Home | History | Annotate | Download | only in common
      1 /*
      2  * Copyright (c) 2016, Alliance for Open Media. All rights reserved
      3  *
      4  * This source code is subject to the terms of the BSD 2 Clause License and
      5  * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
      6  * was not distributed with this source code in the LICENSE file, you can
      7  * obtain it at www.aomedia.org/license/software. If the Alliance for Open
      8  * Media Patent License 1.0 was not distributed with this source code in the
      9  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
     10  */
     11 
     12 #include <assert.h>
     13 #include <limits.h>
     14 #include <math.h>
     15 #include <stdio.h>
     16 #include <stdlib.h>
     17 #include <string.h>
     18 
     19 #include "config/aom_config.h"
     20 
     21 #include "aom_dsp/aom_dsp_common.h"
     22 #include "aom_ports/mem.h"
     23 #include "aom_scale/aom_scale.h"
     24 #include "av1/common/common.h"
     25 #include "av1/common/resize.h"
     26 
     27 #include "config/aom_scale_rtcd.h"
     28 
     29 // Filters for interpolation (0.5-band) - note this also filters integer pels.
     30 static const InterpKernel filteredinterp_filters500[(1 << RS_SUBPEL_BITS)] = {
     31   { -3, 0, 35, 64, 35, 0, -3, 0 },    { -3, 0, 34, 64, 36, 0, -3, 0 },
     32   { -3, -1, 34, 64, 36, 1, -3, 0 },   { -3, -1, 33, 64, 37, 1, -3, 0 },
     33   { -3, -1, 32, 64, 38, 1, -3, 0 },   { -3, -1, 31, 64, 39, 1, -3, 0 },
     34   { -3, -1, 31, 63, 39, 2, -3, 0 },   { -2, -2, 30, 63, 40, 2, -3, 0 },
     35   { -2, -2, 29, 63, 41, 2, -3, 0 },   { -2, -2, 29, 63, 41, 3, -4, 0 },
     36   { -2, -2, 28, 63, 42, 3, -4, 0 },   { -2, -2, 27, 63, 43, 3, -4, 0 },
     37   { -2, -3, 27, 63, 43, 4, -4, 0 },   { -2, -3, 26, 62, 44, 5, -4, 0 },
     38   { -2, -3, 25, 62, 45, 5, -4, 0 },   { -2, -3, 25, 62, 45, 5, -4, 0 },
     39   { -2, -3, 24, 62, 46, 5, -4, 0 },   { -2, -3, 23, 61, 47, 6, -4, 0 },
     40   { -2, -3, 23, 61, 47, 6, -4, 0 },   { -2, -3, 22, 61, 48, 7, -4, -1 },
     41   { -2, -3, 21, 60, 49, 7, -4, 0 },   { -1, -4, 20, 60, 49, 8, -4, 0 },
     42   { -1, -4, 20, 60, 50, 8, -4, -1 },  { -1, -4, 19, 59, 51, 9, -4, -1 },
     43   { -1, -4, 19, 59, 51, 9, -4, -1 },  { -1, -4, 18, 58, 52, 10, -4, -1 },
     44   { -1, -4, 17, 58, 52, 11, -4, -1 }, { -1, -4, 16, 58, 53, 11, -4, -1 },
     45   { -1, -4, 16, 57, 53, 12, -4, -1 }, { -1, -4, 15, 57, 54, 12, -4, -1 },
     46   { -1, -4, 15, 56, 54, 13, -4, -1 }, { -1, -4, 14, 56, 55, 13, -4, -1 },
     47   { -1, -4, 14, 55, 55, 14, -4, -1 }, { -1, -4, 13, 55, 56, 14, -4, -1 },
     48   { -1, -4, 13, 54, 56, 15, -4, -1 }, { -1, -4, 12, 54, 57, 15, -4, -1 },
     49   { -1, -4, 12, 53, 57, 16, -4, -1 }, { -1, -4, 11, 53, 58, 16, -4, -1 },
     50   { -1, -4, 11, 52, 58, 17, -4, -1 }, { -1, -4, 10, 52, 58, 18, -4, -1 },
     51   { -1, -4, 9, 51, 59, 19, -4, -1 },  { -1, -4, 9, 51, 59, 19, -4, -1 },
     52   { -1, -4, 8, 50, 60, 20, -4, -1 },  { 0, -4, 8, 49, 60, 20, -4, -1 },
     53   { 0, -4, 7, 49, 60, 21, -3, -2 },   { -1, -4, 7, 48, 61, 22, -3, -2 },
     54   { 0, -4, 6, 47, 61, 23, -3, -2 },   { 0, -4, 6, 47, 61, 23, -3, -2 },
     55   { 0, -4, 5, 46, 62, 24, -3, -2 },   { 0, -4, 5, 45, 62, 25, -3, -2 },
     56   { 0, -4, 5, 45, 62, 25, -3, -2 },   { 0, -4, 5, 44, 62, 26, -3, -2 },
     57   { 0, -4, 4, 43, 63, 27, -3, -2 },   { 0, -4, 3, 43, 63, 27, -2, -2 },
     58   { 0, -4, 3, 42, 63, 28, -2, -2 },   { 0, -4, 3, 41, 63, 29, -2, -2 },
     59   { 0, -3, 2, 41, 63, 29, -2, -2 },   { 0, -3, 2, 40, 63, 30, -2, -2 },
     60   { 0, -3, 2, 39, 63, 31, -1, -3 },   { 0, -3, 1, 39, 64, 31, -1, -3 },
     61   { 0, -3, 1, 38, 64, 32, -1, -3 },   { 0, -3, 1, 37, 64, 33, -1, -3 },
     62   { 0, -3, 1, 36, 64, 34, -1, -3 },   { 0, -3, 0, 36, 64, 34, 0, -3 },
     63 };
     64 
     65 // Filters for interpolation (0.625-band) - note this also filters integer pels.
     66 static const InterpKernel filteredinterp_filters625[(1 << RS_SUBPEL_BITS)] = {
     67   { -1, -8, 33, 80, 33, -8, -1, 0 }, { -1, -8, 31, 80, 34, -8, -1, 1 },
     68   { -1, -8, 30, 80, 35, -8, -1, 1 }, { -1, -8, 29, 80, 36, -7, -2, 1 },
     69   { -1, -8, 28, 80, 37, -7, -2, 1 }, { -1, -8, 27, 80, 38, -7, -2, 1 },
     70   { 0, -8, 26, 79, 39, -7, -2, 1 },  { 0, -8, 25, 79, 40, -7, -2, 1 },
     71   { 0, -8, 24, 79, 41, -7, -2, 1 },  { 0, -8, 23, 78, 42, -6, -2, 1 },
     72   { 0, -8, 22, 78, 43, -6, -2, 1 },  { 0, -8, 21, 78, 44, -6, -2, 1 },
     73   { 0, -8, 20, 78, 45, -5, -3, 1 },  { 0, -8, 19, 77, 47, -5, -3, 1 },
     74   { 0, -8, 18, 77, 48, -5, -3, 1 },  { 0, -8, 17, 77, 49, -5, -3, 1 },
     75   { 0, -8, 16, 76, 50, -4, -3, 1 },  { 0, -8, 15, 76, 51, -4, -3, 1 },
     76   { 0, -8, 15, 75, 52, -3, -4, 1 },  { 0, -7, 14, 74, 53, -3, -4, 1 },
     77   { 0, -7, 13, 74, 54, -3, -4, 1 },  { 0, -7, 12, 73, 55, -2, -4, 1 },
     78   { 0, -7, 11, 73, 56, -2, -4, 1 },  { 0, -7, 10, 72, 57, -1, -4, 1 },
     79   { 1, -7, 10, 71, 58, -1, -5, 1 },  { 0, -7, 9, 71, 59, 0, -5, 1 },
     80   { 1, -7, 8, 70, 60, 0, -5, 1 },    { 1, -7, 7, 69, 61, 1, -5, 1 },
     81   { 1, -6, 6, 68, 62, 1, -5, 1 },    { 0, -6, 6, 68, 62, 2, -5, 1 },
     82   { 1, -6, 5, 67, 63, 2, -5, 1 },    { 1, -6, 5, 66, 64, 3, -6, 1 },
     83   { 1, -6, 4, 65, 65, 4, -6, 1 },    { 1, -6, 3, 64, 66, 5, -6, 1 },
     84   { 1, -5, 2, 63, 67, 5, -6, 1 },    { 1, -5, 2, 62, 68, 6, -6, 0 },
     85   { 1, -5, 1, 62, 68, 6, -6, 1 },    { 1, -5, 1, 61, 69, 7, -7, 1 },
     86   { 1, -5, 0, 60, 70, 8, -7, 1 },    { 1, -5, 0, 59, 71, 9, -7, 0 },
     87   { 1, -5, -1, 58, 71, 10, -7, 1 },  { 1, -4, -1, 57, 72, 10, -7, 0 },
     88   { 1, -4, -2, 56, 73, 11, -7, 0 },  { 1, -4, -2, 55, 73, 12, -7, 0 },
     89   { 1, -4, -3, 54, 74, 13, -7, 0 },  { 1, -4, -3, 53, 74, 14, -7, 0 },
     90   { 1, -4, -3, 52, 75, 15, -8, 0 },  { 1, -3, -4, 51, 76, 15, -8, 0 },
     91   { 1, -3, -4, 50, 76, 16, -8, 0 },  { 1, -3, -5, 49, 77, 17, -8, 0 },
     92   { 1, -3, -5, 48, 77, 18, -8, 0 },  { 1, -3, -5, 47, 77, 19, -8, 0 },
     93   { 1, -3, -5, 45, 78, 20, -8, 0 },  { 1, -2, -6, 44, 78, 21, -8, 0 },
     94   { 1, -2, -6, 43, 78, 22, -8, 0 },  { 1, -2, -6, 42, 78, 23, -8, 0 },
     95   { 1, -2, -7, 41, 79, 24, -8, 0 },  { 1, -2, -7, 40, 79, 25, -8, 0 },
     96   { 1, -2, -7, 39, 79, 26, -8, 0 },  { 1, -2, -7, 38, 80, 27, -8, -1 },
     97   { 1, -2, -7, 37, 80, 28, -8, -1 }, { 1, -2, -7, 36, 80, 29, -8, -1 },
     98   { 1, -1, -8, 35, 80, 30, -8, -1 }, { 1, -1, -8, 34, 80, 31, -8, -1 },
     99 };
    100 
    101 // Filters for interpolation (0.75-band) - note this also filters integer pels.
    102 static const InterpKernel filteredinterp_filters750[(1 << RS_SUBPEL_BITS)] = {
    103   { 2, -11, 25, 96, 25, -11, 2, 0 }, { 2, -11, 24, 96, 26, -11, 2, 0 },
    104   { 2, -11, 22, 96, 28, -11, 2, 0 }, { 2, -10, 21, 96, 29, -12, 2, 0 },
    105   { 2, -10, 19, 96, 31, -12, 2, 0 }, { 2, -10, 18, 95, 32, -11, 2, 0 },
    106   { 2, -10, 17, 95, 34, -12, 2, 0 }, { 2, -9, 15, 95, 35, -12, 2, 0 },
    107   { 2, -9, 14, 94, 37, -12, 2, 0 },  { 2, -9, 13, 94, 38, -12, 2, 0 },
    108   { 2, -8, 12, 93, 40, -12, 1, 0 },  { 2, -8, 11, 93, 41, -12, 1, 0 },
    109   { 2, -8, 9, 92, 43, -12, 1, 1 },   { 2, -8, 8, 92, 44, -12, 1, 1 },
    110   { 2, -7, 7, 91, 46, -12, 1, 0 },   { 2, -7, 6, 90, 47, -12, 1, 1 },
    111   { 2, -7, 5, 90, 49, -12, 1, 0 },   { 2, -6, 4, 89, 50, -12, 1, 0 },
    112   { 2, -6, 3, 88, 52, -12, 0, 1 },   { 2, -6, 2, 87, 54, -12, 0, 1 },
    113   { 2, -5, 1, 86, 55, -12, 0, 1 },   { 2, -5, 0, 85, 57, -12, 0, 1 },
    114   { 2, -5, -1, 84, 58, -11, 0, 1 },  { 2, -5, -2, 83, 60, -11, 0, 1 },
    115   { 2, -4, -2, 82, 61, -11, -1, 1 }, { 1, -4, -3, 81, 63, -10, -1, 1 },
    116   { 2, -4, -4, 80, 64, -10, -1, 1 }, { 1, -4, -4, 79, 66, -10, -1, 1 },
    117   { 1, -3, -5, 77, 67, -9, -1, 1 },  { 1, -3, -6, 76, 69, -9, -1, 1 },
    118   { 1, -3, -6, 75, 70, -8, -2, 1 },  { 1, -2, -7, 74, 71, -8, -2, 1 },
    119   { 1, -2, -7, 72, 72, -7, -2, 1 },  { 1, -2, -8, 71, 74, -7, -2, 1 },
    120   { 1, -2, -8, 70, 75, -6, -3, 1 },  { 1, -1, -9, 69, 76, -6, -3, 1 },
    121   { 1, -1, -9, 67, 77, -5, -3, 1 },  { 1, -1, -10, 66, 79, -4, -4, 1 },
    122   { 1, -1, -10, 64, 80, -4, -4, 2 }, { 1, -1, -10, 63, 81, -3, -4, 1 },
    123   { 1, -1, -11, 61, 82, -2, -4, 2 }, { 1, 0, -11, 60, 83, -2, -5, 2 },
    124   { 1, 0, -11, 58, 84, -1, -5, 2 },  { 1, 0, -12, 57, 85, 0, -5, 2 },
    125   { 1, 0, -12, 55, 86, 1, -5, 2 },   { 1, 0, -12, 54, 87, 2, -6, 2 },
    126   { 1, 0, -12, 52, 88, 3, -6, 2 },   { 0, 1, -12, 50, 89, 4, -6, 2 },
    127   { 0, 1, -12, 49, 90, 5, -7, 2 },   { 1, 1, -12, 47, 90, 6, -7, 2 },
    128   { 0, 1, -12, 46, 91, 7, -7, 2 },   { 1, 1, -12, 44, 92, 8, -8, 2 },
    129   { 1, 1, -12, 43, 92, 9, -8, 2 },   { 0, 1, -12, 41, 93, 11, -8, 2 },
    130   { 0, 1, -12, 40, 93, 12, -8, 2 },  { 0, 2, -12, 38, 94, 13, -9, 2 },
    131   { 0, 2, -12, 37, 94, 14, -9, 2 },  { 0, 2, -12, 35, 95, 15, -9, 2 },
    132   { 0, 2, -12, 34, 95, 17, -10, 2 }, { 0, 2, -11, 32, 95, 18, -10, 2 },
    133   { 0, 2, -12, 31, 96, 19, -10, 2 }, { 0, 2, -12, 29, 96, 21, -10, 2 },
    134   { 0, 2, -11, 28, 96, 22, -11, 2 }, { 0, 2, -11, 26, 96, 24, -11, 2 },
    135 };
    136 
    137 // Filters for interpolation (0.875-band) - note this also filters integer pels.
    138 static const InterpKernel filteredinterp_filters875[(1 << RS_SUBPEL_BITS)] = {
    139   { 3, -8, 13, 112, 13, -8, 3, 0 },   { 2, -7, 12, 112, 15, -8, 3, -1 },
    140   { 3, -7, 10, 112, 17, -9, 3, -1 },  { 2, -6, 8, 112, 19, -9, 3, -1 },
    141   { 2, -6, 7, 112, 21, -10, 3, -1 },  { 2, -5, 6, 111, 22, -10, 3, -1 },
    142   { 2, -5, 4, 111, 24, -10, 3, -1 },  { 2, -4, 3, 110, 26, -11, 3, -1 },
    143   { 2, -4, 1, 110, 28, -11, 3, -1 },  { 2, -4, 0, 109, 30, -12, 4, -1 },
    144   { 1, -3, -1, 108, 32, -12, 4, -1 }, { 1, -3, -2, 108, 34, -13, 4, -1 },
    145   { 1, -2, -4, 107, 36, -13, 4, -1 }, { 1, -2, -5, 106, 38, -13, 4, -1 },
    146   { 1, -1, -6, 105, 40, -14, 4, -1 }, { 1, -1, -7, 104, 42, -14, 4, -1 },
    147   { 1, -1, -7, 103, 44, -15, 4, -1 }, { 1, 0, -8, 101, 46, -15, 4, -1 },
    148   { 1, 0, -9, 100, 48, -15, 4, -1 },  { 1, 0, -10, 99, 50, -15, 4, -1 },
    149   { 1, 1, -11, 97, 53, -16, 4, -1 },  { 0, 1, -11, 96, 55, -16, 4, -1 },
    150   { 0, 1, -12, 95, 57, -16, 4, -1 },  { 0, 2, -13, 93, 59, -16, 4, -1 },
    151   { 0, 2, -13, 91, 61, -16, 4, -1 },  { 0, 2, -14, 90, 63, -16, 4, -1 },
    152   { 0, 2, -14, 88, 65, -16, 4, -1 },  { 0, 2, -15, 86, 67, -16, 4, 0 },
    153   { 0, 3, -15, 84, 69, -17, 4, 0 },   { 0, 3, -16, 83, 71, -17, 4, 0 },
    154   { 0, 3, -16, 81, 73, -16, 3, 0 },   { 0, 3, -16, 79, 75, -16, 3, 0 },
    155   { 0, 3, -16, 77, 77, -16, 3, 0 },   { 0, 3, -16, 75, 79, -16, 3, 0 },
    156   { 0, 3, -16, 73, 81, -16, 3, 0 },   { 0, 4, -17, 71, 83, -16, 3, 0 },
    157   { 0, 4, -17, 69, 84, -15, 3, 0 },   { 0, 4, -16, 67, 86, -15, 2, 0 },
    158   { -1, 4, -16, 65, 88, -14, 2, 0 },  { -1, 4, -16, 63, 90, -14, 2, 0 },
    159   { -1, 4, -16, 61, 91, -13, 2, 0 },  { -1, 4, -16, 59, 93, -13, 2, 0 },
    160   { -1, 4, -16, 57, 95, -12, 1, 0 },  { -1, 4, -16, 55, 96, -11, 1, 0 },
    161   { -1, 4, -16, 53, 97, -11, 1, 1 },  { -1, 4, -15, 50, 99, -10, 0, 1 },
    162   { -1, 4, -15, 48, 100, -9, 0, 1 },  { -1, 4, -15, 46, 101, -8, 0, 1 },
    163   { -1, 4, -15, 44, 103, -7, -1, 1 }, { -1, 4, -14, 42, 104, -7, -1, 1 },
    164   { -1, 4, -14, 40, 105, -6, -1, 1 }, { -1, 4, -13, 38, 106, -5, -2, 1 },
    165   { -1, 4, -13, 36, 107, -4, -2, 1 }, { -1, 4, -13, 34, 108, -2, -3, 1 },
    166   { -1, 4, -12, 32, 108, -1, -3, 1 }, { -1, 4, -12, 30, 109, 0, -4, 2 },
    167   { -1, 3, -11, 28, 110, 1, -4, 2 },  { -1, 3, -11, 26, 110, 3, -4, 2 },
    168   { -1, 3, -10, 24, 111, 4, -5, 2 },  { -1, 3, -10, 22, 111, 6, -5, 2 },
    169   { -1, 3, -10, 21, 112, 7, -6, 2 },  { -1, 3, -9, 19, 112, 8, -6, 2 },
    170   { -1, 3, -9, 17, 112, 10, -7, 3 },  { -1, 3, -8, 15, 112, 12, -7, 2 },
    171 };
    172 
    173 const int16_t av1_resize_filter_normative[(
    174     1 << RS_SUBPEL_BITS)][UPSCALE_NORMATIVE_TAPS] = {
    175 #if UPSCALE_NORMATIVE_TAPS == 8
    176   { 0, 0, 0, 128, 0, 0, 0, 0 },        { 0, 0, -1, 128, 2, -1, 0, 0 },
    177   { 0, 1, -3, 127, 4, -2, 1, 0 },      { 0, 1, -4, 127, 6, -3, 1, 0 },
    178   { 0, 2, -6, 126, 8, -3, 1, 0 },      { 0, 2, -7, 125, 11, -4, 1, 0 },
    179   { -1, 2, -8, 125, 13, -5, 2, 0 },    { -1, 3, -9, 124, 15, -6, 2, 0 },
    180   { -1, 3, -10, 123, 18, -6, 2, -1 },  { -1, 3, -11, 122, 20, -7, 3, -1 },
    181   { -1, 4, -12, 121, 22, -8, 3, -1 },  { -1, 4, -13, 120, 25, -9, 3, -1 },
    182   { -1, 4, -14, 118, 28, -9, 3, -1 },  { -1, 4, -15, 117, 30, -10, 4, -1 },
    183   { -1, 5, -16, 116, 32, -11, 4, -1 }, { -1, 5, -16, 114, 35, -12, 4, -1 },
    184   { -1, 5, -17, 112, 38, -12, 4, -1 }, { -1, 5, -18, 111, 40, -13, 5, -1 },
    185   { -1, 5, -18, 109, 43, -14, 5, -1 }, { -1, 6, -19, 107, 45, -14, 5, -1 },
    186   { -1, 6, -19, 105, 48, -15, 5, -1 }, { -1, 6, -19, 103, 51, -16, 5, -1 },
    187   { -1, 6, -20, 101, 53, -16, 6, -1 }, { -1, 6, -20, 99, 56, -17, 6, -1 },
    188   { -1, 6, -20, 97, 58, -17, 6, -1 },  { -1, 6, -20, 95, 61, -18, 6, -1 },
    189   { -2, 7, -20, 93, 64, -18, 6, -2 },  { -2, 7, -20, 91, 66, -19, 6, -1 },
    190   { -2, 7, -20, 88, 69, -19, 6, -1 },  { -2, 7, -20, 86, 71, -19, 6, -1 },
    191   { -2, 7, -20, 84, 74, -20, 7, -2 },  { -2, 7, -20, 81, 76, -20, 7, -1 },
    192   { -2, 7, -20, 79, 79, -20, 7, -2 },  { -1, 7, -20, 76, 81, -20, 7, -2 },
    193   { -2, 7, -20, 74, 84, -20, 7, -2 },  { -1, 6, -19, 71, 86, -20, 7, -2 },
    194   { -1, 6, -19, 69, 88, -20, 7, -2 },  { -1, 6, -19, 66, 91, -20, 7, -2 },
    195   { -2, 6, -18, 64, 93, -20, 7, -2 },  { -1, 6, -18, 61, 95, -20, 6, -1 },
    196   { -1, 6, -17, 58, 97, -20, 6, -1 },  { -1, 6, -17, 56, 99, -20, 6, -1 },
    197   { -1, 6, -16, 53, 101, -20, 6, -1 }, { -1, 5, -16, 51, 103, -19, 6, -1 },
    198   { -1, 5, -15, 48, 105, -19, 6, -1 }, { -1, 5, -14, 45, 107, -19, 6, -1 },
    199   { -1, 5, -14, 43, 109, -18, 5, -1 }, { -1, 5, -13, 40, 111, -18, 5, -1 },
    200   { -1, 4, -12, 38, 112, -17, 5, -1 }, { -1, 4, -12, 35, 114, -16, 5, -1 },
    201   { -1, 4, -11, 32, 116, -16, 5, -1 }, { -1, 4, -10, 30, 117, -15, 4, -1 },
    202   { -1, 3, -9, 28, 118, -14, 4, -1 },  { -1, 3, -9, 25, 120, -13, 4, -1 },
    203   { -1, 3, -8, 22, 121, -12, 4, -1 },  { -1, 3, -7, 20, 122, -11, 3, -1 },
    204   { -1, 2, -6, 18, 123, -10, 3, -1 },  { 0, 2, -6, 15, 124, -9, 3, -1 },
    205   { 0, 2, -5, 13, 125, -8, 2, -1 },    { 0, 1, -4, 11, 125, -7, 2, 0 },
    206   { 0, 1, -3, 8, 126, -6, 2, 0 },      { 0, 1, -3, 6, 127, -4, 1, 0 },
    207   { 0, 1, -2, 4, 127, -3, 1, 0 },      { 0, 0, -1, 2, 128, -1, 0, 0 },
    208 #else
    209 #error "Invalid value of UPSCALE_NORMATIVE_TAPS"
    210 #endif  // UPSCALE_NORMATIVE_TAPS == 8
    211 };
    212 
    213 // Filters for interpolation (full-band) - no filtering for integer pixels
    214 #define filteredinterp_filters1000 av1_resize_filter_normative
    215 
    216 // Filters for factor of 2 downsampling.
    217 static const int16_t av1_down2_symeven_half_filter[] = { 56, 12, -3, -1 };
    218 static const int16_t av1_down2_symodd_half_filter[] = { 64, 35, 0, -3 };
    219 
    220 static const InterpKernel *choose_interp_filter(int in_length, int out_length) {
    221   int out_length16 = out_length * 16;
    222   if (out_length16 >= in_length * 16)
    223     return filteredinterp_filters1000;
    224   else if (out_length16 >= in_length * 13)
    225     return filteredinterp_filters875;
    226   else if (out_length16 >= in_length * 11)
    227     return filteredinterp_filters750;
    228   else if (out_length16 >= in_length * 9)
    229     return filteredinterp_filters625;
    230   else
    231     return filteredinterp_filters500;
    232 }
    233 
    234 static void interpolate_core(const uint8_t *const input, int in_length,
    235                              uint8_t *output, int out_length,
    236                              const int16_t *interp_filters, int interp_taps) {
    237   const int32_t delta =
    238       (((uint32_t)in_length << RS_SCALE_SUBPEL_BITS) + out_length / 2) /
    239       out_length;
    240   const int32_t offset =
    241       in_length > out_length
    242           ? (((int32_t)(in_length - out_length) << (RS_SCALE_SUBPEL_BITS - 1)) +
    243              out_length / 2) /
    244                 out_length
    245           : -(((int32_t)(out_length - in_length)
    246                << (RS_SCALE_SUBPEL_BITS - 1)) +
    247               out_length / 2) /
    248                 out_length;
    249   uint8_t *optr = output;
    250   int x, x1, x2, sum, k, int_pel, sub_pel;
    251   int32_t y;
    252 
    253   x = 0;
    254   y = offset + RS_SCALE_EXTRA_OFF;
    255   while ((y >> RS_SCALE_SUBPEL_BITS) < (interp_taps / 2 - 1)) {
    256     x++;
    257     y += delta;
    258   }
    259   x1 = x;
    260   x = out_length - 1;
    261   y = delta * x + offset + RS_SCALE_EXTRA_OFF;
    262   while ((y >> RS_SCALE_SUBPEL_BITS) + (int32_t)(interp_taps / 2) >=
    263          in_length) {
    264     x--;
    265     y -= delta;
    266   }
    267   x2 = x;
    268   if (x1 > x2) {
    269     for (x = 0, y = offset + RS_SCALE_EXTRA_OFF; x < out_length;
    270          ++x, y += delta) {
    271       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    272       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    273       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    274       sum = 0;
    275       for (k = 0; k < interp_taps; ++k) {
    276         const int pk = int_pel - interp_taps / 2 + 1 + k;
    277         sum += filter[k] * input[AOMMAX(AOMMIN(pk, in_length - 1), 0)];
    278       }
    279       *optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
    280     }
    281   } else {
    282     // Initial part.
    283     for (x = 0, y = offset + RS_SCALE_EXTRA_OFF; x < x1; ++x, y += delta) {
    284       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    285       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    286       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    287       sum = 0;
    288       for (k = 0; k < interp_taps; ++k)
    289         sum += filter[k] * input[AOMMAX(int_pel - interp_taps / 2 + 1 + k, 0)];
    290       *optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
    291     }
    292     // Middle part.
    293     for (; x <= x2; ++x, y += delta) {
    294       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    295       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    296       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    297       sum = 0;
    298       for (k = 0; k < interp_taps; ++k)
    299         sum += filter[k] * input[int_pel - interp_taps / 2 + 1 + k];
    300       *optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
    301     }
    302     // End part.
    303     for (; x < out_length; ++x, y += delta) {
    304       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    305       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    306       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    307       sum = 0;
    308       for (k = 0; k < interp_taps; ++k)
    309         sum += filter[k] *
    310                input[AOMMIN(int_pel - interp_taps / 2 + 1 + k, in_length - 1)];
    311       *optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
    312     }
    313   }
    314 }
    315 
    316 static void interpolate_core_double_prec(const double *const input,
    317                                          int in_length, double *output,
    318                                          int out_length,
    319                                          const int16_t *interp_filters,
    320                                          int interp_taps) {
    321   const int32_t delta =
    322       (((uint32_t)in_length << RS_SCALE_SUBPEL_BITS) + out_length / 2) /
    323       out_length;
    324   const int32_t offset =
    325       in_length > out_length
    326           ? (((int32_t)(in_length - out_length) << (RS_SCALE_SUBPEL_BITS - 1)) +
    327              out_length / 2) /
    328                 out_length
    329           : -(((int32_t)(out_length - in_length)
    330                << (RS_SCALE_SUBPEL_BITS - 1)) +
    331               out_length / 2) /
    332                 out_length;
    333   double *optr = output;
    334   int x, x1, x2, k, int_pel, sub_pel;
    335   double sum;
    336   int32_t y;
    337 
    338   x = 0;
    339   y = offset + RS_SCALE_EXTRA_OFF;
    340   while ((y >> RS_SCALE_SUBPEL_BITS) < (interp_taps / 2 - 1)) {
    341     x++;
    342     y += delta;
    343   }
    344   x1 = x;
    345   x = out_length - 1;
    346   y = delta * x + offset + RS_SCALE_EXTRA_OFF;
    347   while ((y >> RS_SCALE_SUBPEL_BITS) + (int32_t)(interp_taps / 2) >=
    348          in_length) {
    349     x--;
    350     y -= delta;
    351   }
    352   x2 = x;
    353   if (x1 > x2) {
    354     for (x = 0, y = offset + RS_SCALE_EXTRA_OFF; x < out_length;
    355          ++x, y += delta) {
    356       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    357       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    358       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    359       sum = 0;
    360       for (k = 0; k < interp_taps; ++k) {
    361         const int pk = int_pel - interp_taps / 2 + 1 + k;
    362         sum += filter[k] * input[AOMMAX(AOMMIN(pk, in_length - 1), 0)];
    363       }
    364       *optr++ = sum / (1 << FILTER_BITS);
    365     }
    366   } else {
    367     // Initial part.
    368     for (x = 0, y = offset + RS_SCALE_EXTRA_OFF; x < x1; ++x, y += delta) {
    369       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    370       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    371       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    372       sum = 0;
    373       for (k = 0; k < interp_taps; ++k)
    374         sum += filter[k] * input[AOMMAX(int_pel - interp_taps / 2 + 1 + k, 0)];
    375       *optr++ = sum / (1 << FILTER_BITS);
    376     }
    377     // Middle part.
    378     for (; x <= x2; ++x, y += delta) {
    379       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    380       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    381       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    382       sum = 0;
    383       for (k = 0; k < interp_taps; ++k)
    384         sum += filter[k] * input[int_pel - interp_taps / 2 + 1 + k];
    385       *optr++ = sum / (1 << FILTER_BITS);
    386     }
    387     // End part.
    388     for (; x < out_length; ++x, y += delta) {
    389       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    390       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    391       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    392       sum = 0;
    393       for (k = 0; k < interp_taps; ++k)
    394         sum += filter[k] *
    395                input[AOMMIN(int_pel - interp_taps / 2 + 1 + k, in_length - 1)];
    396       *optr++ = sum / (1 << FILTER_BITS);
    397     }
    398   }
    399 }
    400 
    401 static void interpolate(const uint8_t *const input, int in_length,
    402                         uint8_t *output, int out_length) {
    403   const InterpKernel *interp_filters =
    404       choose_interp_filter(in_length, out_length);
    405 
    406   interpolate_core(input, in_length, output, out_length, &interp_filters[0][0],
    407                    SUBPEL_TAPS);
    408 }
    409 
    410 static void interpolate_double_prec(const double *const input, int in_length,
    411                                     double *output, int out_length) {
    412   const InterpKernel *interp_filters =
    413       choose_interp_filter(in_length, out_length);
    414 
    415   interpolate_core_double_prec(input, in_length, output, out_length,
    416                                &interp_filters[0][0], SUBPEL_TAPS);
    417 }
    418 
    419 int32_t av1_get_upscale_convolve_step(int in_length, int out_length) {
    420   return ((in_length << RS_SCALE_SUBPEL_BITS) + out_length / 2) / out_length;
    421 }
    422 
    423 static int32_t get_upscale_convolve_x0(int in_length, int out_length,
    424                                        int32_t x_step_qn) {
    425   const int err = out_length * x_step_qn - (in_length << RS_SCALE_SUBPEL_BITS);
    426   const int32_t x0 =
    427       (-((out_length - in_length) << (RS_SCALE_SUBPEL_BITS - 1)) +
    428        out_length / 2) /
    429           out_length +
    430       RS_SCALE_EXTRA_OFF - err / 2;
    431   return (int32_t)((uint32_t)x0 & RS_SCALE_SUBPEL_MASK);
    432 }
    433 
    434 static void down2_symeven(const uint8_t *const input, int length,
    435                           uint8_t *output) {
    436   // Actual filter len = 2 * filter_len_half.
    437   const int16_t *filter = av1_down2_symeven_half_filter;
    438   const int filter_len_half = sizeof(av1_down2_symeven_half_filter) / 2;
    439   int i, j;
    440   uint8_t *optr = output;
    441   int l1 = filter_len_half;
    442   int l2 = (length - filter_len_half);
    443   l1 += (l1 & 1);
    444   l2 += (l2 & 1);
    445   if (l1 > l2) {
    446     // Short input length.
    447     for (i = 0; i < length; i += 2) {
    448       int sum = (1 << (FILTER_BITS - 1));
    449       for (j = 0; j < filter_len_half; ++j) {
    450         sum +=
    451             (input[AOMMAX(i - j, 0)] + input[AOMMIN(i + 1 + j, length - 1)]) *
    452             filter[j];
    453       }
    454       sum >>= FILTER_BITS;
    455       *optr++ = clip_pixel(sum);
    456     }
    457   } else {
    458     // Initial part.
    459     for (i = 0; i < l1; i += 2) {
    460       int sum = (1 << (FILTER_BITS - 1));
    461       for (j = 0; j < filter_len_half; ++j) {
    462         sum += (input[AOMMAX(i - j, 0)] + input[i + 1 + j]) * filter[j];
    463       }
    464       sum >>= FILTER_BITS;
    465       *optr++ = clip_pixel(sum);
    466     }
    467     // Middle part.
    468     for (; i < l2; i += 2) {
    469       int sum = (1 << (FILTER_BITS - 1));
    470       for (j = 0; j < filter_len_half; ++j) {
    471         sum += (input[i - j] + input[i + 1 + j]) * filter[j];
    472       }
    473       sum >>= FILTER_BITS;
    474       *optr++ = clip_pixel(sum);
    475     }
    476     // End part.
    477     for (; i < length; i += 2) {
    478       int sum = (1 << (FILTER_BITS - 1));
    479       for (j = 0; j < filter_len_half; ++j) {
    480         sum +=
    481             (input[i - j] + input[AOMMIN(i + 1 + j, length - 1)]) * filter[j];
    482       }
    483       sum >>= FILTER_BITS;
    484       *optr++ = clip_pixel(sum);
    485     }
    486   }
    487 }
    488 
    489 static void down2_symodd(const uint8_t *const input, int length,
    490                          uint8_t *output) {
    491   // Actual filter len = 2 * filter_len_half - 1.
    492   const int16_t *filter = av1_down2_symodd_half_filter;
    493   const int filter_len_half = sizeof(av1_down2_symodd_half_filter) / 2;
    494   int i, j;
    495   uint8_t *optr = output;
    496   int l1 = filter_len_half - 1;
    497   int l2 = (length - filter_len_half + 1);
    498   l1 += (l1 & 1);
    499   l2 += (l2 & 1);
    500   if (l1 > l2) {
    501     // Short input length.
    502     for (i = 0; i < length; i += 2) {
    503       int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
    504       for (j = 1; j < filter_len_half; ++j) {
    505         sum += (input[(i - j < 0 ? 0 : i - j)] +
    506                 input[(i + j >= length ? length - 1 : i + j)]) *
    507                filter[j];
    508       }
    509       sum >>= FILTER_BITS;
    510       *optr++ = clip_pixel(sum);
    511     }
    512   } else {
    513     // Initial part.
    514     for (i = 0; i < l1; i += 2) {
    515       int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
    516       for (j = 1; j < filter_len_half; ++j) {
    517         sum += (input[(i - j < 0 ? 0 : i - j)] + input[i + j]) * filter[j];
    518       }
    519       sum >>= FILTER_BITS;
    520       *optr++ = clip_pixel(sum);
    521     }
    522     // Middle part.
    523     for (; i < l2; i += 2) {
    524       int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
    525       for (j = 1; j < filter_len_half; ++j) {
    526         sum += (input[i - j] + input[i + j]) * filter[j];
    527       }
    528       sum >>= FILTER_BITS;
    529       *optr++ = clip_pixel(sum);
    530     }
    531     // End part.
    532     for (; i < length; i += 2) {
    533       int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
    534       for (j = 1; j < filter_len_half; ++j) {
    535         sum += (input[i - j] + input[(i + j >= length ? length - 1 : i + j)]) *
    536                filter[j];
    537       }
    538       sum >>= FILTER_BITS;
    539       *optr++ = clip_pixel(sum);
    540     }
    541   }
    542 }
    543 
    544 static int get_down2_length(int length, int steps) {
    545   for (int s = 0; s < steps; ++s) length = (length + 1) >> 1;
    546   return length;
    547 }
    548 
    549 static int get_down2_steps(int in_length, int out_length) {
    550   int steps = 0;
    551   int proj_in_length;
    552   while ((proj_in_length = get_down2_length(in_length, 1)) >= out_length) {
    553     ++steps;
    554     in_length = proj_in_length;
    555     if (in_length == 1) {
    556       // Special case: we break because any further calls to get_down2_length()
    557       // with be with length == 1, which return 1, resulting in an infinite
    558       // loop.
    559       break;
    560     }
    561   }
    562   return steps;
    563 }
    564 
    565 static void resize_multistep(const uint8_t *const input, int length,
    566                              uint8_t *output, int olength, uint8_t *otmp) {
    567   if (length == olength) {
    568     memcpy(output, input, sizeof(output[0]) * length);
    569     return;
    570   }
    571   const int steps = get_down2_steps(length, olength);
    572 
    573   if (steps > 0) {
    574     uint8_t *out = NULL;
    575     int filteredlength = length;
    576 
    577     assert(otmp != NULL);
    578     uint8_t *otmp2 = otmp + get_down2_length(length, 1);
    579     for (int s = 0; s < steps; ++s) {
    580       const int proj_filteredlength = get_down2_length(filteredlength, 1);
    581       const uint8_t *const in = (s == 0 ? input : out);
    582       if (s == steps - 1 && proj_filteredlength == olength)
    583         out = output;
    584       else
    585         out = (s & 1 ? otmp2 : otmp);
    586       if (filteredlength & 1)
    587         down2_symodd(in, filteredlength, out);
    588       else
    589         down2_symeven(in, filteredlength, out);
    590       filteredlength = proj_filteredlength;
    591     }
    592     if (filteredlength != olength) {
    593       interpolate(out, filteredlength, output, olength);
    594     }
    595   } else {
    596     interpolate(input, length, output, olength);
    597   }
    598 }
    599 
    600 static void upscale_multistep_double_prec(const double *const input, int length,
    601                                           double *output, int olength) {
    602   assert(length < olength);
    603   interpolate_double_prec(input, length, output, olength);
    604 }
    605 
    606 static void fill_col_to_arr(uint8_t *img, int stride, int len, uint8_t *arr) {
    607   int i;
    608   uint8_t *iptr = img;
    609   uint8_t *aptr = arr;
    610   for (i = 0; i < len; ++i, iptr += stride) {
    611     *aptr++ = *iptr;
    612   }
    613 }
    614 
    615 static void fill_arr_to_col(uint8_t *img, int stride, int len, uint8_t *arr) {
    616   int i;
    617   uint8_t *iptr = img;
    618   uint8_t *aptr = arr;
    619   for (i = 0; i < len; ++i, iptr += stride) {
    620     *iptr = *aptr++;
    621   }
    622 }
    623 
    624 static void fill_col_to_arr_double_prec(double *img, int stride, int len,
    625                                         double *arr) {
    626   int i;
    627   double *iptr = img;
    628   double *aptr = arr;
    629   for (i = 0; i < len; ++i, iptr += stride) {
    630     *aptr++ = *iptr;
    631   }
    632 }
    633 
    634 static void fill_arr_to_col_double_prec(double *img, int stride, int len,
    635                                         double *arr) {
    636   int i;
    637   double *iptr = img;
    638   double *aptr = arr;
    639   for (i = 0; i < len; ++i, iptr += stride) {
    640     *iptr = *aptr++;
    641   }
    642 }
    643 
    644 void av1_resize_plane(const uint8_t *const input, int height, int width,
    645                       int in_stride, uint8_t *output, int height2, int width2,
    646                       int out_stride) {
    647   int i;
    648   uint8_t *intbuf = (uint8_t *)aom_malloc(sizeof(uint8_t) * width2 * height);
    649   uint8_t *tmpbuf =
    650       (uint8_t *)aom_malloc(sizeof(uint8_t) * AOMMAX(width, height));
    651   uint8_t *arrbuf = (uint8_t *)aom_malloc(sizeof(uint8_t) * height);
    652   uint8_t *arrbuf2 = (uint8_t *)aom_malloc(sizeof(uint8_t) * height2);
    653   if (intbuf == NULL || tmpbuf == NULL || arrbuf == NULL || arrbuf2 == NULL)
    654     goto Error;
    655   assert(width > 0);
    656   assert(height > 0);
    657   assert(width2 > 0);
    658   assert(height2 > 0);
    659   for (i = 0; i < height; ++i)
    660     resize_multistep(input + in_stride * i, width, intbuf + width2 * i, width2,
    661                      tmpbuf);
    662   for (i = 0; i < width2; ++i) {
    663     fill_col_to_arr(intbuf + i, width2, height, arrbuf);
    664     resize_multistep(arrbuf, height, arrbuf2, height2, tmpbuf);
    665     fill_arr_to_col(output + i, out_stride, height2, arrbuf2);
    666   }
    667 
    668 Error:
    669   aom_free(intbuf);
    670   aom_free(tmpbuf);
    671   aom_free(arrbuf);
    672   aom_free(arrbuf2);
    673 }
    674 
    675 void av1_upscale_plane_double_prec(const double *const input, int height,
    676                                    int width, int in_stride, double *output,
    677                                    int height2, int width2, int out_stride) {
    678   int i;
    679   double *intbuf = (double *)aom_malloc(sizeof(double) * width2 * height);
    680   double *arrbuf = (double *)aom_malloc(sizeof(double) * height);
    681   double *arrbuf2 = (double *)aom_malloc(sizeof(double) * height2);
    682   if (intbuf == NULL || arrbuf == NULL || arrbuf2 == NULL) goto Error;
    683   assert(width > 0);
    684   assert(height > 0);
    685   assert(width2 > 0);
    686   assert(height2 > 0);
    687   for (i = 0; i < height; ++i)
    688     upscale_multistep_double_prec(input + in_stride * i, width,
    689                                   intbuf + width2 * i, width2);
    690   for (i = 0; i < width2; ++i) {
    691     fill_col_to_arr_double_prec(intbuf + i, width2, height, arrbuf);
    692     upscale_multistep_double_prec(arrbuf, height, arrbuf2, height2);
    693     fill_arr_to_col_double_prec(output + i, out_stride, height2, arrbuf2);
    694   }
    695 
    696 Error:
    697   aom_free(intbuf);
    698   aom_free(arrbuf);
    699   aom_free(arrbuf2);
    700 }
    701 
    702 static void upscale_normative_rect(const uint8_t *const input, int height,
    703                                    int width, int in_stride, uint8_t *output,
    704                                    int height2, int width2, int out_stride,
    705                                    int x_step_qn, int x0_qn, int pad_left,
    706                                    int pad_right) {
    707   assert(width > 0);
    708   assert(height > 0);
    709   assert(width2 > 0);
    710   assert(height2 > 0);
    711   assert(height2 == height);
    712 
    713   // Extend the left/right pixels of the tile column if needed
    714   // (either because we can't sample from other tiles, or because we're at
    715   // a frame edge).
    716   // Save the overwritten pixels into tmp_left and tmp_right.
    717   // Note: Because we pass input-1 to av1_convolve_horiz_rs, we need one extra
    718   // column of border pixels compared to what we'd naively think.
    719   const int border_cols = UPSCALE_NORMATIVE_TAPS / 2 + 1;
    720   uint8_t *tmp_left =
    721       NULL;  // Silence spurious "may be used uninitialized" warnings
    722   uint8_t *tmp_right = NULL;
    723   uint8_t *const in_tl = (uint8_t *)(input - border_cols);  // Cast off 'const'
    724   uint8_t *const in_tr = (uint8_t *)(input + width);
    725   if (pad_left) {
    726     tmp_left = (uint8_t *)aom_malloc(sizeof(*tmp_left) * border_cols * height);
    727     for (int i = 0; i < height; i++) {
    728       memcpy(tmp_left + i * border_cols, in_tl + i * in_stride, border_cols);
    729       memset(in_tl + i * in_stride, input[i * in_stride], border_cols);
    730     }
    731   }
    732   if (pad_right) {
    733     tmp_right =
    734         (uint8_t *)aom_malloc(sizeof(*tmp_right) * border_cols * height);
    735     for (int i = 0; i < height; i++) {
    736       memcpy(tmp_right + i * border_cols, in_tr + i * in_stride, border_cols);
    737       memset(in_tr + i * in_stride, input[i * in_stride + width - 1],
    738              border_cols);
    739     }
    740   }
    741 
    742   av1_convolve_horiz_rs(input - 1, in_stride, output, out_stride, width2,
    743                         height2, &av1_resize_filter_normative[0][0], x0_qn,
    744                         x_step_qn);
    745 
    746   // Restore the left/right border pixels
    747   if (pad_left) {
    748     for (int i = 0; i < height; i++) {
    749       memcpy(in_tl + i * in_stride, tmp_left + i * border_cols, border_cols);
    750     }
    751     aom_free(tmp_left);
    752   }
    753   if (pad_right) {
    754     for (int i = 0; i < height; i++) {
    755       memcpy(in_tr + i * in_stride, tmp_right + i * border_cols, border_cols);
    756     }
    757     aom_free(tmp_right);
    758   }
    759 }
    760 
    761 static void highbd_interpolate_core(const uint16_t *const input, int in_length,
    762                                     uint16_t *output, int out_length, int bd,
    763                                     const int16_t *interp_filters,
    764                                     int interp_taps) {
    765   const int32_t delta =
    766       (((uint32_t)in_length << RS_SCALE_SUBPEL_BITS) + out_length / 2) /
    767       out_length;
    768   const int32_t offset =
    769       in_length > out_length
    770           ? (((int32_t)(in_length - out_length) << (RS_SCALE_SUBPEL_BITS - 1)) +
    771              out_length / 2) /
    772                 out_length
    773           : -(((int32_t)(out_length - in_length)
    774                << (RS_SCALE_SUBPEL_BITS - 1)) +
    775               out_length / 2) /
    776                 out_length;
    777   uint16_t *optr = output;
    778   int x, x1, x2, sum, k, int_pel, sub_pel;
    779   int32_t y;
    780 
    781   x = 0;
    782   y = offset + RS_SCALE_EXTRA_OFF;
    783   while ((y >> RS_SCALE_SUBPEL_BITS) < (interp_taps / 2 - 1)) {
    784     x++;
    785     y += delta;
    786   }
    787   x1 = x;
    788   x = out_length - 1;
    789   y = delta * x + offset + RS_SCALE_EXTRA_OFF;
    790   while ((y >> RS_SCALE_SUBPEL_BITS) + (int32_t)(interp_taps / 2) >=
    791          in_length) {
    792     x--;
    793     y -= delta;
    794   }
    795   x2 = x;
    796   if (x1 > x2) {
    797     for (x = 0, y = offset + RS_SCALE_EXTRA_OFF; x < out_length;
    798          ++x, y += delta) {
    799       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    800       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    801       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    802       sum = 0;
    803       for (k = 0; k < interp_taps; ++k) {
    804         const int pk = int_pel - interp_taps / 2 + 1 + k;
    805         sum += filter[k] * input[AOMMAX(AOMMIN(pk, in_length - 1), 0)];
    806       }
    807       *optr++ = clip_pixel_highbd(ROUND_POWER_OF_TWO(sum, FILTER_BITS), bd);
    808     }
    809   } else {
    810     // Initial part.
    811     for (x = 0, y = offset + RS_SCALE_EXTRA_OFF; x < x1; ++x, y += delta) {
    812       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    813       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    814       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    815       sum = 0;
    816       for (k = 0; k < interp_taps; ++k)
    817         sum += filter[k] * input[AOMMAX(int_pel - interp_taps / 2 + 1 + k, 0)];
    818       *optr++ = clip_pixel_highbd(ROUND_POWER_OF_TWO(sum, FILTER_BITS), bd);
    819     }
    820     // Middle part.
    821     for (; x <= x2; ++x, y += delta) {
    822       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    823       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    824       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    825       sum = 0;
    826       for (k = 0; k < interp_taps; ++k)
    827         sum += filter[k] * input[int_pel - interp_taps / 2 + 1 + k];
    828       *optr++ = clip_pixel_highbd(ROUND_POWER_OF_TWO(sum, FILTER_BITS), bd);
    829     }
    830     // End part.
    831     for (; x < out_length; ++x, y += delta) {
    832       int_pel = y >> RS_SCALE_SUBPEL_BITS;
    833       sub_pel = (y >> RS_SCALE_EXTRA_BITS) & RS_SUBPEL_MASK;
    834       const int16_t *filter = &interp_filters[sub_pel * interp_taps];
    835       sum = 0;
    836       for (k = 0; k < interp_taps; ++k)
    837         sum += filter[k] *
    838                input[AOMMIN(int_pel - interp_taps / 2 + 1 + k, in_length - 1)];
    839       *optr++ = clip_pixel_highbd(ROUND_POWER_OF_TWO(sum, FILTER_BITS), bd);
    840     }
    841   }
    842 }
    843 
    844 static void highbd_interpolate(const uint16_t *const input, int in_length,
    845                                uint16_t *output, int out_length, int bd) {
    846   const InterpKernel *interp_filters =
    847       choose_interp_filter(in_length, out_length);
    848 
    849   highbd_interpolate_core(input, in_length, output, out_length, bd,
    850                           &interp_filters[0][0], SUBPEL_TAPS);
    851 }
    852 
    853 static void highbd_down2_symeven(const uint16_t *const input, int length,
    854                                  uint16_t *output, int bd) {
    855   // Actual filter len = 2 * filter_len_half.
    856   static const int16_t *filter = av1_down2_symeven_half_filter;
    857   const int filter_len_half = sizeof(av1_down2_symeven_half_filter) / 2;
    858   int i, j;
    859   uint16_t *optr = output;
    860   int l1 = filter_len_half;
    861   int l2 = (length - filter_len_half);
    862   l1 += (l1 & 1);
    863   l2 += (l2 & 1);
    864   if (l1 > l2) {
    865     // Short input length.
    866     for (i = 0; i < length; i += 2) {
    867       int sum = (1 << (FILTER_BITS - 1));
    868       for (j = 0; j < filter_len_half; ++j) {
    869         sum +=
    870             (input[AOMMAX(0, i - j)] + input[AOMMIN(i + 1 + j, length - 1)]) *
    871             filter[j];
    872       }
    873       sum >>= FILTER_BITS;
    874       *optr++ = clip_pixel_highbd(sum, bd);
    875     }
    876   } else {
    877     // Initial part.
    878     for (i = 0; i < l1; i += 2) {
    879       int sum = (1 << (FILTER_BITS - 1));
    880       for (j = 0; j < filter_len_half; ++j) {
    881         sum += (input[AOMMAX(0, i - j)] + input[i + 1 + j]) * filter[j];
    882       }
    883       sum >>= FILTER_BITS;
    884       *optr++ = clip_pixel_highbd(sum, bd);
    885     }
    886     // Middle part.
    887     for (; i < l2; i += 2) {
    888       int sum = (1 << (FILTER_BITS - 1));
    889       for (j = 0; j < filter_len_half; ++j) {
    890         sum += (input[i - j] + input[i + 1 + j]) * filter[j];
    891       }
    892       sum >>= FILTER_BITS;
    893       *optr++ = clip_pixel_highbd(sum, bd);
    894     }
    895     // End part.
    896     for (; i < length; i += 2) {
    897       int sum = (1 << (FILTER_BITS - 1));
    898       for (j = 0; j < filter_len_half; ++j) {
    899         sum +=
    900             (input[i - j] + input[AOMMIN(i + 1 + j, length - 1)]) * filter[j];
    901       }
    902       sum >>= FILTER_BITS;
    903       *optr++ = clip_pixel_highbd(sum, bd);
    904     }
    905   }
    906 }
    907 
    908 static void highbd_down2_symodd(const uint16_t *const input, int length,
    909                                 uint16_t *output, int bd) {
    910   // Actual filter len = 2 * filter_len_half - 1.
    911   static const int16_t *filter = av1_down2_symodd_half_filter;
    912   const int filter_len_half = sizeof(av1_down2_symodd_half_filter) / 2;
    913   int i, j;
    914   uint16_t *optr = output;
    915   int l1 = filter_len_half - 1;
    916   int l2 = (length - filter_len_half + 1);
    917   l1 += (l1 & 1);
    918   l2 += (l2 & 1);
    919   if (l1 > l2) {
    920     // Short input length.
    921     for (i = 0; i < length; i += 2) {
    922       int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
    923       for (j = 1; j < filter_len_half; ++j) {
    924         sum += (input[AOMMAX(i - j, 0)] + input[AOMMIN(i + j, length - 1)]) *
    925                filter[j];
    926       }
    927       sum >>= FILTER_BITS;
    928       *optr++ = clip_pixel_highbd(sum, bd);
    929     }
    930   } else {
    931     // Initial part.
    932     for (i = 0; i < l1; i += 2) {
    933       int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
    934       for (j = 1; j < filter_len_half; ++j) {
    935         sum += (input[AOMMAX(i - j, 0)] + input[i + j]) * filter[j];
    936       }
    937       sum >>= FILTER_BITS;
    938       *optr++ = clip_pixel_highbd(sum, bd);
    939     }
    940     // Middle part.
    941     for (; i < l2; i += 2) {
    942       int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
    943       for (j = 1; j < filter_len_half; ++j) {
    944         sum += (input[i - j] + input[i + j]) * filter[j];
    945       }
    946       sum >>= FILTER_BITS;
    947       *optr++ = clip_pixel_highbd(sum, bd);
    948     }
    949     // End part.
    950     for (; i < length; i += 2) {
    951       int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
    952       for (j = 1; j < filter_len_half; ++j) {
    953         sum += (input[i - j] + input[AOMMIN(i + j, length - 1)]) * filter[j];
    954       }
    955       sum >>= FILTER_BITS;
    956       *optr++ = clip_pixel_highbd(sum, bd);
    957     }
    958   }
    959 }
    960 
    961 static void highbd_resize_multistep(const uint16_t *const input, int length,
    962                                     uint16_t *output, int olength,
    963                                     uint16_t *otmp, int bd) {
    964   if (length == olength) {
    965     memcpy(output, input, sizeof(output[0]) * length);
    966     return;
    967   }
    968   const int steps = get_down2_steps(length, olength);
    969 
    970   if (steps > 0) {
    971     uint16_t *out = NULL;
    972     int filteredlength = length;
    973 
    974     assert(otmp != NULL);
    975     uint16_t *otmp2 = otmp + get_down2_length(length, 1);
    976     for (int s = 0; s < steps; ++s) {
    977       const int proj_filteredlength = get_down2_length(filteredlength, 1);
    978       const uint16_t *const in = (s == 0 ? input : out);
    979       if (s == steps - 1 && proj_filteredlength == olength)
    980         out = output;
    981       else
    982         out = (s & 1 ? otmp2 : otmp);
    983       if (filteredlength & 1)
    984         highbd_down2_symodd(in, filteredlength, out, bd);
    985       else
    986         highbd_down2_symeven(in, filteredlength, out, bd);
    987       filteredlength = proj_filteredlength;
    988     }
    989     if (filteredlength != olength) {
    990       highbd_interpolate(out, filteredlength, output, olength, bd);
    991     }
    992   } else {
    993     highbd_interpolate(input, length, output, olength, bd);
    994   }
    995 }
    996 
    997 static void highbd_fill_col_to_arr(uint16_t *img, int stride, int len,
    998                                    uint16_t *arr) {
    999   int i;
   1000   uint16_t *iptr = img;
   1001   uint16_t *aptr = arr;
   1002   for (i = 0; i < len; ++i, iptr += stride) {
   1003     *aptr++ = *iptr;
   1004   }
   1005 }
   1006 
   1007 static void highbd_fill_arr_to_col(uint16_t *img, int stride, int len,
   1008                                    uint16_t *arr) {
   1009   int i;
   1010   uint16_t *iptr = img;
   1011   uint16_t *aptr = arr;
   1012   for (i = 0; i < len; ++i, iptr += stride) {
   1013     *iptr = *aptr++;
   1014   }
   1015 }
   1016 
   1017 void av1_highbd_resize_plane(const uint8_t *const input, int height, int width,
   1018                              int in_stride, uint8_t *output, int height2,
   1019                              int width2, int out_stride, int bd) {
   1020   int i;
   1021   uint16_t *intbuf = (uint16_t *)aom_malloc(sizeof(uint16_t) * width2 * height);
   1022   uint16_t *tmpbuf =
   1023       (uint16_t *)aom_malloc(sizeof(uint16_t) * AOMMAX(width, height));
   1024   uint16_t *arrbuf = (uint16_t *)aom_malloc(sizeof(uint16_t) * height);
   1025   uint16_t *arrbuf2 = (uint16_t *)aom_malloc(sizeof(uint16_t) * height2);
   1026   if (intbuf == NULL || tmpbuf == NULL || arrbuf == NULL || arrbuf2 == NULL)
   1027     goto Error;
   1028   for (i = 0; i < height; ++i) {
   1029     highbd_resize_multistep(CONVERT_TO_SHORTPTR(input + in_stride * i), width,
   1030                             intbuf + width2 * i, width2, tmpbuf, bd);
   1031   }
   1032   for (i = 0; i < width2; ++i) {
   1033     highbd_fill_col_to_arr(intbuf + i, width2, height, arrbuf);
   1034     highbd_resize_multistep(arrbuf, height, arrbuf2, height2, tmpbuf, bd);
   1035     highbd_fill_arr_to_col(CONVERT_TO_SHORTPTR(output + i), out_stride, height2,
   1036                            arrbuf2);
   1037   }
   1038 
   1039 Error:
   1040   aom_free(intbuf);
   1041   aom_free(tmpbuf);
   1042   aom_free(arrbuf);
   1043   aom_free(arrbuf2);
   1044 }
   1045 
   1046 static void highbd_upscale_normative_rect(const uint8_t *const input,
   1047                                           int height, int width, int in_stride,
   1048                                           uint8_t *output, int height2,
   1049                                           int width2, int out_stride,
   1050                                           int x_step_qn, int x0_qn,
   1051                                           int pad_left, int pad_right, int bd) {
   1052   assert(width > 0);
   1053   assert(height > 0);
   1054   assert(width2 > 0);
   1055   assert(height2 > 0);
   1056   assert(height2 == height);
   1057 
   1058   // Extend the left/right pixels of the tile column if needed
   1059   // (either because we can't sample from other tiles, or because we're at
   1060   // a frame edge).
   1061   // Save the overwritten pixels into tmp_left and tmp_right.
   1062   // Note: Because we pass input-1 to av1_convolve_horiz_rs, we need one extra
   1063   // column of border pixels compared to what we'd naively think.
   1064   const int border_cols = UPSCALE_NORMATIVE_TAPS / 2 + 1;
   1065   const int border_size = border_cols * sizeof(uint16_t);
   1066   uint16_t *tmp_left =
   1067       NULL;  // Silence spurious "may be used uninitialized" warnings
   1068   uint16_t *tmp_right = NULL;
   1069   uint16_t *const input16 = CONVERT_TO_SHORTPTR(input);
   1070   uint16_t *const in_tl = input16 - border_cols;
   1071   uint16_t *const in_tr = input16 + width;
   1072   if (pad_left) {
   1073     tmp_left = (uint16_t *)aom_malloc(sizeof(*tmp_left) * border_cols * height);
   1074     for (int i = 0; i < height; i++) {
   1075       memcpy(tmp_left + i * border_cols, in_tl + i * in_stride, border_size);
   1076       aom_memset16(in_tl + i * in_stride, input16[i * in_stride], border_cols);
   1077     }
   1078   }
   1079   if (pad_right) {
   1080     tmp_right =
   1081         (uint16_t *)aom_malloc(sizeof(*tmp_right) * border_cols * height);
   1082     for (int i = 0; i < height; i++) {
   1083       memcpy(tmp_right + i * border_cols, in_tr + i * in_stride, border_size);
   1084       aom_memset16(in_tr + i * in_stride, input16[i * in_stride + width - 1],
   1085                    border_cols);
   1086     }
   1087   }
   1088 
   1089   av1_highbd_convolve_horiz_rs(CONVERT_TO_SHORTPTR(input - 1), in_stride,
   1090                                CONVERT_TO_SHORTPTR(output), out_stride, width2,
   1091                                height2, &av1_resize_filter_normative[0][0],
   1092                                x0_qn, x_step_qn, bd);
   1093 
   1094   // Restore the left/right border pixels
   1095   if (pad_left) {
   1096     for (int i = 0; i < height; i++) {
   1097       memcpy(in_tl + i * in_stride, tmp_left + i * border_cols, border_size);
   1098     }
   1099     aom_free(tmp_left);
   1100   }
   1101   if (pad_right) {
   1102     for (int i = 0; i < height; i++) {
   1103       memcpy(in_tr + i * in_stride, tmp_right + i * border_cols, border_size);
   1104     }
   1105     aom_free(tmp_right);
   1106   }
   1107 }
   1108 
   1109 void av1_resize_frame420(const uint8_t *const y, int y_stride,
   1110                          const uint8_t *const u, const uint8_t *const v,
   1111                          int uv_stride, int height, int width, uint8_t *oy,
   1112                          int oy_stride, uint8_t *ou, uint8_t *ov,
   1113                          int ouv_stride, int oheight, int owidth) {
   1114   av1_resize_plane(y, height, width, y_stride, oy, oheight, owidth, oy_stride);
   1115   av1_resize_plane(u, height / 2, width / 2, uv_stride, ou, oheight / 2,
   1116                    owidth / 2, ouv_stride);
   1117   av1_resize_plane(v, height / 2, width / 2, uv_stride, ov, oheight / 2,
   1118                    owidth / 2, ouv_stride);
   1119 }
   1120 
   1121 void av1_resize_frame422(const uint8_t *const y, int y_stride,
   1122                          const uint8_t *const u, const uint8_t *const v,
   1123                          int uv_stride, int height, int width, uint8_t *oy,
   1124                          int oy_stride, uint8_t *ou, uint8_t *ov,
   1125                          int ouv_stride, int oheight, int owidth) {
   1126   av1_resize_plane(y, height, width, y_stride, oy, oheight, owidth, oy_stride);
   1127   av1_resize_plane(u, height, width / 2, uv_stride, ou, oheight, owidth / 2,
   1128                    ouv_stride);
   1129   av1_resize_plane(v, height, width / 2, uv_stride, ov, oheight, owidth / 2,
   1130                    ouv_stride);
   1131 }
   1132 
   1133 void av1_resize_frame444(const uint8_t *const y, int y_stride,
   1134                          const uint8_t *const u, const uint8_t *const v,
   1135                          int uv_stride, int height, int width, uint8_t *oy,
   1136                          int oy_stride, uint8_t *ou, uint8_t *ov,
   1137                          int ouv_stride, int oheight, int owidth) {
   1138   av1_resize_plane(y, height, width, y_stride, oy, oheight, owidth, oy_stride);
   1139   av1_resize_plane(u, height, width, uv_stride, ou, oheight, owidth,
   1140                    ouv_stride);
   1141   av1_resize_plane(v, height, width, uv_stride, ov, oheight, owidth,
   1142                    ouv_stride);
   1143 }
   1144 
   1145 void av1_highbd_resize_frame420(const uint8_t *const y, int y_stride,
   1146                                 const uint8_t *const u, const uint8_t *const v,
   1147                                 int uv_stride, int height, int width,
   1148                                 uint8_t *oy, int oy_stride, uint8_t *ou,
   1149                                 uint8_t *ov, int ouv_stride, int oheight,
   1150                                 int owidth, int bd) {
   1151   av1_highbd_resize_plane(y, height, width, y_stride, oy, oheight, owidth,
   1152                           oy_stride, bd);
   1153   av1_highbd_resize_plane(u, height / 2, width / 2, uv_stride, ou, oheight / 2,
   1154                           owidth / 2, ouv_stride, bd);
   1155   av1_highbd_resize_plane(v, height / 2, width / 2, uv_stride, ov, oheight / 2,
   1156                           owidth / 2, ouv_stride, bd);
   1157 }
   1158 
   1159 void av1_highbd_resize_frame422(const uint8_t *const y, int y_stride,
   1160                                 const uint8_t *const u, const uint8_t *const v,
   1161                                 int uv_stride, int height, int width,
   1162                                 uint8_t *oy, int oy_stride, uint8_t *ou,
   1163                                 uint8_t *ov, int ouv_stride, int oheight,
   1164                                 int owidth, int bd) {
   1165   av1_highbd_resize_plane(y, height, width, y_stride, oy, oheight, owidth,
   1166                           oy_stride, bd);
   1167   av1_highbd_resize_plane(u, height, width / 2, uv_stride, ou, oheight,
   1168                           owidth / 2, ouv_stride, bd);
   1169   av1_highbd_resize_plane(v, height, width / 2, uv_stride, ov, oheight,
   1170                           owidth / 2, ouv_stride, bd);
   1171 }
   1172 
   1173 void av1_highbd_resize_frame444(const uint8_t *const y, int y_stride,
   1174                                 const uint8_t *const u, const uint8_t *const v,
   1175                                 int uv_stride, int height, int width,
   1176                                 uint8_t *oy, int oy_stride, uint8_t *ou,
   1177                                 uint8_t *ov, int ouv_stride, int oheight,
   1178                                 int owidth, int bd) {
   1179   av1_highbd_resize_plane(y, height, width, y_stride, oy, oheight, owidth,
   1180                           oy_stride, bd);
   1181   av1_highbd_resize_plane(u, height, width, uv_stride, ou, oheight, owidth,
   1182                           ouv_stride, bd);
   1183   av1_highbd_resize_plane(v, height, width, uv_stride, ov, oheight, owidth,
   1184                           ouv_stride, bd);
   1185 }
   1186 
   1187 void av1_resize_and_extend_frame(const YV12_BUFFER_CONFIG *src,
   1188                                  YV12_BUFFER_CONFIG *dst, int bd,
   1189                                  const int num_planes) {
   1190   // TODO(dkovalev): replace YV12_BUFFER_CONFIG with aom_image_t
   1191 
   1192   // We use AOMMIN(num_planes, MAX_MB_PLANE) instead of num_planes to quiet
   1193   // the static analysis warnings.
   1194   for (int i = 0; i < AOMMIN(num_planes, MAX_MB_PLANE); ++i) {
   1195     const int is_uv = i > 0;
   1196     if (src->flags & YV12_FLAG_HIGHBITDEPTH)
   1197       av1_highbd_resize_plane(src->buffers[i], src->crop_heights[is_uv],
   1198                               src->crop_widths[is_uv], src->strides[is_uv],
   1199                               dst->buffers[i], dst->crop_heights[is_uv],
   1200                               dst->crop_widths[is_uv], dst->strides[is_uv], bd);
   1201     else
   1202       av1_resize_plane(src->buffers[i], src->crop_heights[is_uv],
   1203                        src->crop_widths[is_uv], src->strides[is_uv],
   1204                        dst->buffers[i], dst->crop_heights[is_uv],
   1205                        dst->crop_widths[is_uv], dst->strides[is_uv]);
   1206   }
   1207   aom_extend_frame_borders(dst, num_planes);
   1208 }
   1209 
   1210 void av1_upscale_normative_rows(const AV1_COMMON *cm, const uint8_t *src,
   1211                                 int src_stride, uint8_t *dst, int dst_stride,
   1212                                 int plane, int rows) {
   1213   const int is_uv = (plane > 0);
   1214   const int ss_x = is_uv && cm->seq_params.subsampling_x;
   1215   const int downscaled_plane_width = ROUND_POWER_OF_TWO(cm->width, ss_x);
   1216   const int upscaled_plane_width =
   1217       ROUND_POWER_OF_TWO(cm->superres_upscaled_width, ss_x);
   1218   const int superres_denom = cm->superres_scale_denominator;
   1219 
   1220   TileInfo tile_col;
   1221   const int32_t x_step_qn = av1_get_upscale_convolve_step(
   1222       downscaled_plane_width, upscaled_plane_width);
   1223   int32_t x0_qn = get_upscale_convolve_x0(downscaled_plane_width,
   1224                                           upscaled_plane_width, x_step_qn);
   1225 
   1226   for (int j = 0; j < cm->tile_cols; j++) {
   1227     av1_tile_set_col(&tile_col, cm, j);
   1228     // Determine the limits of this tile column in both the source
   1229     // and destination images.
   1230     // Note: The actual location which we start sampling from is
   1231     // (downscaled_x0 - 1 + (x0_qn/2^14)), and this quantity increases
   1232     // by exactly dst_width * (x_step_qn/2^14) pixels each iteration.
   1233     const int downscaled_x0 = tile_col.mi_col_start << (MI_SIZE_LOG2 - ss_x);
   1234     const int downscaled_x1 = tile_col.mi_col_end << (MI_SIZE_LOG2 - ss_x);
   1235     const int src_width = downscaled_x1 - downscaled_x0;
   1236 
   1237     const int upscaled_x0 = (downscaled_x0 * superres_denom) / SCALE_NUMERATOR;
   1238     int upscaled_x1;
   1239     if (j == cm->tile_cols - 1) {
   1240       // Note that we can't just use AOMMIN here - due to rounding,
   1241       // (downscaled_x1 * superres_denom) / SCALE_NUMERATOR may be less than
   1242       // upscaled_plane_width.
   1243       upscaled_x1 = upscaled_plane_width;
   1244     } else {
   1245       upscaled_x1 = (downscaled_x1 * superres_denom) / SCALE_NUMERATOR;
   1246     }
   1247 
   1248     const uint8_t *const src_ptr = src + downscaled_x0;
   1249     uint8_t *const dst_ptr = dst + upscaled_x0;
   1250     const int dst_width = upscaled_x1 - upscaled_x0;
   1251 
   1252     const int pad_left = (j == 0);
   1253     const int pad_right = (j == cm->tile_cols - 1);
   1254 
   1255     if (cm->seq_params.use_highbitdepth)
   1256       highbd_upscale_normative_rect(src_ptr, rows, src_width, src_stride,
   1257                                     dst_ptr, rows, dst_width, dst_stride,
   1258                                     x_step_qn, x0_qn, pad_left, pad_right,
   1259                                     cm->seq_params.bit_depth);
   1260     else
   1261       upscale_normative_rect(src_ptr, rows, src_width, src_stride, dst_ptr,
   1262                              rows, dst_width, dst_stride, x_step_qn, x0_qn,
   1263                              pad_left, pad_right);
   1264 
   1265     // Update the fractional pixel offset to prepare for the next tile column.
   1266     x0_qn += (dst_width * x_step_qn) - (src_width << RS_SCALE_SUBPEL_BITS);
   1267   }
   1268 }
   1269 
   1270 void av1_upscale_normative_and_extend_frame(const AV1_COMMON *cm,
   1271                                             const YV12_BUFFER_CONFIG *src,
   1272                                             YV12_BUFFER_CONFIG *dst) {
   1273   const int num_planes = av1_num_planes(cm);
   1274   for (int i = 0; i < num_planes; ++i) {
   1275     const int is_uv = (i > 0);
   1276     av1_upscale_normative_rows(cm, src->buffers[i], src->strides[is_uv],
   1277                                dst->buffers[i], dst->strides[is_uv], i,
   1278                                src->crop_heights[is_uv]);
   1279   }
   1280 
   1281   aom_extend_frame_borders(dst, num_planes);
   1282 }
   1283 
   1284 YV12_BUFFER_CONFIG *av1_scale_if_required(AV1_COMMON *cm,
   1285                                           YV12_BUFFER_CONFIG *unscaled,
   1286                                           YV12_BUFFER_CONFIG *scaled) {
   1287   const int num_planes = av1_num_planes(cm);
   1288   if (cm->width != unscaled->y_crop_width ||
   1289       cm->height != unscaled->y_crop_height) {
   1290     av1_resize_and_extend_frame(unscaled, scaled, (int)cm->seq_params.bit_depth,
   1291                                 num_planes);
   1292     return scaled;
   1293   } else {
   1294     return unscaled;
   1295   }
   1296 }
   1297 
   1298 // Calculates the scaled dimension given the original dimension and the scale
   1299 // denominator.
   1300 static void calculate_scaled_size_helper(int *dim, int denom) {
   1301   if (denom != SCALE_NUMERATOR) {
   1302     // We need to ensure the constraint in "Appendix A" of the spec:
   1303     // * FrameWidth is greater than or equal to 16
   1304     // * FrameHeight is greater than or equal to 16
   1305     // For this, we clamp the downscaled dimension to at least 16. One
   1306     // exception: if original dimension itself was < 16, then we keep the
   1307     // downscaled dimension to be same as the original, to ensure that resizing
   1308     // is valid.
   1309     const int min_dim = AOMMIN(16, *dim);
   1310     // Use this version if we need *dim to be even
   1311     // *width = (*width * SCALE_NUMERATOR + denom) / (2 * denom);
   1312     // *width <<= 1;
   1313     *dim = (*dim * SCALE_NUMERATOR + denom / 2) / (denom);
   1314     *dim = AOMMAX(*dim, min_dim);
   1315   }
   1316 }
   1317 
   1318 void av1_calculate_scaled_size(int *width, int *height, int resize_denom) {
   1319   calculate_scaled_size_helper(width, resize_denom);
   1320   calculate_scaled_size_helper(height, resize_denom);
   1321 }
   1322 
   1323 void av1_calculate_scaled_superres_size(int *width, int *height,
   1324                                         int superres_denom) {
   1325   (void)height;
   1326   calculate_scaled_size_helper(width, superres_denom);
   1327 }
   1328 
   1329 void av1_calculate_unscaled_superres_size(int *width, int *height, int denom) {
   1330   if (denom != SCALE_NUMERATOR) {
   1331     // Note: av1_calculate_scaled_superres_size() rounds *up* after division
   1332     // when the resulting dimensions are odd. So here, we round *down*.
   1333     *width = *width * denom / SCALE_NUMERATOR;
   1334     (void)height;
   1335   }
   1336 }
   1337 
   1338 // Copy only the config data from 'src' to 'dst'.
   1339 static void copy_buffer_config(const YV12_BUFFER_CONFIG *const src,
   1340                                YV12_BUFFER_CONFIG *const dst) {
   1341   dst->bit_depth = src->bit_depth;
   1342   dst->color_primaries = src->color_primaries;
   1343   dst->transfer_characteristics = src->transfer_characteristics;
   1344   dst->matrix_coefficients = src->matrix_coefficients;
   1345   dst->monochrome = src->monochrome;
   1346   dst->chroma_sample_position = src->chroma_sample_position;
   1347   dst->color_range = src->color_range;
   1348 }
   1349 
   1350 // TODO(afergs): Look for in-place upscaling
   1351 // TODO(afergs): aom_ vs av1_ functions? Which can I use?
   1352 // Upscale decoded image.
   1353 void av1_superres_upscale(AV1_COMMON *cm, BufferPool *const pool) {
   1354   const int num_planes = av1_num_planes(cm);
   1355   if (!av1_superres_scaled(cm)) return;
   1356   const SequenceHeader *const seq_params = &cm->seq_params;
   1357 
   1358   YV12_BUFFER_CONFIG copy_buffer;
   1359   memset(&copy_buffer, 0, sizeof(copy_buffer));
   1360 
   1361   YV12_BUFFER_CONFIG *const frame_to_show = &cm->cur_frame->buf;
   1362 
   1363   const int aligned_width = ALIGN_POWER_OF_TWO(cm->width, 3);
   1364   if (aom_alloc_frame_buffer(
   1365           &copy_buffer, aligned_width, cm->height, seq_params->subsampling_x,
   1366           seq_params->subsampling_y, seq_params->use_highbitdepth,
   1367           AOM_BORDER_IN_PIXELS, cm->byte_alignment))
   1368     aom_internal_error(&cm->error, AOM_CODEC_MEM_ERROR,
   1369                        "Failed to allocate copy buffer for superres upscaling");
   1370 
   1371   // Copy function assumes the frames are the same size.
   1372   // Note that it does not copy YV12_BUFFER_CONFIG config data.
   1373   aom_yv12_copy_frame(frame_to_show, &copy_buffer, num_planes);
   1374 
   1375   assert(copy_buffer.y_crop_width == aligned_width);
   1376   assert(copy_buffer.y_crop_height == cm->height);
   1377 
   1378   // Realloc the current frame buffer at a higher resolution in place.
   1379   if (pool != NULL) {
   1380     // Use callbacks if on the decoder.
   1381     aom_codec_frame_buffer_t *fb = &cm->cur_frame->raw_frame_buffer;
   1382     aom_release_frame_buffer_cb_fn_t release_fb_cb = pool->release_fb_cb;
   1383     aom_get_frame_buffer_cb_fn_t cb = pool->get_fb_cb;
   1384     void *cb_priv = pool->cb_priv;
   1385 
   1386     // Realloc with callback does not release the frame buffer - release first.
   1387     if (release_fb_cb(cb_priv, fb))
   1388       aom_internal_error(
   1389           &cm->error, AOM_CODEC_MEM_ERROR,
   1390           "Failed to free current frame buffer before superres upscaling");
   1391 
   1392     // aom_realloc_frame_buffer() leaves config data for frame_to_show intact
   1393     if (aom_realloc_frame_buffer(
   1394             frame_to_show, cm->superres_upscaled_width,
   1395             cm->superres_upscaled_height, seq_params->subsampling_x,
   1396             seq_params->subsampling_y, seq_params->use_highbitdepth,
   1397             AOM_BORDER_IN_PIXELS, cm->byte_alignment, fb, cb, cb_priv))
   1398       aom_internal_error(
   1399           &cm->error, AOM_CODEC_MEM_ERROR,
   1400           "Failed to allocate current frame buffer for superres upscaling");
   1401   } else {
   1402     // Make a copy of the config data for frame_to_show in copy_buffer
   1403     copy_buffer_config(frame_to_show, &copy_buffer);
   1404 
   1405     // Don't use callbacks on the encoder.
   1406     // aom_alloc_frame_buffer() clears the config data for frame_to_show
   1407     if (aom_alloc_frame_buffer(
   1408             frame_to_show, cm->superres_upscaled_width,
   1409             cm->superres_upscaled_height, seq_params->subsampling_x,
   1410             seq_params->subsampling_y, seq_params->use_highbitdepth,
   1411             AOM_BORDER_IN_PIXELS, cm->byte_alignment))
   1412       aom_internal_error(
   1413           &cm->error, AOM_CODEC_MEM_ERROR,
   1414           "Failed to reallocate current frame buffer for superres upscaling");
   1415 
   1416     // Restore config data back to frame_to_show
   1417     copy_buffer_config(&copy_buffer, frame_to_show);
   1418   }
   1419   // TODO(afergs): verify frame_to_show is correct after realloc
   1420   //               encoder:
   1421   //               decoder:
   1422 
   1423   assert(frame_to_show->y_crop_width == cm->superres_upscaled_width);
   1424   assert(frame_to_show->y_crop_height == cm->superres_upscaled_height);
   1425 
   1426   // Scale up and back into frame_to_show.
   1427   assert(frame_to_show->y_crop_width != cm->width);
   1428   av1_upscale_normative_and_extend_frame(cm, &copy_buffer, frame_to_show);
   1429 
   1430   // Free the copy buffer
   1431   aom_free_frame_buffer(&copy_buffer);
   1432 }
   1433