omxsp_fir_direct_s16_sfs.c

来自「The OpenMAX DL (Development Layer) APIs 」· C语言 代码 · 共 130 行

/**
 * 
 * File Name:  omxSP_FIR_Direct_S16_Sfs.c
 * OpenMAX DL: v1.0.2
 * Revision:   10586
 * Date:       Wednesday, March 5, 2008
 * 
 * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
 * 
 * 
 * Description:
 *
 */

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

extern 


/**
 * Function:  omxSP_FIR_Direct_S16_Sfs   (2.2.3.1.1)
 *
 * Description:
 * Block FIR filtering for 16-bit data type. This function applies 
 * the FIR filter defined by the coefficient vector pTapsQ15 to a 
 * vector of input data.  The output is multiplied by 2 to the negative 
 * power of scalefactor (i.e., 2^-scalefactor) before returning to the caller.
 * Scaling and rounding conventions are defined in section 1.6.7.  
 * The internal accumulator width must be at least 32 bits.  
 * 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 
 *   sampLen - the number of samples contained in the input and output 
 *            vectors 
 *   pTapsQ15 - pointer to the vector that contains the filter coefficients, 
 *            represented in Q0.15 format (defined in section 1.6.5). Given 
 *            that:
 *                    -32768 = pTapsQ15(k) < 32768, 
 *                     0 = k <tapsLen, 
 *            the range on the actual filter coefficients is -1 = bK <1, and 
 *            therefore coefficient normalization may be required during the 
 *            filter design process. 
 *   tapsLen - the number of taps, or, equivalently, the filter order + 1 
 *   pDelayLine - pointer to the 2.tapsLen -element filter memory buffer 
 *            (state). The user is responsible for allocation, initialization, 
 *            and de-allocation. The filter memory elements are initialized to 
 *            zero in most applications. 
 *   pDelayLineIndex - pointer to the filter memory index that is maintained 
 *            internally by the function. The user should initialize the value 
 *            of this index to zero. 
 *   scaleFactor - saturation fixed scalefactor
 *
 * 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, 
 *          -  pSrcDst, 
 *          -  pTapsQ15, 
 *          -  pDelayLine, or 
 *          -  pDelayLineIndex 
 *    -   samplen < 0 
 *    -   tapslen < 1 
 *    -   scaleFactor < 0 
 *    -   *pDelayLineIndex < 0 or *pDelayLineIndex >= (2 * tapslen). 
 *
 */

OMXResult omxSP_FIR_Direct_S16_Sfs(
     const OMX_S16 * pSrc,
     OMX_S16 * pDst,
     OMX_INT sampLen,
     const OMX_S16 * pTapsQ15,
     OMX_INT tapsLen,
     OMX_S16 * pDelayLine,
     OMX_INT * pDelayLineIndex,
     OMX_INT scaleFactor
 )
 {
    OMX_U32     Count;
    OMXResult  Result = OMX_Sts_NoErr;

    /* Input parameter check */ 
	armRetArgErrIf((pSrc == NULL), OMX_Sts_BadArgErr)
	armRetArgErrIf((pDst == NULL), OMX_Sts_BadArgErr)
	armRetArgErrIf((sampLen <= 0), OMX_Sts_BadArgErr)
	armRetArgErrIf((pTapsQ15 == NULL), OMX_Sts_BadArgErr)
	armRetArgErrIf((tapsLen <= 0), OMX_Sts_BadArgErr)
	armRetArgErrIf((pDelayLine == NULL), OMX_Sts_BadArgErr)
	armRetArgErrIf((pDelayLineIndex == NULL), OMX_Sts_BadArgErr)
	armRetArgErrIf((*pDelayLineIndex < 0), OMX_Sts_BadArgErr)
	armRetArgErrIf((*pDelayLineIndex >= (2 * tapsLen)), OMX_Sts_BadArgErr)
    
    for (Count = 0; Count < sampLen; Count++) 
    {
        if ((Result = omxSP_FIROne_Direct_S16_Sfs (pSrc [Count],
										&(pDst [Count]),
										pTapsQ15,
										tapsLen,
										pDelayLine,
										pDelayLineIndex,
										scaleFactor)) != OMX_Sts_NoErr)
        {
            return Result;
        }
    }
    
    return OMX_Sts_NoErr;
}


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 *                              END OF FILE
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