/*
  * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
  * Copyright (c) 2011 Stefano Sabatini
  *
  * 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 boxblur filter to the input video.
  * Ported from MPlayer libmpcodecs/vf_boxblur.c.
  */
 
 #include "libavutil/avstring.h"

 #include "libavutil/common.h"

 #include "libavutil/eval.h"

 #include "libavutil/opt.h"

 #include "libavutil/pixdesc.h"
 #include "avfilter.h"

 #include "formats.h"

 #include "internal.h"

 #include "video.h"

 static const char *const var_names[] = {

     "w",
     "h",
     "cw",
     "ch",
     "hsub",
     "vsub",
     NULL
 };
 
 enum var_name {
     VAR_W,
     VAR_H,
     VAR_CW,
     VAR_CH,
     VAR_HSUB,
     VAR_VSUB,
     VARS_NB
 };
 

 typedef struct FilterParam {

     int radius;
     int power;

     char *radius_expr;

 } FilterParam;
 

 typedef struct BoxBlurContext {

     const AVClass *class;

     FilterParam luma_param;
     FilterParam chroma_param;
     FilterParam alpha_param;
 
     int hsub, vsub;
     int radius[4];
     int power[4];
     uint8_t *temp[2]; ///< temporary buffer used in blur_power()
 } BoxBlurContext;
 
 #define Y 0
 #define U 1
 #define V 2
 #define A 3
 

 static av_cold int init(AVFilterContext *ctx)

 {

     BoxBlurContext *s = ctx->priv;

     if (!s->luma_param.radius_expr) {

         av_log(ctx, AV_LOG_ERROR, "Luma radius expression is not set.\n");

         return AVERROR(EINVAL);
     }
 

     /* fill missing params */

     if (!s->chroma_param.radius_expr) {
         s->chroma_param.radius_expr = av_strdup(s->luma_param.radius_expr);
         if (!s->chroma_param.radius_expr)

             return AVERROR(ENOMEM);

     }

     if (s->chroma_param.power < 0)
         s->chroma_param.power = s->luma_param.power;

     if (!s->alpha_param.radius_expr) {
         s->alpha_param.radius_expr = av_strdup(s->luma_param.radius_expr);
         if (!s->alpha_param.radius_expr)

             return AVERROR(ENOMEM);

     }

     if (s->alpha_param.power < 0)
         s->alpha_param.power = s->luma_param.power;

 
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {

     BoxBlurContext *s = ctx->priv;

     av_freep(&s->temp[0]);
     av_freep(&s->temp[1]);

 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     AVFilterFormats *formats = NULL;

     int fmt, ret;

 
     for (fmt = 0; av_pix_fmt_desc_get(fmt); fmt++) {
         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
         if (!(desc->flags & (AV_PIX_FMT_FLAG_HWACCEL | AV_PIX_FMT_FLAG_BITSTREAM | AV_PIX_FMT_FLAG_PAL)) &&
             (desc->flags & AV_PIX_FMT_FLAG_PLANAR || desc->nb_components == 1) &&

             (!(desc->flags & AV_PIX_FMT_FLAG_BE) == !HAVE_BIGENDIAN || desc->comp[0].depth == 8) &&
             (ret = ff_add_format(&formats, fmt)) < 0)
             return ret;

     }
 

     return ff_set_common_formats(ctx, formats);

 }
 
 static int config_input(AVFilterLink *inlink)
 {

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

     AVFilterContext    *ctx = inlink->dst;

     BoxBlurContext *s = ctx->priv;

     int w = inlink->w, h = inlink->h;
     int cw, ch;
     double var_values[VARS_NB], res;
     char *expr;
     int ret;
 

     if (!(s->temp[0] = av_malloc(2*FFMAX(w, h))) ||
         !(s->temp[1] = av_malloc(2*FFMAX(w, h))))

         return AVERROR(ENOMEM);
 

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

     var_values[VAR_W]       = inlink->w;
     var_values[VAR_H]       = inlink->h;

     var_values[VAR_CW] = cw = w>>s->hsub;
     var_values[VAR_CH] = ch = h>>s->vsub;
     var_values[VAR_HSUB]    = 1<<s->hsub;
     var_values[VAR_VSUB]    = 1<<s->vsub;

 
 #define EVAL_RADIUS_EXPR(comp)                                          \

     expr = s->comp##_param.radius_expr;                                 \

     ret = av_expr_parse_and_eval(&res, expr, var_names, var_values,     \
                                  NULL, NULL, NULL, NULL, NULL, 0, ctx); \

     s->comp##_param.radius = res;                                       \

     if (ret < 0) {                                                      \
         av_log(NULL, AV_LOG_ERROR,                                      \
                "Error when evaluating " #comp " radius expression '%s'\n", expr); \
         return ret;                                                     \
     }
     EVAL_RADIUS_EXPR(luma);
     EVAL_RADIUS_EXPR(chroma);
     EVAL_RADIUS_EXPR(alpha);
 

     av_log(ctx, AV_LOG_VERBOSE,

            "luma_radius:%d luma_power:%d "
            "chroma_radius:%d chroma_power:%d "
            "alpha_radius:%d alpha_power:%d "
            "w:%d chroma_w:%d h:%d chroma_h:%d\n",

            s->luma_param  .radius, s->luma_param  .power,
            s->chroma_param.radius, s->chroma_param.power,
            s->alpha_param .radius, s->alpha_param .power,

            w, cw, h, ch);
 
 #define CHECK_RADIUS_VAL(w_, h_, comp)                                  \

     if (s->comp##_param.radius < 0 ||                                   \
         2*s->comp##_param.radius > FFMIN(w_, h_)) {                     \

         av_log(ctx, AV_LOG_ERROR,                                       \
                "Invalid " #comp " radius value %d, must be >= 0 and <= %d\n", \

                s->comp##_param.radius, FFMIN(w_, h_)/2);                \

         return AVERROR(EINVAL);                                         \
     }
     CHECK_RADIUS_VAL(w,  h,  luma);
     CHECK_RADIUS_VAL(cw, ch, chroma);
     CHECK_RADIUS_VAL(w,  h,  alpha);
 

     s->radius[Y] = s->luma_param.radius;
     s->radius[U] = s->radius[V] = s->chroma_param.radius;
     s->radius[A] = s->alpha_param.radius;

     s->power[Y] = s->luma_param.power;
     s->power[U] = s->power[V] = s->chroma_param.power;
     s->power[A] = s->alpha_param.power;

 
     return 0;
 }
 

 /* Naive boxblur would sum source pixels from x-radius .. x+radius
  * for destination pixel x. That would be O(radius*width).
  * If you now look at what source pixels represent 2 consecutive
  * output pixels, then you see they are almost identical and only
  * differ by 2 pixels, like:
  * src0       111111111
  * dst0           1
  * src1        111111111
  * dst1            1
  * src0-src1  1       -1
  * so when you know one output pixel you can find the next by just adding
  * and subtracting 1 input pixel.
  * The following code adopts this faster variant.
  */
 #define BLUR(type, depth)                                                   \
 static inline void blur ## depth(type *dst, int dst_step, const type *src,  \
                                  int src_step, int len, int radius)         \
 {                                                                           \
     const int length = radius*2 + 1;                                        \
     const int inv = ((1<<16) + length/2)/length;                            \
     int x, sum = src[radius*src_step];                                      \
                                                                             \
     for (x = 0; x < radius; x++)                                            \
         sum += src[x*src_step]<<1;                                          \
                                                                             \
     sum = sum*inv + (1<<15);                                                \
                                                                             \
     for (x = 0; x <= radius; x++) {                                         \
         sum += (src[(radius+x)*src_step] - src[(radius-x)*src_step])*inv;   \
         dst[x*dst_step] = sum>>16;                                          \
     }                                                                       \
                                                                             \
     for (; x < len-radius; x++) {                                           \
         sum += (src[(radius+x)*src_step] - src[(x-radius-1)*src_step])*inv; \
         dst[x*dst_step] = sum >>16;                                         \
     }                                                                       \
                                                                             \
     for (; x < len; x++) {                                                  \
         sum += (src[(2*len-radius-x-1)*src_step] - src[(x-radius-1)*src_step])*inv; \
         dst[x*dst_step] = sum>>16;                                          \
     }                                                                       \

 }
 

 BLUR(uint8_t,   8)
 BLUR(uint16_t, 16)

 #undef BLUR

 
 static inline void blur(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
                         int len, int radius, int pixsize)
 {
     if (pixsize == 1) blur8 (dst, dst_step   , src, src_step   , len, radius);
     else              blur16((uint16_t*)dst, dst_step>>1, (const uint16_t*)src, src_step>>1, len, radius);
 }
 

 static inline void blur_power(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,

                               int len, int radius, int power, uint8_t *temp[2], int pixsize)

 {
     uint8_t *a = temp[0], *b = temp[1];
 
     if (radius && power) {

         blur(a, pixsize, src, src_step, len, radius, pixsize);

         for (; power > 2; power--) {
             uint8_t *c;

             blur(b, pixsize, a, pixsize, len, radius, pixsize);

             c = a; a = b; b = c;
         }
         if (power > 1) {

             blur(dst, dst_step, a, pixsize, len, radius, pixsize);

         } else {
             int i;

             if (pixsize == 1) {
                 for (i = 0; i < len; i++)
                     dst[i*dst_step] = a[i];
             } else
                 for (i = 0; i < len; i++)
                     *(uint16_t*)(dst + i*dst_step) = ((uint16_t*)a)[i];

         }
     } else {
         int i;

         if (pixsize == 1) {
             for (i = 0; i < len; i++)
                 dst[i*dst_step] = src[i*src_step];
         } else
             for (i = 0; i < len; i++)
                 *(uint16_t*)(dst + i*dst_step) = *(uint16_t*)(src + i*src_step);

     }
 }
 
 static void hblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,

                   int w, int h, int radius, int power, uint8_t *temp[2], int pixsize)

 {
     int y;
 
     if (radius == 0 && dst == src)
         return;
 
     for (y = 0; y < h; y++)

         blur_power(dst + y*dst_linesize, pixsize, src + y*src_linesize, pixsize,
                    w, radius, power, temp, pixsize);

 }
 
 static void vblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,

                   int w, int h, int radius, int power, uint8_t *temp[2], int pixsize)

 {
     int x;
 
     if (radius == 0 && dst == src)
         return;
 
     for (x = 0; x < w; x++)

         blur_power(dst + x*pixsize, dst_linesize, src + x*pixsize, src_linesize,
                    h, radius, power, temp, pixsize);

 }
 

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

 {
     AVFilterContext *ctx = inlink->dst;

     BoxBlurContext *s = ctx->priv;

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

     AVFrame *out;

     int plane;

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

     int w[4] = { inlink->w, cw, cw, inlink->w };

     int h[4] = { in->height, ch, ch, in->height };

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

     const int depth = desc->comp[0].depth;

     const int pixsize = (depth+7)/8;

     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);

     for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)

         hblur(out->data[plane], out->linesize[plane],
               in ->data[plane], in ->linesize[plane],

               w[plane], h[plane], s->radius[plane], s->power[plane],

               s->temp, pixsize);

     for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)

         vblur(out->data[plane], out->linesize[plane],
               out->data[plane], out->linesize[plane],

               w[plane], h[plane], s->radius[plane], s->power[plane],

               s->temp, pixsize);

     av_frame_free(&in);

 
     return ff_filter_frame(outlink, out);

 }
 

 #define OFFSET(x) offsetof(BoxBlurContext, x)

 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 
 static const AVOption boxblur_options[] = {
     { "luma_radius", "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
     { "lr",          "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
     { "luma_power",  "How many times should the boxblur be applied to luma",  OFFSET(luma_param.power), AV_OPT_TYPE_INT, {.i64=2}, 0, INT_MAX, .flags = FLAGS },
     { "lp",          "How many times should the boxblur be applied to luma",  OFFSET(luma_param.power), AV_OPT_TYPE_INT, {.i64=2}, 0, INT_MAX, .flags = FLAGS },
 
     { "chroma_radius", "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
     { "cr",            "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
     { "chroma_power",  "How many times should the boxblur be applied to chroma",  OFFSET(chroma_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
     { "cp",            "How many times should the boxblur be applied to chroma",  OFFSET(chroma_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },

     { "alpha_radius", "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
     { "ar",           "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
     { "alpha_power",  "How many times should the boxblur be applied to alpha",  OFFSET(alpha_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
     { "ap",           "How many times should the boxblur be applied to alpha",  OFFSET(alpha_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
 
     { NULL }

 };
 

 AVFILTER_DEFINE_CLASS(boxblur);
 

 static const AVFilterPad avfilter_vf_boxblur_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = config_input,

         .filter_frame = filter_frame,

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

 AVFilter ff_vf_boxblur = {

     .name          = "boxblur",
     .description   = NULL_IF_CONFIG_SMALL("Blur the input."),
     .priv_size     = sizeof(BoxBlurContext),

     .priv_class    = &boxblur_class,

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

     .inputs        = avfilter_vf_boxblur_inputs,
     .outputs       = avfilter_vf_boxblur_outputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,

 };