1 /* ------------------------------------------------------------------ 2 * Copyright (C) 1998-2009 PacketVideo 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either 13 * express or implied. 14 * See the License for the specific language governing permissions 15 * and limitations under the License. 16 * ------------------------------------------------------------------- 17 */ 18 /* 19 ------------------------------------------------------------------------------ 20 INPUT AND OUTPUT DEFINITIONS 21 22 Inputs: 23 q_block = pointer to buffer of inverse quantized DCT coefficients of type 24 int for intra-VOP mode or buffer of residual data of type int 25 for inter-VOP mode 26 27 Local Stores/Buffers/Pointers Needed: 28 None 29 30 Global Stores/Buffers/Pointers Needed: 31 None 32 33 Outputs: 34 postmode = post processing semaphore with the vertical deblocking, 35 horizontal deblocking, and deringing bits set up accordingly 36 37 Pointers and Buffers Modified: 38 None 39 40 Local Stores Modified: 41 None 42 43 Global Stores Modified: 44 None 45 46 ------------------------------------------------------------------------------ 47 FUNCTION DESCRIPTION 48 49 This function sets up the postmode semaphore based on the contents of the 50 buffer pointed to by q_block. The function starts out with the assumption 51 that all entries of q_block, except for the first entry (q_block[0]), are 52 zero. This case can induce horizontal and vertical blocking artifacts, 53 therefore, both horizontal and vertical deblocking bits are enabled. 54 55 The following conditions are tested when setting up the horizontal/vertical 56 deblocking and deringing bits: 57 1. When only the elements of the top row of the B_SIZE x B_SIZE block 58 (q_block[n], n = 0,..., B_SIZE-1) are non-zero, vertical blocking artifacts 59 may result, therefore, only the vertical deblocking bit is enabled. 60 Otherwise, the vertical deblocking bit is disabled. 61 2. When only the elements of the far left column of the B_SIZE x B_SIZE block 62 (q_block[n*B_SIZE], n = 0, ..., B_SIZE-1) are non-zero, horizontal blocking 63 artifacts may result, therefore, only the horizontal deblocking bit is 64 enabled. Otherwise, the horizontal deblocking bit is disabled. 65 3. If any non-zero elements exist in positions other than q_block[0], 66 q_block[1], or q_block[B_SIZE], the deringing bit is enabled. Otherwise, 67 it is disabled. 68 69 The 3 least significant bits of postmode defines vertical or horizontal 70 deblocking and deringing. 71 72 The valid values are shown below: 73 ------------------------------------------------------- 74 | Type | Enabled | Disabled | 75 ------------------------------------------------------- 76 | Vertical Deblocking (Bit #0) | 1 | 0 | 77 ------------------------------------------------------- 78 | Horizontal Deblocking (Bit #1) | 1 | 0 | 79 ------------------------------------------------------- 80 | Deringing (Bit #2) | 1 | 0 | 81 ------------------------------------------------------- 82 83 */ 84 85 86 /*---------------------------------------------------------------------------- 87 ; INCLUDES 88 ----------------------------------------------------------------------------*/ 89 #include "mp4dec_lib.h" 90 #include "mp4def.h" 91 #include "post_proc.h" 92 93 /*---------------------------------------------------------------------------- 94 ; MACROS 95 ; Define module specific macros here 96 ----------------------------------------------------------------------------*/ 97 98 99 /*---------------------------------------------------------------------------- 100 ; DEFINES 101 ; Include all pre-processor statements here. Include conditional 102 ; compile variables also. 103 ----------------------------------------------------------------------------*/ 104 105 /*---------------------------------------------------------------------------- 106 ; LOCAL FUNCTION DEFINITIONS 107 ; Function Prototype declaration 108 ----------------------------------------------------------------------------*/ 109 110 /*---------------------------------------------------------------------------- 111 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS 112 ; Variable declaration - defined here and used outside this module 113 ----------------------------------------------------------------------------*/ 114 115 /*---------------------------------------------------------------------------- 116 ; EXTERNAL FUNCTION REFERENCES 117 ; Declare functions defined elsewhere and referenced in this module 118 ----------------------------------------------------------------------------*/ 119 120 /*---------------------------------------------------------------------------- 121 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES 122 ; Declare variables used in this module but defined elsewhere 123 ----------------------------------------------------------------------------*/ 124 #ifdef PV_POSTPROC_ON 125 /*---------------------------------------------------------------------------- 126 ; FUNCTION CODE 127 ----------------------------------------------------------------------------*/ 128 int PostProcSemaphore( 129 int16 *q_block) 130 { 131 /*---------------------------------------------------------------------------- 132 ; Define all local variables 133 ----------------------------------------------------------------------------*/ 134 int i, j; 135 136 /* Set default value to vertical and horizontal deblocking enabled */ 137 /* Initial assumption is that only q_block[0] element is non-zero, */ 138 /* therefore, vertical and horizontal deblocking bits are set to 1 */ 139 int postmode = 0x3; 140 141 /*---------------------------------------------------------------------------- 142 ; Function body here 143 ----------------------------------------------------------------------------*/ 144 /* Vertical deblocking bit is enabled when only the entire top row of */ 145 /* the B_SIZE x B_SIZE block, i.e., q_block[n], n = 0,..., B_SIZE-1, */ 146 /* are non-zero. Since initial assumption is that all elements, except */ 147 /* q_block[0], is zero, we need to check the remaining elements in the */ 148 /* top row to determine if all or some are non-zero. */ 149 if (q_block[1] != 0) 150 { 151 /* At this point, q_block[0] and q_block[1] are non-zero, while */ 152 /* q_block[n], n = 2,..., B_SIZE-1, are zero. Therefore, we */ 153 /* need to disable vertical deblocking */ 154 postmode &= 0xE; 155 } 156 157 for (i = 2; i < B_SIZE; i++) 158 { 159 if (q_block[i]) 160 { 161 /* Check if q_block[n], n = 2,..., B_SIZE-1, are non-zero.*/ 162 /* If any of them turn out to be non-zero, we need to */ 163 /* disable vertical deblocking. */ 164 postmode &= 0xE; 165 166 /* Deringing is enabled if any nonzero elements exist in */ 167 /* positions other than q_block[0], q_block[1] or */ 168 /* q_block[B_SIZE]. */ 169 postmode |= 0x4; 170 171 break; 172 } 173 } 174 175 /* Horizontal deblocking bit is enabled when only the entire far */ 176 /* left column, i.e., q_block[n*B_SIZE], n = 0, ..., B_SIZE-1, */ 177 /* are non-zero. Since initial assumption is that all elements, */ 178 /* except q_block[0], is zero, we need to check the remaining */ 179 /* elements in the far left column to determine if all or some */ 180 /* are non-zero. */ 181 if (q_block[B_SIZE]) 182 { 183 /* At this point, only q_block[0] and q_block[B_SIZE] are non-zero, */ 184 /* while q_block[n*B_SIZE], n = 2, 3,..., B_SIZE-1, are zero. */ 185 /* Therefore, we need to disable horizontal deblocking. */ 186 postmode &= 0xD; 187 } 188 189 for (i = 16; i < NCOEFF_BLOCK; i += B_SIZE) 190 { 191 if (q_block[i]) 192 { 193 /* Check if q_block[n], n = 2*B_SIZE,...,(B_SIZE-1)*B_SIZE, */ 194 /* are non-zero. If any of them turn out to be non-zero, */ 195 /* we need to disable horizontal deblocking. */ 196 postmode &= 0xD; 197 198 /* Deringing is enabled if any nonzero elements exist in */ 199 /* positions other than q_block[0], q_block[1] or */ 200 /* q_block[B_SIZE]. */ 201 postmode |= 0x4; 202 203 break; 204 } 205 } 206 207 /* At this point, only the first row and far left column elements */ 208 /* have been tested. If deringing bit is still not set at this */ 209 /* point, check the rest of q_block to determine if the elements */ 210 /* are non-zero. If all elements, besides q_block[0], q_block[1], */ 211 /* or q_block[B_SIZE] are non-zero, deringing bit must be set */ 212 if ((postmode & 0x4) == 0) 213 { 214 for (i = 1; i < B_SIZE; i++) 215 { 216 for (j = 1; j < B_SIZE; j++) 217 { 218 if (q_block[(i<<3)+j]) 219 { 220 /* At this point, q_block[0] and another q_block */ 221 /* element are non-zero, therefore, we need to */ 222 /* disable vertical and horizontal deblocking */ 223 postmode &= 0xC; 224 225 /* Deringing is enabled if any nonzero elements exist in */ 226 /* positions other than q_block[0], q_block[1] or */ 227 /* q_block[B_SIZE]. */ 228 postmode |= 0x4; 229 230 /* Set outer FOR loop count to B_SIZE to get out of */ 231 /* outer FOR loop */ 232 i = B_SIZE; 233 234 /* Get out of inner FOR loop */ 235 break; 236 } 237 } 238 } 239 } 240 241 /*---------------------------------------------------------------------------- 242 ; Return nothing or data or data pointer 243 ----------------------------------------------------------------------------*/ 244 return (postmode); 245 } 246 247 #endif 248
