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