ref: 6d2307b2dda4c2d68a3e65e9ca43b3b39357cd9c
dir: /vp9/encoder/vp9_resize.c/
/*
* Copyright (c) 2014 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 <limits.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "vp9/common/vp9_common.h"
#include "vp9/encoder/vp9_resize.h"
#include "vpx/vpx_integer.h"
#define FILTER_BITS 7
#define INTERP_TAPS 8
#define SUBPEL_BITS 5
#define SUBPEL_MASK ((1 << SUBPEL_BITS) - 1)
#define INTERP_PRECISION_BITS 32
#define ROUND_POWER_OF_TWO(value, n) \
(((value) + (1 << ((n) - 1))) >> (n))
typedef int16_t interp_kernel[INTERP_TAPS];
// Filters for interpolation - note this also filters integer pels.
const interp_kernel vp9_filteredinterp_filters[(1 << SUBPEL_BITS)] = {
{-1, -8, 33, 80, 33, -8, -1, 0},
{-1, -8, 30, 80, 35, -8, -1, 1},
{-1, -8, 28, 80, 37, -7, -2, 1},
{0, -8, 26, 79, 39, -7, -2, 1},
{0, -8, 24, 79, 41, -7, -2, 1},
{0, -8, 22, 78, 43, -6, -2, 1},
{0, -8, 20, 78, 45, -5, -3, 1},
{0, -8, 18, 77, 48, -5, -3, 1},
{0, -8, 16, 76, 50, -4, -3, 1},
{0, -8, 15, 75, 52, -3, -4, 1},
{0, -7, 13, 74, 54, -3, -4, 1},
{0, -7, 11, 73, 56, -2, -4, 1},
{0, -7, 10, 71, 58, -1, -4, 1},
{1, -7, 8, 70, 60, 0, -5, 1},
{1, -6, 6, 68, 62, 1, -5, 1},
{1, -6, 5, 67, 63, 2, -5, 1},
{1, -6, 4, 65, 65, 4, -6, 1},
{1, -5, 2, 63, 67, 5, -6, 1},
{1, -5, 1, 62, 68, 6, -6, 1},
{1, -5, 0, 60, 70, 8, -7, 1},
{1, -4, -1, 58, 71, 10, -7, 0},
{1, -4, -2, 56, 73, 11, -7, 0},
{1, -4, -3, 54, 74, 13, -7, 0},
{1, -4, -3, 52, 75, 15, -8, 0},
{1, -3, -4, 50, 76, 16, -8, 0},
{1, -3, -5, 48, 77, 18, -8, 0},
{1, -3, -5, 45, 78, 20, -8, 0},
{1, -2, -6, 43, 78, 22, -8, 0},
{1, -2, -7, 41, 79, 24, -8, 0},
{1, -2, -7, 39, 79, 26, -8, 0},
{1, -2, -7, 37, 80, 28, -8, -1},
{1, -1, -8, 35, 80, 30, -8, -1},
};
// Filters for factor of 2 downsampling.
static const int16_t vp9_down2_symeven_half_filter[] = {56, 12, -3, -1};
static const int16_t vp9_down2_symodd_half_filter[] = {64, 35, 0, -3};
static void interpolate(const uint8_t *const input, int inlength,
uint8_t *output, int outlength) {
const int64_t delta = (((uint64_t)inlength << 32) + outlength / 2) /
outlength;
const int64_t offset = inlength > outlength ?
(((int64_t)(inlength - outlength) << 31) + outlength / 2) / outlength :
-(((int64_t)(outlength - inlength) << 31) + outlength / 2) / outlength;
uint8_t *optr = output;
int x, x1, x2, sum, k, int_pel, sub_pel;
int64_t y;
x = 0;
y = offset;
while ((y >> INTERP_PRECISION_BITS) < (INTERP_TAPS / 2 - 1)) {
x++;
y += delta;
}
x1 = x;
x = outlength - 1;
y = delta * x + offset;
while ((y >> INTERP_PRECISION_BITS) +
(int64_t)(INTERP_TAPS / 2) >= inlength) {
x--;
y -= delta;
}
x2 = x;
if (x1 > x2) {
for (x = 0, y = offset; x < outlength; ++x, y += delta) {
const int16_t *filter;
int_pel = y >> INTERP_PRECISION_BITS;
sub_pel = (y >> (INTERP_PRECISION_BITS - SUBPEL_BITS)) & SUBPEL_MASK;
filter = vp9_filteredinterp_filters[sub_pel];
sum = 0;
for (k = 0; k < INTERP_TAPS; ++k) {
const int pk = int_pel - INTERP_TAPS / 2 + 1 + k;
sum += filter[k] * input[(pk < 0 ? 0 :
(pk >= inlength ? inlength - 1 : pk))];
}
*optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
}
} else {
// Initial part.
for (x = 0, y = offset; x < x1; ++x, y += delta) {
const int16_t *filter;
int_pel = y >> INTERP_PRECISION_BITS;
sub_pel = (y >> (INTERP_PRECISION_BITS - SUBPEL_BITS)) & SUBPEL_MASK;
filter = vp9_filteredinterp_filters[sub_pel];
sum = 0;
for (k = 0; k < INTERP_TAPS; ++k)
sum += filter[k] * input[(int_pel - INTERP_TAPS / 2 + 1 + k < 0 ?
0 :
int_pel - INTERP_TAPS / 2 + 1 + k)];
*optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
}
// Middle part.
for (; x <= x2; ++x, y += delta) {
const int16_t *filter;
int_pel = y >> INTERP_PRECISION_BITS;
sub_pel = (y >> (INTERP_PRECISION_BITS - SUBPEL_BITS)) & SUBPEL_MASK;
filter = vp9_filteredinterp_filters[sub_pel];
sum = 0;
for (k = 0; k < INTERP_TAPS; ++k)
sum += filter[k] * input[int_pel - INTERP_TAPS / 2 + 1 + k];
*optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
}
// End part.
for (; x < outlength; ++x, y += delta) {
const int16_t *filter;
int_pel = y >> INTERP_PRECISION_BITS;
sub_pel = (y >> (INTERP_PRECISION_BITS - SUBPEL_BITS)) & SUBPEL_MASK;
filter = vp9_filteredinterp_filters[sub_pel];
sum = 0;
for (k = 0; k < INTERP_TAPS; ++k)
sum += filter[k] * input[(int_pel - INTERP_TAPS / 2 + 1 + k >=
inlength ? inlength - 1 :
int_pel - INTERP_TAPS / 2 + 1 + k)];
*optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
}
}
}
static void down2_symeven(const uint8_t *const input, int length,
uint8_t *output) {
// Actual filter len = 2 * filter_len_half.
static const int16_t *filter = vp9_down2_symeven_half_filter;
const int filter_len_half = sizeof(vp9_down2_symeven_half_filter) / 2;
int i, j;
uint8_t *optr = output;
int l1 = filter_len_half;
int l2 = (length - filter_len_half);
l1 += (l1 & 1);
l2 += (l2 & 1);
if (l1 > l2) {
// Short input length.
for (i = 0; i < length; i += 2) {
int sum = (1 << (FILTER_BITS - 1));
for (j = 0; j < filter_len_half; ++j) {
sum += (input[(i - j < 0 ? 0 : i - j)] +
input[(i + 1 + j >= length ? length - 1 : i + 1 + j)]) *
filter[j];
}
sum >>= FILTER_BITS;
*optr++ = clip_pixel(sum);
}
} else {
// Initial part.
for (i = 0; i < l1; i += 2) {
int sum = (1 << (FILTER_BITS - 1));
for (j = 0; j < filter_len_half; ++j) {
sum += (input[(i - j < 0 ? 0 : i - j)] + input[i + 1 + j]) * filter[j];
}
sum >>= FILTER_BITS;
*optr++ = clip_pixel(sum);
}
// Middle part.
for (; i < l2; i += 2) {
int sum = (1 << (FILTER_BITS - 1));
for (j = 0; j < filter_len_half; ++j) {
sum += (input[i - j] + input[i + 1 + j]) * filter[j];
}
sum >>= FILTER_BITS;
*optr++ = clip_pixel(sum);
}
// End part.
for (; i < length; i += 2) {
int sum = (1 << (FILTER_BITS - 1));
for (j = 0; j < filter_len_half; ++j) {
sum += (input[i - j] +
input[(i + 1 + j >= length ? length - 1 : i + 1 + j)]) *
filter[j];
}
sum >>= FILTER_BITS;
*optr++ = clip_pixel(sum);
}
}
}
static void down2_symodd(const uint8_t *const input, int length,
uint8_t *output) {
// Actual filter len = 2 * filter_len_half - 1.
static const int16_t *filter = vp9_down2_symodd_half_filter;
const int filter_len_half = sizeof(vp9_down2_symodd_half_filter) / 2;
int i, j;
uint8_t *optr = output;
int l1 = filter_len_half - 1;
int l2 = (length - filter_len_half + 1);
l1 += (l1 & 1);
l2 += (l2 & 1);
if (l1 > l2) {
// Short input length.
for (i = 0; i < length; i += 2) {
int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
for (j = 1; j < filter_len_half; ++j) {
sum += (input[(i - j < 0 ? 0 : i - j)] +
input[(i + j >= length ? length - 1 : i + j)]) *
filter[j];
}
sum >>= FILTER_BITS;
*optr++ = clip_pixel(sum);
}
} else {
// Initial part.
for (i = 0; i < l1; i += 2) {
int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
for (j = 1; j < filter_len_half; ++j) {
sum += (input[(i - j < 0 ? 0 : i - j)] + input[i + j]) * filter[j];
}
sum >>= FILTER_BITS;
*optr++ = clip_pixel(sum);
}
// Middle part.
for (; i < l2; i += 2) {
int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
for (j = 1; j < filter_len_half; ++j) {
sum += (input[i - j] + input[i + j]) * filter[j];
}
sum >>= FILTER_BITS;
*optr++ = clip_pixel(sum);
}
// End part.
for (; i < length; i += 2) {
int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
for (j = 1; j < filter_len_half; ++j) {
sum += (input[i - j] + input[(i + j >= length ? length - 1 : i + j)]) *
filter[j];
}
sum >>= FILTER_BITS;
*optr++ = clip_pixel(sum);
}
}
}
static int get_down2_length(int length, int steps) {
int s;
for (s = 0; s < steps; ++s)
length = (length + 1) >> 1;
return length;
}
int get_down2_steps(int in_length, int out_length) {
int steps = 0;
int proj_in_length;
while ((proj_in_length = get_down2_length(in_length, 1)) >= out_length) {
++steps;
in_length = proj_in_length;
}
return steps;
}
static void resize_multistep(const uint8_t *const input,
int length,
uint8_t *output,
int olength,
uint8_t *buf) {
int steps;
if (length == olength) {
memcpy(output, input, sizeof(uint8_t) * length);
return;
}
steps = get_down2_steps(length, olength);
if (steps > 0) {
int s;
uint8_t *out = NULL;
uint8_t *tmpbuf = NULL;
uint8_t *otmp, *otmp2;
int filteredlength = length;
if (!tmpbuf) {
tmpbuf = (uint8_t *)malloc(sizeof(uint8_t) * length);
otmp = tmpbuf;
} else {
otmp = buf;
}
otmp2 = otmp + get_down2_length(length, 1);
for (s = 0; s < steps; ++s) {
const int proj_filteredlength = get_down2_length(filteredlength, 1);
const uint8_t *const in = (s == 0 ? input : out);
if (s == steps - 1 && proj_filteredlength == olength)
out = output;
else
out = (s & 1 ? otmp2 : otmp);
if (filteredlength & 1)
down2_symodd(in, filteredlength, out);
else
down2_symeven(in, filteredlength, out);
filteredlength = proj_filteredlength;
}
if (filteredlength != olength) {
interpolate(out, filteredlength, output, olength);
}
if (tmpbuf)
free(tmpbuf);
} else {
interpolate(input, length, output, olength);
}
}
static void fill_col_to_arr(uint8_t *img, int stride, int len, uint8_t *arr) {
int i;
uint8_t *iptr = img;
uint8_t *aptr = arr;
for (i = 0; i < len; ++i, iptr += stride) {
*aptr++ = *iptr;
}
}
static void fill_arr_to_col(uint8_t *img, int stride, int len, uint8_t *arr) {
int i;
uint8_t *iptr = img;
uint8_t *aptr = arr;
for (i = 0; i < len; ++i, iptr += stride) {
*iptr = *aptr++;
}
}
void vp9_resize_plane(const uint8_t *const input,
int height,
int width,
int in_stride,
uint8_t *output,
int height2,
int width2,
int out_stride) {
int i;
uint8_t *intbuf = (uint8_t *)malloc(sizeof(uint8_t) * width2 * height);
uint8_t *tmpbuf = (uint8_t *)malloc(sizeof(uint8_t) *
(width < height ? height : width));
uint8_t *arrbuf = (uint8_t *)malloc(sizeof(uint8_t) * (height + height2));
for (i = 0; i < height; ++i)
resize_multistep(input + in_stride * i, width,
intbuf + width2 * i, width2, tmpbuf);
for (i = 0; i < width2; ++i) {
fill_col_to_arr(intbuf + i, width2, height, arrbuf);
resize_multistep(arrbuf, height, arrbuf + height, height2, tmpbuf);
fill_arr_to_col(output + i, out_stride, height2, arrbuf + height);
}
free(intbuf);
free(tmpbuf);
free(arrbuf);
}
void vp9_resize_frame420(const uint8_t *const y,
int y_stride,
const uint8_t *const u, const uint8_t *const v,
int uv_stride,
int height, int width,
uint8_t *oy, int oy_stride,
uint8_t *ou, uint8_t *ov, int ouv_stride,
int oheight, int owidth) {
vp9_resize_plane(y, height, width, y_stride,
oy, oheight, owidth, oy_stride);
vp9_resize_plane(u, height / 2, width / 2, uv_stride,
ou, oheight / 2, owidth / 2, ouv_stride);
vp9_resize_plane(v, height / 2, width / 2, uv_stride,
ov, oheight / 2, owidth / 2, ouv_stride);
}
void vp9_resize_frame422(const uint8_t *const y, int y_stride,
const uint8_t *const u, const uint8_t *const v,
int uv_stride,
int height, int width,
uint8_t *oy, int oy_stride,
uint8_t *ou, uint8_t *ov, int ouv_stride,
int oheight, int owidth) {
vp9_resize_plane(y, height, width, y_stride,
oy, oheight, owidth, oy_stride);
vp9_resize_plane(u, height, width / 2, uv_stride,
ou, oheight, owidth / 2, ouv_stride);
vp9_resize_plane(v, height, width / 2, uv_stride,
ov, oheight, owidth / 2, ouv_stride);
}
void vp9_resize_frame444(const uint8_t *const y, int y_stride,
const uint8_t *const u, const uint8_t *const v,
int uv_stride,
int height, int width,
uint8_t *oy, int oy_stride,
uint8_t *ou, uint8_t *ov, int ouv_stride,
int oheight, int owidth) {
vp9_resize_plane(y, height, width, y_stride,
oy, oheight, owidth, oy_stride);
vp9_resize_plane(u, height, width, uv_stride,
ou, oheight, owidth, ouv_stride);
vp9_resize_plane(v, height, width, uv_stride,
ov, oheight, owidth, ouv_stride);
}