| /* ------------------------------------------------------------------ |
| * Copyright (C) 1998-2009 PacketVideo |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either |
| * express or implied. |
| * See the License for the specific language governing permissions |
| * and limitations under the License. |
| * ------------------------------------------------------------------- |
| */ |
| /* |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| q_block = pointer to buffer of inverse quantized DCT coefficients of type |
| int for intra-VOP mode or buffer of residual data of type int |
| for inter-VOP mode |
| |
| Local Stores/Buffers/Pointers Needed: |
| None |
| |
| Global Stores/Buffers/Pointers Needed: |
| None |
| |
| Outputs: |
| postmode = post processing semaphore with the vertical deblocking, |
| horizontal deblocking, and deringing bits set up accordingly |
| |
| Pointers and Buffers Modified: |
| None |
| |
| Local Stores Modified: |
| None |
| |
| Global Stores Modified: |
| None |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| This function sets up the postmode semaphore based on the contents of the |
| buffer pointed to by q_block. The function starts out with the assumption |
| that all entries of q_block, except for the first entry (q_block[0]), are |
| zero. This case can induce horizontal and vertical blocking artifacts, |
| therefore, both horizontal and vertical deblocking bits are enabled. |
| |
| The following conditions are tested when setting up the horizontal/vertical |
| deblocking and deringing bits: |
| 1. When only the elements of the top row of the B_SIZE x B_SIZE block |
| (q_block[n], n = 0,..., B_SIZE-1) are non-zero, vertical blocking artifacts |
| may result, therefore, only the vertical deblocking bit is enabled. |
| Otherwise, the vertical deblocking bit is disabled. |
| 2. When only the elements of the far left column of the B_SIZE x B_SIZE block |
| (q_block[n*B_SIZE], n = 0, ..., B_SIZE-1) are non-zero, horizontal blocking |
| artifacts may result, therefore, only the horizontal deblocking bit is |
| enabled. Otherwise, the horizontal deblocking bit is disabled. |
| 3. If any non-zero elements exist in positions other than q_block[0], |
| q_block[1], or q_block[B_SIZE], the deringing bit is enabled. Otherwise, |
| it is disabled. |
| |
| The 3 least significant bits of postmode defines vertical or horizontal |
| deblocking and deringing. |
| |
| The valid values are shown below: |
| ------------------------------------------------------- |
| | Type | Enabled | Disabled | |
| ------------------------------------------------------- |
| | Vertical Deblocking (Bit #0) | 1 | 0 | |
| ------------------------------------------------------- |
| | Horizontal Deblocking (Bit #1) | 1 | 0 | |
| ------------------------------------------------------- |
| | Deringing (Bit #2) | 1 | 0 | |
| ------------------------------------------------------- |
| |
| */ |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| #include "mp4dec_lib.h" |
| #include "mp4def.h" |
| #include "post_proc.h" |
| |
| /*---------------------------------------------------------------------------- |
| ; MACROS |
| ; Define module specific macros here |
| ----------------------------------------------------------------------------*/ |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; DEFINES |
| ; Include all pre-processor statements here. Include conditional |
| ; compile variables also. |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL FUNCTION DEFINITIONS |
| ; Function Prototype declaration |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL STORE/BUFFER/POINTER DEFINITIONS |
| ; Variable declaration - defined here and used outside this module |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; EXTERNAL FUNCTION REFERENCES |
| ; Declare functions defined elsewhere and referenced in this module |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES |
| ; Declare variables used in this module but defined elsewhere |
| ----------------------------------------------------------------------------*/ |
| #ifdef PV_POSTPROC_ON |
| /*---------------------------------------------------------------------------- |
| ; FUNCTION CODE |
| ----------------------------------------------------------------------------*/ |
| int PostProcSemaphore( |
| int16 *q_block) |
| { |
| /*---------------------------------------------------------------------------- |
| ; Define all local variables |
| ----------------------------------------------------------------------------*/ |
| int i, j; |
| |
| /* Set default value to vertical and horizontal deblocking enabled */ |
| /* Initial assumption is that only q_block[0] element is non-zero, */ |
| /* therefore, vertical and horizontal deblocking bits are set to 1 */ |
| int postmode = 0x3; |
| |
| /*---------------------------------------------------------------------------- |
| ; Function body here |
| ----------------------------------------------------------------------------*/ |
| /* Vertical deblocking bit is enabled when only the entire top row of */ |
| /* the B_SIZE x B_SIZE block, i.e., q_block[n], n = 0,..., B_SIZE-1, */ |
| /* are non-zero. Since initial assumption is that all elements, except */ |
| /* q_block[0], is zero, we need to check the remaining elements in the */ |
| /* top row to determine if all or some are non-zero. */ |
| if (q_block[1] != 0) |
| { |
| /* At this point, q_block[0] and q_block[1] are non-zero, while */ |
| /* q_block[n], n = 2,..., B_SIZE-1, are zero. Therefore, we */ |
| /* need to disable vertical deblocking */ |
| postmode &= 0xE; |
| } |
| |
| for (i = 2; i < B_SIZE; i++) |
| { |
| if (q_block[i]) |
| { |
| /* Check if q_block[n], n = 2,..., B_SIZE-1, are non-zero.*/ |
| /* If any of them turn out to be non-zero, we need to */ |
| /* disable vertical deblocking. */ |
| postmode &= 0xE; |
| |
| /* Deringing is enabled if any nonzero elements exist in */ |
| /* positions other than q_block[0], q_block[1] or */ |
| /* q_block[B_SIZE]. */ |
| postmode |= 0x4; |
| |
| break; |
| } |
| } |
| |
| /* Horizontal deblocking bit is enabled when only the entire far */ |
| /* left column, i.e., q_block[n*B_SIZE], n = 0, ..., B_SIZE-1, */ |
| /* are non-zero. Since initial assumption is that all elements, */ |
| /* except q_block[0], is zero, we need to check the remaining */ |
| /* elements in the far left column to determine if all or some */ |
| /* are non-zero. */ |
| if (q_block[B_SIZE]) |
| { |
| /* At this point, only q_block[0] and q_block[B_SIZE] are non-zero, */ |
| /* while q_block[n*B_SIZE], n = 2, 3,..., B_SIZE-1, are zero. */ |
| /* Therefore, we need to disable horizontal deblocking. */ |
| postmode &= 0xD; |
| } |
| |
| for (i = 16; i < NCOEFF_BLOCK; i += B_SIZE) |
| { |
| if (q_block[i]) |
| { |
| /* Check if q_block[n], n = 2*B_SIZE,...,(B_SIZE-1)*B_SIZE, */ |
| /* are non-zero. If any of them turn out to be non-zero, */ |
| /* we need to disable horizontal deblocking. */ |
| postmode &= 0xD; |
| |
| /* Deringing is enabled if any nonzero elements exist in */ |
| /* positions other than q_block[0], q_block[1] or */ |
| /* q_block[B_SIZE]. */ |
| postmode |= 0x4; |
| |
| break; |
| } |
| } |
| |
| /* At this point, only the first row and far left column elements */ |
| /* have been tested. If deringing bit is still not set at this */ |
| /* point, check the rest of q_block to determine if the elements */ |
| /* are non-zero. If all elements, besides q_block[0], q_block[1], */ |
| /* or q_block[B_SIZE] are non-zero, deringing bit must be set */ |
| if ((postmode & 0x4) == 0) |
| { |
| for (i = 1; i < B_SIZE; i++) |
| { |
| for (j = 1; j < B_SIZE; j++) |
| { |
| if (q_block[(i<<3)+j]) |
| { |
| /* At this point, q_block[0] and another q_block */ |
| /* element are non-zero, therefore, we need to */ |
| /* disable vertical and horizontal deblocking */ |
| postmode &= 0xC; |
| |
| /* Deringing is enabled if any nonzero elements exist in */ |
| /* positions other than q_block[0], q_block[1] or */ |
| /* q_block[B_SIZE]. */ |
| postmode |= 0x4; |
| |
| /* Set outer FOR loop count to B_SIZE to get out of */ |
| /* outer FOR loop */ |
| i = B_SIZE; |
| |
| /* Get out of inner FOR loop */ |
| break; |
| } |
| } |
| } |
| } |
| |
| /*---------------------------------------------------------------------------- |
| ; Return nothing or data or data pointer |
| ----------------------------------------------------------------------------*/ |
| return (postmode); |
| } |
| |
| #endif |
