/*
  * Copyright (C) 2012 British Broadcasting Corporation, All Rights Reserved
  * Author of de-interlace algorithm: Jim Easterbrook for BBC R&D
  * Based on the process described by Martin Weston for BBC R&D
  * Author of FFmpeg filter: Mark Himsley for BBC Broadcast Systems Development
  *
  * 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/common.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 typedef struct W3FDIFContext {
     const AVClass *class;
     int filter;           ///< 0 is simple, 1 is more complex
     int deint;            ///< which frames to deinterlace
     int linesize[4];      ///< bytes of pixel data per line for each plane
     int planeheight[4];   ///< height of each plane
     int field;            ///< which field are we on, 0 or 1
     int eof;
     int nb_planes;
     AVFrame *prev, *cur, *next;  ///< previous, current, next frames
     int32_t *work_line;   ///< line we are calculating
 } W3FDIFContext;
 
 #define OFFSET(x) offsetof(W3FDIFContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 #define CONST(name, help, val, unit) { name, help, 0, AV_OPT_TYPE_CONST, {.i64=val}, 0, 0, FLAGS, unit }
 
 static const AVOption w3fdif_options[] = {
     { "filter", "specify the filter", OFFSET(filter), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS, "filter" },
     CONST("simple",  NULL, 0, "filter"),
     CONST("complex", NULL, 1, "filter"),
     { "deint",  "specify which frames to deinterlace", OFFSET(deint), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "deint" },
     CONST("all",        "deinterlace all frames",                       0, "deint"),
     CONST("interlaced", "only deinterlace frames marked as interlaced", 1, "deint"),
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(w3fdif);
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
         AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
         AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
         AV_PIX_FMT_YUVJ411P,
         AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA444P,
         AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,
         AV_PIX_FMT_GRAY8,
         AV_PIX_FMT_NONE
     };
 
     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
 
     return 0;
 }
 
 static int config_input(AVFilterLink *inlink)
 {
     W3FDIFContext *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] = FF_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);
     s->work_line = av_calloc(s->linesize[0], sizeof(*s->work_line));
     if (!s->work_line)
         return AVERROR(ENOMEM);
 
     return 0;
 }
 
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterLink *inlink = outlink->src->inputs[0];
 
     outlink->time_base.num = inlink->time_base.num;
     outlink->time_base.den = inlink->time_base.den * 2;
     outlink->frame_rate.num = inlink->frame_rate.num * 2;
     outlink->frame_rate.den = inlink->frame_rate.den;
     outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
 
     return 0;
 }
 
 /*
  * Filter coefficients from PH-2071, scaled by 256 * 256.
  * Each set of coefficients has a set for low-frequencies and high-frequencies.
  * n_coef_lf[] and n_coef_hf[] are the number of coefs for simple and more-complex.
  * It is important for later that n_coef_lf[] is even and n_coef_hf[] is odd.
  * coef_lf[][] and coef_hf[][] are the coefficients for low-frequencies
  * and high-frequencies for simple and more-complex mode.
  */
 static const int8_t   n_coef_lf[2] = { 2, 4 };
 static const int32_t coef_lf[2][4] = {{ 32768, 32768,     0,     0},
                                       { -1704, 34472, 34472, -1704}};
 static const int8_t   n_coef_hf[2] = { 3, 5 };
 static const int32_t coef_hf[2][5] = {{ -4096,  8192, -4096,     0,     0},
                                       {  2032, -7602, 11140, -7602,  2032}};
 
 static void deinterlace_plane(AVFilterContext *ctx, AVFrame *out,
                               const AVFrame *cur, const AVFrame *adj,
                               const int filter, const int plane)
 {
     W3FDIFContext *s = ctx->priv;
     uint8_t *in_line, *in_lines_cur[5], *in_lines_adj[5];
     uint8_t *out_line, *out_pixel;
     int32_t *work_line, *work_pixel;
     uint8_t *cur_data = cur->data[plane];
     uint8_t *adj_data = adj->data[plane];
     uint8_t *dst_data = out->data[plane];
     const int linesize = s->linesize[plane];
     const int height   = s->planeheight[plane];
     const int cur_line_stride = cur->linesize[plane];
     const int adj_line_stride = adj->linesize[plane];
     const int dst_line_stride = out->linesize[plane];
     int i, j, y_in, y_out;
 
     /* copy unchanged the lines of the field */
     y_out = s->field == cur->top_field_first;
 
     in_line  = cur_data + (y_out * cur_line_stride);
     out_line = dst_data + (y_out * dst_line_stride);
 
     while (y_out < height) {
         memcpy(out_line, in_line, linesize);
         y_out += 2;
         in_line  += cur_line_stride * 2;
         out_line += dst_line_stride * 2;
     }
 
     /* interpolate other lines of the field */
     y_out = s->field != cur->top_field_first;
 
     out_line = dst_data + (y_out * dst_line_stride);
 
     while (y_out < height) {
         /* clear workspace */
         memset(s->work_line, 0, sizeof(*s->work_line) * linesize);
 
         /* get low vertical frequencies from current field */
         for (j = 0; j < n_coef_lf[filter]; j++) {
             y_in = (y_out + 1) + (j * 2) - n_coef_lf[filter];
 
             while (y_in < 0)
                 y_in += 2;
             while (y_in >= height)
                 y_in -= 2;
 
             in_lines_cur[j] = cur_data + (y_in * cur_line_stride);
         }
 
         work_line = s->work_line;
         switch (n_coef_lf[filter]) {
         case 2:
             for (i = 0; i < linesize; i++) {
                 *work_line   += *in_lines_cur[0]++ * coef_lf[filter][0];
                 *work_line++ += *in_lines_cur[1]++ * coef_lf[filter][1];
             }
             break;
         case 4:
             for (i = 0; i < linesize; i++) {
                 *work_line   += *in_lines_cur[0]++ * coef_lf[filter][0];
                 *work_line   += *in_lines_cur[1]++ * coef_lf[filter][1];
                 *work_line   += *in_lines_cur[2]++ * coef_lf[filter][2];
                 *work_line++ += *in_lines_cur[3]++ * coef_lf[filter][3];
             }
         }
 
         /* get high vertical frequencies from adjacent fields */
         for (j = 0; j < n_coef_hf[filter]; j++) {
             y_in = (y_out + 1) + (j * 2) - n_coef_hf[filter];
 
             while (y_in < 0)
                 y_in += 2;
             while (y_in >= height)
                 y_in -= 2;
 
             in_lines_cur[j] = cur_data + (y_in * cur_line_stride);
             in_lines_adj[j] = adj_data + (y_in * adj_line_stride);
         }
 
         work_line = s->work_line;
         switch (n_coef_hf[filter]) {
         case 3:
             for (i = 0; i < linesize; i++) {
                 *work_line   += *in_lines_cur[0]++ * coef_hf[filter][0];
                 *work_line   += *in_lines_adj[0]++ * coef_hf[filter][0];
                 *work_line   += *in_lines_cur[1]++ * coef_hf[filter][1];
                 *work_line   += *in_lines_adj[1]++ * coef_hf[filter][1];
                 *work_line   += *in_lines_cur[2]++ * coef_hf[filter][2];
                 *work_line++ += *in_lines_adj[2]++ * coef_hf[filter][2];
             }
             break;
         case 5:
             for (i = 0; i < linesize; i++) {
                 *work_line   += *in_lines_cur[0]++ * coef_hf[filter][0];
                 *work_line   += *in_lines_adj[0]++ * coef_hf[filter][0];
                 *work_line   += *in_lines_cur[1]++ * coef_hf[filter][1];
                 *work_line   += *in_lines_adj[1]++ * coef_hf[filter][1];
                 *work_line   += *in_lines_cur[2]++ * coef_hf[filter][2];
                 *work_line   += *in_lines_adj[2]++ * coef_hf[filter][2];
                 *work_line   += *in_lines_cur[3]++ * coef_hf[filter][3];
                 *work_line   += *in_lines_adj[3]++ * coef_hf[filter][3];
                 *work_line   += *in_lines_cur[4]++ * coef_hf[filter][4];
                 *work_line++ += *in_lines_adj[4]++ * coef_hf[filter][4];
             }
         }
 
         /* save scaled result to the output frame, scaling down by 256 * 256 */
         work_pixel = s->work_line;
         out_pixel = out_line;
 
         for (j = 0; j < linesize; j++, out_pixel++, work_pixel++)
              *out_pixel = av_clip(*work_pixel, 0, 255 * 256 * 256) >> 16;
 
         /* move on to next line */
         y_out += 2;
         out_line += dst_line_stride * 2;
     }
 }
 

 static int filter(AVFilterContext *ctx, int is_second)

 {
     W3FDIFContext *s = ctx->priv;
     AVFilterLink *outlink = ctx->outputs[0];
     AVFrame *out, *adj;
     int plane;
 
     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!out)
         return AVERROR(ENOMEM);
     av_frame_copy_props(out, s->cur);
     out->interlaced_frame = 0;

 
     if (!is_second) {
         if (out->pts != AV_NOPTS_VALUE)
             out->pts *= 2;
     } else {
         int64_t cur_pts  = s->cur->pts;
         int64_t next_pts = s->next->pts;
 
         if (next_pts != AV_NOPTS_VALUE && cur_pts != AV_NOPTS_VALUE) {
             out->pts = cur_pts + next_pts;
         } else {
             out->pts = AV_NOPTS_VALUE;
         }
     }

 
     adj = s->field ? s->next : s->prev;
     for (plane = 0; plane < s->nb_planes; plane++)
         deinterlace_plane(ctx, out, s->cur, adj, s->filter, plane);
 
     s->field = !s->field;
 
     return ff_filter_frame(outlink, out);
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     AVFilterContext *ctx = inlink->dst;
     W3FDIFContext *s = ctx->priv;
     int ret;
 
     av_frame_free(&s->prev);
     s->prev = s->cur;
     s->cur  = s->next;
     s->next = frame;
 
     if (!s->cur) {
         s->cur = av_frame_clone(s->next);
         if (!s->cur)
             return AVERROR(ENOMEM);
     }
 
     if ((s->deint && !s->cur->interlaced_frame) || ctx->is_disabled) {
         AVFrame *out = av_frame_clone(s->cur);
         if (!out)
             return AVERROR(ENOMEM);
 
         av_frame_free(&s->prev);

         if (out->pts != AV_NOPTS_VALUE)
             out->pts *= 2;

         return ff_filter_frame(ctx->outputs[0], out);
     }
 
     if (!s->prev)
         return 0;
 

     ret = filter(ctx, 0);

     if (ret < 0)
         return ret;
 

     return filter(ctx, 1);

 }
 
 static int request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     W3FDIFContext *s = ctx->priv;
 
     do {
         int ret;
 
         if (s->eof)
             return AVERROR_EOF;
 
         ret = ff_request_frame(ctx->inputs[0]);
 
         if (ret == AVERROR_EOF && s->cur) {
             AVFrame *next = av_frame_clone(s->next);
             if (!next)
                 return AVERROR(ENOMEM);

             next->pts = s->next->pts * 2 - s->cur->pts;

             filter_frame(ctx->inputs[0], next);
             s->eof = 1;
         } else if (ret < 0) {
             return ret;
         }
     } while (!s->cur);
 
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     W3FDIFContext *s = ctx->priv;
 
     av_frame_free(&s->prev);
     av_frame_free(&s->cur );
     av_frame_free(&s->next);
     av_freep(&s->work_line);
 }
 
 static const AVFilterPad w3fdif_inputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .filter_frame  = filter_frame,
         .config_props  = config_input,
     },
     { NULL }
 };
 
 static const AVFilterPad w3fdif_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .config_props  = config_output,
         .request_frame = request_frame,
     },
     { NULL }
 };
 

 AVFilter ff_vf_w3fdif = {

     .name          = "w3fdif",
     .description   = NULL_IF_CONFIG_SMALL("Apply Martin Weston three field deinterlace."),
     .priv_size     = sizeof(W3FDIFContext),
     .priv_class    = &w3fdif_class,
     .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = w3fdif_inputs,
     .outputs       = w3fdif_outputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,
 };