vpx/vp8/common/filter.c

/*
 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */


#include "filter.h"

DECLARE_ALIGNED(16, const short, vp8_bilinear_filters[8][2]) =
{
    { 128,   0 },
    { 112,  16 },
    {  96,  32 },
    {  80,  48 },
    {  64,  64 },
    {  48,  80 },
    {  32,  96 },
    {  16, 112 }
};

DECLARE_ALIGNED(16, const short, vp8_sub_pel_filters[8][6]) =
{

    { 0,  0,  128,    0,   0,  0 },         /* note that 1/8 pel positions are just as per alpha -0.5 bicubic */
    { 0, -6,  123,   12,  -1,  0 },
    { 2, -11, 108,   36,  -8,  1 },         /* New 1/4 pel 6 tap filter */
    { 0, -9,   93,   50,  -6,  0 },
    { 3, -16,  77,   77, -16,  3 },         /* New 1/2 pel 6 tap filter */
    { 0, -6,   50,   93,  -9,  0 },
    { 1, -8,   36,  108, -11,  2 },         /* New 1/4 pel 6 tap filter */
    { 0, -1,   12,  123,  -6,  0 },
};

static void filter_block2d_first_pass
(
    unsigned char *src_ptr,
    int *output_ptr,
    unsigned int src_pixels_per_line,
    unsigned int pixel_step,
    unsigned int output_height,
    unsigned int output_width,
    const short *vp8_filter
)
{
    unsigned int i, j;
    int  Temp;

    for (i = 0; i < output_height; i++)
    {
        for (j = 0; j < output_width; j++)
        {
            Temp = ((int)src_ptr[-2 * (int)pixel_step] * vp8_filter[0]) +
                   ((int)src_ptr[-1 * (int)pixel_step] * vp8_filter[1]) +
                   ((int)src_ptr[0]                 * vp8_filter[2]) +
                   ((int)src_ptr[pixel_step]         * vp8_filter[3]) +
                   ((int)src_ptr[2*pixel_step]       * vp8_filter[4]) +
                   ((int)src_ptr[3*pixel_step]       * vp8_filter[5]) +
                   (VP8_FILTER_WEIGHT >> 1);      /* Rounding */

            /* Normalize back to 0-255 */
            Temp = Temp >> VP8_FILTER_SHIFT;

            if (Temp < 0)
                Temp = 0;
            else if (Temp > 255)
                Temp = 255;

            output_ptr[j] = Temp;
            src_ptr++;
        }

        /* Next row... */
        src_ptr    += src_pixels_per_line - output_width;
        output_ptr += output_width;
    }
}

static void filter_block2d_second_pass
(
    int *src_ptr,
    unsigned char *output_ptr,
    int output_pitch,
    unsigned int src_pixels_per_line,
    unsigned int pixel_step,
    unsigned int output_height,
    unsigned int output_width,
    const short *vp8_filter
)
{
    unsigned int i, j;
    int  Temp;

    for (i = 0; i < output_height; i++)
    {
        for (j = 0; j < output_width; j++)
        {
            /* Apply filter */
            Temp = ((int)src_ptr[-2 * (int)pixel_step] * vp8_filter[0]) +
                   ((int)src_ptr[-1 * (int)pixel_step] * vp8_filter[1]) +
                   ((int)src_ptr[0]                 * vp8_filter[2]) +
                   ((int)src_ptr[pixel_step]         * vp8_filter[3]) +
                   ((int)src_ptr[2*pixel_step]       * vp8_filter[4]) +
                   ((int)src_ptr[3*pixel_step]       * vp8_filter[5]) +
                   (VP8_FILTER_WEIGHT >> 1);   /* Rounding */

            /* Normalize back to 0-255 */
            Temp = Temp >> VP8_FILTER_SHIFT;

            if (Temp < 0)
                Temp = 0;
            else if (Temp > 255)
                Temp = 255;

            output_ptr[j] = (unsigned char)Temp;
            src_ptr++;
        }

        /* Start next row */
        src_ptr    += src_pixels_per_line - output_width;
        output_ptr += output_pitch;
    }
}


static void filter_block2d
(
    unsigned char  *src_ptr,
    unsigned char  *output_ptr,
    unsigned int src_pixels_per_line,
    int output_pitch,
    const short  *HFilter,
    const short  *VFilter
)
{
    int FData[9*4]; /* Temp data buffer used in filtering */

    /* First filter 1-D horizontally... */
    filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 9, 4, HFilter);

    /* then filter verticaly... */
    filter_block2d_second_pass(FData + 8, output_ptr, output_pitch, 4, 4, 4, 4, VFilter);
}


void vp8_sixtap_predict4x4_c
(
    unsigned char  *src_ptr,
    int   src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    unsigned char *dst_ptr,
    int dst_pitch
)
{
    const short  *HFilter;
    const short  *VFilter;

    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */

    filter_block2d(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter);
}
void vp8_sixtap_predict8x8_c
(
    unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    unsigned char *dst_ptr,
    int  dst_pitch
)
{
    const short  *HFilter;
    const short  *VFilter;
    int FData[13*16];   /* Temp data buffer used in filtering */

    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */

    /* First filter 1-D horizontally... */
    filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 13, 8, HFilter);


    /* then filter verticaly... */
    filter_block2d_second_pass(FData + 16, dst_ptr, dst_pitch, 8, 8, 8, 8, VFilter);

}

void vp8_sixtap_predict8x4_c
(
    unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    unsigned char *dst_ptr,
    int  dst_pitch
)
{
    const short  *HFilter;
    const short  *VFilter;
    int FData[13*16];   /* Temp data buffer used in filtering */

    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */

    /* First filter 1-D horizontally... */
    filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 9, 8, HFilter);


    /* then filter verticaly... */
    filter_block2d_second_pass(FData + 16, dst_ptr, dst_pitch, 8, 8, 4, 8, VFilter);

}

void vp8_sixtap_predict16x16_c
(
    unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    unsigned char *dst_ptr,
    int  dst_pitch
)
{
    const short  *HFilter;
    const short  *VFilter;
    int FData[21*24];   /* Temp data buffer used in filtering */


    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */

    /* First filter 1-D horizontally... */
    filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 21, 16, HFilter);

    /* then filter verticaly... */
    filter_block2d_second_pass(FData + 32, dst_ptr, dst_pitch, 16, 16, 16, 16, VFilter);

}


/****************************************************************************
 *
 *  ROUTINE       : filter_block2d_bil_first_pass
 *
 *  INPUTS        : UINT8  *src_ptr    : Pointer to source block.
 *                  UINT32  src_stride : Stride of source block.
 *                  UINT32  height     : Block height.
 *                  UINT32  width      : Block width.
 *                  INT32  *vp8_filter : Array of 2 bi-linear filter taps.
 *
 *  OUTPUTS       : INT32  *dst_ptr    : Pointer to filtered block.
 *
 *  RETURNS       : void
 *
 *  FUNCTION      : Applies a 1-D 2-tap bi-linear filter to the source block
 *                  in the horizontal direction to produce the filtered output
 *                  block. Used to implement first-pass of 2-D separable filter.
 *
 *  SPECIAL NOTES : Produces INT32 output to retain precision for next pass.
 *                  Two filter taps should sum to VP8_FILTER_WEIGHT.
 *
 ****************************************************************************/
static void filter_block2d_bil_first_pass
(
    unsigned char  *src_ptr,
    unsigned short *dst_ptr,
    unsigned int    src_stride,
    unsigned int    height,
    unsigned int    width,
    const short    *vp8_filter
)
{
    unsigned int i, j;

    for (i = 0; i < height; i++)
    {
        for (j = 0; j < width; j++)
        {
            /* Apply bilinear filter */
            dst_ptr[j] = (((int)src_ptr[0] * vp8_filter[0]) +
                          ((int)src_ptr[1] * vp8_filter[1]) +
                          (VP8_FILTER_WEIGHT / 2)) >> VP8_FILTER_SHIFT;
            src_ptr++;
        }

        /* Next row... */
        src_ptr += src_stride - width;
        dst_ptr += width;
    }
}

/****************************************************************************
 *
 *  ROUTINE       : filter_block2d_bil_second_pass
 *
 *  INPUTS        : INT32  *src_ptr    : Pointer to source block.
 *                  UINT32  dst_pitch  : Destination block pitch.
 *                  UINT32  height     : Block height.
 *                  UINT32  width      : Block width.
 *                  INT32  *vp8_filter : Array of 2 bi-linear filter taps.
 *
 *  OUTPUTS       : UINT16 *dst_ptr    : Pointer to filtered block.
 *
 *  RETURNS       : void
 *
 *  FUNCTION      : Applies a 1-D 2-tap bi-linear filter to the source block
 *                  in the vertical direction to produce the filtered output
 *                  block. Used to implement second-pass of 2-D separable filter.
 *
 *  SPECIAL NOTES : Requires 32-bit input as produced by filter_block2d_bil_first_pass.
 *                  Two filter taps should sum to VP8_FILTER_WEIGHT.
 *
 ****************************************************************************/
static void filter_block2d_bil_second_pass
(
    unsigned short *src_ptr,
    unsigned char  *dst_ptr,
    int             dst_pitch,
    unsigned int    height,
    unsigned int    width,
    const short    *vp8_filter
)
{
    unsigned int  i, j;
    int  Temp;

    for (i = 0; i < height; i++)
    {
        for (j = 0; j < width; j++)
        {
            /* Apply filter */
            Temp = ((int)src_ptr[0]     * vp8_filter[0]) +
                   ((int)src_ptr[width] * vp8_filter[1]) +
                   (VP8_FILTER_WEIGHT / 2);
            dst_ptr[j] = (unsigned int)(Temp >> VP8_FILTER_SHIFT);
            src_ptr++;
        }

        /* Next row... */
        dst_ptr += dst_pitch;
    }
}


/****************************************************************************
 *
 *  ROUTINE       : filter_block2d_bil
 *
 *  INPUTS        : UINT8  *src_ptr          : Pointer to source block.
 *                  UINT32  src_pitch        : Stride of source block.
 *                  UINT32  dst_pitch        : Stride of destination block.
 *                  INT32  *HFilter          : Array of 2 horizontal filter taps.
 *                  INT32  *VFilter          : Array of 2 vertical filter taps.
 *                  INT32  Width             : Block width
 *                  INT32  Height            : Block height
 *
 *  OUTPUTS       : UINT16 *dst_ptr       : Pointer to filtered block.
 *
 *  RETURNS       : void
 *
 *  FUNCTION      : 2-D filters an input block by applying a 2-tap
 *                  bi-linear filter horizontally followed by a 2-tap
 *                  bi-linear filter vertically on the result.
 *
 *  SPECIAL NOTES : The largest block size can be handled here is 16x16
 *
 ****************************************************************************/
static void filter_block2d_bil
(
    unsigned char *src_ptr,
    unsigned char *dst_ptr,
    unsigned int   src_pitch,
    unsigned int   dst_pitch,
    const short   *HFilter,
    const short   *VFilter,
    int            Width,
    int            Height
)
{

    unsigned short FData[17*16];    /* Temp data buffer used in filtering */

    /* First filter 1-D horizontally... */
    filter_block2d_bil_first_pass(src_ptr, FData, src_pitch, Height + 1, Width, HFilter);

    /* then 1-D vertically... */
    filter_block2d_bil_second_pass(FData, dst_ptr, dst_pitch, Height, Width, VFilter);
}


void vp8_bilinear_predict4x4_c
(
    unsigned char  *src_ptr,
    int   src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    unsigned char *dst_ptr,
    int dst_pitch
)
{
    const short *HFilter;
    const short *VFilter;

    HFilter = vp8_bilinear_filters[xoffset];
    VFilter = vp8_bilinear_filters[yoffset];
#if 0
    {
        int i;
        unsigned char temp1[16];
        unsigned char temp2[16];

        bilinear_predict4x4_mmx(src_ptr, src_pixels_per_line, xoffset, yoffset, temp1, 4);
        filter_block2d_bil(src_ptr, temp2, src_pixels_per_line, 4, HFilter, VFilter, 4, 4);

        for (i = 0; i < 16; i++)
        {
            if (temp1[i] != temp2[i])
            {
                bilinear_predict4x4_mmx(src_ptr, src_pixels_per_line, xoffset, yoffset, temp1, 4);
                filter_block2d_bil(src_ptr, temp2, src_pixels_per_line, 4, HFilter, VFilter, 4, 4);
            }
        }
    }
#endif
    filter_block2d_bil(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 4, 4);

}

void vp8_bilinear_predict8x8_c
(
    unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    unsigned char *dst_ptr,
    int  dst_pitch
)
{
    const short *HFilter;
    const short *VFilter;

    HFilter = vp8_bilinear_filters[xoffset];
    VFilter = vp8_bilinear_filters[yoffset];

    filter_block2d_bil(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 8, 8);

}

void vp8_bilinear_predict8x4_c
(
    unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    unsigned char *dst_ptr,
    int  dst_pitch
)
{
    const short *HFilter;
    const short *VFilter;

    HFilter = vp8_bilinear_filters[xoffset];
    VFilter = vp8_bilinear_filters[yoffset];

    filter_block2d_bil(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 8, 4);

}

void vp8_bilinear_predict16x16_c
(
    unsigned char  *src_ptr,
    int  src_pixels_per_line,
    int  xoffset,
    int  yoffset,
    unsigned char *dst_ptr,
    int  dst_pitch
)
{
    const short *HFilter;
    const short *VFilter;

    HFilter = vp8_bilinear_filters[xoffset];
    VFilter = vp8_bilinear_filters[yoffset];

    filter_block2d_bil(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 16, 16);
}