/*
  * Copyright (c) 2003 Tobias Diedrich
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 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 General Public License for more details.
  *
  * You should have received a copy of the GNU 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 "avfilter.h"
 #include "internal.h"
 
 typedef struct RepeatFieldsContext {
     const AVClass *class;
     int state;
     int nb_planes;
     int linesize[4];
     int planeheight[4];
     AVFrame *frame;
 } RepeatFieldsContext;
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     RepeatFieldsContext *s = ctx->priv;
 
     av_frame_free(&s->frame);
 }
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pixel_fmts_eq[] = {
         AV_PIX_FMT_GRAY8,
         AV_PIX_FMT_YUV410P,
         AV_PIX_FMT_YUV411P,
         AV_PIX_FMT_YUV420P,
         AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV444P,
         AV_PIX_FMT_NONE
     };
 

     AVFilterFormats *fmts_list = ff_make_format_list(pixel_fmts_eq);
     if (!fmts_list)
         return AVERROR(ENOMEM);
     return ff_set_common_formats(ctx, fmts_list);

 }
 
 static int config_input(AVFilterLink *inlink)
 {
     RepeatFieldsContext *s = inlink->dst->priv;
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
     int ret;
 
     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 void update_pts(AVFilterLink *link, AVFrame *f, int64_t pts, int fields)
 {
     if (av_cmp_q(link->frame_rate, (AVRational){30000, 1001}) == 0 &&
          av_cmp_q(link->time_base, (AVRational){1001, 60000}) <= 0
     ) {
         f->pts = pts + av_rescale_q(fields, (AVRational){1001, 60000}, link->time_base);
     } else
         f->pts = AV_NOPTS_VALUE;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in) {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = inlink->dst->outputs[0];
     RepeatFieldsContext *s = ctx->priv;
     AVFrame *out;
     int ret, i;
     int state = s->state;
 
     if (!s->frame) {
         s->frame = av_frame_clone(in);
         if (!s->frame)
             return AVERROR(ENOMEM);
         s->frame->pts = AV_NOPTS_VALUE;
     }
 
     out = s->frame;
 
     if ((state == 0 && !in->top_field_first) ||
         (state == 1 &&  in->top_field_first)) {
         av_log(ctx, AV_LOG_WARNING, "Unexpected field flags: "
                                     "state=%d top_field_first=%d repeat_first_field=%d\n",
                                     state, in->top_field_first, in->repeat_pict);
         state ^= 1;
     }
 
     if (state == 0) {
         AVFrame *new;
 
         new = av_frame_clone(in);
         if (!new)
             return AVERROR(ENOMEM);
 
         ret = ff_filter_frame(outlink, new);
 
         if (in->repeat_pict) {
             av_frame_make_writable(out);
             update_pts(outlink, out, in->pts, 2);
             for (i = 0; i < s->nb_planes; i++) {
                 av_image_copy_plane(out->data[i], out->linesize[i] * 2,
                                     in->data[i], in->linesize[i] * 2,
                                     s->linesize[i], s->planeheight[i] / 2);
             }
             state = 1;
         }
     } else {
         for (i = 0; i < s->nb_planes; i++) {
             av_frame_make_writable(out);
             av_image_copy_plane(out->data[i] + out->linesize[i], out->linesize[i] * 2,
                                 in->data[i] + in->linesize[i], in->linesize[i] * 2,
                                 s->linesize[i], s->planeheight[i] / 2);
         }
 
         ret = ff_filter_frame(outlink, av_frame_clone(out));
 
         if (in->repeat_pict) {
             AVFrame *new;
 
             new = av_frame_clone(in);
             if (!new)
                 return AVERROR(ENOMEM);
 
             ret = ff_filter_frame(outlink, new);
             state = 0;
         } else {
             av_frame_make_writable(out);
             update_pts(outlink, out, in->pts, 1);
             for (i = 0; i < s->nb_planes; i++) {
                 av_image_copy_plane(out->data[i], out->linesize[i] * 2,
                                     in->data[i], in->linesize[i] * 2,
                                     s->linesize[i], s->planeheight[i] / 2);
             }
         }
     }
 
     s->state = state;
 
     av_frame_free(&in);
     return ret;
 }
 
 static const AVFilterPad repeatfields_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
         .config_props = config_input,
     },
     { NULL }
 };
 
 static const AVFilterPad repeatfields_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
 AVFilter ff_vf_repeatfields = {
     .name          = "repeatfields",
     .description   = NULL_IF_CONFIG_SMALL("Hard repeat fields based on MPEG repeat field flag."),
     .priv_size     = sizeof(RepeatFieldsContext),
     .uninit        = uninit,
     .inputs        = repeatfields_inputs,
     .outputs       = repeatfields_outputs,
     .query_formats = query_formats,
 };