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Diffstat (limited to 'media/libstagefright/codecs/m4v_h263/dec/src/post_proc_semaphore.cpp')
| -rw-r--r-- | media/libstagefright/codecs/m4v_h263/dec/src/post_proc_semaphore.cpp | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/m4v_h263/dec/src/post_proc_semaphore.cpp b/media/libstagefright/codecs/m4v_h263/dec/src/post_proc_semaphore.cpp new file mode 100644 index 0000000..3abc6be --- /dev/null +++ b/media/libstagefright/codecs/m4v_h263/dec/src/post_proc_semaphore.cpp @@ -0,0 +1,247 @@ +/* ------------------------------------------------------------------ + * 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 |