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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: q_normalize.c
------------------------------------------------------------------------------
REVISION HISTORY
Description:
(1) Modify to include search over the scalefactor bands to insure
that the data is using all 31 data-bits.
Description:
(1) Modify to remove search over the scalefactor bands to insure
that the data is using all 31 data-bits.
(Pushed out into separate function)
(2) Change variable "k" to more descriptive "shift_amt"
(3) Update pseudocode to reflect removed code.
(4) Add PV Copyright notice.
Description:
(1) Modified to protect q-normalize from shifting by amounts >= 32.
Description:
(1) Delete local variable idx_count.
Description:
(1) Included search for max in each frame, modified interface.
Description:
(1) unrolled loop based on the fact that the size of each scale band
is always an even number.
Description:Check shift, if zero, do not shift.
Description: Eliminated warning: non use variable "i" and memset function
definition
Who: Date:
Description:
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
qFormat[] = Array of qFormats, one per scalefactor band. [ Int ]
pFrameInfo = Pointer to structure that holds information about each group.
(long block flag, number of windows, scalefactor bands, etc.)
[const FrameInfo]
coef[] = Array of the spectral coefficients for one channel. [ Int32 ]
Local Stores/Buffers/Pointers Needed:
None
Global Stores/Buffers/Pointers Needed:
None
Outputs:
min_q = The common q-format for the entire frame. [Int]
Pointers and Buffers Modified:
coef[] = Array of spectral data, now normalized to one q-format.
Local Stores Modified:
None
Global Stores Modified:
None
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
This module first scans every scalefactor band for the frame, insuring that
at least one element in that scalefactor band is using all available bits.
If not, the elements in the scalefactor band are shifted up to use all 31
data bits. The q-format is adjusted accordingly.
This module then scans the q-formats for each scalefactor band.
Upon finding the minimum q-format in the frame, the coefficients in each
scalefactor band are normalized to the minimum q-format.
The minimum q-format is then returned to the calling function, which is now
the q-format for the entire frame.
------------------------------------------------------------------------------
REQUIREMENTS
------------------------------------------------------------------------------
REFERENCES
------------------------------------------------------------------------------
PSEUDO-CODE
nwin = pFrameInfo->num_win;
pQformat = &(qFormat[0]);
pSfbPerWin = &(pFrameInfo->sfb_per_win[0]);
pCoef = &(coef[0]);
FOR (win = nwin; win > 0; win--)
nsfb = *(pSfbPerWin++);
FOR (sfb = nsfb; sfb > 0; sfb--)
IF ( *(pQformat) < min_q)
min_q = *(pQformat);
ENDIF
pQformat++;
ENDFOR
ENDFOR
pQformat = &(qFormat[0]);
pSfbPerWin = &(pFrameInfo->sfb_per_win[0]);
pCoef = &(coef[0]);
FOR (win = 0; win < nwin; win++)
stop_idx = 0;
nsfb = *(pSfbPerWin++);
pWinSfbTop = &(pFrameInfo->win_sfb_top[win][0]);
FOR (sfb = nsfb; sfb > 0; sfb--)
sfbWidth = *(pWinSfbTop++) - stop_idx;
stop_idx += sfbWidth;
k = *(pQformat++) - min_q;
IF (k < 32)
THEN
FOR (; sfbWidth > 0; sfbWidth--)
*(pCoef++) >>= k;
ENDFOR
ELSE
FOR (; sfbWidth > 0; sfbWidth--)
*(pCoef++) = 0;
ENDFOR
ENDIF
ENDFOR
ENDFOR
return min_q;
------------------------------------------------------------------------------
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 "s_frameinfo.h"
#include "q_normalize.h"
#include "aac_mem_funcs.h" /* For pv_memset */
/*----------------------------------------------------------------------------
; 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 q_normalize(
Int qFormat[],
const FrameInfo *pFrameInfo,
Int32 abs_max_per_window[],
Int32 coef[])
{
Int sfb;
Int nsfb;
Int win;
Int nwin;
Int sfbWidth;
Int shift_amt;
/* Initialize min_q to a very large value */
Int min_q = 1000;
Int stop_idx = 0;
const Int *pSfbPerWin;
const Int16 *pWinSfbTop;
Int *pQformat;
Int32 *pCoef;
nwin = pFrameInfo->num_win;
/* Find the minimum q format */
pQformat = &(qFormat[0]);
pSfbPerWin = &(pFrameInfo->sfb_per_win[0]);
for (win = nwin; win != 0; win--)
{
nsfb = *(pSfbPerWin++);
if (nsfb < 0 || nsfb > MAXBANDS)
{
break; /* avoid any processing on error condition */
}
for (sfb = nsfb; sfb != 0; sfb--)
{
Int qformat = *(pQformat++);
if (qformat < min_q)
{
min_q = qformat;
}
}
} /* for(win) */
/* Normalize the coefs in each scalefactor band to one q-format */
pQformat = &(qFormat[0]);
pSfbPerWin = &(pFrameInfo->sfb_per_win[0]);
pCoef = &(coef[0]);
for (win = 0; win < nwin; win++)
{
Int32 max = 0;
stop_idx = 0;
nsfb = *(pSfbPerWin++);
if (nsfb < 0 || nsfb > MAXBANDS)
{
break; /* avoid any processing on error condition */
}
pWinSfbTop = &(pFrameInfo->win_sfb_top[win][0]);
for (sfb = nsfb; sfb != 0; sfb--)
{
Int tmp1, tmp2;
tmp1 = *(pWinSfbTop++);
tmp2 = *(pQformat++);
sfbWidth = tmp1 - stop_idx;
if (sfbWidth < 2)
{
break; /* will lead to error condition */
}
stop_idx += sfbWidth;
shift_amt = tmp2 - min_q;
if (shift_amt == 0)
{
Int32 tmp1, tmp2;
tmp1 = *(pCoef++);
tmp2 = *(pCoef++);
/*
* sfbWidth is always an even number
* (check tables in pg.66 IS0 14496-3)
*/
for (Int i = (sfbWidth >> 1) - 1; i != 0; i--)
{
max |= (tmp1 >> 31) ^ tmp1;
max |= (tmp2 >> 31) ^ tmp2;
tmp1 = *(pCoef++);
tmp2 = *(pCoef++);
}
max |= (tmp1 >> 31) ^ tmp1;
max |= (tmp2 >> 31) ^ tmp2;
}
else
{
if (shift_amt < 31)
{
Int32 tmp1, tmp2;
tmp1 = *(pCoef++) >> shift_amt;
tmp2 = *(pCoef--) >> shift_amt;
/*
* sfbWidth is always an even number
* (check tables in pg.66 IS0 14496-3)
*/
for (Int i = (sfbWidth >> 1) - 1; i != 0; i--)
{
*(pCoef++) = tmp1;
*(pCoef++) = tmp2;
max |= (tmp1 >> 31) ^ tmp1;
max |= (tmp2 >> 31) ^ tmp2;
tmp1 = *(pCoef++) >> shift_amt;
tmp2 = *(pCoef--) >> shift_amt;
}
*(pCoef++) = tmp1;
*(pCoef++) = tmp2;
max |= (tmp1 >> 31) ^ tmp1;
max |= (tmp2 >> 31) ^ tmp2;
}
else
{
pv_memset(pCoef, 0, sizeof(Int32)*sfbWidth);
pCoef += sfbWidth;
}
}
abs_max_per_window[win] = max;
}
} /* for (win) */
return min_q;
} /* normalize() */
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