omxipcs_ycbcr422tobgr565ls_mcu_s16_u16_p3c3.c

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

/**
 *
 * 
 * File Name:  omxIPCS_YCbCr422ToBGR565LS_MCU_S16_U16_P3C3.c
 * OpenMAX DL: v1.0.2
 * Revision:   10586
 * Date:       Wednesday, March 5, 2008
 * 
 * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
 * 
 * 
 *
 * Description  : Colour Conversion Routine - Converts YUV422 to BGR565 in floating point.
 *                Source data is stored as a JPEG MCU in three channel, planar domain and 
 *                the destination would be in three-channel pixel format.
 *
 */

#include "omxtypes.h"
#include "armOMX.h"
#include "omxIP.h"
#include "armCOMM.h"
#include "armIP.h"


/**
 * Function:  omxIPCS_YCbCr422ToBGR565LS_MCU_S16_U16_P3C3   (4.4.3.8.6)
 *
 * Description:
 * These functions convert sub-sampled YCbCr data to BGR565 data with 
 * level-shift.  The parameter pSrcMCU[0] must point to the start of a 
 * sufficient number of contiguously stored 8x8 Y blocks to constitute a 
 * complete MCU given the source chroma sub-sampling scheme, i.e., 1, 2, or 4 
 * blocks for YCbCr 4:4:4, 4:2:2, or YCbCr 4:2:0, respectively. 
 *
 * Input Arguments:
 *   
 *   pSrcMCU - buffer containing input MCU pointers: pSrcMCU[0] points to the 
 *            first Y block, pSrcMCU[1] points to Cb the block, and pSrcMCU[2] 
 *            points to the Cr block; all three must be aligned on 8-byte 
 *            boundaries.  The parameter pSrcMCU[0] must point to the start of 
 *            a sufficient number of contiguously stored 8x8 Y blocks to 
 *            constitute a complete MCU given the source chroma sub-sampling 
 *            scheme, i.e., 1, 2, or 4 blocks for YCbCr 4:4:4, 4:2:2, or YCbCr 
 *            4:2:0, respectively. Only top-down storage format is supported.  
 *            Input components are represented using Q8 and are bounded on the 
 *            interval [-128, 127]. 
 *   dstStep - distance in bytes between the starts of consecutive lines in 
 *            the destination image; can take negative values to support 
 *            bottom-up storage format. 
 *
 * Output Arguments:
 *   
 *   pDst - output image buffer pointer; data are interleaved as follows:  
 *            [B G R B G R  ], where G is represented using 6 bits, and B and R 
 *            are represented using 5 bits.  Output components are saturated. 
 *            The parameter dstStep can take negative values to support 
 *            bottom-up storage. 
 *
 * Return Value:
 *    
 *    OMX_Sts_NoErr - no error 
 *    OMX_Sts_BadArgErr - bad arguments - returned if one or more of the 
 *              following is true: 
 *    -   a pointer was NULL 
 *    -   the absolute value of dstStep was smaller than 16 (for YCbCr444) 
 *        or 32 (for YCbCr422/YCbCr420) 
 *    -   a pointer in pSrcMCU[] was not 8-byte aligned 
 *
 */
 
OMXResult omxIPCS_YCbCr422ToBGR565LS_MCU_S16_U16_P3C3(
        const OMX_S16 *pSrcMCU[3],
        OMX_U16 *pDstRGB,
        OMX_INT dstStep
       )
{   
    const OMX_S16 *pSrcY, *pSrcCb, *pSrcCr;
    OMX_S16 Ydata, Ydata2, Udata, Vdata;
    OMX_F32 Rdata, Gdata, Bdata, Rdata2, Gdata2, Bdata2;
    OMX_INT i, j;
    OMX_U16 *pRGB;

    OMX_INT blk;
    ARM_BLOCK8x8 *y8x8;
    OMX_INT blkOffset[2] = {0, 8};
    OMX_INT blkOffset_UV[2] = {0, 4};

    armRetArgErrIf(!pSrcMCU, OMX_Sts_BadArgErr);
    armRetArgErrIf(!pDstRGB, OMX_Sts_BadArgErr);
    armRetArgErrIf(!pSrcMCU[0], OMX_Sts_BadArgErr);
    armRetArgErrIf(!pSrcMCU[1], OMX_Sts_BadArgErr);
    armRetArgErrIf(!pSrcMCU[2], OMX_Sts_BadArgErr);
    armRetArgErrIf(!armIs8ByteAligned(pSrcMCU[0]), OMX_Sts_BadArgErr);
    armRetArgErrIf(!armIs8ByteAligned(pSrcMCU[1]), OMX_Sts_BadArgErr);
    armRetArgErrIf(!armIs8ByteAligned(pSrcMCU[2]), OMX_Sts_BadArgErr);
    armRetArgErrIf(((dstStep > (-2 * JPEG_MCU_PIX_WIDTH_422)) && ((dstStep < 2 * JPEG_MCU_PIX_WIDTH_422))), OMX_Sts_BadArgErr);

    /*
    ---------------------------------------------------------------------------------
    With input data (Y, Cb, Cr) belonging to [-128, 127] and output data (R, G, B) 
    belonging to [0, 255], colour conversion equations in the JPEG domain would be - 
    R = (Y + 128) + 1.40200 * Cr
    G = (Y + 128) - 0.34414 * Cb - 0.71414 * Cr
    B = (Y + 128) + 1.77200 * Cb
    
    The armComputeXFromYUV_JPEG() functions apart from doing the colour conversion, 
    takes care of type-conversion from intermediate float values and clipping to U8,
    taking care of rounding errors.  This is followed armIPCS_PackToRGB565() that packs
    the R, G, B data in 565 format.
    ---------------------------------------------------------------------------------
    */
    y8x8 = (ARM_BLOCK8x8 *)pSrcMCU[0];   

    pSrcY   = pSrcMCU[0];
    pSrcCb  = pSrcMCU[1];
    pSrcCr  = pSrcMCU[2];

    for(blk = 0; blk < 2; blk++)
    {
        pSrcY   = (OMX_S16 *)y8x8++;
        pSrcCb  = pSrcMCU[1] + blkOffset_UV[blk];
        pSrcCr  = pSrcMCU[2] + blkOffset_UV[blk];
        pRGB    = pDstRGB + blkOffset[blk];
        for(i = 0; i < 8; i++)
        {
            for(j = 0; j < 4*2; j+=2)
            {
                Ydata       = *pSrcY++;
                Ydata2      = *pSrcY++;
                Udata       = *pSrcCb++;
                Vdata       = *pSrcCr++;
                armIPCS_ComputeRGBFromYUV_JPEG_F32(Ydata, Udata, Vdata, &Rdata, &Gdata, &Bdata);
                armIPCS_ComputeRGBFromYUV_JPEG_F32(Ydata2, Udata, Vdata, &Rdata2, &Gdata2, &Bdata2);

                pRGB[j]   = armIPCS_PackToBGR565_F32(Bdata,  Gdata,  Rdata);
                pRGB[j+1] = armIPCS_PackToBGR565_F32(Bdata2, Gdata2, Rdata2);
            }
            pSrcCb  += 4;
            pSrcCr  += 4;
            pRGB    += dstStep>>1;
        }
    }
    return OMX_Sts_NoErr;
}

/* End of file */