omxacaac_longtermpredict_s32.c

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

/**
 * 
 * File Name:  omxACAAC_LongTermPredict_S32.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 Long Term Prediction used in LTP loop of AAC decoder
 *
 */

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

#include "armCOMM.h"
#include "armACAAC_Tables.h"

/**
 * Function:  omxACAAC_LongTermPredict_S32   (3.2.3.7.4)
 *
 * Description:
 * LTP analysis portion of the LTP loop. 
 *
 * Reference: [ISO14496-3], sub-clause 4.6.7 
 *
 * Input Arguments:
 *   
 *   pSrcTimeSignal - pointer to the time-domain sequence to be predicted; 
 *            samples are represented using Q28.3 
 *   pAACLtpInfo - pointer to the LTP configuration information 
 *
 * Output Arguments:
 *   
 *   pDstEstTimeSignal - pointer to the LTP output sequence; samples are 
 *            represented using Q28.3 
 *
 * Return Value:
 *    
 *    OMX_Sts_NoErr - no error 
 *    OMX_Sts_BadArgErr - bad arguments: 
 *    -   one or more of the following pointers is NULL: 
 *              - pSrcDstTime, 
 *              - pAACLtpInfo, or 
 *              - pDstEstTimeSignal 
 *    -    the value of the parameter pAACLtpInfo->ltpCoef does not lie in 
 *              the range [9352, 22438] 
 *
 */
 
OMXResult omxACAAC_LongTermPredict_S32(
     OMX_S32 *pSrcTimeSignal,
     OMX_S32 *pDstEstTimeSignal,
     OMXAACLtpInfo *pAACLtpInfo
 )
{
    OMX_F64 scale,coeff;
    OMX_INT Offset;
    OMX_INT numSamples,coeffNum;
    
    /* Argument Check */
    armRetArgErrIf( pSrcTimeSignal    == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( pDstEstTimeSignal == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( pAACLtpInfo       == NULL, OMX_Sts_BadArgErr);

    armRetArgErrIf( pAACLtpInfo->ltpCoef > 22438 , OMX_Sts_BadArgErr) 
    armRetArgErrIf( pAACLtpInfo->ltpCoef < 9352 , OMX_Sts_BadArgErr);

    armRetArgErrIf( pAACLtpInfo->ltpLag > 2047 , OMX_Sts_BadArgErr) 
    armRetArgErrIf( pAACLtpInfo->ltpLag < 0    , OMX_Sts_BadArgErr);
    
    /* Processing */
    scale = (OMX_F64) pAACLtpInfo->ltpCoef / (OMX_F64) (1L << 14);
    
    Offset = (ARM_AAC_WIN_LONG << 1) - pAACLtpInfo->ltpLag;
    
    if(pAACLtpInfo->ltpLag > ARM_AAC_WIN_LONG)
    {
        numSamples  = (ARM_AAC_WIN_LONG << 1);
    }
    else
    {
        numSamples = ARM_AAC_WIN_LONG + pAACLtpInfo->ltpLag;
    }

    for (coeffNum = 0; coeffNum < numSamples ; coeffNum++)
    {
        coeff = scale * ( pSrcTimeSignal[Offset + coeffNum] / (OMX_F64)(1 << ARM_AAC_Q_FACTOR) );
        pDstEstTimeSignal[coeffNum] = armSatRoundFloatToS32(coeff * (1 << ARM_AAC_Q_FACTOR));
    }
    
    for(coeffNum = numSamples ; coeffNum < (ARM_AAC_WIN_LONG << 1) ; coeffNum++)
    {
        pDstEstTimeSignal[coeffNum] = 0;
    }

    return OMX_Sts_NoErr;
}

/*End of File*/