// Copyright (c) the JPEG XL Project Authors. All rights reserved. // // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. #include "lib/jpegli/idct.h" #include #include "lib/jpegli/decode_internal.h" #include "lib/jxl/base/compiler_specific.h" #include "lib/jxl/base/status.h" #undef HWY_TARGET_INCLUDE #define HWY_TARGET_INCLUDE "lib/jpegli/idct.cc" #include #include #include "lib/jpegli/transpose-inl.h" HWY_BEFORE_NAMESPACE(); namespace jpegli { namespace HWY_NAMESPACE { // These templates are not found via ADL. using hwy::HWY_NAMESPACE::Abs; using hwy::HWY_NAMESPACE::Add; using hwy::HWY_NAMESPACE::Gt; using hwy::HWY_NAMESPACE::IfThenElseZero; using hwy::HWY_NAMESPACE::Mul; using hwy::HWY_NAMESPACE::MulAdd; using hwy::HWY_NAMESPACE::NegMulAdd; using hwy::HWY_NAMESPACE::Rebind; using hwy::HWY_NAMESPACE::Sub; using hwy::HWY_NAMESPACE::Vec; using hwy::HWY_NAMESPACE::Xor; using D = HWY_FULL(float); using DI = HWY_FULL(int32_t); constexpr D d; constexpr DI di; using D8 = HWY_CAPPED(float, 8); constexpr D8 d8; void DequantBlock(const int16_t* JXL_RESTRICT qblock, const float* JXL_RESTRICT dequant, const float* JXL_RESTRICT biases, float* JXL_RESTRICT block) { for (size_t k = 0; k < 64; k += Lanes(d)) { const auto mul = Load(d, dequant + k); const auto bias = Load(d, biases + k); const Rebind di16; const Vec quant_i = PromoteTo(di, Load(di16, qblock + k)); const Rebind df; const auto quant = ConvertTo(df, quant_i); const auto abs_quant = Abs(quant); const auto not_0 = Gt(abs_quant, Zero(df)); const auto sign_quant = Xor(quant, abs_quant); const auto biased_quant = Sub(quant, Xor(bias, sign_quant)); const auto dequant = IfThenElseZero(not_0, Mul(biased_quant, mul)); Store(dequant, d, block + k); } } template void ForwardEvenOdd(const float* JXL_RESTRICT a_in, size_t a_in_stride, float* JXL_RESTRICT a_out) { for (size_t i = 0; i < N / 2; i++) { auto in1 = LoadU(d8, a_in + 2 * i * a_in_stride); Store(in1, d8, a_out + i * 8); } for (size_t i = N / 2; i < N; i++) { auto in1 = LoadU(d8, a_in + (2 * (i - N / 2) + 1) * a_in_stride); Store(in1, d8, a_out + i * 8); } } template void BTranspose(float* JXL_RESTRICT coeff) { for (size_t i = N - 1; i > 0; i--) { auto in1 = Load(d8, coeff + i * 8); auto in2 = Load(d8, coeff + (i - 1) * 8); Store(Add(in1, in2), d8, coeff + i * 8); } constexpr float kSqrt2 = 1.41421356237f; auto sqrt2 = Set(d8, kSqrt2); auto in1 = Load(d8, coeff); Store(Mul(in1, sqrt2), d8, coeff); } // Constants for DCT implementation. Generated by the following snippet: // for i in range(N // 2): // print(1.0 / (2 * math.cos((i + 0.5) * math.pi / N)), end=", ") template struct WcMultipliers; template <> struct WcMultipliers<4> { static constexpr float kMultipliers[] = { 0.541196100146197, 1.3065629648763764, }; }; template <> struct WcMultipliers<8> { static constexpr float kMultipliers[] = { 0.5097955791041592, 0.6013448869350453, 0.8999762231364156, 2.5629154477415055, }; }; #if JXL_CXX_LANG < JXL_CXX_17 constexpr float WcMultipliers<4>::kMultipliers[]; constexpr float WcMultipliers<8>::kMultipliers[]; #endif template void MultiplyAndAdd(const float* JXL_RESTRICT coeff, float* JXL_RESTRICT out, size_t out_stride) { for (size_t i = 0; i < N / 2; i++) { auto mul = Set(d8, WcMultipliers::kMultipliers[i]); auto in1 = Load(d8, coeff + i * 8); auto in2 = Load(d8, coeff + (N / 2 + i) * 8); auto out1 = MulAdd(mul, in2, in1); auto out2 = NegMulAdd(mul, in2, in1); StoreU(out1, d8, out + i * out_stride); StoreU(out2, d8, out + (N - i - 1) * out_stride); } } template struct IDCT1DImpl; template <> struct IDCT1DImpl<1> { JXL_INLINE void operator()(const float* from, size_t from_stride, float* to, size_t to_stride) { StoreU(LoadU(d8, from), d8, to); } }; template <> struct IDCT1DImpl<2> { JXL_INLINE void operator()(const float* from, size_t from_stride, float* to, size_t to_stride) { JXL_DASSERT(from_stride >= 8); JXL_DASSERT(to_stride >= 8); auto in1 = LoadU(d8, from); auto in2 = LoadU(d8, from + from_stride); StoreU(Add(in1, in2), d8, to); StoreU(Sub(in1, in2), d8, to + to_stride); } }; template struct IDCT1DImpl { void operator()(const float* from, size_t from_stride, float* to, size_t to_stride) { JXL_DASSERT(from_stride >= 8); JXL_DASSERT(to_stride >= 8); HWY_ALIGN float tmp[64]; ForwardEvenOdd(from, from_stride, tmp); IDCT1DImpl()(tmp, 8, tmp, 8); BTranspose(tmp + N * 4); IDCT1DImpl()(tmp + N * 4, 8, tmp + N * 4, 8); MultiplyAndAdd(tmp, to, to_stride); } }; template void IDCT1D(float* JXL_RESTRICT from, float* JXL_RESTRICT output, size_t output_stride) { for (size_t i = 0; i < 8; i += Lanes(d8)) { IDCT1DImpl()(from + i, 8, output + i, output_stride); } } void ComputeScaledIDCT(float* JXL_RESTRICT block0, float* JXL_RESTRICT block1, float* JXL_RESTRICT output, size_t output_stride) { Transpose8x8Block(block0, block1); IDCT1D<8>(block1, block0, 8); Transpose8x8Block(block0, block1); IDCT1D<8>(block1, output, output_stride); } void InverseTransformBlock8x8(const int16_t* JXL_RESTRICT qblock, const float* JXL_RESTRICT dequant, const float* JXL_RESTRICT biases, float* JXL_RESTRICT scratch_space, float* JXL_RESTRICT output, size_t output_stride, size_t dctsize) { float* JXL_RESTRICT block0 = scratch_space; float* JXL_RESTRICT block1 = scratch_space + DCTSIZE2; DequantBlock(qblock, dequant, biases, block0); ComputeScaledIDCT(block0, block1, output, output_stride); } // Computes the N-point IDCT of in[], and stores the result in out[]. The in[] // array is at most 8 values long, values in[8:N-1] are assumed to be 0. void Compute1dIDCT(const float* in, float* out, size_t N) { switch (N) { case 3: { static constexpr float kC3[3] = { 1.414213562373, 1.224744871392, 0.707106781187, }; float even0 = in[0] + kC3[2] * in[2]; float even1 = in[0] - kC3[0] * in[2]; float odd0 = kC3[1] * in[1]; out[0] = even0 + odd0; out[2] = even0 - odd0; out[1] = even1; break; } case 5: { static constexpr float kC5[5] = { 1.414213562373, 1.344997023928, 1.144122805635, 0.831253875555, 0.437016024449, }; float even0 = in[0] + kC5[2] * in[2] + kC5[4] * in[4]; float even1 = in[0] - kC5[4] * in[2] - kC5[2] * in[4]; float even2 = in[0] - kC5[0] * in[2] + kC5[0] * in[4]; float odd0 = kC5[1] * in[1] + kC5[3] * in[3]; float odd1 = kC5[3] * in[1] - kC5[1] * in[3]; out[0] = even0 + odd0; out[4] = even0 - odd0; out[1] = even1 + odd1; out[3] = even1 - odd1; out[2] = even2; break; } case 6: { static constexpr float kC6[6] = { 1.414213562373, 1.366025403784, 1.224744871392, 1.000000000000, 0.707106781187, 0.366025403784, }; float even0 = in[0] + kC6[2] * in[2] + kC6[4] * in[4]; float even1 = in[0] - kC6[0] * in[4]; float even2 = in[0] - kC6[2] * in[2] + kC6[4] * in[4]; float odd0 = kC6[1] * in[1] + kC6[3] * in[3] + kC6[5] * in[5]; float odd1 = kC6[3] * in[1] - kC6[3] * in[3] - kC6[3] * in[5]; float odd2 = kC6[5] * in[1] - kC6[3] * in[3] + kC6[1] * in[5]; out[0] = even0 + odd0; out[5] = even0 - odd0; out[1] = even1 + odd1; out[4] = even1 - odd1; out[2] = even2 + odd2; out[3] = even2 - odd2; break; } case 7: { static constexpr float kC7[7] = { 1.414213562373, 1.378756275744, 1.274162392264, 1.105676685997, 0.881747733790, 0.613604268353, 0.314692122713, }; float even0 = in[0] + kC7[2] * in[2] + kC7[4] * in[4] + kC7[6] * in[6]; float even1 = in[0] + kC7[6] * in[2] - kC7[2] * in[4] - kC7[4] * in[6]; float even2 = in[0] - kC7[4] * in[2] - kC7[6] * in[4] + kC7[2] * in[6]; float even3 = in[0] - kC7[0] * in[2] + kC7[0] * in[4] - kC7[0] * in[6]; float odd0 = kC7[1] * in[1] + kC7[3] * in[3] + kC7[5] * in[5]; float odd1 = kC7[3] * in[1] - kC7[5] * in[3] - kC7[1] * in[5]; float odd2 = kC7[5] * in[1] - kC7[1] * in[3] + kC7[3] * in[5]; out[0] = even0 + odd0; out[6] = even0 - odd0; out[1] = even1 + odd1; out[5] = even1 - odd1; out[2] = even2 + odd2; out[4] = even2 - odd2; out[3] = even3; break; } case 9: { static constexpr float kC9[9] = { 1.414213562373, 1.392728480640, 1.328926048777, 1.224744871392, 1.083350440839, 0.909038955344, 0.707106781187, 0.483689525296, 0.245575607938, }; float even0 = in[0] + kC9[2] * in[2] + kC9[4] * in[4] + kC9[6] * in[6]; float even1 = in[0] + kC9[6] * in[2] - kC9[6] * in[4] - kC9[0] * in[6]; float even2 = in[0] - kC9[8] * in[2] - kC9[2] * in[4] + kC9[6] * in[6]; float even3 = in[0] - kC9[4] * in[2] + kC9[8] * in[4] + kC9[6] * in[6]; float even4 = in[0] - kC9[0] * in[2] + kC9[0] * in[4] - kC9[0] * in[6]; float odd0 = kC9[1] * in[1] + kC9[3] * in[3] + kC9[5] * in[5] + kC9[7] * in[7]; float odd1 = kC9[3] * in[1] - kC9[3] * in[5] - kC9[3] * in[7]; float odd2 = kC9[5] * in[1] - kC9[3] * in[3] - kC9[7] * in[5] + kC9[1] * in[7]; float odd3 = kC9[7] * in[1] - kC9[3] * in[3] + kC9[1] * in[5] - kC9[5] * in[7]; out[0] = even0 + odd0; out[8] = even0 - odd0; out[1] = even1 + odd1; out[7] = even1 - odd1; out[2] = even2 + odd2; out[6] = even2 - odd2; out[3] = even3 + odd3; out[5] = even3 - odd3; out[4] = even4; break; } case 10: { static constexpr float kC10[10] = { 1.414213562373, 1.396802246667, 1.344997023928, 1.260073510670, 1.144122805635, 1.000000000000, 0.831253875555, 0.642039521920, 0.437016024449, 0.221231742082, }; float even0 = in[0] + kC10[2] * in[2] + kC10[4] * in[4] + kC10[6] * in[6]; float even1 = in[0] + kC10[6] * in[2] - kC10[8] * in[4] - kC10[2] * in[6]; float even2 = in[0] - kC10[0] * in[4]; float even3 = in[0] - kC10[6] * in[2] - kC10[8] * in[4] + kC10[2] * in[6]; float even4 = in[0] - kC10[2] * in[2] + kC10[4] * in[4] - kC10[6] * in[6]; float odd0 = kC10[1] * in[1] + kC10[3] * in[3] + kC10[5] * in[5] + kC10[7] * in[7]; float odd1 = kC10[3] * in[1] + kC10[9] * in[3] - kC10[5] * in[5] - kC10[1] * in[7]; float odd2 = kC10[5] * in[1] - kC10[5] * in[3] - kC10[5] * in[5] + kC10[5] * in[7]; float odd3 = kC10[7] * in[1] - kC10[1] * in[3] + kC10[5] * in[5] + kC10[9] * in[7]; float odd4 = kC10[9] * in[1] - kC10[7] * in[3] + kC10[5] * in[5] - kC10[3] * in[7]; out[0] = even0 + odd0; out[9] = even0 - odd0; out[1] = even1 + odd1; out[8] = even1 - odd1; out[2] = even2 + odd2; out[7] = even2 - odd2; out[3] = even3 + odd3; out[6] = even3 - odd3; out[4] = even4 + odd4; out[5] = even4 - odd4; break; } case 11: { static constexpr float kC11[11] = { 1.414213562373, 1.399818907436, 1.356927976287, 1.286413904599, 1.189712155524, 1.068791297809, 0.926112931411, 0.764581576418, 0.587485545401, 0.398430002847, 0.201263574413, }; float even0 = in[0] + kC11[2] * in[2] + kC11[4] * in[4] + kC11[6] * in[6]; float even1 = in[0] + kC11[6] * in[2] - kC11[10] * in[4] - kC11[4] * in[6]; float even2 = in[0] + kC11[10] * in[2] - kC11[2] * in[4] - kC11[8] * in[6]; float even3 = in[0] - kC11[8] * in[2] - kC11[6] * in[4] + kC11[2] * in[6]; float even4 = in[0] - kC11[4] * in[2] + kC11[8] * in[4] + kC11[10] * in[6]; float even5 = in[0] - kC11[0] * in[2] + kC11[0] * in[4] - kC11[0] * in[6]; float odd0 = kC11[1] * in[1] + kC11[3] * in[3] + kC11[5] * in[5] + kC11[7] * in[7]; float odd1 = kC11[3] * in[1] + kC11[9] * in[3] - kC11[7] * in[5] - kC11[1] * in[7]; float odd2 = kC11[5] * in[1] - kC11[7] * in[3] - kC11[3] * in[5] + kC11[9] * in[7]; float odd3 = kC11[7] * in[1] - kC11[1] * in[3] + kC11[9] * in[5] + kC11[5] * in[7]; float odd4 = kC11[9] * in[1] - kC11[5] * in[3] + kC11[1] * in[5] - kC11[3] * in[7]; out[0] = even0 + odd0; out[10] = even0 - odd0; out[1] = even1 + odd1; out[9] = even1 - odd1; out[2] = even2 + odd2; out[8] = even2 - odd2; out[3] = even3 + odd3; out[7] = even3 - odd3; out[4] = even4 + odd4; out[6] = even4 - odd4; out[5] = even5; break; } case 12: { static constexpr float kC12[12] = { 1.414213562373, 1.402114769300, 1.366025403784, 1.306562964876, 1.224744871392, 1.121971053594, 1.000000000000, 0.860918669154, 0.707106781187, 0.541196100146, 0.366025403784, 0.184591911283, }; float even0 = in[0] + kC12[2] * in[2] + kC12[4] * in[4] + kC12[6] * in[6]; float even1 = in[0] + kC12[6] * in[2] - kC12[6] * in[6]; float even2 = in[0] + kC12[10] * in[2] - kC12[4] * in[4] - kC12[6] * in[6]; float even3 = in[0] - kC12[10] * in[2] - kC12[4] * in[4] + kC12[6] * in[6]; float even4 = in[0] - kC12[6] * in[2] + kC12[6] * in[6]; float even5 = in[0] - kC12[2] * in[2] + kC12[4] * in[4] - kC12[6] * in[6]; float odd0 = kC12[1] * in[1] + kC12[3] * in[3] + kC12[5] * in[5] + kC12[7] * in[7]; float odd1 = kC12[3] * in[1] + kC12[9] * in[3] - kC12[9] * in[5] - kC12[3] * in[7]; float odd2 = kC12[5] * in[1] - kC12[9] * in[3] - kC12[1] * in[5] - kC12[11] * in[7]; float odd3 = kC12[7] * in[1] - kC12[3] * in[3] - kC12[11] * in[5] + kC12[1] * in[7]; float odd4 = kC12[9] * in[1] - kC12[3] * in[3] + kC12[3] * in[5] - kC12[9] * in[7]; float odd5 = kC12[11] * in[1] - kC12[9] * in[3] + kC12[7] * in[5] - kC12[5] * in[7]; out[0] = even0 + odd0; out[11] = even0 - odd0; out[1] = even1 + odd1; out[10] = even1 - odd1; out[2] = even2 + odd2; out[9] = even2 - odd2; out[3] = even3 + odd3; out[8] = even3 - odd3; out[4] = even4 + odd4; out[7] = even4 - odd4; out[5] = even5 + odd5; out[6] = even5 - odd5; break; } case 13: { static constexpr float kC13[13] = { 1.414213562373, 1.403902353238, 1.373119086479, 1.322312651445, 1.252223920364, 1.163874944761, 1.058554051646, 0.937797056801, 0.803364869133, 0.657217812653, 0.501487040539, 0.338443458124, 0.170464607981, }; float even0 = in[0] + kC13[2] * in[2] + kC13[4] * in[4] + kC13[6] * in[6]; float even1 = in[0] + kC13[6] * in[2] + kC13[12] * in[4] - kC13[8] * in[6]; float even2 = in[0] + kC13[10] * in[2] - kC13[6] * in[4] - kC13[4] * in[6]; float even3 = in[0] - kC13[12] * in[2] - kC13[2] * in[4] + kC13[10] * in[6]; float even4 = in[0] - kC13[8] * in[2] - kC13[10] * in[4] + kC13[2] * in[6]; float even5 = in[0] - kC13[4] * in[2] + kC13[8] * in[4] - kC13[12] * in[6]; float even6 = in[0] - kC13[0] * in[2] + kC13[0] * in[4] - kC13[0] * in[6]; float odd0 = kC13[1] * in[1] + kC13[3] * in[3] + kC13[5] * in[5] + kC13[7] * in[7]; float odd1 = kC13[3] * in[1] + kC13[9] * in[3] - kC13[11] * in[5] - kC13[5] * in[7]; float odd2 = kC13[5] * in[1] - kC13[11] * in[3] - kC13[1] * in[5] - kC13[9] * in[7]; float odd3 = kC13[7] * in[1] - kC13[5] * in[3] - kC13[9] * in[5] + kC13[3] * in[7]; float odd4 = kC13[9] * in[1] - kC13[1] * in[3] + kC13[7] * in[5] + kC13[11] * in[7]; float odd5 = kC13[11] * in[1] - kC13[7] * in[3] + kC13[3] * in[5] - kC13[1] * in[7]; out[0] = even0 + odd0; out[12] = even0 - odd0; out[1] = even1 + odd1; out[11] = even1 - odd1; out[2] = even2 + odd2; out[10] = even2 - odd2; out[3] = even3 + odd3; out[9] = even3 - odd3; out[4] = even4 + odd4; out[8] = even4 - odd4; out[5] = even5 + odd5; out[7] = even5 - odd5; out[6] = even6; break; } case 14: { static constexpr float kC14[14] = { 1.414213562373, 1.405321284327, 1.378756275744, 1.334852607020, 1.274162392264, 1.197448846138, 1.105676685997, 1.000000000000, 0.881747733790, 0.752406978226, 0.613604268353, 0.467085128785, 0.314692122713, 0.158341680609, }; float even0 = in[0] + kC14[2] * in[2] + kC14[4] * in[4] + kC14[6] * in[6]; float even1 = in[0] + kC14[6] * in[2] + kC14[12] * in[4] - kC14[10] * in[6]; float even2 = in[0] + kC14[10] * in[2] - kC14[8] * in[4] - kC14[2] * in[6]; float even3 = in[0] - kC14[0] * in[4]; float even4 = in[0] - kC14[10] * in[2] - kC14[8] * in[4] + kC14[2] * in[6]; float even5 = in[0] - kC14[6] * in[2] + kC14[12] * in[4] + kC14[10] * in[6]; float even6 = in[0] - kC14[2] * in[2] + kC14[4] * in[4] - kC14[6] * in[6]; float odd0 = kC14[1] * in[1] + kC14[3] * in[3] + kC14[5] * in[5] + kC14[7] * in[7]; float odd1 = kC14[3] * in[1] + kC14[9] * in[3] - kC14[13] * in[5] - kC14[7] * in[7]; float odd2 = kC14[5] * in[1] - kC14[13] * in[3] - kC14[3] * in[5] - kC14[7] * in[7]; float odd3 = kC14[7] * in[1] - kC14[7] * in[3] - kC14[7] * in[5] + kC14[7] * in[7]; float odd4 = kC14[9] * in[1] - kC14[1] * in[3] + kC14[11] * in[5] + kC14[7] * in[7]; float odd5 = kC14[11] * in[1] - kC14[5] * in[3] + kC14[1] * in[5] - kC14[7] * in[7]; float odd6 = kC14[13] * in[1] - kC14[11] * in[3] + kC14[9] * in[5] - kC14[7] * in[7]; out[0] = even0 + odd0; out[13] = even0 - odd0; out[1] = even1 + odd1; out[12] = even1 - odd1; out[2] = even2 + odd2; out[11] = even2 - odd2; out[3] = even3 + odd3; out[10] = even3 - odd3; out[4] = even4 + odd4; out[9] = even4 - odd4; out[5] = even5 + odd5; out[8] = even5 - odd5; out[6] = even6 + odd6; out[7] = even6 - odd6; break; } case 15: { static constexpr float kC15[15] = { 1.414213562373, 1.406466352507, 1.383309602960, 1.344997023928, 1.291948376043, 1.224744871392, 1.144122805635, 1.050965490998, 0.946293578512, 0.831253875555, 0.707106781187, 0.575212476952, 0.437016024449, 0.294031532930, 0.147825570407, }; float even0 = in[0] + kC15[2] * in[2] + kC15[4] * in[4] + kC15[6] * in[6]; float even1 = in[0] + kC15[6] * in[2] + kC15[12] * in[4] - kC15[12] * in[6]; float even2 = in[0] + kC15[10] * in[2] - kC15[10] * in[4] - kC15[0] * in[6]; float even3 = in[0] + kC15[14] * in[2] - kC15[2] * in[4] - kC15[12] * in[6]; float even4 = in[0] - kC15[12] * in[2] - kC15[6] * in[4] + kC15[6] * in[6]; float even5 = in[0] - kC15[8] * in[2] - kC15[14] * in[4] + kC15[6] * in[6]; float even6 = in[0] - kC15[4] * in[2] + kC15[8] * in[4] - kC15[12] * in[6]; float even7 = in[0] - kC15[0] * in[2] + kC15[0] * in[4] - kC15[0] * in[6]; float odd0 = kC15[1] * in[1] + kC15[3] * in[3] + kC15[5] * in[5] + kC15[7] * in[7]; float odd1 = kC15[3] * in[1] + kC15[9] * in[3] - kC15[9] * in[7]; float odd2 = kC15[5] * in[1] - kC15[5] * in[5] - kC15[5] * in[7]; float odd3 = kC15[7] * in[1] - kC15[9] * in[3] - kC15[5] * in[5] + kC15[11] * in[7]; float odd4 = kC15[9] * in[1] - kC15[3] * in[3] + kC15[3] * in[7]; float odd5 = kC15[11] * in[1] - kC15[3] * in[3] + kC15[5] * in[5] - kC15[13] * in[7]; float odd6 = kC15[13] * in[1] - kC15[9] * in[3] + kC15[5] * in[5] - kC15[1] * in[7]; out[0] = even0 + odd0; out[14] = even0 - odd0; out[1] = even1 + odd1; out[13] = even1 - odd1; out[2] = even2 + odd2; out[12] = even2 - odd2; out[3] = even3 + odd3; out[11] = even3 - odd3; out[4] = even4 + odd4; out[10] = even4 - odd4; out[5] = even5 + odd5; out[9] = even5 - odd5; out[6] = even6 + odd6; out[8] = even6 - odd6; out[7] = even7; break; } case 16: { static constexpr float kC16[16] = { 1.414213562373, 1.407403737526, 1.387039845322, 1.353318001174, 1.306562964876, 1.247225012987, 1.175875602419, 1.093201867002, 1.000000000000, 0.897167586343, 0.785694958387, 0.666655658478, 0.541196100146, 0.410524527522, 0.275899379283, 0.138617169199, }; float even0 = in[0] + kC16[2] * in[2] + kC16[4] * in[4] + kC16[6] * in[6]; float even1 = in[0] + kC16[6] * in[2] + kC16[12] * in[4] - kC16[14] * in[6]; float even2 = in[0] + kC16[10] * in[2] - kC16[12] * in[4] - kC16[2] * in[6]; float even3 = in[0] + kC16[14] * in[2] - kC16[4] * in[4] - kC16[10] * in[6]; float even4 = in[0] - kC16[14] * in[2] - kC16[4] * in[4] + kC16[10] * in[6]; float even5 = in[0] - kC16[10] * in[2] - kC16[12] * in[4] + kC16[2] * in[6]; float even6 = in[0] - kC16[6] * in[2] + kC16[12] * in[4] + kC16[14] * in[6]; float even7 = in[0] - kC16[2] * in[2] + kC16[4] * in[4] - kC16[6] * in[6]; float odd0 = (kC16[1] * in[1] + kC16[3] * in[3] + kC16[5] * in[5] + kC16[7] * in[7]); float odd1 = (kC16[3] * in[1] + kC16[9] * in[3] + kC16[15] * in[5] - kC16[11] * in[7]); float odd2 = (kC16[5] * in[1] + kC16[15] * in[3] - kC16[7] * in[5] - kC16[3] * in[7]); float odd3 = (kC16[7] * in[1] - kC16[11] * in[3] - kC16[3] * in[5] + kC16[15] * in[7]); float odd4 = (kC16[9] * in[1] - kC16[5] * in[3] - kC16[13] * in[5] + kC16[1] * in[7]); float odd5 = (kC16[11] * in[1] - kC16[1] * in[3] + kC16[9] * in[5] + kC16[13] * in[7]); float odd6 = (kC16[13] * in[1] - kC16[7] * in[3] + kC16[1] * in[5] - kC16[5] * in[7]); float odd7 = (kC16[15] * in[1] - kC16[13] * in[3] + kC16[11] * in[5] - kC16[9] * in[7]); out[0] = even0 + odd0; out[15] = even0 - odd0; out[1] = even1 + odd1; out[14] = even1 - odd1; out[2] = even2 + odd2; out[13] = even2 - odd2; out[3] = even3 + odd3; out[12] = even3 - odd3; out[4] = even4 + odd4; out[11] = even4 - odd4; out[5] = even5 + odd5; out[10] = even5 - odd5; out[6] = even6 + odd6; out[9] = even6 - odd6; out[7] = even7 + odd7; out[8] = even7 - odd7; break; } default: JXL_DEBUG_ABORT("Unreachable"); break; } } void InverseTransformBlockGeneric(const int16_t* JXL_RESTRICT qblock, const float* JXL_RESTRICT dequant, const float* JXL_RESTRICT biases, float* JXL_RESTRICT scratch_space, float* JXL_RESTRICT output, size_t output_stride, size_t dctsize) { float* JXL_RESTRICT block0 = scratch_space; float* JXL_RESTRICT block1 = scratch_space + DCTSIZE2; DequantBlock(qblock, dequant, biases, block0); if (dctsize == 1) { *output = *block0; } else if (dctsize == 2 || dctsize == 4) { float* JXL_RESTRICT block2 = scratch_space + 2 * DCTSIZE2; ComputeScaledIDCT(block0, block1, block2, 8); if (dctsize == 4) { for (size_t iy = 0; iy < 4; ++iy) { for (size_t ix = 0; ix < 4; ++ix) { float* block = &block2[16 * iy + 2 * ix]; output[iy * output_stride + ix] = 0.25f * (block[0] + block[1] + block[8] + block[9]); } } } else { for (size_t iy = 0; iy < 2; ++iy) { for (size_t ix = 0; ix < 2; ++ix) { float* block = &block2[32 * iy + 4 * ix]; output[iy * output_stride + ix] = 0.0625f * (block[0] + block[1] + block[2] + block[3] + block[8] + block[9] + block[10] + block[11] + block[16] + block[17] + block[18] + block[19] + block[24] + block[25] + block[26] + block[27]); } } } } else { float dctin[DCTSIZE]; float dctout[DCTSIZE * 2]; size_t insize = std::min(dctsize, DCTSIZE); for (size_t ix = 0; ix < insize; ++ix) { for (size_t iy = 0; iy < insize; ++iy) { dctin[iy] = block0[iy * DCTSIZE + ix]; } Compute1dIDCT(dctin, dctout, dctsize); for (size_t iy = 0; iy < dctsize; ++iy) { block1[iy * dctsize + ix] = dctout[iy]; } } for (size_t iy = 0; iy < dctsize; ++iy) { Compute1dIDCT(block1 + iy * dctsize, output + iy * output_stride, dctsize); } } } // NOLINTNEXTLINE(google-readability-namespace-comments) } // namespace HWY_NAMESPACE } // namespace jpegli HWY_AFTER_NAMESPACE(); #if HWY_ONCE namespace jpegli { HWY_EXPORT(InverseTransformBlock8x8); HWY_EXPORT(InverseTransformBlockGeneric); jxl::Status ChooseInverseTransform(j_decompress_ptr cinfo) { jpeg_decomp_master* m = cinfo->master; for (int c = 0; c < cinfo->num_components; ++c) { int dct_size = m->scaled_dct_size[c]; if (dct_size < 1 || dct_size > 16) { return JXL_FAILURE("Compute1dIDCT does not support N=%d", dct_size); } if (dct_size == DCTSIZE) { m->inverse_transform[c] = HWY_DYNAMIC_DISPATCH(InverseTransformBlock8x8); } else { m->inverse_transform[c] = HWY_DYNAMIC_DISPATCH(InverseTransformBlockGeneric); } } return true; } } // namespace jpegli #endif // HWY_ONCE