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FFmpeg/libavfilter/vf_perspective.c
Paul B Mahol b211607b5c avfilter: various cosmetics 
Signed-off-by: Paul B Mahol <onemda@gmail.com>
2013-09-12 14:01:43 +00:00

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/*
* Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
* Copyright (c) 2013 Paul B Mahol
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 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 General Public License for more details.
*
* You should have received a copy of the GNU 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
*/
#include "libavutil/eval.h"
#include "libavutil/imgutils.h"
#include "libavutil/pixdesc.h"
#include "libavutil/opt.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
#define SUB_PIXEL_BITS 8
#define SUB_PIXELS (1 << SUB_PIXEL_BITS)
#define COEFF_BITS 11
#define LINEAR 0
#define CUBIC 1
typedef struct PerspectiveContext {
const AVClass *class;
char *expr_str[4][2];
double ref[4][2];
int32_t (*pv)[2];
int32_t coeff[SUB_PIXELS][4];
int interpolation;
int linesize[4];
int height[4];
int hsub, vsub;
int nb_planes;
void (*perspective)(struct PerspectiveContext *s,
uint8_t *dst, int dst_linesize,
uint8_t *src, int src_linesize,
int w, int h, int hsub, int vsub);
} PerspectiveContext;
#define OFFSET(x) offsetof(PerspectiveContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption perspective_options[] = {
{ "x0", "set top left x coordinate", OFFSET(expr_str[0][0]), AV_OPT_TYPE_STRING, {.str="0"}, 0, 0, FLAGS },
{ "y0", "set top left y coordinate", OFFSET(expr_str[0][1]), AV_OPT_TYPE_STRING, {.str="0"}, 0, 0, FLAGS },
{ "x1", "set top right x coordinate", OFFSET(expr_str[1][0]), AV_OPT_TYPE_STRING, {.str="W"}, 0, 0, FLAGS },
{ "y1", "set top right y coordinate", OFFSET(expr_str[1][1]), AV_OPT_TYPE_STRING, {.str="0"}, 0, 0, FLAGS },
{ "x2", "set bottom left x coordinate", OFFSET(expr_str[2][0]), AV_OPT_TYPE_STRING, {.str="0"}, 0, 0, FLAGS },
{ "y2", "set bottom left y coordinate", OFFSET(expr_str[2][1]), AV_OPT_TYPE_STRING, {.str="H"}, 0, 0, FLAGS },
{ "x3", "set bottom right x coordinate", OFFSET(expr_str[3][0]), AV_OPT_TYPE_STRING, {.str="W"}, 0, 0, FLAGS },
{ "y3", "set bottom right y coordinate", OFFSET(expr_str[3][1]), AV_OPT_TYPE_STRING, {.str="H"}, 0, 0, FLAGS },
{ "interpolation", "set interpolation", OFFSET(interpolation), AV_OPT_TYPE_INT, {.i64=LINEAR}, 0, 1, FLAGS, "interpolation" },
{ "linear", "", 0, AV_OPT_TYPE_CONST, {.i64=LINEAR}, 0, 0, FLAGS, "interpolation" },
{ "cubic", "", 0, AV_OPT_TYPE_CONST, {.i64=CUBIC}, 0, 0, FLAGS, "interpolation" },
{ NULL }
};
AVFILTER_DEFINE_CLASS(perspective);
static int query_formats(AVFilterContext *ctx)
{
static const enum AVPixelFormat pix_fmts[] = {
AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ422P,AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ411P,
AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
};
ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
return 0;
}
static inline double get_coeff(double d)
{
double coeff, A = -0.60;
d = fabs(d);
if (d < 1.0)
coeff = (1.0 - (A + 3.0) * d * d + (A + 2.0) * d * d * d);
else if (d < 2.0)
coeff = (-4.0 * A + 8.0 * A * d - 5.0 * A * d * d + A * d * d * d);
else
coeff = 0.0;
return coeff;
}
static const char *const var_names[] = { "W", "H", NULL };
enum { VAR_W, VAR_H, VAR_VARS_NB };
static int config_input(AVFilterLink *inlink)
{
double x0, x1, x2, x3, x4, x5, x6, x7, q;
AVFilterContext *ctx = inlink->dst;
PerspectiveContext *s = ctx->priv;
double (*ref)[2] = s->ref;
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
double values[VAR_VARS_NB] = { [VAR_W] = inlink->w, [VAR_H] = inlink->h };
int h = inlink->h;
int w = inlink->w;
int x, y, i, j, ret;
for (i = 0; i < 4; i++) {
for (j = 0; j < 2; j++) {
if (!s->expr_str[i][j])
return AVERROR(EINVAL);
ret = av_expr_parse_and_eval(&s->ref[i][j], s->expr_str[i][j],
var_names, &values[0],
NULL, NULL, NULL, NULL,
0, 0, ctx);
if (ret < 0)
return ret;
}
}
s->hsub = desc->log2_chroma_w;
s->vsub = desc->log2_chroma_h;
s->nb_planes = av_pix_fmt_count_planes(inlink->format);
if ((ret = av_image_fill_linesizes(s->linesize, inlink->format, inlink->w)) < 0)
return ret;
s->height[1] = s->height[2] = FF_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
s->height[0] = s->height[3] = inlink->h;
s->pv = av_realloc_f(s->pv, w * h, 2 * sizeof(*s->pv));
if (!s->pv)
return AVERROR(ENOMEM);
x6 = ((ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0]) *
(ref[2][1] - ref[3][1]) -
( ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1]) *
(ref[2][0] - ref[3][0])) * h;
x7 = ((ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1]) *
(ref[1][0] - ref[3][0]) -
( ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0]) *
(ref[1][1] - ref[3][1])) * w;
q = ( ref[1][0] - ref[3][0]) * (ref[2][1] - ref[3][1]) -
( ref[2][0] - ref[3][0]) * (ref[1][1] - ref[3][1]);
x0 = q * (ref[1][0] - ref[0][0]) * h + x6 * ref[1][0];
x1 = q * (ref[2][0] - ref[0][0]) * w + x7 * ref[2][0];
x2 = q * ref[0][0] * w * h;
x3 = q * (ref[1][1] - ref[0][1]) * h + x6 * ref[1][1];
x4 = q * (ref[2][1] - ref[0][1]) * w + x7 * ref[2][1];
x5 = q * ref[0][1] * w * h;
for (y = 0; y < h; y++){
for (x = 0; x < w; x++){
int u, v;
u = (int)floor(SUB_PIXELS * (x0 * x + x1 * y + x2) /
(x6 * x + x7 * y + q * w * h) + 0.5);
v = (int)floor(SUB_PIXELS * (x3 * x + x4 * y + x5) /
(x6 * x + x7 * y + q * w * h) + 0.5);
s->pv[x + y * w][0] = u;
s->pv[x + y * w][1] = v;
}
}
for (i = 0; i < SUB_PIXELS; i++){
double d = i / (double)SUB_PIXELS;
double temp[4];
double sum = 0;
for (j = 0; j < 4; j++)
temp[j] = get_coeff(j - d - 1);
for (j = 0; j < 4; j++)
sum += temp[j];
for (j = 0; j < 4; j++)
s->coeff[i][j] = (int)floor((1 << COEFF_BITS) * temp[j] / sum + 0.5);
}
return 0;
}
static void resample_cubic(PerspectiveContext *s,
uint8_t *dst, int dst_linesize,
uint8_t *src, int src_linesize,
int w, int h, int hsub, int vsub)
{
const int linesize = s->linesize[0];
int x, y;
for (y = 0; y < h; y++) {
int sy = y << vsub;
for (x = 0; x < w; x++) {
int u, v, subU, subV, sum, sx;
sx = x << hsub;
u = s->pv[sx + sy * linesize][0] >> hsub;
v = s->pv[sx + sy * linesize][1] >> vsub;
subU = u & (SUB_PIXELS - 1);
subV = v & (SUB_PIXELS - 1);
u >>= SUB_PIXEL_BITS;
v >>= SUB_PIXEL_BITS;
if (u > 0 && v > 0 && u < w - 2 && v < h - 2){
const int index = u + v*src_linesize;
const int a = s->coeff[subU][0];
const int b = s->coeff[subU][1];
const int c = s->coeff[subU][2];
const int d = s->coeff[subU][3];
sum = s->coeff[subV][0] * (a * src[index - 1 - src_linesize] + b * src[index - 0 - src_linesize] +
c * src[index + 1 - src_linesize] + d * src[index + 2 - src_linesize]) +
s->coeff[subV][1] * (a * src[index - 1 ] + b * src[index - 0 ] +
c * src[index + 1 ] + d * src[index + 2 ]) +
s->coeff[subV][2] * (a * src[index - 1 + src_linesize] + b * src[index - 0 + src_linesize] +
c * src[index + 1 + src_linesize] + d * src[index + 2 + src_linesize]) +
s->coeff[subV][3] * (a * src[index - 1 + 2 * src_linesize] + b * src[index - 0 + 2 * src_linesize] +
c * src[index + 1 + 2 * src_linesize] + d * src[index + 2 + 2 * src_linesize]);
} else {
int dx, dy;
sum = 0;
for (dy = 0; dy < 4; dy++) {
int iy = v + dy - 1;
if (iy < 0)
iy = 0;
else if (iy >= h)
iy = h-1;
for (dx = 0; dx < 4; dx++) {
int ix = u + dx - 1;
if (ix < 0)
ix = 0;
else if (ix >= w)
ix = w - 1;
sum += s->coeff[subU][dx] * s->coeff[subV][dy] * src[ ix + iy * src_linesize];
}
}
}
sum = (sum + (1<<(COEFF_BITS * 2 - 1))) >> (COEFF_BITS * 2);
sum = av_clip(sum, 0, 255);
dst[x + y * dst_linesize] = sum;
}
}
}
static void resample_linear(PerspectiveContext *s,
uint8_t *dst, int dst_linesize,
uint8_t *src, int src_linesize,
int w, int h, int hsub, int vsub)
{
const int linesize = s->linesize[0];
int x, y;
for (y = 0; y < h; y++){
int sy = y << vsub;
for (x = 0; x < w; x++){
int u, v, subU, subV, sum, sx, index, subUI, subVI;
sx = x << hsub;
u = s->pv[sx + sy * linesize][0] >> hsub;
v = s->pv[sx + sy * linesize][1] >> vsub;
subU = u & (SUB_PIXELS - 1);
subV = v & (SUB_PIXELS - 1);
u >>= SUB_PIXEL_BITS;
v >>= SUB_PIXEL_BITS;
index = u + v * src_linesize;
subUI = SUB_PIXELS - subU;
subVI = SUB_PIXELS - subV;
if ((unsigned)u < (unsigned)(w - 1)){
if((unsigned)v < (unsigned)(h - 1)){
sum = subVI * (subUI * src[index] + subU * src[index + 1]) +
subV * (subUI * src[index + src_linesize] + subU * src[index + src_linesize + 1]);
sum = (sum + (1 << (SUB_PIXEL_BITS * 2 - 1)))>> (SUB_PIXEL_BITS * 2);
} else {
if (v < 0)
v = 0;
else
v = h - 1;
index = u + v * src_linesize;
sum = subUI * src[index] + subU * src[index + 1];
sum = (sum + (1 << (SUB_PIXEL_BITS - 1))) >> SUB_PIXEL_BITS;
}
} else {
if (u < 0)
u = 0;
else
u = w - 1;
if ((unsigned)v < (unsigned)(h - 1)){
index = u + v * src_linesize;
sum = subVI * src[index] + subV * src[index + src_linesize];
sum = (sum + (1 << (SUB_PIXEL_BITS - 1))) >> SUB_PIXEL_BITS;
} else {
if (v < 0)
v = 0;
else
v = h - 1;
index = u + v * src_linesize;
sum = src[index];
}
}
sum = av_clip(sum, 0, 255);
dst[x + y * dst_linesize] = sum;
}
}
}
static av_cold int init(AVFilterContext *ctx)
{
PerspectiveContext *s = ctx->priv;
switch (s->interpolation) {
case LINEAR: s->perspective = resample_linear; break;
case CUBIC: s->perspective = resample_cubic; break;
}
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
PerspectiveContext *s = ctx->priv;
AVFrame *out;
int plane;
out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
if (!out) {
av_frame_free(&frame);
return AVERROR(ENOMEM);
}
av_frame_copy_props(out, frame);
for (plane = 0; plane < s->nb_planes; plane++) {
int hsub = plane == 1 || plane == 2 ? s->hsub : 0;
int vsub = plane == 1 || plane == 2 ? s->vsub : 0;
s->perspective(s, out->data[plane], out->linesize[plane],
frame->data[plane], frame->linesize[plane],
s->linesize[plane], s->height[plane], hsub, vsub);
}
av_frame_free(&frame);
return ff_filter_frame(outlink, out);
}
static av_cold void uninit(AVFilterContext *ctx)
{
PerspectiveContext *s = ctx->priv;
av_freep(&s->pv);
}
static const AVFilterPad perspective_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
.config_props = config_input,
},
{ NULL }
};
static const AVFilterPad perspective_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
{ NULL }
};
AVFilter avfilter_vf_perspective = {
.name = "perspective",
.description = NULL_IF_CONFIG_SMALL("Correct the perspective of video."),
.priv_size = sizeof(PerspectiveContext),
.init = init,
.uninit = uninit,
.query_formats = query_formats,
.inputs = perspective_inputs,
.outputs = perspective_outputs,
.priv_class = &perspective_class,
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
};
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