omxacmp3_mdctinv_s32.c

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

/**
 * 
 * File Name:  omxACMP3_MDCTInv_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 function will do Alias reduction, Inverse MDCT, overlap add and 
 * frequency inversion
 */

#include <math.h>
#include "omxtypes.h"
#include "armOMX.h"
#include "omxAC.h"
#include "armCOMM_Bitstream.h"
#include "armCOMM.h"
#include "armACMP3_CommonTables.h"
#include "armACMP3_Tables.h"
#include "armAC.h"

/**
 * Function:  omxACMP3_MDCTInv_S32   (3.1.3.4.1)
 *
 * Description:
 * Stage 1 of the hybrid synthesis filter bank. This performs the following 
 * operations: a) Alias reduction b) Inverse MDCT according to block size 
 * specifiers and mixed block modes c) Overlap add of IMDCT outputs, and d) 
 * Frequency inversion prior to PQMF bank Because the IMDCT is a lapped 
 * transform, the user must preallocate a buffer referenced by 
 * pSrcDstOverlapAdd to maintain the IMDCT overlap-add state. The buffer must 
 * contain 576 elements. Prior to the first call to the synthesis filter bank, 
 * all elements of the overlap-add buffer should be set equal to zero. In 
 * between all subsequent calls, the contents of the overlap-add buffer should 
 * be preserved. Upon entry to omxACMP3_MDCTInv_S32, the overlap-add buffer 
 * should contain the IMDCT output generated by operating on the previous 
 * granule; upon exit from omxACMP3_MDCTInv_S32, the overlap-add buffer will 
 * contain the overlapped portion of the output generated by operating on the 
 * current granule. Upon return from the function, the IMDCT sub-band output 
 * samples are organized as follows: pDstY[j*32+subband], for j=0 to 17; 
 * sub-band=0 to 31.  Note: The pointers pSrcXr (input argument) and pDstY 
 * (output argument) must reference different buffers. Reference [ISO13818-3], 
 * sub-clause 2.5.3.3.2 
 *
 * Input Arguments:
 *   
 *   pSrcXr - pointer to the vector of requantized spectral samples for the 
 *            current channel and granule, represented in Q5.26 format.  Note: 
 *            The vector buffer is used as a workspace buffer when the input 
 *            data has been processed. So the data in the buffer is 
 *            meaningless when exiting the function 
 *   pSrcDstOverlapAdd - pointer to the overlap-add buffer; contains the 
 *            overlapped portion of the previous granule s IMDCT output 
 *   nonZeroBound - the bound above which all spectral coefficients are zero 
 *            for the current granule and channel 
 *   pPrevNumOfImdct - pointer to the number of IMDCTs computed for the 
 *            current channel of the previous granule 
 *   blockType - block type indicator 
 *   mixedBlock - mixed block indicator 
 *
 * Output Arguments:
 *   
 *   pDstY - pointer to the vector of IMDCT outputs in Q7.24 format, for 
 *            input to PQMF bank 
 *   pSrcDstOverlapAdd - pointer to the updated overlap-add buffer; contains 
 *            overlapped portion of the current granule s IMDCT output 
 *   pPrevNumOfImdct - pointer to the number of IMDCTs, for current granule, 
 *            current channel 
 *
 * Return Value:
 *    
 *    OMX_Sts_NoErr - no error 
 *    OMX_Sts_BadArgErr - bad arguments detected; one or more of the pointers 
 *              pSrcXr, pDstY, pSrcDstOverlapAdd, and/or pPrevNumOfImdct is 
 *              NULL 
 *    OMX_Sts_Err - one or more of the following input data errors detected: 
 *              either blockType exceeds [0,3], mixedBlock exceeds [0,1], 
 *              nonZeroBound exceeds [0,576], or *pPrevNumOfImdctexceeds 
 *              [0,32] 
 *
 */
OMXResult omxACMP3_MDCTInv_S32 (
     OMX_S32 *pSrcXr,
     OMX_S32 *pDstY,
     OMX_S32 *pSrcDstOverlapAdd,
     OMX_INT nonZeroBound,
     OMX_INT *pPrevNumOfImdct,
     OMX_INT blockType,
     OMX_INT mixedBlock
)
{
    OMX_S32     sb, i, N, Nby2, win, k, MaxSB;
    OMX_F64     xar [OMX_MP3_GRANULE_LEN], xr [OMX_MP3_GRANULE_LEN];
    OMX_F64     out [ARM_MP3_WINDOW_SZ], Win [ARM_MP3_WINDOW_SZ];
    OMX_F64     xi, tmp, temp [ARM_MP3_SHORTBLOCK_SZ];
    OMX_F64     prvout [OMX_MP3_GRANULE_LEN];

    /* Arguments check */
    armRetArgErrIf(pSrcXr == NULL, OMX_Sts_BadArgErr)
    armRetArgErrIf(pDstY == NULL, OMX_Sts_BadArgErr)
    armRetArgErrIf(pSrcDstOverlapAdd == NULL, OMX_Sts_BadArgErr)
    armRetArgErrIf(pPrevNumOfImdct == NULL, OMX_Sts_BadArgErr)

    /* Validate Arguments */
    armRetArgErrIf(blockType < 0, OMX_Sts_Err)
    armRetArgErrIf(blockType > 3, OMX_Sts_Err)

    armRetArgErrIf(mixedBlock < 0, OMX_Sts_Err)
    armRetArgErrIf(mixedBlock > 1, OMX_Sts_Err)

    armRetArgErrIf(nonZeroBound < 0, OMX_Sts_Err)
    armRetArgErrIf(nonZeroBound > OMX_MP3_GRANULE_LEN, OMX_Sts_Err)

    armRetArgErrIf(*pPrevNumOfImdct < 0, OMX_Sts_Err)
    armRetArgErrIf(*pPrevNumOfImdct > ARM_MP3_NO_OF_SUBBANDS, OMX_Sts_Err)

    /* Copy into local float buffer */
    for (i = 0; i < nonZeroBound; i++)
    {
        /* convert the Q5.26 into float */
        xr [i] = (OMX_F64) pSrcXr [i] / (1 << 26);
    }

    for (; i < OMX_MP3_GRANULE_LEN; i++)
    {
        /* convert the Q5.26 into float */
        xr [i] = 0;
    }

    for (i = 0; i < ARM_MP3_SUBBAND_SZ; i++)
    {
        for (sb = 0; sb < *pPrevNumOfImdct; sb++)
        {
            prvout [i * ARM_MP3_NO_OF_SUBBANDS + sb] = 
                (OMX_F64) pSrcDstOverlapAdd [i * ARM_MP3_NO_OF_SUBBANDS + sb] / (1 << 24);
        }
    }

    /* create Widnow coeffs */
    switch (blockType)
    {
    case 0:
        /* Normal Block */
        for (i = 0; i < ARM_MP3_WINDOW_SZ; i++)
        {
            Win [i] = armACMP3_LongWindow [i];
        }
        break;
    case 1:
        /* Start Block */
        for (i = 0; i < 18; i++)
        {
            Win [i] = armACMP3_LongWindow [i];
        }
        for (i = 18; i < 24; i++)
        {
            Win [i] = 1.0;
        }
        for (i = 24; i < 30; i++)
        {
            Win [i] = armACMP3_ShortWindow [i-18];
        }
        for (i = 30; i < ARM_MP3_WINDOW_SZ; i++)
        {
            Win [i] = 0;
        }
        break;
    case 2:
        /* Short Block */
        if (mixedBlock)
        {
            for (i = 0; i < ARM_MP3_WINDOW_SZ; i++)
            {
                Win [i] = armACMP3_LongWindow [i];
            }
        }
        else
        {
            for (i = 0; i < ARM_MP3_SHORTBLOCK_SZ; i++)
            {
                Win [i] = armACMP3_ShortWindow [i];
            }
        }

        break;
    case 3:
        /* Stop Block */
        for (i = 0; i < 6; i++)
        {
            Win [i] = 0;
        }
        for (i = 6; i < 12; i++)
        {
            Win [i] = armACMP3_ShortWindow [i-6];
        }
        for (i = 12; i < 18; i++)
        {
            Win [i] = 1.0;
        }
        for (i = 18; i < ARM_MP3_WINDOW_SZ; i++)
        {
            Win [i] = armACMP3_LongWindow [i];
        }
        break;
    }

    MaxSB = nonZeroBound / ARM_MP3_SUBBAND_SZ;
    if ((MaxSB * ARM_MP3_SUBBAND_SZ) < nonZeroBound)
    {
        MaxSB++;
    }    

    /* Alias Reduction */
    for (i = 0; i < OMX_MP3_GRANULE_LEN; i++)
    {
        xar [i] = xr [i];
    }
    
    /* get the No of sub-bands for alias reduction */
    if (blockType == 2 && mixedBlock == 1)
    {
        N = 2;
    }
    else if (blockType != 2)
    {
        N = ARM_MP3_NO_OF_SUBBANDS;
    }
    else
    {
        /* case of pure short blocks */
        N = 0;
    }
    
    for (sb = 1; sb < N; sb++)
    {
        for (i = 0; i < ARM_MP3_ALIAS_BFLY_NOS; i++)
        {
            xar [ARM_MP3_SUBBAND_SZ*sb - 1 - i] = 
                xr [ARM_MP3_SUBBAND_SZ*sb - 1 - i] * armACMP3_BflyCoeffCS[i] - 
                xr [ARM_MP3_SUBBAND_SZ*sb + i] * armACMP3_BflyCoeffCA[i]; 
            xar [ARM_MP3_SUBBAND_SZ*sb + i] = 
                xr [ARM_MP3_SUBBAND_SZ*sb + i] * armACMP3_BflyCoeffCS[i] + 
                xr [ARM_MP3_SUBBAND_SZ*sb - 1 - i] * armACMP3_BflyCoeffCA[i]; 
        }
    }

    /* Aliasing reduction will increase no of mdctinv needed by one */
    if ((N != 0) && (MaxSB < ARM_MP3_NO_OF_SUBBANDS))
    {
        MaxSB++;
    }
    /* IMDCT */
    
    for (sb = 0; sb < MaxSB; sb++)
    {
        if ((blockType == 2 && mixedBlock == 0) ||
            (blockType == 2 && mixedBlock == 1 && sb > 1))
        {
            /* Short */
            if (blockType == 2 && mixedBlock == 1 && sb == 2)
            {
                for (i = 0; i < ARM_MP3_SHORTBLOCK_SZ; i++)
                {
                    Win [i] = armACMP3_ShortWindow [i];
                }
            }
            N = ARM_MP3_SHORTBLOCK_SZ;
            Nby2 = N / 2;
            for (i = 0; i < ARM_MP3_WINDOW_SZ; i++)
            {
                out [i] = 0;
            }

            for (win = 0; win < 3; win++)
            {
                for (i = 0; i < N; i++)
                {
                    tmp = ((2 * i + 1 + Nby2) * PI)/(2 * N);

                    for (k = 0, xi = 0.0; k < Nby2; k++)
                    {
                        xi += xar [sb * 18 + Nby2*win + k] * cos (tmp * (2 * k + 1));
                    }
                    
                    temp [i] =  xi * Win [i];
                }
                for (i = 0; i < N; i++)
                {
                    out [6*win+i+6] += temp [i];
                }
            }
        }
        else
        {
            if(mixedBlock == 1)
			{
			  if(blockType != 0 && sb < 2)
			  {
				/* Normal Block */
				for (i = 0; i < ARM_MP3_WINDOW_SZ; i++)
				{
					Win [i] = armACMP3_LongWindow [i];
				}
			  }
			  else if(blockType == 1)
			  {
				/* Start Block */
				for (i = 0; i < 18; i++)
				{
					Win [i] = armACMP3_LongWindow [i];
				}
				for (i = 18; i < 24; i++)
				{
					Win [i] = 1.0;
				}
				for (i = 24; i < 30; i++)
				{
					Win [i] = armACMP3_ShortWindow [i-18];
				}
				for (i = 30; i < ARM_MP3_WINDOW_SZ; i++)
				{
					Win [i] = 0;
				}
			  }
              else if(blockType == 3)
			  {
                /* Stop Block */
				for (i = 0; i < 6; i++)
				{
					Win [i] = 0;
				}
				for (i = 6; i < 12; i++)
				{
					Win [i] = armACMP3_ShortWindow [i-6];
				}
				for (i = 12; i < 18; i++)
				{
					Win [i] = 1.0;
				}
				for (i = 18; i < ARM_MP3_WINDOW_SZ; i++)
				{
					Win [i] = armACMP3_LongWindow [i];
				}
			  }
			}
            /* Long */
            /* Update IMDCT parameters */
            N = ARM_MP3_LONGBLOCK_SZ;
            Nby2 = N / 2;

            for (i = 0; i < N; i++)
            {
                tmp = ((2 * i + 1 + Nby2) * PI)/(2 * N);

                for (k = 0, xi = 0.0; k < Nby2; k++)
                {
                    xi += xar [sb * Nby2 + k] * cos (tmp * (2 * k + 1));
                }
                out [i] = xi * Win [i];
            }
        }

        /* Overlap addition */
        if (sb < *pPrevNumOfImdct)
        {
            for (i = 0; i < ARM_MP3_SUBBAND_SZ; i++)
            {
                xr [i * ARM_MP3_NO_OF_SUBBANDS + sb] = 
                    prvout [i * ARM_MP3_NO_OF_SUBBANDS + sb] + out [i];

                prvout [i * ARM_MP3_NO_OF_SUBBANDS + sb] = 
                    out [i + ARM_MP3_SUBBAND_SZ];
            }
        }
        else
        {
            for (i = 0; i < ARM_MP3_SUBBAND_SZ; i++)
            {
                xr [i * ARM_MP3_NO_OF_SUBBANDS + sb] = out [i];

                prvout [i * ARM_MP3_NO_OF_SUBBANDS + sb] = 
                    out [i + ARM_MP3_SUBBAND_SZ];
            }
        }
    }

    /* Update remaining output values corresponding to zero imdct */
    for (; sb < *pPrevNumOfImdct; sb++)
    {
        /* Overlap addition for zero values */
        for (i = 0; i < ARM_MP3_SUBBAND_SZ; i++)
        {
            xr [i * ARM_MP3_NO_OF_SUBBANDS + sb] = 
                prvout [i * ARM_MP3_NO_OF_SUBBANDS + sb];
        }
    }

    /* Update number of IMDCT calculated for current granule */
    *pPrevNumOfImdct = MaxSB; 
    
    MaxSB = sb;

    /* Frequency Inversion */
    for (sb = 1; sb < MaxSB; sb += 2)
    {
        for (i = 1; i < ARM_MP3_SUBBAND_SZ; i += 2)
        {
            xr [i * ARM_MP3_NO_OF_SUBBANDS + sb] = 
                -xr [i * ARM_MP3_NO_OF_SUBBANDS + sb];
        }
    }
    
    
    /* Copy from local float buffer */
    for (i = 0; i < ARM_MP3_SUBBAND_SZ; i++)
    {
        for (sb = 0; sb < MaxSB; sb++)
        {
            /* convert to the Q7.24 from float */
            pDstY [i * ARM_MP3_NO_OF_SUBBANDS + sb] = 
                armSatRoundFloatToS32 (xr [i * ARM_MP3_NO_OF_SUBBANDS + sb] * (1 << 24));
        }
        for (; sb < ARM_MP3_NO_OF_SUBBANDS; sb++)
        {
            /* convert to the Q7.24 from float */
            pDstY [i * ARM_MP3_NO_OF_SUBBANDS + sb] = 0;

        }
    }

    for (i = 0; i < ARM_MP3_SUBBAND_SZ; i++)
    {
        for (sb = 0; sb < *pPrevNumOfImdct; sb++)
        {
            /* convert to the Q7.24 from float */
            pSrcDstOverlapAdd [i * ARM_MP3_NO_OF_SUBBANDS + sb] = 
                armSatRoundFloatToS32 (prvout [i * ARM_MP3_NO_OF_SUBBANDS + sb] * (1 << 24));
        }
        
        for (; sb < ARM_MP3_NO_OF_SUBBANDS; sb++)
        {
            /* convert to the Q7.24 from float */
            pSrcDstOverlapAdd [i * ARM_MP3_NO_OF_SUBBANDS + sb] = 0;

        }
    }

    return OMX_Sts_NoErr;
}

/*****************************************************************************
 *                              END OF FILE
 *****************************************************************************/