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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: huffdecode.c
------------------------------------------------------------------------------
REVISION HISTORY
Description: Modified from original shareware code
Description: Modified to pass variables by reference to eliminate use
of global variables.
Description: Change variable types.
Description: (1) Modified to bring in-line with PV standards.
(2) Eliminated global_gain on stack,
getics() has to define this parameter on its stack.
(3) Eliminated multiple returns
(4) Altered return logic of getics()
(5) Convert Real coef -> Int32 coef
(6) Move BITS *pInputStream to 2nd parameter of huffdecode.c
and getics.c
(7) Pass pFrameInfo per channel, because two channels can have
different windows
Description: (1) Eliminated function call to chn_config
(2) Eliminate widx calculation
(3) copy channel info from left to right when common_window
is enabled
(4) add error checking of getmask return value
Description: Change default_position to current_program
Description: Remove prstflag
Description: Modify call to get_ics_info
Description: Modified so getmask is NOT called if the status returned
from get_ics_info indicates an error.
Description:
(1) Added include of "e_ElementId.h"
Previously, this function was relying on another include file
to include e_ElementId.h
(2) Updated the copyright header.
Description: Modified to include usage of the new "shared memory" structures
defined in s_tDec_Int_File.h and s_tDec_Int_Chan.h
Description:
(1) Updated to reflect the fact that the temporary FrameInfo used by getics.c
was moved into the region of memory shared with fxpCoef.
Description:
(1) Removed first parameter to getics. The temporary FrameInfo was
unnecessary.
Description: Replace some instances of getbits to get9_n_lessbits
when the number of bits read is 9 or less and get1bits
when only 1 bit is read.
Description: Relaxed tag verification. Some encoder do not match the tag
to the channel ID (as the standard request to differentiate
different channel), in our wireless work, with only mono
or stereo channel, this become restrictive to some encoders
Description:
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
id_syn_ele = identification flag for channel syntactic element, Int
pInputStream= pointer to input bitstream, BITS.
pVars = pointer to structure that holds information for decoding,
tDec_Int_File
pChVars[] = pointer to structure that holds channel information,
tDec_Int_Chan
Local Stores/Buffers/Pointers Needed:
None
Global Stores/Buffers/Pointers Needed:
None
Outputs:
status = 0 if success
non-zero otherwise
Pointers and Buffers Modified:
pChVars->sect contents updated by newly decoded section information
of current frame
pChVars->factors contents updated by newly decoded scalefactors
pChVars->ch_coef contents updated by newly decoded spectral coefficients
PChVars->tns contents updated by newly decoded TNS information
pVars->hasmask contents updated by newly decoded Mid/Side mask
information
pVars->pulseInfo contents updated by newly decoded pulse data information
Local Stores Modified:
None
Global Stores Modified:
None
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
This function offers a framework for decoding the data of the next 1024
samples. It maps the channel configuration according to the id_syn_ele flag,
configures the channel information, and calls getics to do huffman decoding
The function returns 1 if there was an error
------------------------------------------------------------------------------
REQUIREMENTS
This function should set up the channel configuration for huffman decoding
------------------------------------------------------------------------------
REFERENCES
(1) MPEG-2 NBC Audio Decoder
"This software module was originally developed by AT&T, Dolby
Laboratories, Fraunhofer Gesellschaft IIS in the course of development
of the MPEG-2 NBC/MPEG-4 Audio standard ISO/IEC 13818-7, 14496-1,2 and
3. This software module is an implementation of a part of one or more
MPEG-2 NBC/MPEG-4 Audio tools as specified by the MPEG-2 NBC/MPEG-4
Audio standard. ISO/IEC gives users of the MPEG-2 NBC/MPEG-4 Audio
standards free license to this software module or modifications thereof
for use in hardware or software products claiming conformance to the
MPEG-2 NBC/MPEG-4 Audio standards. Those intending to use this software
module in hardware or software products are advised that this use may
infringe existing patents. The original developer of this software
module and his/her company, the subsequent editors and their companies,
and ISO/IEC have no liability for use of this software module or
modifications thereof in an implementation. Copyright is not released
for non MPEG-2 NBC/MPEG-4 Audio conforming products.The original
developer retains full right to use the code for his/her own purpose,
assign or donate the code to a third party and to inhibit third party
from using the code for non MPEG-2 NBC/MPEG-4 Audio conforming products.
This copyright notice must be included in all copies or derivative
works."
Copyright(c)1996.
(2) ISO/IEC 14496-3: 1999(E)
Subpart 4 p15 (single_channel_element, channel_pair_element)
p15 (Table 4.4.5 getmask)
p16 (Table 4.4.6 get_ics_info)
p24 (Table 4.4.24 getics)
------------------------------------------------------------------------------
PSEUDO-CODE
tag = CALL getbits(LEN_TAG,pInputStream)
MODIFYING(pInputStream)
RETURNING(tag)
common_window = 0;
IF (id_syn_ele == ID_CPE)
THEN
common_window = CALL getbits(LEN_COM_WIN,pInputStream);
MODIFYING(pInputStream)
RETURNING(common_window)
ENDIF
pMcInfo = &pVars->mc_info;
IF ( (pMcInfo->ch_info[0].cpe != id_syn_ele) OR
(pMcInfo->ch_info[0].tag != tag) )
THEN
status = 1;
ENDIF
IF (status == SUCCESS)
THEN
IF (id_syn_ele == ID_SCE)
THEN
leftCh = 0;
RIGHT = 0;
pChVars[leftCh]->hasmask = 0;
ELSEIF (id_syn_ele == ID_CPE)
leftCh = 0;
rightCh = 1;
IF (common_window != FALSE)
THEN
CALL get_ics_info(
audioObjectType = pVars->mc_info.audioObjectType,
pInputStream = pInputStream,
common_window = common_window,
pWindowSequence = &pChVars[leftCh]->wnd,
&pChVars[leftCh]->wnd_shape_this_bk,
pChVars[leftCh]->group,
&pChVars[leftCh]->max_sfb,
pVars->winmap,
&pChVars[leftCh]->lt_status,
&pChVars[rightCh]->lt_status);
MODIFYING(pInputStream, wnd, wnd_shape_this_bk,group,
max_sfb, lt_status)
RETURNING(status)
IF (status == SUCCESS)
THEN
pChVars[rightCh]->wnd = pChVars[leftCh]->wnd;
pChVars[rightCh]->wnd_shape_this_bk =
pChVars[leftCh]->wnd_shape_this_bk;
pChVars[rightCh]->max_sfb = pChVars[leftCh]->max_sfb;
pv_memcpy(
pChVars[rightCh]->group,
pChVars[leftCh]->group,
NSHORT*sizeof(pChVars[leftCh]->group[0]));
hasmask = CALL getmask(
pVars->winmap[pChVars[leftCh]->wnd],
pInputStream,
pChVars[leftCh]->group,
pChVars[leftCh]->max_sfb,
pChVars[leftCh]->mask);
MODIFYING(pInputStream, mask)
RETURNING(hasmask)
IF (hasmask == MASK_ERROR)
THEN
status = 1;
ENDIF
pChVars[leftCh]->hasmask = hasmask;
pChVars[rightCh]->hasmask = hasmask;
ENDIF
ELSE
pChVars[leftCh]->hasmask = 0;
pChVars[rightCh]->hasmask = 0;
ENDIF(common_window)
ENDIF(id_syn_ele)
ENDIF (status)
ch = leftCh;
WHILE((ch <= rightCh) AND (status == SUCCESS))
status = CALL getics(
pInputStream,
common_window,
pVars,
pChVars[ch],
pChVars[ch]->group,
&pChVars[ch]->max_sfb,
pChVars[ch]->cb_map,
&pChVars[ch]->tns,
pVars->winmap,
&pVars->pulseInfo,
pChVars[ch]->sect);
MODIFYING(pInputStream,pVarsp,ChVars[ch],group,
max_sfb,tns,pulseInfo,sect)
RETURNING(status)
ch++;
ENDWHILE
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 "aac_mem_funcs.h"
#include "huffman.h"
#include "e_maskstatus.h"
#include "e_elementid.h"
#include "get_ics_info.h"
/*----------------------------------------------------------------------------
; MACROS
; Define module specific macros here
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; DEFINES
; Include all pre-processor statements here. Include conditional
; compile variables also.
----------------------------------------------------------------------------*/
#define LEFT (0)
#define RIGHT (1)
/*----------------------------------------------------------------------------
; 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 huffdecode(
Int id_syn_ele,
BITS *pInputStream,
tDec_Int_File *pVars,
tDec_Int_Chan *pChVars[])
{
/*----------------------------------------------------------------------------
; Define all local variables
----------------------------------------------------------------------------*/
Int ch;
Int common_window;
Int hasmask;
Int status = SUCCESS;
Int num_channels = 0;
MC_Info *pMcInfo;
per_chan_share_w_fxpCoef *pChLeftShare; /* Helper pointer */
per_chan_share_w_fxpCoef *pChRightShare; /* Helper pointer */
/*----------------------------------------------------------------------------
; Function body here
----------------------------------------------------------------------------*/
get9_n_lessbits(
LEN_TAG,
pInputStream);
/* suppose an un-supported id_syn_ele will never be passed */
common_window = 0;
if (id_syn_ele == ID_CPE)
{
common_window =
get1bits(pInputStream);
}
pMcInfo = &pVars->mc_info;
/*
* check if provided info (num of channels) on audio config,
* matches read bitstream data, if not, allow update only once.
* In almost all cases it should match.
*/
if ((pMcInfo->ch_info[0].cpe != id_syn_ele))
{
if (pVars->mc_info.implicit_channeling) /* check done only once */
{
pMcInfo->ch_info[0].cpe = id_syn_ele & 1; /* collect info from bitstream
* implicit_channeling flag is locked
* after 1st frame, to avoid toggling
* parameter in the middle of the clip
*/
pMcInfo->nch = (id_syn_ele & 1) + 1; /* update number of channels */
}
else
{
status = 1; /* ERROR break if syntax error persist */
}
}
if (status == SUCCESS)
{
if (id_syn_ele == ID_SCE)
{
num_channels = 1;
pVars->hasmask = 0;
}
else if (id_syn_ele == ID_CPE)
{
pChLeftShare = pChVars[LEFT]->pShareWfxpCoef;
pChRightShare = pChVars[RIGHT]->pShareWfxpCoef;
num_channels = 2;
if (common_window != FALSE)
{
status = get_ics_info(
(tMP4AudioObjectType) pVars->mc_info.audioObjectType,
pInputStream,
(Bool)common_window,
(WINDOW_SEQUENCE *) & pChVars[LEFT]->wnd,
(WINDOW_SHAPE *) & pChVars[LEFT]->wnd_shape_this_bk,
pChLeftShare->group,
(Int *) & pChLeftShare->max_sfb,
pVars->winmap,
(LT_PRED_STATUS *) & pChLeftShare->lt_status,
(LT_PRED_STATUS *) & pChRightShare->lt_status);
if (status == SUCCESS)
{
/* copy left channel info to right channel */
pChVars[RIGHT]->wnd = pChVars[LEFT]->wnd;
pChVars[RIGHT]->wnd_shape_this_bk =
pChVars[LEFT]->wnd_shape_this_bk;
pChRightShare->max_sfb = pChLeftShare->max_sfb;
pv_memcpy(
pChRightShare->group,
pChLeftShare->group,
NSHORT*sizeof(pChLeftShare->group[0]));
hasmask = getmask(
pVars->winmap[pChVars[LEFT]->wnd],
pInputStream,
pChLeftShare->group,
pChLeftShare->max_sfb,
pVars->mask);
if (hasmask == MASK_ERROR)
{
status = 1; /* ERROR code */
}
pVars->hasmask = hasmask;
} /* if (status == 0) */
}
else
{
pVars->hasmask = 0;
} /* if (common_window) */
} /* if (id_syn_ele) */
} /* if (status) */
ch = 0;
while ((ch < num_channels) && (status == SUCCESS))
{
pChLeftShare = pChVars[ch]->pShareWfxpCoef;
status = getics(
pInputStream,
common_window,
pVars,
pChVars[ch],
pChLeftShare->group,
&pChLeftShare->max_sfb,
pChLeftShare->cb_map,
&pChLeftShare->tns,
pVars->winmap,
&pVars->share.a.pulseInfo,
pVars->share.a.sect);
ch++;
} /* while (ch) */
/*----------------------------------------------------------------------------
; Return status
----------------------------------------------------------------------------*/
return status;
} /* huffdecode */
|
