/*
  * Copyright (c) 2004 Ville Saari
  *
  * 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/avassert.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/pixdesc.h"
 #include "libavutil/opt.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 enum PhaseMode {
     PROGRESSIVE,
     TOP_FIRST,
     BOTTOM_FIRST,
     TOP_FIRST_ANALYZE,
     BOTTOM_FIRST_ANALYZE,
     ANALYZE,
     FULL_ANALYZE,
     AUTO,
     AUTO_ANALYZE
 };
 
 typedef struct PhaseContext {
     const AVClass *class;

     int mode;                   ///<PhaseMode

     AVFrame *frame; /* previous frame */

     int nb_planes;
     int planeheight[4];
     int linesize[4];
 } PhaseContext;
 
 #define OFFSET(x) offsetof(PhaseContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 #define CONST(name, help, val, unit) { name, help, 0, AV_OPT_TYPE_CONST, {.i64=val}, 0, 0, FLAGS, unit }
 
 static const AVOption phase_options[] = {
     { "mode", "set phase mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=AUTO_ANALYZE}, PROGRESSIVE, AUTO_ANALYZE, FLAGS, "mode" },
     CONST("p", "progressive",          PROGRESSIVE,          "mode"),
     CONST("t", "top first",            TOP_FIRST,            "mode"),
     CONST("b", "bottom first",         BOTTOM_FIRST,         "mode"),
     CONST("T", "top first analyze",    TOP_FIRST_ANALYZE,    "mode"),
     CONST("B", "bottom first analyze", BOTTOM_FIRST_ANALYZE, "mode"),
     CONST("u", "analyze",              ANALYZE,              "mode"),
     CONST("U", "full analyze",         FULL_ANALYZE,         "mode"),
     CONST("a", "auto",                 AUTO,                 "mode"),
     CONST("A", "auto analyze",         AUTO_ANALYZE,         "mode"),
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(phase);
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ422P,AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ411P,
         AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
         AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
     };
 

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

 }
 
 static int config_input(AVFilterLink *inlink)
 {
     PhaseContext *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;
 }
 
 /*
  * This macro interpolates the value of both fields at a point halfway
  * between lines and takes the squared difference. In field resolution
  * the point is a quarter pixel below a line in one field and a quarter
  * pixel above a line in other.
  *
  * (The result is actually multiplied by 25)
  */

 #define DIFF(a, as, b, bs) ((t) = ((*(a) - (b)[bs]) << 2) + (a)[(as) << 1] - (b)[-(bs)], (t) * (t))

 
 /*
  * Find which field combination has the smallest average squared difference
  * between the fields.
  */

 static enum PhaseMode analyze_plane(void *ctx, enum PhaseMode mode, AVFrame *old, AVFrame *new)

 {

     double bdiff, tdiff, pdiff;

 
     if (mode == AUTO) {
         mode = new->interlaced_frame ? new->top_field_first ?
                TOP_FIRST : BOTTOM_FIRST : PROGRESSIVE;
     } else if (mode == AUTO_ANALYZE) {
         mode = new->interlaced_frame ? new->top_field_first ?
                TOP_FIRST_ANALYZE : BOTTOM_FIRST_ANALYZE : FULL_ANALYZE;
     }
 
     if (mode <= BOTTOM_FIRST) {
         bdiff = pdiff = tdiff = 65536.0;
     } else {

         const int ns = new->linesize[0];
         const int os = old->linesize[0];
         const uint8_t *nptr = new->data[0];
         const uint8_t *optr = old->data[0];
         const int h = new->height;
         const int w = new->width;
         int bdif, tdif, pdif;
         double scale;
 

         int top = 0, t;
         const uint8_t *rend, *end = nptr + (h - 2) * ns;
 

         bdiff = pdiff = tdiff = 0.0;
 

         nptr += ns;
         optr += os;
         while (nptr < end) {

             pdif = tdif = bdif = 0;
 
             switch (mode) {
             case TOP_FIRST_ANALYZE:
                 if (top) {
                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
                         pdif += DIFF(nptr, ns, nptr, ns);
                         tdif += DIFF(nptr, ns, optr, os);
                     }
                 } else {
                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
                         pdif += DIFF(nptr, ns, nptr, ns);
                         tdif += DIFF(optr, os, nptr, ns);
                     }
                 }
                 break;
             case BOTTOM_FIRST_ANALYZE:
                 if (top) {
                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
                         pdif += DIFF(nptr, ns, nptr, ns);
                         bdif += DIFF(optr, os, nptr, ns);
                     }
                 } else {
                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
                         pdif += DIFF(nptr, ns, nptr, ns);
                         bdif += DIFF(nptr, ns, optr, os);
                     }
                 }
                 break;
             case ANALYZE:
                 if (top) {
                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
                         tdif += DIFF(nptr, ns, optr, os);
                         bdif += DIFF(optr, os, nptr, ns);
                     }
                 } else {
                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
                         bdif += DIFF(nptr, ns, optr, os);
                         tdif += DIFF(optr, os, nptr, ns);
                     }
                 }
                 break;
             case FULL_ANALYZE:
                 if (top) {
                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
                         pdif += DIFF(nptr, ns, nptr, ns);
                         tdif += DIFF(nptr, ns, optr, os);
                         bdif += DIFF(optr, os, nptr, ns);
                     }
                 } else {
                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
                         pdif += DIFF(nptr, ns, nptr, ns);
                         bdif += DIFF(nptr, ns, optr, os);
                         tdif += DIFF(optr, os, nptr, ns);
                     }
                 }
                 break;
             default:
                 av_assert0(0);
             }
 
             pdiff += (double)pdif;
             tdiff += (double)tdif;
             bdiff += (double)bdif;

             nptr += ns - w;
             optr += os - w;
             top ^= 1;

         }
 
         scale = 1.0 / (w * (h - 3)) / 25.0;
         pdiff *= scale;
         tdiff *= scale;
         bdiff *= scale;
 
         if (mode == TOP_FIRST_ANALYZE) {
             bdiff = 65536.0;
         } else if (mode == BOTTOM_FIRST_ANALYZE) {
             tdiff = 65536.0;
         } else if (mode == ANALYZE) {
             pdiff = 65536.0;
         }
 
         if (bdiff < pdiff && bdiff < tdiff) {
             mode = BOTTOM_FIRST;
         } else if (tdiff < pdiff && tdiff < bdiff) {
             mode = TOP_FIRST;
         } else {
             mode = PROGRESSIVE;
         }
     }
 
     av_log(ctx, AV_LOG_DEBUG, "mode=%c tdiff=%f bdiff=%f pdiff=%f\n",
            mode == BOTTOM_FIRST ? 'b' : mode == TOP_FIRST ? 't' : 'p',
            tdiff, bdiff, pdiff);
     return mode;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     PhaseContext *s = ctx->priv;

     enum PhaseMode mode;

     int plane, top, y;
     AVFrame *out;
 

     if (ctx->is_disabled) {
         av_frame_free(&s->frame);
         /* we keep a reference to the previous frame so the filter can start
          * being useful as soon as it's not disabled, avoiding the 1-frame
          * delay. */
         s->frame = av_frame_clone(in);
         return ff_filter_frame(outlink, in);
     }
 

     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!out) {
         av_frame_free(&in);
         return AVERROR(ENOMEM);
     }
     av_frame_copy_props(out, in);
 
     if (!s->frame) {

         s->frame = in;

         mode = PROGRESSIVE;
     } else {

         mode = analyze_plane(ctx, s->mode, s->frame, in);

     }
 
     for (plane = 0; plane < s->nb_planes; plane++) {

         const uint8_t *buf = s->frame->data[plane];
         const uint8_t *from = in->data[plane];

         uint8_t *to = out->data[plane];
 
         for (y = 0, top = 1; y < s->planeheight[plane]; y++, top ^= 1) {
             memcpy(to, mode == (top ? BOTTOM_FIRST : TOP_FIRST) ? buf : from, s->linesize[plane]);
 
             buf += s->frame->linesize[plane];
             from += in->linesize[plane];
             to += out->linesize[plane];
         }
     }
 

     if (in != s->frame)
         av_frame_free(&s->frame);
     s->frame = in;

     return ff_filter_frame(outlink, out);
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     PhaseContext *s = ctx->priv;
 
     av_frame_free(&s->frame);
 }
 
 static const AVFilterPad phase_inputs[] = {
     {

         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
         .config_props = config_input,

     },
     { NULL }
 };
 
 static const AVFilterPad phase_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 

 AVFilter ff_vf_phase = {

     .name          = "phase",
     .description   = NULL_IF_CONFIG_SMALL("Phase shift fields."),
     .priv_size     = sizeof(PhaseContext),
     .priv_class    = &phase_class,
     .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = phase_inputs,
     .outputs       = phase_outputs,

     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,

 };