/*
* Copyright (c) 2007 Bobby Bingham
*
* 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
* video crop filter
*/
#include <stdio.h>
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
#include "libavutil/eval.h"
#include "libavutil/avstring.h"
#include "libavutil/internal.h"
#include "libavutil/libm.h"
#include "libavutil/imgutils.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
static const char *const var_names[] = {
"in_w", "iw", ///< width of the input video
"in_h", "ih", ///< height of the input video
"out_w", "ow", ///< width of the cropped video
"out_h", "oh", ///< height of the cropped video
"a",
"sar",
"dar",
"hsub",
"vsub",
"x",
"y",
"n", ///< number of frame
"pos", ///< position in the file
"t", ///< timestamp expressed in seconds
NULL
};
enum var_name {
VAR_IN_W, VAR_IW,
VAR_IN_H, VAR_IH,
VAR_OUT_W, VAR_OW,
VAR_OUT_H, VAR_OH,
VAR_A,
VAR_SAR,
VAR_DAR,
VAR_HSUB,
VAR_VSUB,
VAR_X,
VAR_Y,
VAR_N,
VAR_POS,
VAR_T,
VAR_VARS_NB
};
typedef struct CropContext {
const AVClass *class;
int x; ///< x offset of the non-cropped area with respect to the input area
int y; ///< y offset of the non-cropped area with respect to the input area
int w; ///< width of the cropped area
int h; ///< height of the cropped area
AVRational out_sar; ///< output sample aspect ratio
int keep_aspect; ///< keep display aspect ratio when cropping
int max_step[4]; ///< max pixel step for each plane, expressed as a number of bytes
int hsub, vsub; ///< chroma subsampling
char *x_expr, *y_expr, *w_expr, *h_expr;
AVExpr *x_pexpr, *y_pexpr; /* parsed expressions for x and y */
double var_values[VAR_VARS_NB];
} CropContext;
static int query_formats(AVFilterContext *ctx)
{
AVFilterFormats *formats = NULL;
int fmt;
for (fmt = 0; av_pix_fmt_desc_get(fmt); fmt++) {
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
if (!(desc->flags & (AV_PIX_FMT_FLAG_HWACCEL | AV_PIX_FMT_FLAG_BITSTREAM)) &&
!((desc->log2_chroma_w || desc->log2_chroma_h) && !(desc->flags & AV_PIX_FMT_FLAG_PLANAR)))
ff_add_format(&formats, fmt);
}
return ff_set_common_formats(ctx, formats);
}
static av_cold void uninit(AVFilterContext *ctx)
{
CropContext *s = ctx->priv;
av_expr_free(s->x_pexpr);
s->x_pexpr = NULL;
av_expr_free(s->y_pexpr);
s->y_pexpr = NULL;
}
static inline int normalize_double(int *n, double d)
{
int ret = 0;
if (isnan(d)) {
ret = AVERROR(EINVAL);
} else if (d > INT_MAX || d < INT_MIN) {
*n = d > INT_MAX ? INT_MAX : INT_MIN;
ret = AVERROR(EINVAL);
} else
*n = round(d);
return ret;
}
static int config_input(AVFilterLink *link)
{
AVFilterContext *ctx = link->dst;
CropContext *s = ctx->priv;
const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(link->format);
int ret;
const char *expr;
double res;
s->var_values[VAR_IN_W] = s->var_values[VAR_IW] = ctx->inputs[0]->w;
s->var_values[VAR_IN_H] = s->var_values[VAR_IH] = ctx->inputs[0]->h;
s->var_values[VAR_A] = (float) link->w / link->h;
s->var_values[VAR_SAR] = link->sample_aspect_ratio.num ? av_q2d(link->sample_aspect_ratio) : 1;
s->var_values[VAR_DAR] = s->var_values[VAR_A] * s->var_values[VAR_SAR];
s->var_values[VAR_HSUB] = 1<<pix_desc->log2_chroma_w;
s->var_values[VAR_VSUB] = 1<<pix_desc->log2_chroma_h;
s->var_values[VAR_X] = NAN;
s->var_values[VAR_Y] = NAN;
s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = NAN;
s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = NAN;
s->var_values[VAR_N] = 0;
s->var_values[VAR_T] = NAN;
s->var_values[VAR_POS] = NAN;
av_image_fill_max_pixsteps(s->max_step, NULL, pix_desc);
s->hsub = pix_desc->log2_chroma_w;
s->vsub = pix_desc->log2_chroma_h;
if ((ret = av_expr_parse_and_eval(&res, (expr = s->w_expr),
var_names, s->var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
goto fail_expr;
s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = res;
if ((ret = av_expr_parse_and_eval(&res, (expr = s->h_expr),
var_names, s->var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
goto fail_expr;
s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = res;
/* evaluate again ow as it may depend on oh */
if ((ret = av_expr_parse_and_eval(&res, (expr = s->w_expr),
var_names, s->var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
goto fail_expr;
s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = res;
if (normalize_double(&s->w, s->var_values[VAR_OUT_W]) < 0 ||
normalize_double(&s->h, s->var_values[VAR_OUT_H]) < 0) {
av_log(ctx, AV_LOG_ERROR,
"Too big value or invalid expression for out_w/ow or out_h/oh. "
"Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
s->w_expr, s->h_expr);
return AVERROR(EINVAL);
}
s->w &= ~((1 << s->hsub) - 1);
s->h &= ~((1 << s->vsub) - 1);
av_expr_free(s->x_pexpr);
av_expr_free(s->y_pexpr);
s->x_pexpr = s->y_pexpr = NULL;
if ((ret = av_expr_parse(&s->x_pexpr, s->x_expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||
(ret = av_expr_parse(&s->y_pexpr, s->y_expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0)
return AVERROR(EINVAL);
if (s->keep_aspect) {
AVRational dar = av_mul_q(link->sample_aspect_ratio,
(AVRational){ link->w, link->h });
av_reduce(&s->out_sar.num, &s->out_sar.den,
dar.num * s->h, dar.den * s->w, INT_MAX);
} else
s->out_sar = link->sample_aspect_ratio;
av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d sar:%d/%d -> w:%d h:%d sar:%d/%d\n",
link->w, link->h, link->sample_aspect_ratio.num, link->sample_aspect_ratio.den,
s->w, s->h, s->out_sar.num, s->out_sar.den);
if (s->w <= 0 || s->h <= 0 ||
s->w > link->w || s->h > link->h) {
av_log(ctx, AV_LOG_ERROR,
"Invalid too big or non positive size for width '%d' or height '%d'\n",
s->w, s->h);
return AVERROR(EINVAL);
}
/* set default, required in the case the first computed value for x/y is NAN */
s->x = (link->w - s->w) / 2;
s->y = (link->h - s->h) / 2;
s->x &= ~((1 << s->hsub) - 1);
s->y &= ~((1 << s->vsub) - 1);
return 0;
fail_expr:
av_log(NULL, AV_LOG_ERROR, "Error when evaluating the expression '%s'\n", expr);
return ret;
}
static int config_output(AVFilterLink *link)
{
CropContext *s = link->src->priv;
link->w = s->w;
link->h = s->h;
link->sample_aspect_ratio = s->out_sar;
return 0;
}
static int filter_frame(AVFilterLink *link, AVFrame *frame)
{
AVFilterContext *ctx = link->dst;
CropContext *s = ctx->priv;
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
int i;
frame->width = s->w;
frame->height = s->h;
s->var_values[VAR_N] = link->frame_count;
s->var_values[VAR_T] = frame->pts == AV_NOPTS_VALUE ?
NAN : frame->pts * av_q2d(link->time_base);
s->var_values[VAR_POS] = av_frame_get_pkt_pos(frame) == -1 ?
NAN : av_frame_get_pkt_pos(frame);
s->var_values[VAR_X] = av_expr_eval(s->x_pexpr, s->var_values, NULL);
s->var_values[VAR_Y] = av_expr_eval(s->y_pexpr, s->var_values, NULL);
s->var_values[VAR_X] = av_expr_eval(s->x_pexpr, s->var_values, NULL);
normalize_double(&s->x, s->var_values[VAR_X]);
normalize_double(&s->y, s->var_values[VAR_Y]);
if (s->x < 0)
s->x = 0;
if (s->y < 0)
s->y = 0;
if ((unsigned)s->x + (unsigned)s->w > link->w)
s->x = link->w - s->w;
if ((unsigned)s->y + (unsigned)s->h > link->h)
s->y = link->h - s->h;
s->x &= ~((1 << s->hsub) - 1);
s->y &= ~((1 << s->vsub) - 1);
av_log(ctx, AV_LOG_TRACE, "n:%d t:%f pos:%f x:%d y:%d x+w:%d y+h:%d\n",
(int)s->var_values[VAR_N], s->var_values[VAR_T], s->var_values[VAR_POS],
s->x, s->y, s->x+s->w, s->y+s->h);
frame->data[0] += s->y * frame->linesize[0];
frame->data[0] += s->x * s->max_step[0];
if (!(desc->flags & AV_PIX_FMT_FLAG_PAL || desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL)) {
for (i = 1; i < 3; i ++) {
if (frame->data[i]) {
frame->data[i] += (s->y >> s->vsub) * frame->linesize[i];
frame->data[i] += (s->x * s->max_step[i]) >> s->hsub;
}
}
}
/* alpha plane */
if (frame->data[3]) {
frame->data[3] += s->y * frame->linesize[3];
frame->data[3] += s->x * s->max_step[3];
}
return ff_filter_frame(link->dst->outputs[0], frame);
}
static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
char *res, int res_len, int flags)
{
CropContext *s = ctx->priv;
int ret;
int old_x = s->x;
int old_y = s->y;
int old_w = s->w;
int old_h = s->h;
AVFilterLink *outlink = ctx->outputs[0];
AVFilterLink *inlink = ctx->inputs[0];
av_opt_set(s, cmd, args, 0);
if ((ret = config_input(inlink)) < 0) {
s->x = old_x;
s->y = old_y;
s->w = old_w;
s->h = old_h;
return ret;
}
ret = config_output(outlink);
} else
ret = AVERROR(ENOSYS);
return ret;
}
#define OFFSET(x) offsetof(CropContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption crop_options[] = {
{ "out_w", "set the width crop area expression", OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "w", "set the width crop area expression", OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "out_h", "set the height crop area expression", OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "h", "set the height crop area expression", OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "x", "set the x crop area expression", OFFSET(x_expr), AV_OPT_TYPE_STRING, {.str = "(in_w-out_w)/2"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "y", "set the y crop area expression", OFFSET(y_expr), AV_OPT_TYPE_STRING, {.str = "(in_h-out_h)/2"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "keep_aspect", "keep aspect ratio", OFFSET(keep_aspect), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(crop);
static const AVFilterPad avfilter_vf_crop_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
.config_props = config_input,
},
{ NULL }
};
static const AVFilterPad avfilter_vf_crop_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_output,
},
{ NULL }
};
AVFilter ff_vf_crop = {
.name = "crop",
.description = NULL_IF_CONFIG_SMALL("Crop the input video."),
.priv_size = sizeof(CropContext),
.priv_class = &crop_class,
.query_formats = query_formats,
.uninit = uninit,
.inputs = avfilter_vf_crop_inputs,
.outputs = avfilter_vf_crop_outputs,
.process_command = process_command,
};