ref: c1f77a3689a6cf5e95e1c1ae35d76f4f171f5ef3
dir: /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 <assert.h>
#include "./vp8_rtcd.h"
#include "vp8/common/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;
// This represents a copy and is not required to be handled by optimizations.
assert((xoffset | yoffset) != 0);
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, 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;
assert((xoffset | yoffset) != 0);
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;
assert((xoffset | yoffset) != 0);
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;
assert((xoffset | yoffset) != 0);
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);
}