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/* ------------------------------------------------------------------
* 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.
* -------------------------------------------------------------------
*/
/*
Pathname: get_GA_specific_config.c
------------------------------------------------------------------------------
REVISION HISTORY
Description: Modified per review comments
Description: Change getbits.h to ibstream.h
Description: (1) use enum type for audioObjectType (2) update revision history
Description: Updated the SW template to include the full pathname to the
source file and a slightly modified copyright header.
Description: Updated to use scratch memory for the temporary prog config.
Description: Replace some instances of getbits to get1bits
when only 1 bit is read.
Who: Date:
Description:
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
pVars = pointer to the structure that holds all information for
this instance of the library. pVars->prog_config
pVars->mc_info, pVars->pWinSeqInfo, pVars->SFBWidth128
are needed for calling set_mc_info.
Data type pointer to tDec_Int_File
channel_config = variable that indicates the channel configuration
information, in this decoder library, only values
0, 1, and 2 are allowed.
Data type UInt
audioObjectType = variable that indicates the Audio Object Type.
Data type UInt.
pInputStream = pointer to a BITS structure that holds information
regarding the input stream.
Local Stores/Buffers/Pointers Needed:
None
Global Stores/Buffers/Pointers Needed:
None
Outputs:
status = 0 if success
1 otherwise
Pointers and Buffers Modified:
pVars->mc_info contents are updated with channel information.
if infoinit is called within set_mc_info, then
pVars->pWinSeqInfo contents are updated with window information.
pVars->SFBWidth128 contents are updated with scale factor band width data.
Local Stores Modified:
None
Global Stores Modified:
None
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
This function takes the sampling_rate_idx, channel_config, and
audioObjectType from AudioSpecificConfig() and set the decoder configuration
necessary for the decoder to decode properly.
It also reads the bitstream for frame length, scalable bitstream information
and extension information to General Audio defined in MPEG-4 phase 1
------------------------------------------------------------------------------
REQUIREMENTS
This function shall not use global variables
------------------------------------------------------------------------------
REFERENCES
(1) ISO/IEC 14496-3: 1999(E)
Part 3
Subpart 1 p18 1.6 Interface to MPEG-4 Systems
Subpart 4 p13 4.4.1 GA Specific Configuration
Amendment p10 6.2.1 AudioSpecificInfo
Amendment p78 8.2 Decoder configuration (GASpecificConfig)
(2) AAC DecoderSpecificInfo Information
PacketVideo descriptions - San Diego
------------------------------------------------------------------------------
PSEUDO-CODE
frameLenFlag = CALL getbits(
neededBits = LEN_FRAME_LEN_FLAG,
pInputStream = pInputStream);
MODIFYING (pInputStream)
RETURNING (frameLenFlag)
dependsOnCoreCoder = CALL getbits(
neededBits = LEN_DEPEND_ON_CORE,
pInputStream = pInputStream);
MODIFYING (pInputStream)
RETURNING (dependsOnCoreCoder)
IF (dependsOnCoreCoder != FALSE)
THEN
coreCoderDelay = CALL getbits(
neededBits = LEN_CORE_DELAY,
pInputStream = pInputStream);
MODIFYING (pInputStream)
RETURNING (coreCoderDelay)
ENDIF
extFlag = CALL getbits(
neededBits = LEN_EXT_FLAG,
pInputStream = pInputStream);
MODIFYING (pInputStream)
RETURNING (extFlag)
IF (channel_config == 0)
THEN
status = CALL get_prog_config(
pVars = pVars,
pScratchPCE = &pVars->scratch_prog_config);
MODIFYING (pVars, pScratchPCE)
RETURNING (status)
ELSE
channel_config--;
pVars->prog_config.front.ele_is_cpe[0] = channel_config;
pVars->prog_config.front.ele_tag[0] = 0;
status = CALL set_mc_info(
pMC_Info = &(pVars->mc_info),
audioObjectType = audioObjectType,
sampling_rate_idx = pVars->prog_config.sampling_rate_idx,
tag = pVars->prog_config.front.ele_tag[0],
is_cpe = pVars->prog_config.front.ele_is_cpe[0],
pWinSeqInfo = pVars->pWinSeqInfo,
sfbwidth128 = pVars->SFBWidth128);
MODIFYING (pMC_Info, pWinSeqInfo, sfbwidth128)
RETURNING (SUCCESS)
ENDIF
IF ((audioObjectType == MP4AUDIO_AAC_SCALABLE) OR
(audioObjectType == MP4AUDIO_ER_AAC_SCALABLE))
THEN
layer_num = CALL getbits(
neededBits = LEN_LAYER_NUM,
pInputStream = pInputStream);
MODIFYING (pInputStream)
RETURNING (layer_num)
status = 1;
ENDIF
IF (extFlag != FALSE)
THEN
IF (audioObjectType == MP4AUDIO_ER_BSAC)
THEN
numOfSubFrame = CALL getbits(
neededBits = LEN_SUB_FRAME,
pInputStream = pInputStream);
MODIFYING (pInputStream)
RETURNING (numOfSubFrame)
layer_len = CALL getbits(
neededBits = LEN_LAYER_LEN,
pInputStream = pInputStream);
MODIFYING (pInputStream)
RETURNING (layer_len)
ENDIF
IF (((audioObjectType > 16) AND (audioObjectType < 22)) OR
(audioObjectType == 23))
THEN
aacSectionDataResilienceFlag =
CALL getbits(
neededBits = LEN_SECT_RES_FLAG,
pInputStream = pInputStream);
MODIFYING (pInputStream)
RETURNING (aacSectionDataResilienceFlag)
aacScalefactorDataResilienceFlag =
CALL getbits(
neededBits = LEN_SFB_RES_FLAG,
pInputStream = pInputStream);
MODIFYING (pInputStream)
RETURNING (aacScalefactorDataResilienceFlag)
aacSpectralDataResilienceFlag =
CALL getbits(
neededBits = LEN_SPEC_RES_FLAG,
pInputStream = pInputStream);
MODIFYING (pInputStream)
RETURNING (aacSpectralDataResilienceFlag)
ENDIF
status = 1;
ENDIF
RETURN status;
------------------------------------------------------------------------------
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 "pv_audio_type_defs.h"
#include "e_mp4ff_const.h"
#include "e_tmp4audioobjecttype.h"
#include "s_tdec_int_file.h"
#include "get_ga_specific_config.h"
#include "set_mc_info.h"
#include "get_prog_config.h"
#include "ibstream.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 get_GA_specific_config(
tDec_Int_File * const pVars,
BITS *pInputStream,
UInt channel_config,
const tMP4AudioObjectType audioObjectType
)
{
Int status = SUCCESS;
UInt dependsOnCoreCoder;
/* Int coreCoderDelay; */
UInt extFlag;
/* These variables are left for future implementation */
/* UInt layer_num; */
/* UInt numOfSubFrame; */
/* UInt layer_len; */
/* UInt aacSectionDataResilienceFlag; */
/* UInt aacScalefactorDataResilienceFlag; */
/* UInt aacSpectralDataResilienceFlag; */
Int extFlag3;
/*
* frame length flag == 0, 1024 samples/frame
* frame length flag == 1, 960 samples/frame
*/
get1bits(/* LEN_FRAME_LEN_FLAG,*/
pInputStream);
/*
* dependsOnCoreCoder == 1, core coder has different sampling rate
* in a scalable bitstream
*/
dependsOnCoreCoder =
get1bits(/* LEN_DEPEND_ON_CORE,*/
pInputStream);
if (dependsOnCoreCoder != FALSE)
{
/*coreCoderDelay =
* getbits(
* LEN_CORE_DELAY,
* pInputStream);
*/
status = 1; /* do not support scalable coding in this release */
}
/*
* extension flag indicates if Amendment 1 objects are used or not
* extension flag == 0 objects = 1, 2, 3, 4, 6, 7
* extension flag == 1 objects = 17, 19, 20, 21, 22, 23
*/
extFlag = get1bits(pInputStream); /* LEN_EXT_FLAG,*/
/* Force checks for implicit channel configuration */
pVars->mc_info.implicit_channeling = 1;
if (status == SUCCESS)
{
if (channel_config == 0)
{
status = get_prog_config(pVars,
&pVars->scratch.scratch_prog_config);
if (status != SUCCESS)
{
pVars->prog_config.front.ele_is_cpe[0] = 0; /* default to mono */
pVars->mc_info.nch = 1;
pVars->prog_config.front.ele_tag[0] = 0;
status = SUCCESS;
}
}
else
{
/*
* dummy tag = 0 and
* set up decoding configurations
*/
channel_config--;
pVars->prog_config.front.ele_is_cpe[0] = channel_config;
pVars->prog_config.front.ele_tag[0] = 0;
status =
set_mc_info(
&(pVars->mc_info),
audioObjectType, /* previously profile */
pVars->prog_config.sampling_rate_idx,
pVars->prog_config.front.ele_tag[0],
pVars->prog_config.front.ele_is_cpe[0],
pVars->winmap, /*pVars->pWinSeqInfo,*/
pVars->SFBWidth128);
} /* if (channel_config) */
} /* if(status) */
/*
* This layer_num is not found in ISO/IEC specs,
* but it is defined in San Diego spec for scalable bitstream
*/
if ((audioObjectType == MP4AUDIO_AAC_SCALABLE) ||
(audioObjectType == MP4AUDIO_ER_AAC_SCALABLE))
{
/*layer_num =
* getbits(
* LEN_LAYER_NUM,
* pInputStream);
*/
status = 1; /* for this release only */
}
if (extFlag)
{
/*
* currently do not implement these functionalities
* defined in Amendment 1
* keep it here for future release
*/
if (audioObjectType == MP4AUDIO_ER_BSAC)
{
status = 1; /* NOT SUPPORTED */
/*
numOfSubFrame = getbits( LEN_SUB_FRAME, pInputStream);
layer_len = getbits( LEN_LAYER_LEN, pInputStream);
*/
}
/*
* The following code is equivalent to
* if ((audioObjectType == 17) || (audioObjectType == 18) ||
* (audioObjectType == 19) || (audioObjectType == 20) ||
* (audioObjectType == 21) || (audioObjectType == 23))
*/
if (((audioObjectType > 16) && (audioObjectType < 22)) ||
(audioObjectType == 23))
{
status = 1; /* NOT SUPPORTED */
/*
aacSectionDataResilienceFlag = getbits( LEN_SECT_RES_FLAG,
pInputStream);
aacScalefactorDataResilienceFlag = getbits( LEN_SCF_RES_FLAG,
pInputStream);
aacSpectralDataResilienceFlag = getbits( LEN_SPEC_RES_FLAG,
pInputStream);
*/
}
/*
* this flag is tbd in version 3 of ISO/IEC spec
* if the encoder generates this bit, then it has to be read
* current adif2mp4ff does not write this bit. If this bit is to
* be read, it can be done by the following code:
*/
extFlag3 = get1bits(pInputStream); /* LEN_EXT_FLAG3 */
if (extFlag3)
{
status = 1; /* NOT SUPPORTED */
}
}
return status;
}
|
