coeff_order.h (2141B)
1 // Copyright (c) the JPEG XL Project Authors. All rights reserved. 2 // 3 // Use of this source code is governed by a BSD-style 4 // license that can be found in the LICENSE file. 5 6 #ifndef LIB_JXL_COEFF_ORDER_H_ 7 #define LIB_JXL_COEFF_ORDER_H_ 8 9 #include <stddef.h> 10 #include <stdint.h> 11 12 #include "lib/jxl/ac_strategy.h" 13 #include "lib/jxl/base/common.h" 14 #include "lib/jxl/base/compiler_specific.h" 15 #include "lib/jxl/base/status.h" 16 #include "lib/jxl/coeff_order_fwd.h" 17 #include "lib/jxl/frame_dimensions.h" 18 19 namespace jxl { 20 21 class BitReader; 22 23 // Those offsets get multiplied by kDCTBlockSize. 24 25 static constexpr size_t kCoeffOrderLimit = 6156; 26 27 static constexpr std::array<size_t, 3 * kNumOrders + 1> kCoeffOrderOffset = { 28 0, 1, 2, 3, 4, 5, 6, 10, 14, 18, 29 34, 50, 66, 68, 70, 72, 76, 80, 84, 92, 30 100, 108, 172, 236, 300, 332, 364, 396, 652, 908, 31 1164, 1292, 1420, 1548, 2572, 3596, 4620, 5132, 5644, kCoeffOrderLimit}; 32 33 static JXL_MAYBE_UNUSED constexpr size_t CoeffOrderOffset(size_t order, 34 size_t c) { 35 return kCoeffOrderOffset[3 * order + c] * kDCTBlockSize; 36 } 37 38 static JXL_MAYBE_UNUSED constexpr size_t kCoeffOrderMaxSize = 39 kCoeffOrderLimit * kDCTBlockSize; 40 41 // Mapping from AC strategy to order bucket. Strategies with different natural 42 // orders must have different buckets. 43 constexpr uint8_t kStrategyOrder[] = { 44 0, 1, 1, 1, 2, 3, 4, 4, 5, 5, 6, 6, 1, 1, 45 1, 1, 1, 1, 7, 8, 8, 9, 10, 10, 11, 12, 12, 46 }; 47 48 static_assert(AcStrategy::kNumValidStrategies == 49 sizeof(kStrategyOrder) / sizeof(*kStrategyOrder), 50 "Update this array when adding or removing AC strategies."); 51 52 constexpr JXL_MAYBE_UNUSED uint32_t kPermutationContexts = 8; 53 54 uint32_t CoeffOrderContext(uint32_t val); 55 56 Status DecodeCoeffOrders(uint16_t used_orders, uint32_t used_acs, 57 coeff_order_t* order, BitReader* br); 58 59 Status DecodePermutation(size_t skip, size_t size, coeff_order_t* order, 60 BitReader* br); 61 62 } // namespace jxl 63 64 #endif // LIB_JXL_COEFF_ORDER_H_