/*
  * Copyright (C) 2012 Michael Niedermayer <michaelni@gmx.at>
  *
  * 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 <float.h> /* FLT_MAX */
 

 #include "libavutil/cpu.h"
 #include "libavutil/common.h"

 #include "libavutil/opt.h"

 #include "internal.h"

 #include "vf_idet.h"

 #define OFFSET(x) offsetof(IDETContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 
 static const AVOption idet_options[] = {

     { "intl_thres", "set interlacing threshold", OFFSET(interlace_threshold),   AV_OPT_TYPE_FLOAT, {.dbl = 1.04}, -1, FLT_MAX, FLAGS },
     { "prog_thres", "set progressive threshold", OFFSET(progressive_threshold), AV_OPT_TYPE_FLOAT, {.dbl = 1.5},  -1, FLT_MAX, FLAGS },

     { "rep_thres",  "set repeat threshold",      OFFSET(repeat_threshold),      AV_OPT_TYPE_FLOAT, {.dbl = 3.0},  -1, FLT_MAX, FLAGS },

     { "half_life", "half life of cumulative statistics", OFFSET(half_life),     AV_OPT_TYPE_FLOAT, {.dbl = 0.0},  -1, INT_MAX, FLAGS },

     { "analyze_interlaced_flag", "set number of frames to use to determine if the interlace flag is accurate", OFFSET(analyze_interlaced_flag), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, FLAGS },

     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(idet);
 

 static const char *type2str(Type type)
 {
     switch(type) {

         case TFF          : return "tff";
         case BFF          : return "bff";
         case PROGRESSIVE  : return "progressive";
         case UNDETERMINED : return "undetermined";

     }
     return NULL;
 }

 #define PRECISION 1048576
 
 static uint64_t uintpow(uint64_t b,unsigned int e)
 {
     uint64_t r=1;
     while(e--) r*=b;
     return r;
 }
 
 static int av_dict_set_fxp(AVDictionary **pm, const char *key, uint64_t value, unsigned int digits,
                 int flags)
 {
     char valuestr[44];

     uint64_t print_precision = uintpow(10, digits);
 
     value = av_rescale(value, print_precision, PRECISION);
 

     snprintf(valuestr, sizeof(valuestr), "%"PRId64".%0*"PRId64,

              value / print_precision, digits, value % print_precision);
 

     return av_dict_set(pm, key, valuestr, flags);
 }
 

 static const char *rep2str(RepeatedField repeated_field)
 {
     switch(repeated_field) {
         case REPEAT_NONE    : return "neither";
         case REPEAT_TOP     : return "top";
         case REPEAT_BOTTOM  : return "bottom";
     }
     return NULL;
 }
 

 int ff_idet_filter_line_c(const uint8_t *a, const uint8_t *b, const uint8_t *c, int w)

 {
     int x;
     int ret=0;
 
     for(x=0; x<w; x++){

         int v = (*a++ + *c++) - 2 * *b++;
         ret += FFABS(v);

     }
 
     return ret;
 }
 

 int ff_idet_filter_line_c_16bit(const uint16_t *a, const uint16_t *b, const uint16_t *c, int w)

 {
     int x;
     int ret=0;
 
     for(x=0; x<w; x++){

         int v = (*a++ + *c++) - 2 * *b++;
         ret += FFABS(v);

     }
 
     return ret;
 }
 
 static void filter(AVFilterContext *ctx)
 {
     IDETContext *idet = ctx->priv;
     int y, i;
     int64_t alpha[2]={0};
     int64_t delta=0;

     int64_t gamma[2]={0};

     Type type, best_type;

     RepeatedField repeat;

     int match = 0;

     AVDictionary **metadata = &idet->cur->metadata;

 
     for (i = 0; i < idet->csp->nb_components; i++) {

         int w = idet->cur->width;
         int h = idet->cur->height;

         int refs = idet->cur->linesize[i];
 
         if (i && i<3) {

             w = AV_CEIL_RSHIFT(w, idet->csp->log2_chroma_w);
             h = AV_CEIL_RSHIFT(h, idet->csp->log2_chroma_h);

         }
 
         for (y = 2; y < h - 2; y++) {
             uint8_t *prev = &idet->prev->data[i][y*refs];
             uint8_t *cur  = &idet->cur ->data[i][y*refs];
             uint8_t *next = &idet->next->data[i][y*refs];
             alpha[ y   &1] += idet->filter_line(cur-refs, prev, cur+refs, w);
             alpha[(y^1)&1] += idet->filter_line(cur-refs, next, cur+refs, w);
             delta          += idet->filter_line(cur-refs,  cur, cur+refs, w);

             gamma[(y^1)&1] += idet->filter_line(cur     , prev, cur     , w);

         }
     }
 

     if      (alpha[0] > idet->interlace_threshold * alpha[1]){

         type = TFF;

     }else if(alpha[1] > idet->interlace_threshold * alpha[0]){

         type = BFF;

     }else if(alpha[1] > idet->progressive_threshold * delta){

         type = PROGRESSIVE;

     }else{
         type = UNDETERMINED;
     }
 

     if ( gamma[0] > idet->repeat_threshold * gamma[1] ){
         repeat = REPEAT_TOP;
     } else if ( gamma[1] > idet->repeat_threshold * gamma[0] ){
         repeat = REPEAT_BOTTOM;
     } else {
         repeat = REPEAT_NONE;
     }
 

     memmove(idet->history+1, idet->history, HIST_SIZE-1);
     idet->history[0] = type;
     best_type = UNDETERMINED;
     for(i=0; i<HIST_SIZE; i++){
         if(idet->history[i] != UNDETERMINED){
             if(best_type == UNDETERMINED)
                 best_type = idet->history[i];
 
             if(idet->history[i] == best_type) {
                 match++;
             }else{
                 match=0;
                 break;
             }
         }
     }
     if(idet->last_type == UNDETERMINED){
         if(match  ) idet->last_type = best_type;
     }else{
         if(match>2) idet->last_type = best_type;
     }

 
     if      (idet->last_type == TFF){

         idet->cur->top_field_first = 1;
         idet->cur->interlaced_frame = 1;

     }else if(idet->last_type == BFF){

         idet->cur->top_field_first = 0;
         idet->cur->interlaced_frame = 1;

     }else if(idet->last_type == PROGRESSIVE){

         idet->cur->interlaced_frame = 0;

     }

     for(i=0; i<3; i++)
         idet->repeats[i]  = av_rescale(idet->repeats [i], idet->decay_coefficient, PRECISION);

 
     for(i=0; i<4; i++){

         idet->prestat [i] = av_rescale(idet->prestat [i], idet->decay_coefficient, PRECISION);
         idet->poststat[i] = av_rescale(idet->poststat[i], idet->decay_coefficient, PRECISION);

     }
 

     idet->total_repeats [         repeat] ++;
     idet->repeats       [         repeat] += PRECISION;
 

     idet->total_prestat [           type] ++;
     idet->prestat       [           type] += PRECISION;
 
     idet->total_poststat[idet->last_type] ++;
     idet->poststat      [idet->last_type] += PRECISION;

     av_log(ctx, AV_LOG_DEBUG, "Repeated Field:%12s, Single frame:%12s, Multi frame:%12s\n",
            rep2str(repeat), type2str(type), type2str(idet->last_type));
 
     av_dict_set    (metadata, "lavfi.idet.repeated.current_frame", rep2str(repeat), 0);
     av_dict_set_fxp(metadata, "lavfi.idet.repeated.neither",       idet->repeats[REPEAT_NONE], 2, 0);
     av_dict_set_fxp(metadata, "lavfi.idet.repeated.top",           idet->repeats[REPEAT_TOP], 2, 0);
     av_dict_set_fxp(metadata, "lavfi.idet.repeated.bottom",        idet->repeats[REPEAT_BOTTOM], 2, 0);

     av_dict_set    (metadata, "lavfi.idet.single.current_frame",   type2str(type), 0);
     av_dict_set_fxp(metadata, "lavfi.idet.single.tff",             idet->prestat[TFF], 2 , 0);
     av_dict_set_fxp(metadata, "lavfi.idet.single.bff",             idet->prestat[BFF], 2, 0);
     av_dict_set_fxp(metadata, "lavfi.idet.single.progressive",     idet->prestat[PROGRESSIVE], 2, 0);
     av_dict_set_fxp(metadata, "lavfi.idet.single.undetermined",    idet->prestat[UNDETERMINED], 2, 0);

     av_dict_set    (metadata, "lavfi.idet.multiple.current_frame", type2str(idet->last_type), 0);

     av_dict_set_fxp(metadata, "lavfi.idet.multiple.tff",           idet->poststat[TFF], 2, 0);
     av_dict_set_fxp(metadata, "lavfi.idet.multiple.bff",           idet->poststat[BFF], 2, 0);
     av_dict_set_fxp(metadata, "lavfi.idet.multiple.progressive",   idet->poststat[PROGRESSIVE], 2, 0);
     av_dict_set_fxp(metadata, "lavfi.idet.multiple.undetermined",  idet->poststat[UNDETERMINED], 2, 0);

 }
 

 static int filter_frame(AVFilterLink *link, AVFrame *picref)

 {
     AVFilterContext *ctx = link->dst;
     IDETContext *idet = ctx->priv;
 

     // initial frame(s) and not interlaced, just pass through for
     // the analyze_interlaced_flag mode
     if (idet->analyze_interlaced_flag &&
         !picref->interlaced_frame &&
         !idet->next) {
         return ff_filter_frame(ctx->outputs[0], picref);
     }
     if (idet->analyze_interlaced_flag_done) {
         if (picref->interlaced_frame && idet->interlaced_flag_accuracy < 0)
             picref->interlaced_frame = 0;
         return ff_filter_frame(ctx->outputs[0], picref);
     }
 

     av_frame_free(&idet->prev);
 

     if(   picref->width  != link->w
        || picref->height != link->h
        || picref->format != link->format) {
         link->dst->inputs[0]->format = picref->format;
         link->dst->inputs[0]->w      = picref->width;
         link->dst->inputs[0]->h      = picref->height;
 
         av_frame_free(&idet->cur );
         av_frame_free(&idet->next);
     }
 

     idet->prev = idet->cur;
     idet->cur  = idet->next;
     idet->next = picref;
 

     if (!idet->cur &&
         !(idet->cur = av_frame_clone(idet->next)))
         return AVERROR(ENOMEM);

 
     if (!idet->prev)

         return 0;

 
     if (!idet->csp)

         idet->csp = av_pix_fmt_desc_get(link->format);

     if (idet->csp->comp[0].depth > 8){

         idet->filter_line = (ff_idet_filter_func)ff_idet_filter_line_c_16bit;
         if (ARCH_X86)
             ff_idet_init_x86(idet, 1);
     }

     if (idet->analyze_interlaced_flag) {
         if (idet->cur->interlaced_frame) {
             idet->cur->interlaced_frame = 0;
             filter(ctx);
             if (idet->last_type == PROGRESSIVE) {
                 idet->interlaced_flag_accuracy --;
                 idet->analyze_interlaced_flag --;
             } else if (idet->last_type != UNDETERMINED) {
                 idet->interlaced_flag_accuracy ++;
                 idet->analyze_interlaced_flag --;
             }
             if (idet->analyze_interlaced_flag == 1) {
                 ff_filter_frame(ctx->outputs[0], av_frame_clone(idet->cur));
 
                 if (idet->next->interlaced_frame && idet->interlaced_flag_accuracy < 0)
                     idet->next->interlaced_frame = 0;
                 idet->analyze_interlaced_flag_done = 1;
                 av_log(ctx, AV_LOG_INFO, "Final flag accuracy %d\n", idet->interlaced_flag_accuracy);
                 return ff_filter_frame(ctx->outputs[0], av_frame_clone(idet->next));
             }
         }
     } else {
         filter(ctx);
     }

     return ff_filter_frame(ctx->outputs[0], av_frame_clone(idet->cur));

 }
 

 static int request_frame(AVFilterLink *link)
 {
     AVFilterContext *ctx = link->src;
     IDETContext *idet = ctx->priv;

     int ret;

     if (idet->eof)
         return AVERROR_EOF;

     ret = ff_request_frame(link->src->inputs[0]);

     if (ret == AVERROR_EOF && idet->cur && !idet->analyze_interlaced_flag_done) {
         AVFrame *next = av_frame_clone(idet->next);

         if (!next)
             return AVERROR(ENOMEM);

         ret = filter_frame(link->src->inputs[0], next);
         idet->eof = 1;
     }

     return ret;

 }
 

 static av_cold void uninit(AVFilterContext *ctx)
 {
     IDETContext *idet = ctx->priv;

     int level = strncmp(ctx->name, "auto-inserted", 13) ? AV_LOG_INFO : AV_LOG_DEBUG;

     av_log(ctx, level, "Repeated Fields: Neither:%6"PRId64" Top:%6"PRId64" Bottom:%6"PRId64"\n",

            idet->total_repeats[REPEAT_NONE],
            idet->total_repeats[REPEAT_TOP],
            idet->total_repeats[REPEAT_BOTTOM]
         );

     av_log(ctx, level, "Single frame detection: TFF:%6"PRId64" BFF:%6"PRId64" Progressive:%6"PRId64" Undetermined:%6"PRId64"\n",

            idet->total_prestat[TFF],
            idet->total_prestat[BFF],
            idet->total_prestat[PROGRESSIVE],
            idet->total_prestat[UNDETERMINED]
         );

     av_log(ctx, level, "Multi frame detection: TFF:%6"PRId64" BFF:%6"PRId64" Progressive:%6"PRId64" Undetermined:%6"PRId64"\n",

            idet->total_poststat[TFF],
            idet->total_poststat[BFF],
            idet->total_poststat[PROGRESSIVE],
            idet->total_poststat[UNDETERMINED]
         );

     av_frame_free(&idet->prev);
     av_frame_free(&idet->cur );
     av_frame_free(&idet->next);

 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_YUV420P,
         AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV444P,
         AV_PIX_FMT_YUV410P,
         AV_PIX_FMT_YUV411P,
         AV_PIX_FMT_GRAY8,
         AV_PIX_FMT_YUVJ420P,
         AV_PIX_FMT_YUVJ422P,
         AV_PIX_FMT_YUVJ444P,

         AV_PIX_FMT_GRAY16,

         AV_PIX_FMT_YUV440P,
         AV_PIX_FMT_YUVJ440P,

         AV_PIX_FMT_YUV420P9,
         AV_PIX_FMT_YUV422P9,
         AV_PIX_FMT_YUV444P9,

         AV_PIX_FMT_YUV420P10,
         AV_PIX_FMT_YUV422P10,
         AV_PIX_FMT_YUV444P10,

         AV_PIX_FMT_YUV420P12,
         AV_PIX_FMT_YUV422P12,
         AV_PIX_FMT_YUV444P12,
         AV_PIX_FMT_YUV420P14,
         AV_PIX_FMT_YUV422P14,
         AV_PIX_FMT_YUV444P14,

         AV_PIX_FMT_YUV420P16,
         AV_PIX_FMT_YUV422P16,
         AV_PIX_FMT_YUV444P16,

         AV_PIX_FMT_YUVA420P,
         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 av_cold int init(AVFilterContext *ctx)

 {
     IDETContext *idet = ctx->priv;
 

     idet->eof = 0;

     idet->last_type = UNDETERMINED;

     memset(idet->history, UNDETERMINED, HIST_SIZE);

     if( idet->half_life > 0 )

         idet->decay_coefficient = lrint( PRECISION * exp2(-1.0 / idet->half_life) );

     else
         idet->decay_coefficient = PRECISION;
 

     idet->filter_line = ff_idet_filter_line_c;
 
     if (ARCH_X86)

         ff_idet_init_x86(idet, 0);

 
     return 0;
 }
 

 static const AVFilterPad idet_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,

         .filter_frame = filter_frame,

     },
     { NULL }
 };
 
 static const AVFilterPad idet_outputs[] = {
     {

         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,

         .request_frame = request_frame

     },
     { NULL }
 };
 

 AVFilter ff_vf_idet = {

     .name          = "idet",
     .description   = NULL_IF_CONFIG_SMALL("Interlace detect Filter."),
     .priv_size     = sizeof(IDETContext),
     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,

     .inputs        = idet_inputs,
     .outputs       = idet_outputs,

     .priv_class    = &idet_class,

 };