img_ycbcr422p_rgb565.h

编程环境：TI CCS3.0 芯片： DM642 功能： 实现运动物体的检测。

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/*  TEXAS INSTRUMENTS, INC.                                                 */
/*                                                                          */
/*  IMGLIB  DSP Image/Video Processing Library                              */
/*                                                                          */
/*      Release:        Version 1.03                                        */
/*      CVS Revision:   1.12    Fri Oct 25 00:19:49 2002 (UTC)              */
/*      Snapshot date:  28-Oct-2002                                         */
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/*                                                                          */
/*  This software is licensed for use with Texas Instruments TMS320         */
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/*  TI_license.PDF which accompanies the files in this library.             */
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/*          Copyright (C) 2002 Texas Instruments, Incorporated.             */
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/*  Assembler compatibility shim for assembling 4.30 and later code on      */
/*  tools prior to 4.30.                                                    */
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/*  End of assembler compatibility shim.                                    */
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/*  TEXAS INSTRUMENTS, INC.                                                 */
/*                                                                          */
/*  NAME                                                                    */
/*      IMG_ycbcr422p_rgb565 -- Planarized YCbCr 4:2:2/4:2:0 to 16-bit      */
/*                              RGB 5:6:5 color space conversion.           */
/*                                                                          */
/*  REVISION DATE                                                           */
/*      21-Oct-2002                                                         */
/*                                                                          */
/*  USAGE                                                                   */
/*      This function is C callable, and is called according to this        */
/*      C prototype:                                                        */
/*                                                                          */
/*      void IMG_ycbcr422p_rgb565                                           */
/*      (                                                                   */
/*        const short         coeff[5],  // Matrix coefficients.        //  */
/*        const unsigned char *y_data,   // Luminence data  (Y')        //  */
/*        const unsigned char *cb_data,  // Blue color-diff (B'-Y')     //  */
/*        const unsigned char *cr_data,  // Red color-diff  (R'-Y')     //  */
/*        unsigned short                                                    */
/*                   *restrict rgb_data, // RGB 5:6:5 packed pixel out. //  */
/*        unsigned            num_pixels // # of luma pixels to process //  */
/*      );                                                                  */
/*                                                                          */
/*      The 'coeff[]' array contains the color-space-conversion matrix      */
/*      coefficients.  The 'y_data', 'cb_data' and 'cr_data' pointers       */
/*      point to the separate input image planes.  The 'rgb_data' pointer   */
/*                                                                          */
/*      The kernel is designed to process arbitrary amounts of 4:2:2        */
/*      image data, although 4:2:0 image data may be processed as well.     */
/*      For 4:2:2 input data, the 'y_data', 'cb_data' and 'cr_data'         */
/*      arrays may hold an arbitrary amount of image data, including        */
/*      multiple scan lines of image data.                                  */
/*                                                                          */
/*      For 4:2:0 input data, only a single scan-line (or portion           */
/*      thereof) may be processed at a time.  This is achieved by           */
/*      calling the function twice using the same row data for              */
/*      'cr_data' and 'cb_data', and providing new row data for             */
/*      'y_data'.  This is numerically equivalent to replicating the Cr     */
/*      and Cb pixels vertically.                                           */
/*                                                                          */
/*      The coefficients in the coeff array must be in signed Q13 form.     */
/*      These coefficients correspond to the following matrix equation:     */
/*                                                                          */
/*          [ coeff[0] 0.0000   coeff[1] ]   [ Y' -  16 ]     [ R']         */
/*          [ coeff[0] coeff[2] coeff[3] ] * [ Cb - 128 ]  =  [ G']         */
/*          [ coeff[0] coeff[4] 0.0000   ]   [ Cr - 128 ]     [ B']         */
/*                                                                          */
/*      The output from this kernel is 16-bit RGB in 5:6:5 format.          */
/*      The RGB components are packed into halfwords as shown below.        */
/*                                                                          */
/*                     15      11 10       5 4        0                     */
/*                    +----------+----------+----------+                    */
/*                    |   Red    |  Green   |   Blue   |                    */
/*                    +----------+----------+----------+                    */
/*                                                                          */
/*      This kernel can also return the red, green, and blue values in      */
/*      the opposite order if a particular application requires it.         */
/*      This is achieved by exchanging the 'cb_data' and 'cr_data'          */
/*      arguments when calling the function, and by reversing the order     */
/*      of coefficients in coeff[1] through coeff[4].  This essentially     */
/*      implements the following matrix multiply:                           */
/*                                                                          */
/*          [ coeff[0] 0.0000   coeff[4] ]   [ Y' -  16 ]     [ B']         */
/*          [ coeff[0] coeff[3] coeff[2] ] * [ Cr - 128 ]  =  [ G']         */
/*          [ coeff[0] coeff[1] 0.0000   ]   [ Cb - 128 ]     [ R']         */
/*                                                                          */
/*      The reversed RGB ordering output by this mode is as follows:        */
/*                                                                          */
/*                     15      11 10       5 4        0                     */
/*                    +----------+----------+----------+                    */
/*                    |   Blue   |  Green   |   Red    |                    */
/*                    +----------+----------+----------+                    */
/*                                                                          */
/*  DESCRIPTION                                                             */
/*      This kernel performs Y'CbCr to RGB conversion.  From the Color      */
/*      FAQ, http://home.inforamp.net/~poynton/ColorFAQ.html :              */
/*                                                                          */
/*          Various scale factors are applied to (B'-Y') and (R'-Y')        */
/*          for different applications.  The Y'PbPr scale factors are       */
/*          optimized for component analog video.  The Y'CbCr scaling       */
/*          is appropriate for component digital video, JPEG and MPEG.      */
/*          Kodak's PhotoYCC(tm) uses scale factors optimized for the       */
/*          gamut of film colors.  Y'UV scaling is appropriate as an        */
/*          intermediate step in the formation of composite NTSC or PAL     */
/*          video signals, but is not appropriate when the components       */
/*          are keps separate.  Y'UV nomenclature is now used rather        */
/*          loosely, and it sometimes denotes any scaling of (B'-Y')        */
/*          and (R'-Y').  Y'IQ coding is obsolete.                          */
/*                                                                          */
/*      This code can perform various flavors of Y'CbCr to RGB              */
/*      conversion as long as the offsets on Y, Cb, and Cr are -16,         */
/*      -128, and -128, respectively, and the coefficients match the        */
/*      pattern shown.                                                      */
/*                                                                          */
/*      The kernel implements the following matrix form, which involves 5   */
/*      unique coefficients:                                                */
/*                                                                          */
/*          [ coeff[0] 0.0000   coeff[1] ]   [ Y' -  16 ]     [ R']         */
/*          [ coeff[0] coeff[2] coeff[3] ] * [ Cb - 128 ]  =  [ G']         */
/*          [ coeff[0] coeff[4] 0.0000   ]   [ Cr - 128 ]     [ B']         */
/*                                                                          */
/*                                                                          */
/*      Below are some common coefficient sets, along with the matrix       */
/*      equation that they correspond to.   Coefficients are in signed      */
/*      Q13 notation, which gives a suitable balance between precision      */
/*      and range.                                                          */
/*                                                                          */
/*      1.  Y'CbCr -> RGB conversion with RGB levels that correspond to     */