + 1 + (input < 0)) >> 2;
   return rv;
 }
 static void dct32_1d(const int *input, int *output, int round) {
   int step[32];
   // Stage 1
   step[0] = input[0] + input[(32 - 1)];
   step[1] = input[1] + input[(32 - 2)];
   step[2] = input[2] + input[(32 - 3)];
   step[3] = input[3] + input[(32 - 4)];
   step[4] = input[4] + input[(32 - 5)];
   step[5] = input[5] + input[(32 - 6)];
   step[6] = input[6] + input[(32 - 7)];
   step[7] = input[7] + input[(32 - 8)];
   step[8] = input[8] + input[(32 - 9)];
   step[9] = input[9] + input[(32 - 10)];
   step[10] = input[10] + input[(32 - 11)];
   step[11] = input[11] + input[(32 - 12)];
   step[12] = input[12] + input[(32 - 13)];
   step[13] = input[13] + input[(32 - 14)];
   step[14] = input[14] + input[(32 - 15)];
   step[15] = input[15] + input[(32 - 16)];
   step[16] = -input[16] + input[(32 - 17)];
   step[17] = -input[17] + input[(32 - 18)];
   step[18] = -input[18] + input[(32 - 19)];
   step[19] = -input[19] + input[(32 - 20)];
   step[20] = -input[20] + input[(32 - 21)];
   step[21] = -input[21] + input[(32 - 22)];
   step[22] = -input[22] + input[(32 - 23)];
   step[23] = -input[23] + input[(32 - 24)];
   step[24] = -input[24] + input[(32 - 25)];
   step[25] = -input[25] + input[(32 - 26)];
   step[26] = -input[26] + input[(32 - 27)];
   step[27] = -input[27] + input[(32 - 28)];
   step[28] = -input[28] + input[(32 - 29)];
   step[29] = -input[29] + input[(32 - 30)];
   step[30] = -input[30] + input[(32 - 31)];
   step[31] = -input[31] + input[(32 - 32)];
   // Stage 2
   output[0] = step[0] + step[16 - 1];
   output[1] = step[1] + step[16 - 2];
   output[2] = step[2] + step[16 - 3];
   output[3] = step[3] + step[16 - 4];
   output[4] = step[4] + step[16 - 5];
   output[5] = step[5] + step[16 - 6];
   output[6] = step[6] + step[16 - 7];
   output[7] = step[7] + step[16 - 8];
   output[8] = -step[8] + step[16 - 9];
   output[9] = -step[9] + step[16 - 10];
   output[10] = -step[10] + step[16 - 11];
   output[11] = -step[11] + step[16 - 12];
   output[12] = -step[12] + step[16 - 13];
   output[13] = -step[13] + step[16 - 14];
   output[14] = -step[14] + step[16 - 15];
   output[15] = -step[15] + step[16 - 16];
   output[16] = step[16];
   output[17] = step[17];
   output[18] = step[18];
   output[19] = step[19];
   output[20] = dct_32_round((-step[20] + step[27]) * cospi_16_64);
   output[21] = dct_32_round((-step[21] + step[26]) * cospi_16_64);
   output[22] = dct_32_round((-step[22] + step[25]) * cospi_16_64);
   output[23] = dct_32_round((-step[23] + step[24]) * cospi_16_64);
   output[24] = dct_32_round((step[24] + step[23]) * cospi_16_64);
   output[25] = dct_32_round((step[25] + step[22]) * cospi_16_64);
   output[26] = dct_32_round((step[26] + step[21]) * cospi_16_64);
   output[27] = dct_32_round((step[27] + step[20]) * cospi_16_64);
   output[28] = step[28];
   output[29] = step[29];
   output[30] = step[30];
   output[31] = step[31];
   // dump the magnitude by 4, hence the intermediate values are within
   // the range of 16 bits.
   if (round) {
     output[0] = half_round_shift(output[0]);
     output[1] = half_round_shift(output[1]);
     output[2] = half_round_shift(output[2]);
     output[3] = half_round_shift(output[3]);
     output[4] = half_round_shift(output[4]);
     output[5] = half_round_shift(output[5]);
     output[6] = half_round_shift(output[6]);
     output[7] = half_round_shift(output[7]);
     output[8] = half_round_shift(output[8]);
     output[9] = half_round_shift(output[9]);
     output[10] = half_round_shift(output[10]);
     output[11] = half_round_shift(output[11]);
     output[12] = half_round_shift(output[12]);
     output[13] = half_round_shift(output[13]);
     output[14] = half_round_shift(output[14]);
     output[15] = half_round_shift(output[15]);
     output[16] = half_round_shift(output[16]);
     output[17] = half_round_shift(output[17]);
     output[18] = half_round_shift(output[18]);
     output[19] = half_round_shift(output[19]);
     output[20] = half_round_shift(output[20]);
     output[21] = half_round_shift(output[21]);
     output[22] = half_round_shift(output[22]);
     output[23] = half_round_shift(output[23]);
     output[24] = half_round_shift(output[24]);
     output[25] = half_round_shift(output[25]);
     output[26] = half_round_shift(output[26]);
     output[27] = half_round_shift(output[27]);
     output[28] = half_round_shift(output[28]);
     output[29] = half_round_shift(output[29]);
     output[30] = half_round_shift(output[30]);
     output[31] = half_round_shift(output[31]);
   }
   // Stage 3
   step[0] = output[0] + output[(8 - 1)];
   step[1] = output[1] + output[(8 - 2)];
   step[2] = output[2] + output[(8 - 3)];
   step[3] = output[3] + output[(8 - 4)];
   step[4] = -output[4] + output[(8 - 5)];
   step[5] = -output[5] + output[(8 - 6)];
   step[6] = -output[6] + output[(8 - 7)];
   step[7] = -output[7] + output[(8 - 8)];
   step[8] = output[8];
   step[9] = output[9];
   step[10] = dct_32_round((-output[10] + output[13]) * cospi_16_64);
   step[11] = dct_32_round((-output[11] + output[12]) * cospi_16_64);
   step[12] = dct_32_round((output[12] + output[11]) * cospi_16_64);
   step[13] = dct_32_round((output[13] + output[10]) * cospi_16_64);
   step[14] = output[14];
   step[15] = output[15];
   step[16] = output[16] + output[23];
   step[17] = output[17] + output[22];
   step[18] = output[18] + output[21];
   step[19] = output[19] + output[20];
   step[20] = -output[20] + output[19];
   step[21] = -output[21] + output[18];
   step[22] = -output[22] + output[17];
   step[23] = -output[23] + output[16];
   step[24] = -output[24] + output[31];
   step[25] = -output[25] + output[30];
   step[26] = -output[26] + output[29];
   step[27] = -output[27] + output[28];
   step[28] = output[28] + output[27];
   step[29] = output[29] + output[26];
   step[30] = output[30] + output[25];
   step[31] = output[31] + output[24];
   // Stage 4
   output[0] = step[0] + step[3];
   output[1] = step[1] + step[2];
   output[2] = -step[2] + step[1];
   output[3] = -step[3] + step[0];
   output[4] = step[4];
   output[5] = dct_32_round((-step[5] + step[6]) * cospi_16_64);
   output[6] = dct_32_round((step[6] + step[5]) * cospi_16_64);
   output[7] = step[7];
   output[8] = step[8] + step[11];
   output[9] = step[9] + step[10];
   output[10] = -step[10] + step[9];
   output[11] = -step[11] + step[8];
   output[12] = -step[12] + step[15];
   output[13] = -step[13] + step[14];
   output[14] = step[14] + step[13];
   output[15] = step[15] + step[12];
   output[16] = step[16];
   output[17] = step[17];
   output[18] = dct_32_round(step[18] * -cospi_8_64 + step[29] * cospi_24_64);
   output[19] = dct_32_round(step[19] * -cospi_8_64 + step[28] * cospi_24_64);
   output[20] = dct_32_round(step[20] * -cospi_24_64 + step[27] * -cospi_8_64);
   output[21] = dct_32_round(step[21] * -cospi_24_64 + step[26] * -cospi_8_64);
   output[22] = step[22];
   output[23] = step[23];
   output[24] = step[24];
   output[25] = step[25];
   output[26] = dct_32_round(step[26] * cospi_24_64 + step[21] * -cospi_8_64);
   output[27] = dct_32_round(step[27] * cospi_24_64 + step[20] * -cospi_8_64);
   output[28] = dct_32_round(step[28] * cospi_8_64 + step[19] * cospi_24_64);
   output[29] = dct_32_round(step[29] * cospi_8_64 + step[18] * cospi_24_64);
   output[30] = step[30];
   output[31] = step[31];
   // Stage 5
   step[0] = dct_32_round((output[0] + output[1]) * cospi_16_64);
   step[1] = dct_32_round((-output[1] + output[0]) * cospi_16_64);
   step[2] = dct_32_round(output[2] * cospi_24_64 + output[3] * cospi_8_64);
   step[3] = dct_32_round(output[3] * cospi_24_64 - output[2] * cospi_8_64);
   step[4] = output[4] + output[5];
   step[5] = -output[5] + output[4];
   step[6] = -output[6] + output[7];
   step[7] = output[7] + output[6];
   step[8] = output[8];
   step[9] = dct_32_round(output[9] * -cospi_8_64 + output[14] * cospi_24_64);
   step[10] = dct_32_round(output[10] * -cospi_24_64 + output[13] * -cospi_8_64);
   step[11] = output[11];
   step[12] = output[12];
   step[13] = dct_32_round(output[13] * cospi_24_64 + output[10] * -cospi_8_64);
   step[14] = dct_32_round(output[14] * cospi_8_64 + output[9] * cospi_24_64);
   step[15] = output[15];
   step[16] = output[16] + output[19];
   step[17] = output[17] + output[18];
   step[18] = -output[18] + output[17];
   step[19] = -output[19] + output[16];
   step[20] = -output[20] + output[23];
   step[21] = -output[21] + output[22];
   step[22] = output[22] + output[21];
   step[23] = output[23] + output[20];
   step[24] = output[24] + output[27];
   step[25] = output[25] + output[26];
   step[26] = -output[26] + output[25];
   step[27] = -output[27] + output[24];
   step[28] = -output[28] + output[31];
   step[29] = -output[29] + output[30];
   step[30] = output[30] + output[29];
   step[31] = output[31] + output[28];
   // Stage 6
   output[0] = step[0];
   output[1] = step[1];
   output[2] = step[2];
   output[3] = step[3];
   output[4] = dct_32_round(step[4] * cospi_28_64 + step[7] * cospi_4_64);
   output[5] = dct_32_round(step[5] * cospi_12_64 + step[6] * cospi_20_64);
   output[6] = dct_32_round(step[6] * cospi_12_64 + step[5] * -cospi_20_64);
   output[7] = dct_32_round(step[7] * cospi_28_64 + step[4] * -cospi_4_64);
   output[8] = step[8] + step[9];
   output[9] = -step[9] + step[8];
   output[10] = -step[10] + step[11];
   output[11] = step[11] + step[10];
   output[12] = step[12] + step[13];
   output[13] = -step[13] + step[12];
   output[14] = -step[14] + step[15];
   output[15] = step[15] + step[14];
   output[16] = step[16];
   output[17] = dct_32_round(step[17] * -cospi_4_64 + step[30] * cospi_28_64);
   output[18] = dct_32_round(step[18] * -cospi_28_64 + step[29] * -cospi_4_64);
   output[19] = step[19];
   output[20] = step[20];
   output[21] = dct_32_round(step[21] * -cospi_20_64 + step[26] * cospi_12_64);
   output[22] = dct_32_round(step[22] * -cospi_12_64 + step[25] * -cospi_20_64);
   output[23] = step[23];
   output[24] = step[24];
   output[25] = dct_32_round(step[25] * cospi_12_64 + step[22] * -cospi_20_64);
   output[26] = dct_32_round(step[26] * cospi_20_64 + step[21] * cospi_12_64);
   output[27] = step[27];
   output[28] = step[28];
   output[29] = dct_32_round(step[29] * cospi_28_64 + step[18] * -cospi_4_64);
   output[30] = dct_32_round(step[30] * cospi_4_64 + step[17] * cospi_28_64);
   output[31] = step[31];
   // Stage 7
   step[0] = output[0];
   step[1] = output[1];
   step[2] = output[2];
   step[3] = output[3];
   step[4] = output[4];
   step[5] = output[5];
   step[6] = output[6];
   step[7] = output[7];
   step[8] = dct_32_round(output[8] * cospi_30_64 + output[15] * cospi_2_64);
   step[9] = dct_32_round(output[9] * cospi_14_64 + output[14] * cospi_18_64);
   step[10] = dct_32_round(output[10] * cospi_22_64 + output[13] * cospi_10_64);
   step[11] = dct_32_round(output[11] * cospi_6_64 + output[12] * cospi_26_64);
   step[12] = dct_32_round(output[12] * cospi_6_64 + output[11] * -cospi_26_64);
   step[13] = dct_32_round(output[13] * cospi_22_64 + output[10] * -cospi_10_64);
   step[14] = dct_32_round(output[14] * cospi_14_64 + output[9] * -cospi_18_64);
   step[15] = dct_32_round(output[15] * cospi_30_64 + output[8] * -cospi_2_64);
   step[16] = output[16] + output[17];
   step[17] = -output[17] + output[16];
   step[18] = -output[18] + output[19];
   step[19] = output[19] + output[18];
   step[20] = output[20] + output[21];
   step[21] = -output[21] + output[20];
   step[22] = -output[22] + output[23];
   step[23] = output[23] + output[22];
   step[24] = output[24] + output[25];
   step[25] = -output[25] + output[24];
   step[26] = -output[26] + output[27];
   step[27] = output[27] + output[26];
   step[28] = output[28] + output[29];
   step[29] = -output[29] + output[28];
   step[30] = -output[30] + output[31];
   step[31] = output[31] + output[30];
   // Final stage --- outputs indices are bit-reversed.
   output[0]  = step[0];
   output[16] = step[1];
   output[8]  = step[2];
   output[24] = step[3];
   output[4]  = step[4];
   output[20] = step[5];
   output[12] = step[6];
   output[28] = step[7];
   output[2]  = step[8];
   output[18] = step[9];
   output[10] = step[10];
   output[26] = step[11];
   output[6]  = step[12];
   output[22] = step[13];
   output[14] = step[14];
   output[30] = step[15];
   output[1]  = dct_32_round(step[16] * cospi_31_64 + step[31] * cospi_1_64);
   output[17] = dct_32_round(step[17] * cospi_15_64 + step[30] * cospi_17_64);
   output[9]  = dct_32_round(step[18] * cospi_23_64 + step[29] * cospi_9_64);
   output[25] = dct_32_round(step[19] * cospi_7_64 + step[28] * cospi_25_64);
   output[5]  = dct_32_round(step[20] * cospi_27_64 + step[27] * cospi_5_64);
   output[21] = dct_32_round(step[21] * cospi_11_64 + step[26] * cospi_21_64);
   output[13] = dct_32_round(step[22] * cospi_19_64 + step[25] * cospi_13_64);
   output[29] = dct_32_round(step[23] * cospi_3_64 + step[24] * cospi_29_64);
   output[3]  = dct_32_round(step[24] * cospi_3_64 + step[23] * -cospi_29_64);
   output[19] = dct_32_round(step[25] * cospi_19_64 + step[22] * -cospi_13_64);
   output[11] = dct_32_round(step[26] * cospi_11_64 + step[21] * -cospi_21_64);
   output[27] = dct_32_round(step[27] * cospi_27_64 + step[20] * -cospi_5_64);
   output[7]  = dct_32_round(step[28] * cospi_7_64 + step[19] * -cospi_25_64);
   output[23] = dct_32_round(step[29] * cospi_23_64 + step[18] * -cospi_9_64);
   output[15] = dct_32_round(step[30] * cospi_15_64 + step[17] * -cospi_17_64);
   output[31] = dct_32_round(step[31] * cospi_31_64 + step[16] * -cospi_1_64);
 }
 void vp9_fdct32x32_c(const int16_t *input, int16_t *out, int stride) {
   int i, j;
   int output[32 * 32];
   // Columns
   for (i = 0; i < 32; ++i) {
     int temp_in[32], temp_out[32];
     for (j = 0; j < 32; ++j)
       temp_in[j] = input[j * stride + i] * 4;
     dct32_1d(temp_in, temp_out, 0);
     for (j = 0; j < 32; ++j)
       output[j * 32 + i] = (temp_out[j] + 1 + (temp_out[j] > 0)) >> 2;
   }
   // Rows
   for (i = 0; i < 32; ++i) {
     int temp_in[32], temp_out[32];
     for (j = 0; j < 32; ++j)
       temp_in[j] = output[j + i * 32];
     dct32_1d(temp_in, temp_out, 0);
     for (j = 0; j < 32; ++j)
       out[j + i * 32] = (temp_out[j] + 1 + (temp_out[j] < 0)) >> 2;
   }
 }
 // Note that although we use dct_32_round in dct32_1d computation flow,
 // this 2d fdct32x32 for rate-distortion optimization loop is operating
 // within 16 bits precision.
 void vp9_fdct32x32_rd_c(const int16_t *input, int16_t *out, int stride) {
   int i, j;
   int output[32 * 32];
   // Columns
   for (i = 0; i < 32; ++i) {
     int temp_in[32], temp_out[32];
     for (j = 0; j < 32; ++j)
       temp_in[j] = input[j * stride + i] * 4;
     dct32_1d(temp_in, temp_out, 0);
     for (j = 0; j < 32; ++j)
       // TODO(cd): see quality impact of only doing
       //           output[j * 32 + i] = (temp_out[j] + 1) >> 2;
       //           PS: also change code in vp9/encoder/x86/vp9_dct_sse2.c
       output[j * 32 + i] = (temp_out[j] + 1 + (temp_out[j] > 0)) >> 2;
   }
   // Rows
   for (i = 0; i < 32; ++i) {
     int temp_in[32], temp_out[32];
     for (j = 0; j < 32; ++j)
       temp_in[j] = output[j + i * 32];
     dct32_1d(temp_in, temp_out, 1);
     for (j = 0; j < 32; ++j)
       out[j + i * 32] = temp_out[j];
   }
 }
 void vp9_fht4x4(TX_TYPE tx_type, const int16_t *input, int16_t *output,
                 int stride) {
   if (tx_type == DCT_DCT)
     vp9_fdct4x4(input, output, stride);
   else
     vp9_short_fht4x4(input, output, stride, tx_type);
 }
 void vp9_fht8x8(TX_TYPE tx_type, const int16_t *input, int16_t *output,
                 int stride) {
   if (tx_type == DCT_DCT)
     vp9_fdct8x8(input, output, stride);
   else
     vp9_short_fht8x8(input, output, stride, tx_type);
 }
 void vp9_fht16x16(TX_TYPE tx_type, const int16_t *input, int16_t *output,
                   int stride) {
   if (tx_type == DCT_DCT)
     vp9_fdct16x16(input, output, stride);
   else
     vp9_short_fht16x16(input, output, stride, tx_type);
 }

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media/libvpx/vp9/encoder/vp9_dct.c@b8a032363ba2 (annotated)

media/libvpx/vp9/encoder/vp9_dct.c