omxsp_iir_direct_s16.c

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

/**
 * 
 * File Name:  omxSP_IIR_Direct_S16.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 block IIR filtering
 *
 */

#include "omxtypes.h"
#include "armOMX.h"
#include "omxSP.h"

#include "armCOMM.h"

/**
 * Function:  omxSP_IIR_Direct_S16   (2.2.3.2.1)
 *
 * Description:
 * Block IIR filtering for 16-bit data. This function applies the direct form 
 * II IIR filter defined by the coefficient vector pTaps to a vector of input 
 * data.  The internal accumulator width must be at least 32 bits, and the 
 * result is saturated if the operation produces a value outside the range of 
 * a signed 16-bit integer, i.e., the output will saturate to 0x8000 (-32768) 
 * for a negative overflow or 0x7fff (32767) for a positive overflow.  The 
 * result is undefined if any of the partially accumulated values exceeds the 
 * range of a signed 32-bit integer. 
 *
 * Input Arguments:
 *   
 *   pSrc  - pointer to the vector of input samples to which the 
 *            filter is applied 
 *   len - the number of samples contained in both the input and output 
 *            vectors 
 *   pTaps - pointer to the 2L+2-element vector that contains the combined 
 *            numerator and denominator filter coefficients from the system 
 *            transfer function, H(z). Coefficient scaling and coefficient 
 *            vector organization should follow the conventions described 
 *            above. The value of the coefficient scaleFactor exponent must be 
 *            non-negative (sf=0). 
 *   order - the maximum of the degrees of the numerator and denominator 
 *            coefficient polynomials from the system transfer function, H(z). 
 *            In the notation of section 2.2.3.2, the parameter 
 *            order=max(K,M)=L gives the maximum delay, in samples, used to 
 *            compute each output sample. 
 *   pDelayLine - pointer to the L-element filter memory buffer (state). The 
 *            user is responsible for allocation, initialization, and 
 *            deallocation. The filter memory elements are initialized to zero 
 *            in most applications. 
 *
 * Output Arguments:
 *   
 *   pDst - pointer to the vector of filtered output samples 
 *
 * Return Value:
 *    
 *    OMX_Sts_NoErr - no error 
 *    OMX_Sts_BadArgErr - bad arguments; returned if one or more of the 
 *              following is true: 
 *    -    one or more of the following pointers is NULL: 
 *             -  pSrc, 
 *             -  pDst, 
 *             -  pTaps, or 
 *             -  pDelayLine. 
 *    -    len < 0 
 *    -    pTaps[order+1] < 0 (negative scaling) 
 *    -    order < 1 
 *
 */
 

 
OMXResult omxSP_IIR_Direct_S16(
     const OMX_S16 * pSrc,
     OMX_S16 * pDst,
     OMX_INT len,
     const OMX_S16 * pTaps,
     OMX_INT order,
     OMX_S32 * pDelayLine
 )
{
    /* Argument Check */
    armRetArgErrIf( pSrc       == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( pDst       == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( pDelayLine == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( pTaps      == NULL, OMX_Sts_BadArgErr);

    armRetArgErrIf( len   <= 0, OMX_Sts_BadArgErr);
    armRetArgErrIf( order <  0, OMX_Sts_BadArgErr);
    armRetArgErrIf( pTaps[order + 1]  <  0 , OMX_Sts_BadArgErr);

    /* Processing */

    while(len != 0)
    {
        omxSP_IIROne_Direct_S16(
                    *pSrc,
                    pDst,
                    pTaps,
                    order,
                    pDelayLine);
        
        pSrc++;
        pDst++;
        len--;
    }
    
    return OMX_Sts_NoErr;
    
}