/*
  * Copyright (c) 2013 Paul B Mahol
  *
  * 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
  */
 
 #include "libavutil/imgutils.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"
 #include "internal.h"
 
 typedef struct WeaveContext {
     const AVClass *class;
     int first_field;

     int double_weave;

     int nb_planes;
     int planeheight[4];
     int linesize[4];
 
     AVFrame *prev;
 } WeaveContext;
 
 #define OFFSET(x) offsetof(WeaveContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
 static const AVOption weave_options[] = {
     { "first_field", "set first field", OFFSET(first_field), AV_OPT_TYPE_INT,   {.i64=0}, 0, 1, FLAGS, "field"},
         { "top",     "set top field first",               0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "field"},
         { "t",       "set top field first",               0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "field"},
         { "bottom",  "set bottom field first",            0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "field"},
         { "b",       "set bottom field first",            0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "field"},
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(weave);
 
 static int config_props_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     WeaveContext *s = ctx->priv;
     AVFilterLink *inlink = ctx->inputs[0];
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
     int ret;
 

     if (!s->double_weave) {
         outlink->time_base.num = inlink->time_base.num * 2;
         outlink->time_base.den = inlink->time_base.den;
         outlink->frame_rate.num = inlink->frame_rate.num;
         outlink->frame_rate.den = inlink->frame_rate.den * 2;
     }

     outlink->w = inlink->w;
     outlink->h = inlink->h * 2;
 
     if ((ret = av_image_fill_linesizes(s->linesize, inlink->format, inlink->w)) < 0)
         return ret;
 
     s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
     s->planeheight[0] = s->planeheight[3] = inlink->h;
 
     s->nb_planes = av_pix_fmt_count_planes(inlink->format);
 
     return 0;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     WeaveContext *s = ctx->priv;
     AVFilterLink *outlink = ctx->outputs[0];
     AVFrame *out;
     int i;
 
     if (!s->prev) {
         s->prev = in;
         return 0;
     }
 
     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!out) {
         av_frame_free(&in);
         av_frame_free(&s->prev);
         return AVERROR(ENOMEM);
     }
     av_frame_copy_props(out, in);
 
     for (i = 0; i < s->nb_planes; i++) {

         if (s->double_weave && !(inlink->frame_count_out & 1)) {

             av_image_copy_plane(out->data[i] + out->linesize[i] * s->first_field,

                                 out->linesize[i] * 2,
                                 in->data[i], in->linesize[i],
                                 s->linesize[i], s->planeheight[i]);

             av_image_copy_plane(out->data[i] + out->linesize[i] * !s->first_field,

                                 out->linesize[i] * 2,
                                 s->prev->data[i], s->prev->linesize[i],
                                 s->linesize[i], s->planeheight[i]);
         } else {

             av_image_copy_plane(out->data[i] + out->linesize[i] * !s->first_field,

                                 out->linesize[i] * 2,
                                 in->data[i], in->linesize[i],
                                 s->linesize[i], s->planeheight[i]);

             av_image_copy_plane(out->data[i] + out->linesize[i] * s->first_field,

                                 out->linesize[i] * 2,
                                 s->prev->data[i], s->prev->linesize[i],
                                 s->linesize[i], s->planeheight[i]);
         }

     }
 

     out->pts = s->double_weave ? s->prev->pts : in->pts / 2;

     out->interlaced_frame = 1;
     out->top_field_first = !s->first_field;
 

     if (!s->double_weave)
         av_frame_free(&in);

     av_frame_free(&s->prev);

     if (s->double_weave)
         s->prev = in;

     return ff_filter_frame(outlink, out);
 }
 

 static av_cold void uninit(AVFilterContext *ctx)
 {
     WeaveContext *s = ctx->priv;
 
     av_frame_free(&s->prev);
 }
 

 static const AVFilterPad weave_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,
         .filter_frame     = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad weave_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .config_props  = config_props_output,
     },
     { NULL }
 };
 
 AVFilter ff_vf_weave = {
     .name          = "weave",
     .description   = NULL_IF_CONFIG_SMALL("Weave input video fields into frames."),
     .priv_size     = sizeof(WeaveContext),
     .priv_class    = &weave_class,

     .uninit        = uninit,

     .inputs        = weave_inputs,
     .outputs       = weave_outputs,
 };

 
 static av_cold int init(AVFilterContext *ctx)
 {
     WeaveContext *s = ctx->priv;
 
     if (!strcmp(ctx->filter->name, "doubleweave"))
         s->double_weave = 1;
 
     return 0;
 }
 
 #define doubleweave_options weave_options
 AVFILTER_DEFINE_CLASS(doubleweave);
 
 AVFilter ff_vf_doubleweave = {
     .name          = "doubleweave",
     .description   = NULL_IF_CONFIG_SMALL("Weave input video fields into double number of frames."),
     .priv_size     = sizeof(WeaveContext),
     .priv_class    = &doubleweave_class,
     .init          = init,
     .uninit        = uninit,
     .inputs        = weave_inputs,
     .outputs       = weave_outputs,
 };