yading@10: /*
yading@10:  * Copyright (c) 2003 Rich Felker
yading@10:  * Copyright (c) 2012 Stefano Sabatini
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * field filter, based on libmpcodecs/vf_field.c by Rich Felker
yading@10:  */
yading@10: 
yading@10: #include "libavutil/opt.h"
yading@10: #include "libavutil/pixdesc.h"
yading@10: #include "avfilter.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: enum FieldType { FIELD_TYPE_TOP = 0, FIELD_TYPE_BOTTOM };
yading@10: 
yading@10: typedef struct {
yading@10:     const AVClass *class;
yading@10:     enum FieldType type;
yading@10:     int nb_planes;              ///< number of planes of the current format
yading@10: } FieldContext;
yading@10: 
yading@10: #define OFFSET(x) offsetof(FieldContext, x)
yading@10: #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
yading@10: 
yading@10: static const AVOption field_options[] = {
yading@10:     {"type", "set field type (top or bottom)", OFFSET(type), AV_OPT_TYPE_INT, {.i64=FIELD_TYPE_TOP}, 0, 1, FLAGS, "field_type" },
yading@10:     {"top",    "select top field",    0, AV_OPT_TYPE_CONST, {.i64=FIELD_TYPE_TOP},    INT_MIN, INT_MAX, FLAGS, "field_type"},
yading@10:     {"bottom", "select bottom field", 0, AV_OPT_TYPE_CONST, {.i64=FIELD_TYPE_BOTTOM}, INT_MIN, INT_MAX, FLAGS, "field_type"},
yading@10: 
yading@10:     {NULL}
yading@10: };
yading@10: 
yading@10: AVFILTER_DEFINE_CLASS(field);
yading@10: 
yading@10: static int config_props_output(AVFilterLink *outlink)
yading@10: {
yading@10:     AVFilterContext *ctx = outlink->src;
yading@10:     FieldContext *field = ctx->priv;
yading@10:     AVFilterLink *inlink = ctx->inputs[0];
yading@10:     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
yading@10:     int i;
yading@10: 
yading@10:     for (i = 0; i < desc->nb_components; i++)
yading@10:         field->nb_planes = FFMAX(field->nb_planes, desc->comp[i].plane);
yading@10:     field->nb_planes++;
yading@10: 
yading@10:     outlink->w = inlink->w;
yading@10:     outlink->h = (inlink->h + (field->type == FIELD_TYPE_TOP)) / 2;
yading@10: 
yading@10:     av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d type:%s -> w:%d h:%d\n",
yading@10:            inlink->w, inlink->h, field->type == FIELD_TYPE_BOTTOM ? "bottom" : "top",
yading@10:            outlink->w, outlink->h);
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int filter_frame(AVFilterLink *inlink, AVFrame *inpicref)
yading@10: {
yading@10:     FieldContext *field = inlink->dst->priv;
yading@10:     AVFilterLink *outlink = inlink->dst->outputs[0];
yading@10:     int i;
yading@10: 
yading@10:     inpicref->height = outlink->h;
yading@10:     inpicref->interlaced_frame = 0;
yading@10: 
yading@10:     for (i = 0; i < field->nb_planes; i++) {
yading@10:         if (field->type == FIELD_TYPE_BOTTOM)
yading@10:             inpicref->data[i] = inpicref->data[i] + inpicref->linesize[i];
yading@10:         inpicref->linesize[i] = 2 * inpicref->linesize[i];
yading@10:     }
yading@10:     return ff_filter_frame(outlink, inpicref);
yading@10: }
yading@10: 
yading@10: static const AVFilterPad field_inputs[] = {
yading@10:     {
yading@10:         .name             = "default",
yading@10:         .type             = AVMEDIA_TYPE_VIDEO,
yading@10:         .get_video_buffer = ff_null_get_video_buffer,
yading@10:         .filter_frame     = filter_frame,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: static const AVFilterPad field_outputs[] = {
yading@10:     {
yading@10:         .name          = "default",
yading@10:         .type          = AVMEDIA_TYPE_VIDEO,
yading@10:         .config_props  = config_props_output,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: AVFilter avfilter_vf_field = {
yading@10:     .name          = "field",
yading@10:     .description   = NULL_IF_CONFIG_SMALL("Extract a field from the input video."),
yading@10: 
yading@10:     .priv_size     = sizeof(FieldContext),
yading@10:     .inputs        = field_inputs,
yading@10:     .outputs       = field_outputs,
yading@10:     .priv_class    = &field_class,
yading@10: };