/*
  * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
  * Copyright (c) 2012 Jeremy Tran
  *
  * 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.
  */
 
 /**
  * @file
  * Apply a smartblur filter to the input video
  * Ported from MPlayer libmpcodecs/vf_smartblur.c by Michael Niedermayer.
  */
 

 #include "libavutil/opt.h"

 #include "libavutil/pixdesc.h"
 #include "libswscale/swscale.h"
 
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 
 #define RADIUS_MIN 0.1
 #define RADIUS_MAX 5.0
 
 #define STRENGTH_MIN -1.0
 #define STRENGTH_MAX 1.0
 
 #define THRESHOLD_MIN -30
 #define THRESHOLD_MAX 30
 
 typedef struct {
     float              radius;
     float              strength;
     int                threshold;
     float              quality;
     struct SwsContext *filter_context;
 } FilterParam;
 
 typedef struct {

     const AVClass *class;

     FilterParam  luma;
     FilterParam  chroma;
     int          hsub;
     int          vsub;
     unsigned int sws_flags;
 } SmartblurContext;
 

 #define OFFSET(x) offsetof(SmartblurContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
 static const AVOption smartblur_options[] = {
     { "luma_radius",    "set luma radius",    OFFSET(luma.radius),    AV_OPT_TYPE_FLOAT, {.dbl=1.0}, RADIUS_MIN, RADIUS_MAX, .flags=FLAGS },
     { "lr"         ,    "set luma radius",    OFFSET(luma.radius),    AV_OPT_TYPE_FLOAT, {.dbl=1.0}, RADIUS_MIN, RADIUS_MAX, .flags=FLAGS },
     { "luma_strength",  "set luma strength",  OFFSET(luma.strength),  AV_OPT_TYPE_FLOAT, {.dbl=1.0}, STRENGTH_MIN, STRENGTH_MAX, .flags=FLAGS },
     { "ls",             "set luma strength",  OFFSET(luma.strength),  AV_OPT_TYPE_FLOAT, {.dbl=1.0}, STRENGTH_MIN, STRENGTH_MAX, .flags=FLAGS },
     { "luma_threshold", "set luma threshold", OFFSET(luma.threshold), AV_OPT_TYPE_INT,   {.i64=0}, THRESHOLD_MIN, THRESHOLD_MAX, .flags=FLAGS },
     { "lt",             "set luma threshold", OFFSET(luma.threshold), AV_OPT_TYPE_INT,   {.i64=0}, THRESHOLD_MIN, THRESHOLD_MAX, .flags=FLAGS },
 
     { "chroma_radius",    "set chroma radius",    OFFSET(chroma.radius),    AV_OPT_TYPE_FLOAT, {.dbl=RADIUS_MIN-1},   RADIUS_MIN-1, RADIUS_MAX, .flags=FLAGS },
     { "cr",               "set chroma radius",    OFFSET(chroma.radius),    AV_OPT_TYPE_FLOAT, {.dbl=RADIUS_MIN-1},   RADIUS_MIN-1, RADIUS_MAX, .flags=FLAGS },
     { "chroma_strength",  "set chroma strength",  OFFSET(chroma.strength),  AV_OPT_TYPE_FLOAT, {.dbl=STRENGTH_MIN-1}, STRENGTH_MIN-1, STRENGTH_MAX, .flags=FLAGS },
     { "cs",               "set chroma strength",  OFFSET(chroma.strength),  AV_OPT_TYPE_FLOAT, {.dbl=STRENGTH_MIN-1}, STRENGTH_MIN-1, STRENGTH_MAX, .flags=FLAGS },
     { "chroma_threshold", "set chroma threshold", OFFSET(chroma.threshold), AV_OPT_TYPE_INT,   {.i64=THRESHOLD_MIN-1}, THRESHOLD_MIN-1, THRESHOLD_MAX, .flags=FLAGS },
     { "ct",               "set chroma threshold", OFFSET(chroma.threshold), AV_OPT_TYPE_INT,   {.i64=THRESHOLD_MIN-1}, THRESHOLD_MIN-1, THRESHOLD_MAX, .flags=FLAGS },
 
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(smartblur);

 static av_cold int init(AVFilterContext *ctx)

 {

     SmartblurContext *s = ctx->priv;

 
     /* make chroma default to luma values, if not explicitly set */

     if (s->chroma.radius < RADIUS_MIN)
         s->chroma.radius = s->luma.radius;
     if (s->chroma.strength < STRENGTH_MIN)
         s->chroma.strength  = s->luma.strength;
     if (s->chroma.threshold < THRESHOLD_MIN)
         s->chroma.threshold = s->luma.threshold;

     s->luma.quality = s->chroma.quality = 3.0;
     s->sws_flags = SWS_BICUBIC;

     av_log(ctx, AV_LOG_VERBOSE,
            "luma_radius:%f luma_strength:%f luma_threshold:%d "

            "chroma_radius:%f chroma_strength:%f chroma_threshold:%d\n",

            s->luma.radius, s->luma.strength, s->luma.threshold,
            s->chroma.radius, s->chroma.strength, s->chroma.threshold);

     return 0;

 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {

     SmartblurContext *s = ctx->priv;

     sws_freeContext(s->luma.filter_context);
     sws_freeContext(s->chroma.filter_context);

 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_YUV444P,      AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV420P,      AV_PIX_FMT_YUV411P,
         AV_PIX_FMT_YUV410P,      AV_PIX_FMT_YUV440P,
         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 alloc_sws_context(FilterParam *f, int width, int height, unsigned int flags)
 {
     SwsVector *vec;
     SwsFilter sws_filter;
 
     vec = sws_getGaussianVec(f->radius, f->quality);
 
     if (!vec)
         return AVERROR(EINVAL);
 
     sws_scaleVec(vec, f->strength);
     vec->coeff[vec->length / 2] += 1.0 - f->strength;
     sws_filter.lumH = sws_filter.lumV = vec;
     sws_filter.chrH = sws_filter.chrV = NULL;
     f->filter_context = sws_getCachedContext(NULL,

                                              width, height, AV_PIX_FMT_GRAY8,
                                              width, height, AV_PIX_FMT_GRAY8,

                                              flags, &sws_filter, NULL, NULL);
 
     sws_freeVec(vec);
 
     if (!f->filter_context)
         return AVERROR(EINVAL);
 
     return 0;
 }
 
 static int config_props(AVFilterLink *inlink)
 {

     SmartblurContext *s = inlink->dst->priv;

     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);

     s->hsub = desc->log2_chroma_w;
     s->vsub = desc->log2_chroma_h;

     alloc_sws_context(&s->luma, inlink->w, inlink->h, s->sws_flags);
     alloc_sws_context(&s->chroma,

                       AV_CEIL_RSHIFT(inlink->w, s->hsub),
                       AV_CEIL_RSHIFT(inlink->h, s->vsub),

                       s->sws_flags);

 
     return 0;
 }
 
 static void blur(uint8_t       *dst, const int dst_linesize,
                  const uint8_t *src, const int src_linesize,
                  const int w, const int h, const int threshold,
                  struct SwsContext *filter_context)
 {
     int x, y;
     int orig, filtered;
     int diff;
     /* Declare arrays of 4 to get aligned data */
     const uint8_t* const src_array[4] = {src};
     uint8_t *dst_array[4]             = {dst};
     int src_linesize_array[4] = {src_linesize};
     int dst_linesize_array[4] = {dst_linesize};
 
     sws_scale(filter_context, src_array, src_linesize_array,
               0, h, dst_array, dst_linesize_array);
 
     if (threshold > 0) {
         for (y = 0; y < h; ++y) {
             for (x = 0; x < w; ++x) {
                 orig     = src[x + y * src_linesize];
                 filtered = dst[x + y * dst_linesize];
                 diff     = orig - filtered;
 
                 if (diff > 0) {
                     if (diff > 2 * threshold)
                         dst[x + y * dst_linesize] = orig;
                     else if (diff > threshold)

                         /* add 'diff' and subtract 'threshold' from 'filtered' */

                         dst[x + y * dst_linesize] = orig - threshold;
                 } else {
                     if (-diff > 2 * threshold)
                         dst[x + y * dst_linesize] = orig;
                     else if (-diff > threshold)
                         /* add 'diff' and 'threshold' to 'filtered' */
                         dst[x + y * dst_linesize] = orig + threshold;
                 }
             }
         }
     } else if (threshold < 0) {
         for (y = 0; y < h; ++y) {
             for (x = 0; x < w; ++x) {
                 orig     = src[x + y * src_linesize];
                 filtered = dst[x + y * dst_linesize];
                 diff     = orig - filtered;
 
                 if (diff > 0) {
                     if (diff <= -threshold)
                         dst[x + y * dst_linesize] = orig;
                     else if (diff <= -2 * threshold)

                         /* subtract 'diff' and 'threshold' from 'orig' */

                         dst[x + y * dst_linesize] = filtered - threshold;
                 } else {
                     if (diff >= threshold)
                         dst[x + y * dst_linesize] = orig;
                     else if (diff >= 2 * threshold)

                         /* add 'threshold' and subtract 'diff' from 'orig' */

                         dst[x + y * dst_linesize] = filtered + threshold;
                 }
             }
         }
     }
 }
 

 static int filter_frame(AVFilterLink *inlink, AVFrame *inpic)

 {

     SmartblurContext  *s  = inlink->dst->priv;

     AVFilterLink *outlink     = inlink->dst->outputs[0];

     AVFrame *outpic;

     int cw = AV_CEIL_RSHIFT(inlink->w, s->hsub);
     int ch = AV_CEIL_RSHIFT(inlink->h, s->vsub);

     outpic = ff_get_video_buffer(outlink, outlink->w, outlink->h);

     if (!outpic) {

         av_frame_free(&inpic);

         return AVERROR(ENOMEM);
     }

     av_frame_copy_props(outpic, inpic);

     blur(outpic->data[0], outpic->linesize[0],
          inpic->data[0],  inpic->linesize[0],

          inlink->w, inlink->h, s->luma.threshold,
          s->luma.filter_context);

 
     if (inpic->data[2]) {
         blur(outpic->data[1], outpic->linesize[1],
              inpic->data[1],  inpic->linesize[1],

              cw, ch, s->chroma.threshold,
              s->chroma.filter_context);

         blur(outpic->data[2], outpic->linesize[2],
              inpic->data[2],  inpic->linesize[2],

              cw, ch, s->chroma.threshold,
              s->chroma.filter_context);

     }
 

     av_frame_free(&inpic);

     return ff_filter_frame(outlink, outpic);

 }
 

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

         .filter_frame = filter_frame,

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

 AVFilter ff_vf_smartblur = {

     .name          = "smartblur",
     .description   = NULL_IF_CONFIG_SMALL("Blur the input video without impacting the outlines."),
     .priv_size     = sizeof(SmartblurContext),

     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,

     .inputs        = smartblur_inputs,
     .outputs       = smartblur_outputs,

     .priv_class    = &smartblur_class,

     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,

 };