omxipcs_bgr565toycbcr422ls_mcu_u16_s16_c3p3.c

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

/**
*
* 
* File Name:  omxIPCS_BGR565ToYCbCr422LS_MCU_U16_S16_C3P3.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 BGR565 to YUV422 in floating point.
*                Source is in three channel, pixel domain and the destination would be in 
*                three-channel planar format. Output is a JPEG MCU.
*
*/

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

/**
* Function:  omxIPCS_BGR565ToYCbCr422LS_MCU_U16_S16_C3P3   (4.4.3.7.6)
*
* Description:
* This function converts packed BGR565 image data to the following 
* sub-sampled color spaces:  YCbCr4:4:4, YCbCr4:2:2, and YCbCr4:2:0.  The 
* parameter pDstMCU[0] must point to the start of a buffer with sufficient 
* free space to contain the particular number of contiguously stored 8x8 Y 
* blocks that constitute a complete MCU given the output chroma sub-sampling 
* scheme, i.e., 1, 2, or 4 of 8x8 Y blocks for YCbCr 4:4:4, 4:2:2, or 4:2:0 
* output, respectively. 
*
* Input Arguments:
*   
*   pSrc - references the source image data buffer.  Pixel intensities are 
*            interleaved as shown in Table 4 1, and G, B, and R are 
*            represented using, respectively, 6, 5, and 5 bits.  The image 
*            data buffer pSrcsupports bottom-up storage format, for which 
*            srcStep can be less than 0. 
*   srcStep - distance in bytes between the starts of consecutive lines in 
*            the source image; can be less than 0 to support bottom-up 
*            storage format. 
*
* Output Arguments:
*   
*   pDstMCU[3] - output MCU pointers.  The parameter pDstMCU[0] must point 
*            to the start of a buffer with sufficient free space to contain 
*            the particular number of contiguously stored 8x8 Y blocks that 
*            constitute a complete MCU given the output chroma sub-sampling 
*            scheme, i.e., 1, 2, or 4 of 8x8 Y blocks for YCbCr 4:4:4, 4:2:2, 
*            or 4:2:0 output, respectively. The parameter pDstMCU[1] points to 
*            the Cb block, and the parameter pDstMCU[2] points to the Cr 
*            block.  Output components are expressed using a Q8 
*            representation and are bounded on the interval [-128, 127].  The 
*            buffers referenced by pDstMCU[] support top-down storage format 
*            only, and all pointers pDstMCU[0..2] must be 8-byte aligned. 
*
* Return Value:
*    
*    OMX_Sts_NoErr - no error 
*    OMX_Sts_BadArgErr - bad arguments. Returned for any of the following 
*              conditions: 
*    -   a pointer was NULL 
*    -   srcStep was an odd number or its absolute value was less 
*        than 16 for YCbCr444 or 32 for YCbCr422/YCbCr420. 
*    -   a pointer in pDstMCU[] was not 8-byte aligned 
*
*/

OMXResult omxIPCS_BGR565ToYCbCr422LS_MCU_U16_S16_C3P3(
    const OMX_U16 *pSrc,
    OMX_INT srcStep,
    OMX_S16 * pDstMCU[3]
    )
    {
        OMX_S16 *pDstY, *pDstCb, *pDstCr;
        OMX_U8  Rdata, Gdata, Bdata, Rdata2, Gdata2, Bdata2;
        OMX_INT i, j, blk;
        ARM_BLOCK8x8 *y8x8;
        OMX_INT blkOffset[2] = {0, 8};
        OMX_INT blkOffset_UV[2] = {0, 4};
        const OMX_U16 *pRGB;

        armRetArgErrIf(!pSrc, OMX_Sts_BadArgErr);
        armRetArgErrIf(!pDstMCU, OMX_Sts_BadArgErr);
        armRetArgErrIf(!pDstMCU[0], OMX_Sts_BadArgErr);
        armRetArgErrIf(!pDstMCU[1], OMX_Sts_BadArgErr);
        armRetArgErrIf(!pDstMCU[2], OMX_Sts_BadArgErr);
        armRetArgErrIf(!armIs8ByteAligned(pDstMCU[0]), OMX_Sts_BadArgErr);
        armRetArgErrIf(!armIs8ByteAligned(pDstMCU[1]), OMX_Sts_BadArgErr);
        armRetArgErrIf(!armIs8ByteAligned(pDstMCU[2]), OMX_Sts_BadArgErr);
        armRetArgErrIf(((srcStep > (-2 * JPEG_MCU_PIX_WIDTH_422)) && (srcStep < (2 * JPEG_MCU_PIX_WIDTH_422))), OMX_Sts_BadArgErr);
        armRetArgErrIf((srcStep % 2), OMX_Sts_BadArgErr);

        /*
        --------------------------------------------------------------------------
        With input data (R, G, B) belonging to [0, 255] and output data (Y,Cb,Cr) 
        expected in [-128, 127], CC equations in JPEG domain would be - 
        Y  =  0.29900*R  + 0.58700*G  + 0.11400*B - 128
        Cb = -0.16874*R  - 0.33126*G  + 0.50000*B
        Cr =  0.50000*R  - 0.41869*G  - 0.08131*B

        The armComputeXFromRGB_JPEG() functions apart from doing the colour conversion, 
        takes care of type-conversion from intermediate float values and clipping to 
        S16, taking care of rounding errors.

        The cases of Nearest Neighbour interpolation and Bilinear interpolation 
        are separately handled.
        --------------------------------------------------------------------------
        */


        y8x8 = (ARM_BLOCK8x8 *)pDstMCU[0];
        pDstY   = (OMX_S16 *)y8x8++;
        for(blk = 0; blk < 2; blk++)
        {
            pDstCb  = pDstMCU[1] + blkOffset_UV[blk];
            pDstCr  = pDstMCU[2] + blkOffset_UV[blk];
            pRGB    = pSrc + blkOffset[blk];
            for(i = 0; i < 8; i++)
            {
                for(j = 0; j < 4*2; j+=2)
                {
                    armIPCS_UnpackBGR565(pSrc[j],   &Bdata,  &Gdata,  &Rdata);
                    armIPCS_UnpackBGR565(pSrc[j+1], &Bdata2, &Gdata2, &Rdata2);

                    armIPCS_ComputeYFromRGB_JPEG_F32_S16(Rdata,  Gdata,  Bdata,  pDstY++);
                    armIPCS_ComputeYFromRGB_JPEG_F32_S16(Rdata2, Gdata2, Bdata2, pDstY++);            

                    {
                        OMX_F32 interpPixR = (Rdata + Rdata2) / (OMX_F32)2;
                        OMX_F32 interpPixG = (Gdata + Gdata2) / (OMX_F32)2;
                        OMX_F32 interpPixB = (Bdata + Bdata2) / (OMX_F32)2;

                        armIPCS_ComputeUFromRGB_JPEG_F32_S16(interpPixR, interpPixG, interpPixB, pDstCb++);
                        armIPCS_ComputeVFromRGB_JPEG_F32_S16(interpPixR, interpPixG, interpPixB, pDstCr++);
                    }


                } 
                pDstCb  += 4;
                pDstCr  += 4;
                pRGB    += srcStep>>1;
            }
        }
        return OMX_Sts_NoErr;
    }

    /* End of file */