2 * Copyright (c) 2003 Rich Felker
3 * Copyright (c) 2012 Stefano Sabatini
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * field filter, based on libmpcodecs/vf_field.c by Rich Felker
27 #include "libavutil/opt.h"
28 #include "libavutil/pixdesc.h"
32 enum FieldType { FIELD_TYPE_TOP = 0, FIELD_TYPE_BOTTOM };
37 int nb_planes; ///< number of planes of the current format
40 #define OFFSET(x) offsetof(FieldContext, x)
41 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
43 static const AVOption field_options[] = {
44 {"type", "set field type (top or bottom)", OFFSET(type), AV_OPT_TYPE_INT, {.i64=FIELD_TYPE_TOP}, 0, 1, FLAGS, "field_type" },
45 {"top", "select top field", 0, AV_OPT_TYPE_CONST, {.i64=FIELD_TYPE_TOP}, INT_MIN, INT_MAX, FLAGS, "field_type"},
46 {"bottom", "select bottom field", 0, AV_OPT_TYPE_CONST, {.i64=FIELD_TYPE_BOTTOM}, INT_MIN, INT_MAX, FLAGS, "field_type"},
51 AVFILTER_DEFINE_CLASS(field);
53 static av_cold int init(AVFilterContext *ctx, const char *args)
55 FieldContext *field = ctx->priv;
56 static const char *shorthand[] = { "type", NULL };
58 field->class = &field_class;
59 av_opt_set_defaults(field);
61 return av_opt_set_from_string(field, args, shorthand, "=", ":");
64 static int config_props_output(AVFilterLink *outlink)
66 AVFilterContext *ctx = outlink->src;
67 FieldContext *field = ctx->priv;
68 AVFilterLink *inlink = ctx->inputs[0];
69 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
72 for (i = 0; i < desc->nb_components; i++)
73 field->nb_planes = FFMAX(field->nb_planes, desc->comp[i].plane);
76 outlink->w = inlink->w;
77 outlink->h = (inlink->h + (field->type == FIELD_TYPE_TOP)) / 2;
79 av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d type:%s -> w:%d h:%d\n",
80 inlink->w, inlink->h, field->type == FIELD_TYPE_BOTTOM ? "bottom" : "top",
81 outlink->w, outlink->h);
85 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
87 FieldContext *field = inlink->dst->priv;
88 AVFilterLink *outlink = inlink->dst->outputs[0];
91 inpicref->video->h = outlink->h;
92 inpicref->video->interlaced = 0;
94 for (i = 0; i < field->nb_planes; i++) {
95 if (field->type == FIELD_TYPE_BOTTOM)
96 inpicref->data[i] = inpicref->data[i] + inpicref->linesize[i];
97 inpicref->linesize[i] = 2 * inpicref->linesize[i];
99 return ff_filter_frame(outlink, inpicref);
102 static const AVFilterPad field_inputs[] = {
105 .type = AVMEDIA_TYPE_VIDEO,
106 .get_video_buffer = ff_null_get_video_buffer,
107 .filter_frame = filter_frame,
112 static const AVFilterPad field_outputs[] = {
115 .type = AVMEDIA_TYPE_VIDEO,
116 .config_props = config_props_output,
121 AVFilter avfilter_vf_field = {
123 .description = NULL_IF_CONFIG_SMALL("Extract a field from the input video."),
125 .priv_size = sizeof(FieldContext),
128 .inputs = field_inputs,
129 .outputs = field_outputs,
130 .priv_class = &field_class,