1/* 2 * Copyright (c) 2003 Rich Felker 3 * Copyright (c) 2012 Stefano Sabatini 4 * 5 * This file is part of FFmpeg. 6 * 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. 11 * 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. 16 * 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 20 */ 21 22/** 23 * @file 24 * field filter, based on libmpcodecs/vf_field.c by Rich Felker 25 */ 26 27#include "libavutil/opt.h" 28#include "libavutil/pixdesc.h" 29#include "avfilter.h" 30#include "internal.h" 31 32enum FieldType { FIELD_TYPE_TOP = 0, FIELD_TYPE_BOTTOM }; 33 34typedef struct { 35 const AVClass *class; 36 enum FieldType type; 37 int nb_planes; ///< number of planes of the current format 38} FieldContext; 39 40#define OFFSET(x) offsetof(FieldContext, x) 41#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM 42 43static 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"}, 47 {NULL} 48}; 49 50AVFILTER_DEFINE_CLASS(field); 51 52static int config_props_output(AVFilterLink *outlink) 53{ 54 AVFilterContext *ctx = outlink->src; 55 FieldContext *field = ctx->priv; 56 AVFilterLink *inlink = ctx->inputs[0]; 57 58 field->nb_planes = av_pix_fmt_count_planes(outlink->format); 59 60 outlink->w = inlink->w; 61 outlink->h = (inlink->h + (field->type == FIELD_TYPE_TOP)) / 2; 62 63 av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d type:%s -> w:%d h:%d\n", 64 inlink->w, inlink->h, field->type == FIELD_TYPE_BOTTOM ? "bottom" : "top", 65 outlink->w, outlink->h); 66 return 0; 67} 68 69static int filter_frame(AVFilterLink *inlink, AVFrame *inpicref) 70{ 71 FieldContext *field = inlink->dst->priv; 72 AVFilterLink *outlink = inlink->dst->outputs[0]; 73 int i; 74 75 inpicref->height = outlink->h; 76 inpicref->interlaced_frame = 0; 77 78 for (i = 0; i < field->nb_planes; i++) { 79 if (field->type == FIELD_TYPE_BOTTOM) 80 inpicref->data[i] = inpicref->data[i] + inpicref->linesize[i]; 81 inpicref->linesize[i] = 2 * inpicref->linesize[i]; 82 } 83 return ff_filter_frame(outlink, inpicref); 84} 85 86static const AVFilterPad field_inputs[] = { 87 { 88 .name = "default", 89 .type = AVMEDIA_TYPE_VIDEO, 90 .filter_frame = filter_frame, 91 }, 92 { NULL } 93}; 94 95static const AVFilterPad field_outputs[] = { 96 { 97 .name = "default", 98 .type = AVMEDIA_TYPE_VIDEO, 99 .config_props = config_props_output, 100 }, 101 { NULL } 102}; 103 104AVFilter ff_vf_field = { 105 .name = "field", 106 .description = NULL_IF_CONFIG_SMALL("Extract a field from the input video."), 107 .priv_size = sizeof(FieldContext), 108 .inputs = field_inputs, 109 .outputs = field_outputs, 110 .priv_class = &field_class, 111}; 112