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libavfilter: image transform code

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Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
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danielgtaylor 13 years ago committed by Michael Niedermayer
parent eaa21b6870
commit 7985381e23
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  1. 182
      libavfilter/transform.c
  2. 125
      libavfilter/transform.h

182
libavfilter/transform.c
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/*
* Copyright (C) 2010 Georg Martius <georg.martius@web.de>
* Copyright (C) 2010 Daniel G. Taylor <dan@programmer-art.org>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file libavfilter/transform.c
* transform input video
*/
#include "libavutil/common.h"
#include "transform.h"
#define INTERPOLATE_METHOD(name) \
static uint8_t name(float x, float y, const uint8_t *src, \
int width, int height, int stride, uint8_t def)
#define PIXEL(img, x, y, w, h, stride, def) \
((x) < 0 || (y) < 0) ? (def) : \
(((x) >= (w) || (y) >= (h)) ? (def) : \
img[(x) + (y) * (stride)])
/**
* Nearest neighbor interpolation
*/
INTERPOLATE_METHOD(interpolate_nearest)
{
return PIXEL(src, (int)(x + 0.5), (int)(y + 0.5), width, height, stride, def);
}
/**
* Bilinear interpolation
*/
INTERPOLATE_METHOD(interpolate_bilinear)
{
int x_c, x_f, y_c, y_f;
int v1, v2, v3, v4;
if (x < -1 || x > width || y < -1 || y > height) {
return def;
} else {
x_f = (int)x;
x_c = x_f + 1;
y_f = (int)y;
y_c = y_f + 1;
v1 = PIXEL(src, x_c, y_c, width, height, stride, def);
v2 = PIXEL(src, x_c, y_f, width, height, stride, def);
v3 = PIXEL(src, x_f, y_c, width, height, stride, def);
v4 = PIXEL(src, x_f, y_f, width, height, stride, def);
return (v1*(x - x_f)*(y - y_f) + v2*((x - x_f)*(y_c - y)) +
v3*(x_c - x)*(y - y_f) + v4*((x_c - x)*(y_c - y)));
}
}
/**
* Biquadratic interpolation
*/
INTERPOLATE_METHOD(interpolate_biquadratic)
{
int x_c, x_f, y_c, y_f;
uint8_t v1, v2, v3, v4;
float f1, f2, f3, f4;
if (x < - 1 || x > width || y < -1 || y > height)
return def;
else {
x_f = (int)x;
x_c = x_f + 1;
y_f = (int)y;
y_c = y_f + 1;
v1 = PIXEL(src, x_c, y_c, width, height, stride, def);
v2 = PIXEL(src, x_c, y_f, width, height, stride, def);
v3 = PIXEL(src, x_f, y_c, width, height, stride, def);
v4 = PIXEL(src, x_f, y_f, width, height, stride, def);
f1 = 1 - sqrt((x_c - x) * (y_c - y));
f2 = 1 - sqrt((x_c - x) * (y - y_f));
f3 = 1 - sqrt((x - x_f) * (y_c - y));
f4 = 1 - sqrt((x - x_f) * (y - y_f));
return (v1 * f1 + v2 * f2 + v3 * f3 + v4 * f4) / (f1 + f2 + f3 + f4);
}
}
void avfilter_get_matrix(float x_shift, float y_shift, float angle, float zoom, float *matrix) {
matrix[0] = zoom * cos(angle);
matrix[1] = -sin(angle);
matrix[2] = x_shift;
matrix[3] = -matrix[1];
matrix[4] = matrix[0];
matrix[5] = y_shift;
matrix[6] = 0;
matrix[7] = 0;
matrix[8] = 1;
}
void avfilter_add_matrix(const float *m1, const float *m2, float *result)
{
for (int i = 0; i < 9; i++)
result[i] = m1[i] + m2[i];
}
void avfilter_sub_matrix(const float *m1, const float *m2, float *result)
{
for (int i = 0; i < 9; i++)
result[i] = m1[i] - m2[i];
}
void avfilter_mul_matrix(const float *m1, float scalar, float *result)
{
for (int i = 0; i < 9; i++)
result[i] = m1[i] * scalar;
}
void avfilter_transform(const uint8_t *src, uint8_t *dst,
int src_stride, int dst_stride,
int width, int height, const float *matrix,
enum InterpolateMethod interpolate,
enum FillMethod fill)
{
int x, y;
float x_s, y_s;
uint8_t def = 0;
uint8_t (*func)(float, float, const uint8_t *, int, int, int, uint8_t) = NULL;
switch(interpolate) {
case INTERPOLATE_NEAREST:
func = interpolate_nearest;
break;
case INTERPOLATE_BILINEAR:
func = interpolate_bilinear;
break;
case INTERPOLATE_BIQUADRATIC:
func = interpolate_biquadratic;
break;
}
for (y = 0; y < height; y++) {
for(x = 0; x < width; x++) {
x_s = x * matrix[0] + y * matrix[1] + matrix[2];
y_s = x * matrix[3] + y * matrix[4] + matrix[5];
switch(fill) {
case FILL_ORIGINAL:
def = src[y * src_stride + x];
break;
case FILL_CLAMP:
y_s = av_clipf(y_s, 0, height - 1);
x_s = av_clipf(x_s, 0, width - 1);
def = src[(int)y_s * src_stride + (int)x_s];
break;
case FILL_MIRROR:
y_s = (y_s < 0) ? -y_s : (y_s >= height) ? (height + height - y_s) : y_s;
x_s = (x_s < 0) ? -x_s : (x_s >= width) ? (width + width - x_s) : x_s;
def = src[(int)y_s * src_stride + (int)x_s];
}
dst[y * dst_stride + x] = func(x_s, y_s, src, width, height, src_stride, def);
}
}
}

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libavfilter/transform.h
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/*
* Copyright (C) 2010 Georg Martius <georg.martius@web.de>
* Copyright (C) 2010 Daniel G. Taylor <dan@programmer-art.org>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file libavfilter/transform.h
* transform input video
*
* All matrices are defined as a single 9-item block of contiguous memory. For
* example, the identity matrix would be:
*
* float *matrix = {1, 0, 0,
* 0, 1, 0,
* 0, 0, 1};
*/
enum InterpolateMethod {
INTERPOLATE_NEAREST, //< Nearest-neighbor (fast)
INTERPOLATE_BILINEAR, //< Bilinear
INTERPOLATE_BIQUADRATIC, //< Biquadratic (best)
INTERPOLATE_COUNT, //< Number of interpolation methods
};
// Shortcuts for the fastest and best interpolation methods
#define INTERPOLATE_DEFAULT INTERPOLATE_BILINEAR
#define INTERPOLATE_FAST INTERPOLATE_NEAREST
#define INTERPOLATE_BEST INTERPOLATE_BIQUADRATIC
enum FillMethod {
FILL_BLANK, //< Fill zeroes at blank locations
FILL_ORIGINAL, //< Original image at blank locations
FILL_CLAMP, //< Extruded edge value at blank locations
FILL_MIRROR, //< Mirrored edge at blank locations
FILL_COUNT, //< Number of edge fill methods
};
// Shortcuts for fill methods
#define FILL_DEFAULT FILL_ORIGINAL
/**
* Get an affine transformation matrix from a given translation, rotation, and
* zoom factor. The matrix will look like:
*
* [ zoom * cos(angle), -sin(angle), x_shift,
* sin(angle), zoom * cos(angle), y_shift,
0, 0, 1 ]
*
* Paramters:
* x_shift: Horizontal translation
* y_shift: Vertical translation
* angle: Rotation in radians
* zoom: Scale percent (1.0 = 100%)
* matrix: 9-item affine transformation matrix
*/
void avfilter_get_matrix(float x_shift, float y_shift, float angle, float zoom, float *matrix);
/**
* Add two matrices together. result = m1 + m2.
*
* Parameters:
* m1: 9-item transformation matrix
* m2: 9-item transformation matrix
* result: 9-item transformation matrix
*/
void avfilter_add_matrix(const float *m1, const float *m2, float *result);
/**
* Subtract one matrix from another. result = m1 - m2.
*
* Parameters:
* m1: 9-item transformation matrix
* m2: 9-item transformation matrix
* result: 9-item transformation matrix
*/
void avfilter_sub_matrix(const float *m1, const float *m2, float *result);
/**
* Multiply a matrix by a scalar value. result = m1 * scalar.
*
* Parameters:
* m1: 9-item transformation matrix
* scalar: A number
* result: 9-item transformation matrix
*/
void avfilter_mul_matrix(const float *m1, float scalar, float *result);
/**
* Do an affine transformation with the given interpolation method. This
* multiplies each vector [x,y,1] by the matrix and then interpolates to
* get the final value.
*
* Parameters:
* src: Source image
* dst: Destination image
* src_stride: Source image line size in bytes
* dst_stride: Destination image line size in bytes
* width: Image width in pixels
* height: Image height in pixels
* matrix: 9-item affine transformation matrix
* interpolate: Pixel interpolation method
* fill: Edge fill method
*/
void avfilter_transform(const uint8_t *src, uint8_t *dst,
int src_stride, int dst_stride,
int width, int height, const float *matrix,
enum InterpolateMethod interpolate,
enum FillMethod fill);
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