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Diffstat (limited to 'media/libstagefright/codecs/m4v_h263/dec/src/cal_dc_scaler.cpp')
| -rw-r--r-- | media/libstagefright/codecs/m4v_h263/dec/src/cal_dc_scaler.cpp | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/m4v_h263/dec/src/cal_dc_scaler.cpp b/media/libstagefright/codecs/m4v_h263/dec/src/cal_dc_scaler.cpp new file mode 100644 index 0000000..85889d3 --- /dev/null +++ b/media/libstagefright/codecs/m4v_h263/dec/src/cal_dc_scaler.cpp @@ -0,0 +1,182 @@ +/* ------------------------------------------------------------------ + * 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: + [input_variable_name] = [description of the input to module, its type + definition, and length (when applicable)] + + Local Stores/Buffers/Pointers Needed: + [local_store_name] = [description of the local store, its type + definition, and length (when applicable)] + [local_buffer_name] = [description of the local buffer, its type + definition, and length (when applicable)] + [local_ptr_name] = [description of the local pointer, its type + definition, and length (when applicable)] + + Global Stores/Buffers/Pointers Needed: + [global_store_name] = [description of the global store, its type + definition, and length (when applicable)] + [global_buffer_name] = [description of the global buffer, its type + definition, and length (when applicable)] + [global_ptr_name] = [description of the global pointer, its type + definition, and length (when applicable)] + + Outputs: + [return_variable_name] = [description of data/pointer returned + by module, its type definition, and length + (when applicable)] + + Pointers and Buffers Modified: + [variable_bfr_ptr] points to the [describe where the + variable_bfr_ptr points to, its type definition, and length + (when applicable)] + [variable_bfr] contents are [describe the new contents of + variable_bfr] + + Local Stores Modified: + [local_store_name] = [describe new contents, its type + definition, and length (when applicable)] + + Global Stores Modified: + [global_store_name] = [describe new contents, its type + definition, and length (when applicable)] + +------------------------------------------------------------------------------ + FUNCTION DESCRIPTION + + This module calculates the DC quantization scale according + to the incoming Q and type. + +------------------------------------------------------------------------------ + REQUIREMENTS + + [List requirements to be satisfied by this module.] + +------------------------------------------------------------------------------ + REFERENCES + + [List all references used in designing this module.] + +------------------------------------------------------------------------------ + PSEUDO-CODE + +------------------------------------------------------------------------------ + RESOURCES USED + When the code is written for a specific target processor the + the resources used should be documented below. + + STACK USAGE: [stack count for this module] + [variable to represent + stack usage for each subroutine called] + + where: [stack usage variable] = stack usage for [subroutine + name] (see [filename].ext) + + DATA MEMORY USED: x words + + PROGRAM MEMORY USED: x words + + CLOCK CYCLES: [cycle count equation for this module] + [variable + used to represent cycle count for each subroutine + called] + + where: [cycle count variable] = cycle count for [subroutine + name] (see [filename].ext) + +------------------------------------------------------------------------------ +*/ + + +/*---------------------------------------------------------------------------- +; INCLUDES +----------------------------------------------------------------------------*/ +#include "mp4dec_lib.h" +#include "vlc_decode.h" +#include "bitstream.h" +#include "zigzag.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 +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; FUNCTION CODE +----------------------------------------------------------------------------*/ +int cal_dc_scaler( + int QP, + int type) +{ + + /*---------------------------------------------------------------------------- + ; Define all local variables + ----------------------------------------------------------------------------*/ + int dc_scaler; + + /*---------------------------------------------------------------------------- + ; Function body here + ----------------------------------------------------------------------------*/ + if (type == LUMINANCE_DC_TYPE) + { + if (QP > 0 && QP < 5) dc_scaler = 8; + else if (QP > 4 && QP < 9) dc_scaler = 2 * QP; + else if (QP > 8 && QP < 25) dc_scaler = QP + 8; + else dc_scaler = 2 * QP - 16; + } + else /* if (type == CHROMINANCE_DC_TYPE), there is no other types. */ + { + if (QP > 0 && QP < 5) dc_scaler = 8; + else if (QP > 4 && QP < 25) dc_scaler = (QP + 13) >> 1; + else dc_scaler = QP - 6; + } + + /*---------------------------------------------------------------------------- + ; Return nothing or data or data pointer + ----------------------------------------------------------------------------*/ + return dc_scaler; +} + |