omxacaac_decodemsstereo_s32_i.c

The OpenMAX DL (Development Layer) APIs contain a comprehensive set of audio, video, signal processi

/**
 * 
 * File Name:  omxACAAC_DecodeMsStereo_S32_I.c
 * OpenMAX DL: v1.0.2
 * Revision:   10586
 * Date:       Wednesday, March 5, 2008
 * 
 * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
 * 
 * 
 *
 * Description:
 * This file contains module for M/S Stereo decoding for an AAC decoder
 *
 */


#include "omxtypes.h"
#include "armOMX.h"
#include "omxAC.h"

#include "armCOMM_Bitstream.h"
#include "armAC.h"
#include "armCOMM.h"

#include "armACAAC_Tables.h"

/**
 * Function:  omxACAAC_DecodeMsStereo_S32_I   (3.2.3.3.1)
 *
 * Description:
 * Performs M-S stereo decoding; converts the MS stereo jointly-coded 
 * scalefactor bands of a channel pair from the M-S representation to the L-R 
 * representation; also performs the invert_intensity(group,sfb) function and 
 * stores the values in the pSfbCb buffer.  If invert_intensity(group, sfb) = 
 *  1, and if *pSfbCb = INTERITY_HCB, let *pSfbCb = INTERITY_HCB2; else if 
 * *pSfbCb = INTERITY_HCB2, let *pSfbCb = INTERITY_HCB. For scalefactor bands 
 * in which the MS stereo flag is asserted, the individual left and right 
 * channel spectral samples pSrcDstL[i] and pSrcDstR[i] are computed as 
 * follows: 
 *            pSrcDstL'[i] = pSrcDstL[i] + pSrcDstR[i], 
 *            pSrcDstR'[i] = pSrcDstL[i] - pSrcDstR[i]. 
 *
 * Reference: [ISO14496-3], sub-clause 4.6.8.1 
 *
 * Input Arguments:
 *   
 *   pSrcDstL - pointer to left channel data in Q28.3 format. For short 
 *            blocks, the coefficients are interleaved by scalefactor window 
 *            bands in each group, of length 1024. pSrcDstL must be 8-byte 
 *            aligned. 
 *   pSrcDstR - pointer to right channel data in Q28.3 format. For short 
 *            block, the coefficients are interleaved by scalefactor window 
 *            bands in each group, of length 1024. pSrcDstR must be 8-byte 
 *            aligned. 
 *   pChanPairElt - pointer to a Channel Pair Element structure that has been 
 *            previously populated. At minimum, the contents of msMaskPres and 
 *            pMsUsed fields are used to control MS decoding process and must 
 *            be valid.  These provide, respectively, the MS stereo mask for a 
 *            scalefactor band (0: MS Off, 1: MS On, 2: all bands on), and the 
 *            MS stereo flag buffer, of length 120. 
 *   pSfbCb -pointer to the scalefactor band codebook, of length 120.  Stores 
 *            maxSfb elements for each group.  There is no space between the 
 *            sequence groups 
 *   numWinGrp - group number 
 *   pWinGrpLen - pointer to the number of windows in each group, of length 8 
 *   maxSfb - max scalefactor bands number for the current block 
 *   samplingRateIndex - sampling rate index; valid in the range [0, 11] 
 *   winLen - the data number in one window 
 *
 * Output Arguments:
 *   
 *   pSrcDstL - pointer to left channel data in Q28.3 format. For short 
 *            blocks, the coefficients are interleaved by scalefactor window 
 *            bands in each group, of length 1024. pSrcDstL must be 8-byte 
 *            aligned. 
 *   pSrcDstR - pointer to right channel data in Q28.3 format. For short 
 *            blocks, the coefficients are interleaved by scalefactor window 
 *            bands in each group, of length 1024. pSrcDstR must be 8-byte 
 *            aligned. 
 *   pSfbCb- pointer to the scalefactor band codebook. If invert_intensity 
 *            group, sfb) = -1, and if *pSfbCb = INTERITY_HCB, let *pSfbCb = 
 *            INTERITY_HCB2; else if *pSfbCb = INTERITY_HCB2, let *pSfbCb = 
 *            INTERITY_HCB. Buffer length is 120. Store maxSfb elements for 
 *            each group. There is no space between the sequence groups. 
 *
 * Return Value:
 *    
 *    OMX_Sts_NoErr - no error 
 *    OMX_Sts_BadArgErr - bad arguments:
 *    -       At least one of the following pointers is NULL:
 *            - pSrcDstL, 
 *            - pSrcDstR, 
 *            - pMsUsed, 
 *            - pWinGrpLen, 
 *            - pSfbCb 
 *    -     pSrcDstL or pSrcDstR is not 8-byte aligned 
 *    -     For short blocks, numWinGrpexceeds [1, 8] 
 *    -     For long blocks, numWinGrp != 1 
 *    -     maxSfb exceeds [0, 51] 
 *    -     msMaskPres exceeds [1, 2] 
 *    -     samplingRateIndex exceeds [0, 11] 
 *    -     winLen is neither 1024 nor 128 
 *    OMX_StsACAAC_MaxSfbErr - invalid maxSfb value in relation to numSwb 
 *
 */

OMXResult omxACAAC_DecodeMsStereo_S32_I(
     OMX_S32 *pSrcDstL,
     OMX_S32 *pSrcDstR,
     OMXAACChanPairElt *pChanPairElt,
     OMX_U8 *pSfbCb,
     OMX_INT numWinGrp,
     const OMX_INT *pWinGrpLen,
     OMX_INT maxSfb,
     OMX_INT samplingRateIndex,
     OMX_INT winLen
)
{
    OMX_INT groupNum,winNum,sfbNum,cbNum;
    OMX_INT msMask,coeff;
    OMX_S32 diff;
    const OMX_U16 *pOffsetTable;
    OMX_U16 width,numSwb;
    OMX_INT msMaskPres;
    
    /* Argument Check */        
    armRetArgErrIf( pChanPairElt == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( pSrcDstL     == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( pSrcDstR     == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( pSfbCb       == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( pWinGrpLen   == NULL, OMX_Sts_BadArgErr);

    armRetArgErrIf( (maxSfb > 51)    || (maxSfb < 0)    , OMX_Sts_BadArgErr);
    armRetArgErrIf( pChanPairElt->msMaskPres > 2, OMX_Sts_BadArgErr);
    armRetArgErrIf( pChanPairElt->msMaskPres < 1, OMX_Sts_BadArgErr);
    
    armRetArgErrIf( samplingRateIndex > 11, OMX_Sts_BadArgErr);
    armRetArgErrIf( samplingRateIndex < 0 , OMX_Sts_BadArgErr);

    armRetArgErrIf( armNot8ByteAligned(pSrcDstL), OMX_Sts_BadArgErr)
    armRetArgErrIf( armNot8ByteAligned(pSrcDstR), OMX_Sts_BadArgErr)
    
    armRetArgErrIf( ( winLen != ARM_AAC_WIN_SHORT ) && 
                    ( winLen != ARM_AAC_WIN_LONG  ),
                    OMX_Sts_BadArgErr );

    armRetArgErrIf( ( winLen == ARM_AAC_WIN_SHORT ) && 
                    ( (numWinGrp > 8) || (numWinGrp < 1) ), 
                    OMX_Sts_BadArgErr );

    armRetArgErrIf( ( winLen == ARM_AAC_WIN_LONG ) && 
                    ( numWinGrp != 1),
                    OMX_Sts_BadArgErr );
    

    /* Processing */
    msMaskPres = pChanPairElt->msMaskPres;
    
    if(winLen == ARM_AAC_WIN_SHORT)
    {
        pOffsetTable = armACAAC_swbOffsetShortWindow[samplingRateIndex];
        numSwb       = armACAAC_numSwbShort[samplingRateIndex];
    }
    else
    {
        pOffsetTable = armACAAC_swbOffsetLongWindow[samplingRateIndex];
        numSwb       = armACAAC_numSwbLong[samplingRateIndex];
    }
  
    armRetArgErrIf( maxSfb > numSwb, OMX_StsACAAC_MaxSfbErr);

    for (groupNum = 0; groupNum < numWinGrp; groupNum++)
    {
        for(sfbNum = 0; sfbNum < maxSfb; sfbNum++)
        {
            msMask = pChanPairElt->ppMsMask[groupNum][sfbNum];
            cbNum  = *pSfbCb;
            
            /*inverting the intensity*/
            if(msMask == 1 && cbNum  == ARM_AAC_INTENSITY_HCB)
            {
                cbNum   = ARM_AAC_INTENSITY_HCB2;
                *pSfbCb = ARM_AAC_INTENSITY_HCB2;
            }
            else if(msMask == 1 && cbNum  == ARM_AAC_INTENSITY_HCB2)
            {
                cbNum   = ARM_AAC_INTENSITY_HCB;
                *pSfbCb = ARM_AAC_INTENSITY_HCB;
            }
            
            width  = pOffsetTable[sfbNum + 1] - pOffsetTable[sfbNum];
            pSfbCb++;
            
            if
            (   ( msMask == 1                     || 
                  msMaskPres == 2 )               &&
                  cbNum != ARM_AAC_INTENSITY_HCB  &&
                  cbNum != ARM_AAC_INTENSITY_HCB2 &&
                  cbNum != ARM_AAC_NOISE_HCB
            )
            {
                
                for (winNum = 0; winNum < pWinGrpLen[groupNum]; winNum++)
                {
                    for (coeff = 0; coeff < width; coeff++)
                    {
                        diff      = armSatSub_S32(*pSrcDstL,*pSrcDstR);
                        *pSrcDstL = armSatAdd_S32(*pSrcDstL,*pSrcDstR);
                        *pSrcDstR = diff;
                        
                        pSrcDstL++;
                        pSrcDstR++;
                    }
                }
            }
            else
            {
                pSrcDstL += pWinGrpLen[groupNum] * width;
                pSrcDstR += pWinGrpLen[groupNum] * width;
            }
        }
    }

    return OMX_Sts_NoErr;
}

/* End of File */