omxipcs_bgr565toycbcr444ls_mcu_u16_s16_c3p3.c

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

/**
 *
 * 
 * File Name:  omxIPCS_BGR565ToYCbCr444LS_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 RGB565 to YUV444 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_BGR565ToYCbCr444LS_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_BGR565ToYCbCr444LS_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;
    OMX_INT i, j;
    
    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_444)) && (srcStep < (2 * JPEG_MCU_PIX_WIDTH_444))), 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.
    --------------------------------------------------------------------------
    */
    
    pDstY   = pDstMCU[0];
    pDstCb  = pDstMCU[1];
    pDstCr  = pDstMCU[2];
    
    for(i = 0; i < 8; i++)
    {
        for(j = 0; j < 8; j++)
        {
            armIPCS_UnpackBGR565(pSrc[j], &Bdata, &Gdata, &Rdata);
            armIPCS_ComputeYUVFromRGB_JPEG_F32_S16(Rdata, Gdata, Bdata, pDstY++, pDstCb++, pDstCr++);
        }
        pSrc += srcStep>>1;
    }
    return OMX_Sts_NoErr;
}
 
/* End of file */