third_party/libwebp/dsp/dec.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
DspInitTables
clip_8b
TransformOne
TransformAC3
TransformTwo
TransformUV
TransformDC
TransformDCUV
TransformWHT
TrueMotion
TM4
TM8uv
TM16
VE16
HE16
Put16
DC16
DC16NoTop
DC16NoLeft
DC16NoTopLeft
VE4
HE4
DC4
RD4
LD4
VR4
VL4
HU4
HD4
VE8uv
HE8uv
Put8x8uv
DC8uv
DC8uvNoLeft
DC8uvNoTop
DC8uvNoTopLeft
do_filter2
do_filter4
do_filter6
hev
needs_filter
needs_filter2
SimpleVFilter16
SimpleHFilter16
SimpleVFilter16i
SimpleHFilter16i
FilterLoop26
FilterLoop24
VFilter16
HFilter16
VFilter16i
HFilter16i
VFilter8
HFilter8
VFilter8i
HFilter8i
VP8DspInit
// Copyright 2010 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING 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.
// -----------------------------------------------------------------------------
//
// Speed-critical decoding functions.
//
// Author: Skal (pascal.massimino@gmail.com)

#include "./dsp.h"
#include "../dec/vp8i.h"

//------------------------------------------------------------------------------
// run-time tables (~4k)

static uint8_t abs0[255 + 255 + 1];     // abs(i)
static uint8_t abs1[255 + 255 + 1];     // abs(i)>>1
static int8_t sclip1[1020 + 1020 + 1];  // clips [-1020, 1020] to [-128, 127]
static int8_t sclip2[112 + 112 + 1];    // clips [-112, 112] to [-16, 15]
static uint8_t clip1[255 + 510 + 1];    // clips [-255,510] to [0,255]

// We declare this variable 'volatile' to prevent instruction reordering
// and make sure it's set to true _last_ (so as to be thread-safe)
static volatile int tables_ok = 0;

static void DspInitTables(void) {
  if (!tables_ok) {
    int i;
    for (i = -255; i <= 255; ++i) {
      abs0[255 + i] = (i < 0) ? -i : i;
      abs1[255 + i] = abs0[255 + i] >> 1;
    }
    for (i = -1020; i <= 1020; ++i) {
      sclip1[1020 + i] = (i < -128) ? -128 : (i > 127) ? 127 : i;
    }
    for (i = -112; i <= 112; ++i) {
      sclip2[112 + i] = (i < -16) ? -16 : (i > 15) ? 15 : i;
    }
    for (i = -255; i <= 255 + 255; ++i) {
      clip1[255 + i] = (i < 0) ? 0 : (i > 255) ? 255 : i;
    }
    tables_ok = 1;
  }
}

static WEBP_INLINE uint8_t clip_8b(int v) {
  return (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
}

//------------------------------------------------------------------------------
// Transforms (Paragraph 14.4)

#define STORE(x, y, v) \
  dst[x + y * BPS] = clip_8b(dst[x + y * BPS] + ((v) >> 3))

#define STORE2(y, dc, d, c) do {    \
  const int DC = (dc);              \
  STORE(0, y, DC + (d));            \
  STORE(1, y, DC + (c));            \
  STORE(2, y, DC - (c));            \
  STORE(3, y, DC - (d));            \
} while (0)

static const int kC1 = 20091 + (1 << 16);
static const int kC2 = 35468;
#define MUL(a, b) (((a) * (b)) >> 16)

static void TransformOne(const int16_t* in, uint8_t* dst) {
  int C[4 * 4], *tmp;
  int i;
  tmp = C;
  for (i = 0; i < 4; ++i) {    // vertical pass
    const int a = in[0] + in[8];    // [-4096, 4094]
    const int b = in[0] - in[8];    // [-4095, 4095]
    const int c = MUL(in[4], kC2) - MUL(in[12], kC1);   // [-3783, 3783]
    const int d = MUL(in[4], kC1) + MUL(in[12], kC2);   // [-3785, 3781]
    tmp[0] = a + d;   // [-7881, 7875]
    tmp[1] = b + c;   // [-7878, 7878]
    tmp[2] = b - c;   // [-7878, 7878]
    tmp[3] = a - d;   // [-7877, 7879]
    tmp += 4;
    in++;
  }
  // Each pass is expanding the dynamic range by ~3.85 (upper bound).
  // The exact value is (2. + (kC1 + kC2) / 65536).
  // After the second pass, maximum interval is [-3794, 3794], assuming
  // an input in [-2048, 2047] interval. We then need to add a dst value
  // in the [0, 255] range.
  // In the worst case scenario, the input to clip_8b() can be as large as
  // [-60713, 60968].
  tmp = C;
  for (i = 0; i < 4; ++i) {    // horizontal pass
    const int dc = tmp[0] + 4;
    const int a =  dc +  tmp[8];
    const int b =  dc -  tmp[8];
    const int c = MUL(tmp[4], kC2) - MUL(tmp[12], kC1);
    const int d = MUL(tmp[4], kC1) + MUL(tmp[12], kC2);
    STORE(0, 0, a + d);
    STORE(1, 0, b + c);
    STORE(2, 0, b - c);
    STORE(3, 0, a - d);
    tmp++;
    dst += BPS;
  }
}

// Simplified transform when only in[0], in[1] and in[4] are non-zero
static void TransformAC3(const int16_t* in, uint8_t* dst) {
  const int a = in[0] + 4;
  const int c4 = MUL(in[4], kC2);
  const int d4 = MUL(in[4], kC1);
  const int c1 = MUL(in[1], kC2);
  const int d1 = MUL(in[1], kC1);
  STORE2(0, a + d4, d1, c1);
  STORE2(1, a + c4, d1, c1);
  STORE2(2, a - c4, d1, c1);
  STORE2(3, a - d4, d1, c1);
}
#undef MUL
#undef STORE2

static void TransformTwo(const int16_t* in, uint8_t* dst, int do_two) {
  TransformOne(in, dst);
  if (do_two) {
    TransformOne(in + 16, dst + 4);
  }
}

static void TransformUV(const int16_t* in, uint8_t* dst) {
  VP8Transform(in + 0 * 16, dst, 1);
  VP8Transform(in + 2 * 16, dst + 4 * BPS, 1);
}

static void TransformDC(const int16_t *in, uint8_t* dst) {
  const int DC = in[0] + 4;
  int i, j;
  for (j = 0; j < 4; ++j) {
    for (i = 0; i < 4; ++i) {
      STORE(i, j, DC);
    }
  }
}

static void TransformDCUV(const int16_t* in, uint8_t* dst) {
  if (in[0 * 16]) TransformDC(in + 0 * 16, dst);
  if (in[1 * 16]) TransformDC(in + 1 * 16, dst + 4);
  if (in[2 * 16]) TransformDC(in + 2 * 16, dst + 4 * BPS);
  if (in[3 * 16]) TransformDC(in + 3 * 16, dst + 4 * BPS + 4);
}

#undef STORE

//------------------------------------------------------------------------------
// Paragraph 14.3

static void TransformWHT(const int16_t* in, int16_t* out) {
  int tmp[16];
  int i;
  for (i = 0; i < 4; ++i) {
    const int a0 = in[0 + i] + in[12 + i];
    const int a1 = in[4 + i] + in[ 8 + i];
    const int a2 = in[4 + i] - in[ 8 + i];
    const int a3 = in[0 + i] - in[12 + i];
    tmp[0  + i] = a0 + a1;
    tmp[8  + i] = a0 - a1;
    tmp[4  + i] = a3 + a2;
    tmp[12 + i] = a3 - a2;
  }
  for (i = 0; i < 4; ++i) {
    const int dc = tmp[0 + i * 4] + 3;    // w/ rounder
    const int a0 = dc             + tmp[3 + i * 4];
    const int a1 = tmp[1 + i * 4] + tmp[2 + i * 4];
    const int a2 = tmp[1 + i * 4] - tmp[2 + i * 4];
    const int a3 = dc             - tmp[3 + i * 4];
    out[ 0] = (a0 + a1) >> 3;
    out[16] = (a3 + a2) >> 3;
    out[32] = (a0 - a1) >> 3;
    out[48] = (a3 - a2) >> 3;
    out += 64;
  }
}

void (*VP8TransformWHT)(const int16_t* in, int16_t* out) = TransformWHT;

//------------------------------------------------------------------------------
// Intra predictions

#define DST(x, y) dst[(x) + (y) * BPS]

static WEBP_INLINE void TrueMotion(uint8_t *dst, int size) {
  const uint8_t* top = dst - BPS;
  const uint8_t* const clip0 = clip1 + 255 - top[-1];
  int y;
  for (y = 0; y < size; ++y) {
    const uint8_t* const clip = clip0 + dst[-1];
    int x;
    for (x = 0; x < size; ++x) {
      dst[x] = clip[top[x]];
    }
    dst += BPS;
  }
}
static void TM4(uint8_t *dst)   { TrueMotion(dst, 4); }
static void TM8uv(uint8_t *dst) { TrueMotion(dst, 8); }
static void TM16(uint8_t *dst)  { TrueMotion(dst, 16); }

//------------------------------------------------------------------------------
// 16x16

static void VE16(uint8_t *dst) {     // vertical
  int j;
  for (j = 0; j < 16; ++j) {
    memcpy(dst + j * BPS, dst - BPS, 16);
  }
}

static void HE16(uint8_t *dst) {     // horizontal
  int j;
  for (j = 16; j > 0; --j) {
    memset(dst, dst[-1], 16);
    dst += BPS;
  }
}

static WEBP_INLINE void Put16(int v, uint8_t* dst) {
  int j;
  for (j = 0; j < 16; ++j) {
    memset(dst + j * BPS, v, 16);
  }
}

static void DC16(uint8_t *dst) {    // DC
  int DC = 16;
  int j;
  for (j = 0; j < 16; ++j) {
    DC += dst[-1 + j * BPS] + dst[j - BPS];
  }
  Put16(DC >> 5, dst);
}

static void DC16NoTop(uint8_t *dst) {   // DC with top samples not available
  int DC = 8;
  int j;
  for (j = 0; j < 16; ++j) {
    DC += dst[-1 + j * BPS];
  }
  Put16(DC >> 4, dst);
}

static void DC16NoLeft(uint8_t *dst) {  // DC with left samples not available
  int DC = 8;
  int i;
  for (i = 0; i < 16; ++i) {
    DC += dst[i - BPS];
  }
  Put16(DC >> 4, dst);
}

static void DC16NoTopLeft(uint8_t *dst) {  // DC with no top and left samples
  Put16(0x80, dst);
}

//------------------------------------------------------------------------------
// 4x4

#define AVG3(a, b, c) (((a) + 2 * (b) + (c) + 2) >> 2)
#define AVG2(a, b) (((a) + (b) + 1) >> 1)

static void VE4(uint8_t *dst) {    // vertical
  const uint8_t* top = dst - BPS;
  const uint8_t vals[4] = {
    AVG3(top[-1], top[0], top[1]),
    AVG3(top[ 0], top[1], top[2]),
    AVG3(top[ 1], top[2], top[3]),
    AVG3(top[ 2], top[3], top[4])
  };
  int i;
  for (i = 0; i < 4; ++i) {
    memcpy(dst + i * BPS, vals, sizeof(vals));
  }
}

static void HE4(uint8_t *dst) {    // horizontal
  const int A = dst[-1 - BPS];
  const int B = dst[-1];
  const int C = dst[-1 + BPS];
  const int D = dst[-1 + 2 * BPS];
  const int E = dst[-1 + 3 * BPS];
  *(uint32_t*)(dst + 0 * BPS) = 0x01010101U * AVG3(A, B, C);
  *(uint32_t*)(dst + 1 * BPS) = 0x01010101U * AVG3(B, C, D);
  *(uint32_t*)(dst + 2 * BPS) = 0x01010101U * AVG3(C, D, E);
  *(uint32_t*)(dst + 3 * BPS) = 0x01010101U * AVG3(D, E, E);
}

static void DC4(uint8_t *dst) {   // DC
  uint32_t dc = 4;
  int i;
  for (i = 0; i < 4; ++i) dc += dst[i - BPS] + dst[-1 + i * BPS];
  dc >>= 3;
  for (i = 0; i < 4; ++i) memset(dst + i * BPS, dc, 4);
}

static void RD4(uint8_t *dst) {   // Down-right
  const int I = dst[-1 + 0 * BPS];
  const int J = dst[-1 + 1 * BPS];
  const int K = dst[-1 + 2 * BPS];
  const int L = dst[-1 + 3 * BPS];
  const int X = dst[-1 - BPS];
  const int A = dst[0 - BPS];
  const int B = dst[1 - BPS];
  const int C = dst[2 - BPS];
  const int D = dst[3 - BPS];
  DST(0, 3)                                     = AVG3(J, K, L);
  DST(0, 2) = DST(1, 3)                         = AVG3(I, J, K);
  DST(0, 1) = DST(1, 2) = DST(2, 3)             = AVG3(X, I, J);
  DST(0, 0) = DST(1, 1) = DST(2, 2) = DST(3, 3) = AVG3(A, X, I);
  DST(1, 0) = DST(2, 1) = DST(3, 2)             = AVG3(B, A, X);
  DST(2, 0) = DST(3, 1)                         = AVG3(C, B, A);
  DST(3, 0)                                     = AVG3(D, C, B);
}

static void LD4(uint8_t *dst) {   // Down-Left
  const int A = dst[0 - BPS];
  const int B = dst[1 - BPS];
  const int C = dst[2 - BPS];
  const int D = dst[3 - BPS];
  const int E = dst[4 - BPS];
  const int F = dst[5 - BPS];
  const int G = dst[6 - BPS];
  const int H = dst[7 - BPS];
  DST(0, 0)                                     = AVG3(A, B, C);
  DST(1, 0) = DST(0, 1)                         = AVG3(B, C, D);
  DST(2, 0) = DST(1, 1) = DST(0, 2)             = AVG3(C, D, E);
  DST(3, 0) = DST(2, 1) = DST(1, 2) = DST(0, 3) = AVG3(D, E, F);
  DST(3, 1) = DST(2, 2) = DST(1, 3)             = AVG3(E, F, G);
  DST(3, 2) = DST(2, 3)                         = AVG3(F, G, H);
  DST(3, 3)                                     = AVG3(G, H, H);
}

static void VR4(uint8_t *dst) {   // Vertical-Right
  const int I = dst[-1 + 0 * BPS];
  const int J = dst[-1 + 1 * BPS];
  const int K = dst[-1 + 2 * BPS];
  const int X = dst[-1 - BPS];
  const int A = dst[0 - BPS];
  const int B = dst[1 - BPS];
  const int C = dst[2 - BPS];
  const int D = dst[3 - BPS];
  DST(0, 0) = DST(1, 2) = AVG2(X, A);
  DST(1, 0) = DST(2, 2) = AVG2(A, B);
  DST(2, 0) = DST(3, 2) = AVG2(B, C);
  DST(3, 0)             = AVG2(C, D);

  DST(0, 3) =             AVG3(K, J, I);
  DST(0, 2) =             AVG3(J, I, X);
  DST(0, 1) = DST(1, 3) = AVG3(I, X, A);
  DST(1, 1) = DST(2, 3) = AVG3(X, A, B);
  DST(2, 1) = DST(3, 3) = AVG3(A, B, C);
  DST(3, 1) =             AVG3(B, C, D);
}

static void VL4(uint8_t *dst) {   // Vertical-Left
  const int A = dst[0 - BPS];
  const int B = dst[1 - BPS];
  const int C = dst[2 - BPS];
  const int D = dst[3 - BPS];
  const int E = dst[4 - BPS];
  const int F = dst[5 - BPS];
  const int G = dst[6 - BPS];
  const int H = dst[7 - BPS];
  DST(0, 0) =             AVG2(A, B);
  DST(1, 0) = DST(0, 2) = AVG2(B, C);
  DST(2, 0) = DST(1, 2) = AVG2(C, D);
  DST(3, 0) = DST(2, 2) = AVG2(D, E);

  DST(0, 1) =             AVG3(A, B, C);
  DST(1, 1) = DST(0, 3) = AVG3(B, C, D);
  DST(2, 1) = DST(1, 3) = AVG3(C, D, E);
  DST(3, 1) = DST(2, 3) = AVG3(D, E, F);
              DST(3, 2) = AVG3(E, F, G);
              DST(3, 3) = AVG3(F, G, H);
}

static void HU4(uint8_t *dst) {   // Horizontal-Up
  const int I = dst[-1 + 0 * BPS];
  const int J = dst[-1 + 1 * BPS];
  const int K = dst[-1 + 2 * BPS];
  const int L = dst[-1 + 3 * BPS];
  DST(0, 0) =             AVG2(I, J);
  DST(2, 0) = DST(0, 1) = AVG2(J, K);
  DST(2, 1) = DST(0, 2) = AVG2(K, L);
  DST(1, 0) =             AVG3(I, J, K);
  DST(3, 0) = DST(1, 1) = AVG3(J, K, L);
  DST(3, 1) = DST(1, 2) = AVG3(K, L, L);
  DST(3, 2) = DST(2, 2) =
    DST(0, 3) = DST(1, 3) = DST(2, 3) = DST(3, 3) = L;
}

static void HD4(uint8_t *dst) {  // Horizontal-Down
  const int I = dst[-1 + 0 * BPS];
  const int J = dst[-1 + 1 * BPS];
  const int K = dst[-1 + 2 * BPS];
  const int L = dst[-1 + 3 * BPS];
  const int X = dst[-1 - BPS];
  const int A = dst[0 - BPS];
  const int B = dst[1 - BPS];
  const int C = dst[2 - BPS];

  DST(0, 0) = DST(2, 1) = AVG2(I, X);
  DST(0, 1) = DST(2, 2) = AVG2(J, I);
  DST(0, 2) = DST(2, 3) = AVG2(K, J);
  DST(0, 3)             = AVG2(L, K);

  DST(3, 0)             = AVG3(A, B, C);
  DST(2, 0)             = AVG3(X, A, B);
  DST(1, 0) = DST(3, 1) = AVG3(I, X, A);
  DST(1, 1) = DST(3, 2) = AVG3(J, I, X);
  DST(1, 2) = DST(3, 3) = AVG3(K, J, I);
  DST(1, 3)             = AVG3(L, K, J);
}

#undef DST
#undef AVG3
#undef AVG2

//------------------------------------------------------------------------------
// Chroma

static void VE8uv(uint8_t *dst) {    // vertical
  int j;
  for (j = 0; j < 8; ++j) {
    memcpy(dst + j * BPS, dst - BPS, 8);
  }
}

static void HE8uv(uint8_t *dst) {    // horizontal
  int j;
  for (j = 0; j < 8; ++j) {
    memset(dst, dst[-1], 8);
    dst += BPS;
  }
}

// helper for chroma-DC predictions
static WEBP_INLINE void Put8x8uv(uint8_t value, uint8_t* dst) {
  int j;
#ifndef WEBP_REFERENCE_IMPLEMENTATION
  const uint64_t v = (uint64_t)value * 0x0101010101010101ULL;
  for (j = 0; j < 8; ++j) {
    *(uint64_t*)(dst + j * BPS) = v;
  }
#else
  for (j = 0; j < 8; ++j) memset(dst + j * BPS, value, 8);
#endif
}

static void DC8uv(uint8_t *dst) {     // DC
  int dc0 = 8;
  int i;
  for (i = 0; i < 8; ++i) {
    dc0 += dst[i - BPS] + dst[-1 + i * BPS];
  }
  Put8x8uv(dc0 >> 4, dst);
}

static void DC8uvNoLeft(uint8_t *dst) {   // DC with no left samples
  int dc0 = 4;
  int i;
  for (i = 0; i < 8; ++i) {
    dc0 += dst[i - BPS];
  }
  Put8x8uv(dc0 >> 3, dst);
}

static void DC8uvNoTop(uint8_t *dst) {  // DC with no top samples
  int dc0 = 4;
  int i;
  for (i = 0; i < 8; ++i) {
    dc0 += dst[-1 + i * BPS];
  }
  Put8x8uv(dc0 >> 3, dst);
}

static void DC8uvNoTopLeft(uint8_t *dst) {    // DC with nothing
  Put8x8uv(0x80, dst);
}

//------------------------------------------------------------------------------
// default C implementations

const VP8PredFunc VP8PredLuma4[NUM_BMODES] = {
  DC4, TM4, VE4, HE4, RD4, VR4, LD4, VL4, HD4, HU4
};

const VP8PredFunc VP8PredLuma16[NUM_B_DC_MODES] = {
  DC16, TM16, VE16, HE16,
  DC16NoTop, DC16NoLeft, DC16NoTopLeft
};

const VP8PredFunc VP8PredChroma8[NUM_B_DC_MODES] = {
  DC8uv, TM8uv, VE8uv, HE8uv,
  DC8uvNoTop, DC8uvNoLeft, DC8uvNoTopLeft
};

//------------------------------------------------------------------------------
// Edge filtering functions

// 4 pixels in, 2 pixels out
static WEBP_INLINE void do_filter2(uint8_t* p, int step) {
  const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
  const int a = 3 * (q0 - p0) + sclip1[1020 + p1 - q1];
  const int a1 = sclip2[112 + ((a + 4) >> 3)];
  const int a2 = sclip2[112 + ((a + 3) >> 3)];
  p[-step] = clip1[255 + p0 + a2];
  p[    0] = clip1[255 + q0 - a1];
}

// 4 pixels in, 4 pixels out
static WEBP_INLINE void do_filter4(uint8_t* p, int step) {
  const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
  const int a = 3 * (q0 - p0);
  const int a1 = sclip2[112 + ((a + 4) >> 3)];
  const int a2 = sclip2[112 + ((a + 3) >> 3)];
  const int a3 = (a1 + 1) >> 1;
  p[-2*step] = clip1[255 + p1 + a3];
  p[-  step] = clip1[255 + p0 + a2];
  p[      0] = clip1[255 + q0 - a1];
  p[   step] = clip1[255 + q1 - a3];
}

// 6 pixels in, 6 pixels out
static WEBP_INLINE void do_filter6(uint8_t* p, int step) {
  const int p2 = p[-3*step], p1 = p[-2*step], p0 = p[-step];
  const int q0 = p[0], q1 = p[step], q2 = p[2*step];
  const int a = sclip1[1020 + 3 * (q0 - p0) + sclip1[1020 + p1 - q1]];
  const int a1 = (27 * a + 63) >> 7;  // eq. to ((3 * a + 7) * 9) >> 7
  const int a2 = (18 * a + 63) >> 7;  // eq. to ((2 * a + 7) * 9) >> 7
  const int a3 = (9  * a + 63) >> 7;  // eq. to ((1 * a + 7) * 9) >> 7
  p[-3*step] = clip1[255 + p2 + a3];
  p[-2*step] = clip1[255 + p1 + a2];
  p[-  step] = clip1[255 + p0 + a1];
  p[      0] = clip1[255 + q0 - a1];
  p[   step] = clip1[255 + q1 - a2];
  p[ 2*step] = clip1[255 + q2 - a3];
}

static WEBP_INLINE int hev(const uint8_t* p, int step, int thresh) {
  const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
  return (abs0[255 + p1 - p0] > thresh) || (abs0[255 + q1 - q0] > thresh);
}

static WEBP_INLINE int needs_filter(const uint8_t* p, int step, int thresh) {
  const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
  return (2 * abs0[255 + p0 - q0] + abs1[255 + p1 - q1]) <= thresh;
}

static WEBP_INLINE int needs_filter2(const uint8_t* p,
                                     int step, int t, int it) {
  const int p3 = p[-4*step], p2 = p[-3*step], p1 = p[-2*step], p0 = p[-step];
  const int q0 = p[0], q1 = p[step], q2 = p[2*step], q3 = p[3*step];
  if ((2 * abs0[255 + p0 - q0] + abs1[255 + p1 - q1]) > t)
    return 0;
  return abs0[255 + p3 - p2] <= it && abs0[255 + p2 - p1] <= it &&
         abs0[255 + p1 - p0] <= it && abs0[255 + q3 - q2] <= it &&
         abs0[255 + q2 - q1] <= it && abs0[255 + q1 - q0] <= it;
}

//------------------------------------------------------------------------------
// Simple In-loop filtering (Paragraph 15.2)

static void SimpleVFilter16(uint8_t* p, int stride, int thresh) {
  int i;
  for (i = 0; i < 16; ++i) {
    if (needs_filter(p + i, stride, thresh)) {
      do_filter2(p + i, stride);
    }
  }
}

static void SimpleHFilter16(uint8_t* p, int stride, int thresh) {
  int i;
  for (i = 0; i < 16; ++i) {
    if (needs_filter(p + i * stride, 1, thresh)) {
      do_filter2(p + i * stride, 1);
    }
  }
}

static void SimpleVFilter16i(uint8_t* p, int stride, int thresh) {
  int k;
  for (k = 3; k > 0; --k) {
    p += 4 * stride;
    SimpleVFilter16(p, stride, thresh);
  }
}

static void SimpleHFilter16i(uint8_t* p, int stride, int thresh) {
  int k;
  for (k = 3; k > 0; --k) {
    p += 4;
    SimpleHFilter16(p, stride, thresh);
  }
}

//------------------------------------------------------------------------------
// Complex In-loop filtering (Paragraph 15.3)

static WEBP_INLINE void FilterLoop26(uint8_t* p,
                                     int hstride, int vstride, int size,
                                     int thresh, int ithresh, int hev_thresh) {
  while (size-- > 0) {
    if (needs_filter2(p, hstride, thresh, ithresh)) {
      if (hev(p, hstride, hev_thresh)) {
        do_filter2(p, hstride);
      } else {
        do_filter6(p, hstride);
      }
    }
    p += vstride;
  }
}

static WEBP_INLINE void FilterLoop24(uint8_t* p,
                                     int hstride, int vstride, int size,
                                     int thresh, int ithresh, int hev_thresh) {
  while (size-- > 0) {
    if (needs_filter2(p, hstride, thresh, ithresh)) {
      if (hev(p, hstride, hev_thresh)) {
        do_filter2(p, hstride);
      } else {
        do_filter4(p, hstride);
      }
    }
    p += vstride;
  }
}

// on macroblock edges
static void VFilter16(uint8_t* p, int stride,
                      int thresh, int ithresh, int hev_thresh) {
  FilterLoop26(p, stride, 1, 16, thresh, ithresh, hev_thresh);
}

static void HFilter16(uint8_t* p, int stride,
                      int thresh, int ithresh, int hev_thresh) {
  FilterLoop26(p, 1, stride, 16, thresh, ithresh, hev_thresh);
}

// on three inner edges
static void VFilter16i(uint8_t* p, int stride,
                       int thresh, int ithresh, int hev_thresh) {
  int k;
  for (k = 3; k > 0; --k) {
    p += 4 * stride;
    FilterLoop24(p, stride, 1, 16, thresh, ithresh, hev_thresh);
  }
}

static void HFilter16i(uint8_t* p, int stride,
                       int thresh, int ithresh, int hev_thresh) {
  int k;
  for (k = 3; k > 0; --k) {
    p += 4;
    FilterLoop24(p, 1, stride, 16, thresh, ithresh, hev_thresh);
  }
}

// 8-pixels wide variant, for chroma filtering
static void VFilter8(uint8_t* u, uint8_t* v, int stride,
                     int thresh, int ithresh, int hev_thresh) {
  FilterLoop26(u, stride, 1, 8, thresh, ithresh, hev_thresh);
  FilterLoop26(v, stride, 1, 8, thresh, ithresh, hev_thresh);
}

static void HFilter8(uint8_t* u, uint8_t* v, int stride,
                     int thresh, int ithresh, int hev_thresh) {
  FilterLoop26(u, 1, stride, 8, thresh, ithresh, hev_thresh);
  FilterLoop26(v, 1, stride, 8, thresh, ithresh, hev_thresh);
}

static void VFilter8i(uint8_t* u, uint8_t* v, int stride,
                      int thresh, int ithresh, int hev_thresh) {
  FilterLoop24(u + 4 * stride, stride, 1, 8, thresh, ithresh, hev_thresh);
  FilterLoop24(v + 4 * stride, stride, 1, 8, thresh, ithresh, hev_thresh);
}

static void HFilter8i(uint8_t* u, uint8_t* v, int stride,
                      int thresh, int ithresh, int hev_thresh) {
  FilterLoop24(u + 4, 1, stride, 8, thresh, ithresh, hev_thresh);
  FilterLoop24(v + 4, 1, stride, 8, thresh, ithresh, hev_thresh);
}

//------------------------------------------------------------------------------

VP8DecIdct2 VP8Transform;
VP8DecIdct VP8TransformAC3;
VP8DecIdct VP8TransformUV;
VP8DecIdct VP8TransformDC;
VP8DecIdct VP8TransformDCUV;

VP8LumaFilterFunc VP8VFilter16;
VP8LumaFilterFunc VP8HFilter16;
VP8ChromaFilterFunc VP8VFilter8;
VP8ChromaFilterFunc VP8HFilter8;
VP8LumaFilterFunc VP8VFilter16i;
VP8LumaFilterFunc VP8HFilter16i;
VP8ChromaFilterFunc VP8VFilter8i;
VP8ChromaFilterFunc VP8HFilter8i;
VP8SimpleFilterFunc VP8SimpleVFilter16;
VP8SimpleFilterFunc VP8SimpleHFilter16;
VP8SimpleFilterFunc VP8SimpleVFilter16i;
VP8SimpleFilterFunc VP8SimpleHFilter16i;

extern void VP8DspInitSSE2(void);
extern void VP8DspInitNEON(void);

void VP8DspInit(void) {
  DspInitTables();

  VP8Transform = TransformTwo;
  VP8TransformUV = TransformUV;
  VP8TransformDC = TransformDC;
  VP8TransformDCUV = TransformDCUV;
  VP8TransformAC3 = TransformAC3;

  VP8VFilter16 = VFilter16;
  VP8HFilter16 = HFilter16;
  VP8VFilter8 = VFilter8;
  VP8HFilter8 = HFilter8;
  VP8VFilter16i = VFilter16i;
  VP8HFilter16i = HFilter16i;
  VP8VFilter8i = VFilter8i;
  VP8HFilter8i = HFilter8i;
  VP8SimpleVFilter16 = SimpleVFilter16;
  VP8SimpleHFilter16 = SimpleHFilter16;
  VP8SimpleVFilter16i = SimpleVFilter16i;
  VP8SimpleHFilter16i = SimpleHFilter16i;

  // If defined, use CPUInfo() to overwrite some pointers with faster versions.
  if (VP8GetCPUInfo) {
#if defined(WEBP_USE_SSE2)
    if (VP8GetCPUInfo(kSSE2)) {
      VP8DspInitSSE2();
    }
#elif defined(WEBP_USE_NEON)
    if (VP8GetCPUInfo(kNEON)) {
      VP8DspInitNEON();
    }
#endif
  }
}
/* [<][>][^][v][top][bottom][index][help] */
root/third_party/libwebp/dsp/dec.c

DEFINITIONS
