| /* ------------------------------------------------------------------ |
| * 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. |
| * ------------------------------------------------------------------- |
| */ |
| /* |
| ------------------------------------------------------------------------------ |
| |
| PacketVideo Corp. |
| MP3 Decoder Library |
| |
| Filename: pvmp3_get_main_data_size.cpp |
| |
| Date: 09/21/2007 |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| |
| Description: |
| |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Input |
| mp3Header *info, pointer to mp3 header info structure |
| tmp3dec_file *pVars |
| contains information that needs to persist |
| between calls to this function, or is too big to |
| be placed on the stack, even though the data is |
| only needed during execution of this function |
| |
| Returns |
| |
| main data frame size |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| get main data frame size |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| [1] ISO MPEG Audio Subgroup Software Simulation Group (1996) |
| ISO 13818-3 MPEG-2 Audio Decoder - Lower Sampling Frequency Extension |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| |
| #include "pvmp3_tables.h" |
| #include "pvmp3_get_main_data_size.h" |
| #include "pv_mp3dec_fxd_op.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 |
| ----------------------------------------------------------------------------*/ |
| |
| int32 pvmp3_get_main_data_size(mp3Header *info, |
| tmp3dec_file *pVars) |
| { |
| |
| |
| int32 numBytes = fxp_mul32_Q28(mp3_bitrate[info->version_x][info->bitrate_index] << 20, |
| inv_sfreq[info->sampling_frequency]); |
| |
| |
| numBytes >>= (20 - info->version_x); |
| |
| /* |
| * Remove the size of the side information from the main data total |
| */ |
| if (info->version_x == MPEG_1) |
| { |
| pVars->predicted_frame_size = numBytes; |
| if (info->mode == MPG_MD_MONO) |
| { |
| numBytes -= 17; |
| } |
| else |
| { |
| numBytes -= 32; |
| } |
| } |
| else |
| { |
| numBytes >>= 1; |
| pVars->predicted_frame_size = numBytes; |
| |
| if (info->mode == MPG_MD_MONO) |
| { |
| numBytes -= 9; |
| } |
| else |
| { |
| numBytes -= 17; |
| } |
| } |
| |
| if (info->padding) |
| { |
| numBytes++; |
| pVars->predicted_frame_size++; |
| } |
| |
| if (info->error_protection) |
| { |
| numBytes -= 6; |
| } |
| else |
| { |
| numBytes -= 4; |
| } |
| |
| |
| if (numBytes < 0) |
| { |
| numBytes = 0; |
| } |
| |
| return(numBytes); |
| } |
| |