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/*
* Copyright (c) 2002 A'rpi
* 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.
*/
/**
* @file
* border detection filter
* Ported from MPlayer libmpcodecs/vf_cropdetect.c.
*/
#include "libavutil/imgutils.h"
#include "libavutil/internal.h"
#include "libavutil/opt.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
typedef struct {
const AVClass *class;
int x1, y1, x2, y2;
int limit;
int round;
int reset_count;
int frame_nb;
int max_pixsteps[4];
} CropDetectContext;
static int query_formats(AVFilterContext *ctx)
{
static const enum AVPixelFormat pix_fmts[] = {
AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUVJ420P,
AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUVJ422P,
AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUVJ444P,
AV_PIX_FMT_YUV411P, AV_PIX_FMT_GRAY8,
AV_PIX_FMT_NV12, AV_PIX_FMT_NV21,
AV_PIX_FMT_NONE
};
ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
return 0;
}
static int checkline(void *ctx, const unsigned char *src, int stride, int len, int bpp)
{
int total = 0;
int div = len;
switch (bpp) {
case 1:
while (--len >= 0) {
total += src[0];
src += stride;
}
break;
case 3:
case 4:
while (--len >= 0) {
total += src[0] + src[1] + src[2];
src += stride;
}
div *= 3;
break;
}
total /= div;
av_log(ctx, AV_LOG_DEBUG, "total:%d\n", total);
return total;
}
static av_cold int init(AVFilterContext *ctx, const char *args)
{
CropDetectContext *cd = ctx->priv;
cd->frame_nb = -2;
av_log(ctx, AV_LOG_VERBOSE, "limit:%d round:%d reset_count:%d\n",
cd->limit, cd->round, cd->reset_count);
return 0;
}
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
CropDetectContext *cd = ctx->priv;
av_image_fill_max_pixsteps(cd->max_pixsteps, NULL,
av_pix_fmt_desc_get(inlink->format));
cd->x1 = inlink->w - 1;
cd->y1 = inlink->h - 1;
cd->x2 = 0;
cd->y2 = 0;
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
{
AVFilterContext *ctx = inlink->dst;
CropDetectContext *cd = ctx->priv;
int bpp = cd->max_pixsteps[0];
int w, h, x, y, shrink_by;
// ignore first 2 frames - they may be empty
if (++cd->frame_nb > 0) {
// Reset the crop area every reset_count frames, if reset_count is > 0
if (cd->reset_count > 0 && cd->frame_nb > cd->reset_count) {
cd->x1 = frame->width - 1;
cd->y1 = frame->height - 1;
cd->x2 = 0;
cd->y2 = 0;
cd->frame_nb = 1;
}
for (y = 0; y < cd->y1; y++) {
if (checkline(ctx, frame->data[0] + frame->linesize[0] * y, bpp, frame->width, bpp) > cd->limit) {
cd->y1 = y;
break;
}
}
for (y = frame->height - 1; y > cd->y2; y--) {
if (checkline(ctx, frame->data[0] + frame->linesize[0] * y, bpp, frame->width, bpp) > cd->limit) {
cd->y2 = y;
break;
}
}
for (y = 0; y < cd->x1; y++) {
if (checkline(ctx, frame->data[0] + bpp*y, frame->linesize[0], frame->height, bpp) > cd->limit) {
cd->x1 = y;
break;
}
}
for (y = frame->width - 1; y > cd->x2; y--) {
if (checkline(ctx, frame->data[0] + bpp*y, frame->linesize[0], frame->height, bpp) > cd->limit) {
cd->x2 = y;
break;
}
}
// round x and y (up), important for yuv colorspaces
// make sure they stay rounded!
x = (cd->x1+1) & ~1;
y = (cd->y1+1) & ~1;
w = cd->x2 - x + 1;
h = cd->y2 - y + 1;
// w and h must be divisible by 2 as well because of yuv
// colorspace problems.
if (cd->round <= 1)
cd->round = 16;
if (cd->round % 2)
cd->round *= 2;
shrink_by = w % cd->round;
w -= shrink_by;
x += (shrink_by/2 + 1) & ~1;
shrink_by = h % cd->round;
h -= shrink_by;
y += (shrink_by/2 + 1) & ~1;
av_log(ctx, AV_LOG_INFO,
"x1:%d x2:%d y1:%d y2:%d w:%d h:%d x:%d y:%d pts:%"PRId64" t:%f crop=%d:%d:%d:%d\n",
cd->x1, cd->x2, cd->y1, cd->y2, w, h, x, y, frame->pts,
frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base),
w, h, x, y);
}
return ff_filter_frame(inlink->dst->outputs[0], frame);
}
#define OFFSET(x) offsetof(CropDetectContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption cropdetect_options[] = {
{ "limit", "Threshold below which the pixel is considered black", OFFSET(limit), AV_OPT_TYPE_INT, { .i64 = 24 }, 0, 255, FLAGS },
{ "round", "Value by which the width/height should be divisible", OFFSET(round), AV_OPT_TYPE_INT, { .i64 = 16 }, 0, INT_MAX, FLAGS },
{ "reset", "Recalculate the crop area after this many frames", OFFSET(reset_count), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS },
{ "reset_count", "Recalculate the crop area after this many frames",OFFSET(reset_count),AV_OPT_TYPE_INT,{ .i64 = 0 }, 0, INT_MAX, FLAGS },
{ NULL },
};
AVFILTER_DEFINE_CLASS(cropdetect);
static const AVFilterPad avfilter_vf_cropdetect_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_input,
.get_video_buffer = ff_null_get_video_buffer,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad avfilter_vf_cropdetect_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO
},
{ NULL }
};
AVFilter avfilter_vf_cropdetect = {
.name = "cropdetect",
.description = NULL_IF_CONFIG_SMALL("Auto-detect crop size."),
.priv_size = sizeof(CropDetectContext),
.priv_class = &cropdetect_class,
.init = init,
.query_formats = query_formats,
.inputs = avfilter_vf_cropdetect_inputs,
.outputs = avfilter_vf_cropdetect_outputs,
};
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