1 /****************************************************************************** 2 * 3 * Copyright (C) 2015 The Android Open Source Project 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at: 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 ***************************************************************************** 18 * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore 19 */ 20 /** 21 ******************************************************************************* 22 * @file 23 * ih264_trans_data.h 24 * 25 * @brief 26 * Contains declaration of global variables for H264 transform , qnat and inverse quant 27 * 28 * @author 29 * Ittiam 30 * 31 * @remarks 32 * 33 ******************************************************************************* 34 */ 35 #ifndef IH264_GLOBAL_DATA_H_ 36 #define IH264_GLOBAL_DATA_H_ 37 38 /*****************************************************************************/ 39 /* Extern global declarations */ 40 /*****************************************************************************/ 41 42 /* Scaling matrices for h264 quantization */ 43 extern const UWORD16 g_scal_coff_h264_4x4[16]; 44 extern const UWORD16 g_scal_coff_h264_8x8[16]; 45 46 47 /** 48 ****************************************************************************** 49 * @brief Scale Table for quantizing 4x4 subblock. To quantize a given 4x4 DCT 50 * transformed block, the coefficient at index location (i,j) is scaled by one of 51 * the constants in this table and right shift the result by (QP_BITS_h264_4x4 + 52 * floor(qp/6)), here qp is the quantization parameter used to quantize the mb. 53 * 54 * input : qp%6, index location (i,j) 55 * output : scale constant. 56 * 57 * @remarks 16 constants for each index position of the subblock and 6 for each 58 * qp%6 in the range 0-5 inclusive. 59 ****************************************************************************** 60 */ 61 extern const UWORD16 gu2_quant_scale_matrix_4x4[96]; 62 63 /** 64 ****************************************************************************** 65 * @brief Round Factor for quantizing subblock. While quantizing a given 4x4 DCT 66 * transformed block, the coefficient at index location (i,j) is scaled by one of 67 * the constants in the table gu2_forward_quant_scalar_4x4 and then right shift 68 * the result by (QP_BITS_h264_4x4 + floor(qp/6)). 69 * Before right shifting a round factor is added. 70 * The round factor can be any value [a * (1 << (QP_BITS_h264_4x4 + floor(qp/6)))] 71 * for 'a' lies in the range 0-0.5. 72 * Here qp is the quantization parameter used to quantize the mb. 73 * 74 * input : qp/6 75 * output : round factor. 76 * 77 * @remarks The round factor is constructed by setting a = 1/3 78 ****************************************************************************** 79 */ 80 extern const UWORD32 gu4_forward_quant_round_factor_4x4[9]; 81 82 /** 83 ****************************************************************************** 84 * @brief Threshold Table. Quantizing the given DCT coefficient is done only if 85 * it exceeds the threshold value presented in this table. 86 * 87 * input : qp/6, qp%6, index location (i,j) 88 * output : Threshold constant. 89 * 90 * @remarks 16 constants for each index position of the subblock and 6 for each 91 * qp%6 in the range 0-5 inclusive and 9 for each qp/6 in the range 0-51. 92 ****************************************************************************** 93 */ 94 extern const UWORD16 gu2_forward_quant_threshold_4x4[96]; 95 96 /** 97 ****************************************************************************** 98 * @brief Scale Table for quantizing 8x8 subblock. To quantize a given 8x8 DCT 99 * transformed block, the coefficient at index location (i,j) is scaled by one of 100 * the constants in this table and right shift the result by (QP_BITS_h264_8x8 + 101 * floor(qp/6)), here qp is the quantization parameter used to quantize the mb. 102 * 103 * input : qp%6, index location (i,j) 104 * output : scale constant. 105 * 106 * @remarks 64 constants for each index position of the subblock and 6 for each 107 * qp%6 in the range 0-5 inclusive. 108 ****************************************************************************** 109 */ 110 extern const UWORD16 gu2_quant_scale_matrix_8x8 [384]; 111 112 /** 113 ****************************************************************************** 114 * @brief Specification of QPc as a function of qPi 115 * 116 * input : qp luma 117 * output : qp chroma. 118 * 119 * @remarks Refer Table 8-15 of h264 specification. 120 ****************************************************************************** 121 */ 122 extern const UWORD8 gu1_qpc_fqpi[52]; 123 124 125 #endif /* IH264_GLOBAL_DATA_H_ */ 126
