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/*
* Copyright (c) 2003 Rich Felker
* Copyright (c) 2012 Stefano Sabatini
*
* 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
* field filter, based on libmpcodecs/vf_field.c by Rich Felker
*/
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "internal.h"
enum FieldType { FIELD_TYPE_TOP = 0, FIELD_TYPE_BOTTOM };
typedef struct {
const AVClass *class;
enum FieldType type;
int nb_planes; ///< number of planes of the current format
} FieldContext;
#define OFFSET(x) offsetof(FieldContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption field_options[] = {
{"type", "set field type (top or bottom)", OFFSET(type), AV_OPT_TYPE_INT, {.i64=FIELD_TYPE_TOP}, 0, 1, FLAGS, "field_type" },
{"top", "select top field", 0, AV_OPT_TYPE_CONST, {.i64=FIELD_TYPE_TOP}, INT_MIN, INT_MAX, FLAGS, "field_type"},
{"bottom", "select bottom field", 0, AV_OPT_TYPE_CONST, {.i64=FIELD_TYPE_BOTTOM}, INT_MIN, INT_MAX, FLAGS, "field_type"},
{NULL}
};
AVFILTER_DEFINE_CLASS(field);
static av_cold int init(AVFilterContext *ctx, const char *args)
{
FieldContext *field = ctx->priv;
static const char *shorthand[] = { "type", NULL };
field->class = &field_class;
av_opt_set_defaults(field);
return av_opt_set_from_string(field, args, shorthand, "=", ":");
}
static int config_props_output(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
FieldContext *field = ctx->priv;
AVFilterLink *inlink = ctx->inputs[0];
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
int i;
for (i = 0; i < desc->nb_components; i++)
field->nb_planes = FFMAX(field->nb_planes, desc->comp[i].plane);
field->nb_planes++;
outlink->w = inlink->w;
outlink->h = (inlink->h + (field->type == FIELD_TYPE_TOP)) / 2;
av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d type:%s -> w:%d h:%d\n",
inlink->w, inlink->h, field->type == FIELD_TYPE_BOTTOM ? "bottom" : "top",
outlink->w, outlink->h);
return 0;
}
static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
{
FieldContext *field = inlink->dst->priv;
AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
AVFilterLink *outlink = inlink->dst->outputs[0];
int i;
if (!outpicref)
return AVERROR(ENOMEM);
outpicref->video->h = outlink->h;
outpicref->video->interlaced = 0;
for (i = 0; i < field->nb_planes; i++) {
if (field->type == FIELD_TYPE_BOTTOM)
outpicref->data[i] = inpicref->data[i] + inpicref->linesize[i];
outpicref->linesize[i] = 2 * inpicref->linesize[i];
}
return ff_start_frame(outlink, outpicref);
}
static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
{
FieldContext *field = inlink->dst->priv;
int y1 = (y + (field->type == FIELD_TYPE_TOP)) / 2;
int h1 = (h + (field->type == FIELD_TYPE_TOP)) / 2;
return ff_draw_slice(inlink->dst->outputs[0], y1, h1, slice_dir);
}
static const AVFilterPad field_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.get_video_buffer = ff_null_get_video_buffer,
.start_frame = start_frame,
.draw_slice = draw_slice,
.end_frame = ff_null_end_frame,
},
{ NULL }
};
static const AVFilterPad field_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_props_output,
},
{ NULL }
};
AVFilter avfilter_vf_field = {
.name = "field",
.description = NULL_IF_CONFIG_SMALL("Extract a field from the input video."),
.priv_size = sizeof(FieldContext),
.init = init,
.inputs = field_inputs,
.outputs = field_outputs,
.priv_class = &field_class,
};
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