/*
  * Original MPlayer filters by Richard Felker, Hampa Hug, Daniel Moreno,
  * and Michael Niedermeyer.
  *
  * Copyright (c) 2014 James Darnley <james.darnley@gmail.com>
  * Copyright (c) 2015 Arwa Arif <arwaarif1994@gmail.com>
  *
  * 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
  * very simple video equalizer
  */
 
 #include "libavfilter/internal.h"
 #include "libavutil/common.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "vf_eq.h"
 
 static void create_lut(EQParameters *param)
 {
     int i;
     double   g  = 1.0 / param->gamma;
     double   lw = 1.0 - param->gamma_weight;
 
     for (i = 0; i < 256; i++) {
         double v = i / 255.0;
         v = param->contrast * (v - 0.5) + 0.5 + param->brightness;
 
         if (v <= 0.0) {
             param->lut[i] = 0;
         } else {
             v = v * lw + pow(v, g) * param->gamma_weight;
 
             if (v >= 1.0)
                 param->lut[i] = 255;
             else
                 param->lut[i] = 256.0 * v;
         }
     }
 
     param->lut_clean = 1;
 }
 
 static void apply_lut(EQParameters *param, uint8_t *dst, int dst_stride,

                       const uint8_t *src, int src_stride, int w, int h)

 {
     int x, y;
 
     if (!param->lut_clean)
         create_lut(param);
 
     for (y = 0; y < h; y++) {
         for (x = 0; x < w; x++) {
             dst[y * dst_stride + x] = param->lut[src[y * src_stride + x]];
         }
     }
 }
 
 static void process_c(EQParameters *param, uint8_t *dst, int dst_stride,

                       const uint8_t *src, int src_stride, int w, int h)

 {
     int x, y, pel;
 
     int contrast = (int) (param->contrast * 256 * 16);
     int brightness = ((int) (100.0 * param->brightness + 100.0) * 511) / 200 - 128 - contrast / 32;
 
     for (y = 0; y < h; y++) {
         for (x = 0; x < w; x++) {
             pel = ((src[y * src_stride + x] * contrast) >> 12) + brightness;
 

             if (pel & ~255)

                 pel = (-pel) >> 31;
 
             dst[y * dst_stride + x] = pel;
         }
     }
 }
 
 static void check_values(EQParameters *param, EQContext *eq)
 {
     if (param->contrast == 1.0 && param->brightness == 0.0 && param->gamma == 1.0)
         param->adjust = NULL;

     else if (param->gamma == 1.0 && fabs(param->contrast) < 7.9)

         param->adjust = eq->process;
     else
         param->adjust = apply_lut;
 }
 
 static void set_contrast(EQContext *eq)
 {

     eq->contrast = av_clipf(av_expr_eval(eq->contrast_pexpr, eq->var_values, eq), -1000.0, 1000.0);

     eq->param[0].contrast = eq->contrast;

     eq->param[0].lut_clean = 0;
     check_values(&eq->param[0], eq);
 }
 
 static void set_brightness(EQContext *eq)
 {

     eq->brightness = av_clipf(av_expr_eval(eq->brightness_pexpr, eq->var_values, eq), -1.0, 1.0);
     eq->param[0].brightness = eq->brightness;

     eq->param[0].lut_clean = 0;
     check_values(&eq->param[0], eq);
 }
 
 static void set_gamma(EQContext *eq)
 {
     int i;

     eq->gamma        = av_clipf(av_expr_eval(eq->gamma_pexpr,        eq->var_values, eq), 0.1, 10.0);
     eq->gamma_r      = av_clipf(av_expr_eval(eq->gamma_r_pexpr,      eq->var_values, eq), 0.1, 10.0);
     eq->gamma_g      = av_clipf(av_expr_eval(eq->gamma_g_pexpr,      eq->var_values, eq), 0.1, 10.0);
     eq->gamma_b      = av_clipf(av_expr_eval(eq->gamma_b_pexpr,      eq->var_values, eq), 0.1, 10.0);
     eq->gamma_weight = av_clipf(av_expr_eval(eq->gamma_weight_pexpr, eq->var_values, eq), 0.0,  1.0);

     eq->param[0].gamma = eq->gamma * eq->gamma_g;
     eq->param[1].gamma = sqrt(eq->gamma_b / eq->gamma_g);
     eq->param[2].gamma = sqrt(eq->gamma_r / eq->gamma_g);

 
     for (i = 0; i < 3; i++) {

         eq->param[i].gamma_weight = eq->gamma_weight;

         eq->param[i].lut_clean = 0;
         check_values(&eq->param[i], eq);
     }
 }
 
 static void set_saturation(EQContext *eq)
 {
     int i;

     eq->saturation = av_clipf(av_expr_eval(eq->saturation_pexpr, eq->var_values, eq), 0.0, 3.0);

     for (i = 1; i < 3; i++) {

         eq->param[i].contrast = eq->saturation;

         eq->param[i].lut_clean = 0;
         check_values(&eq->param[i], eq);
     }
 }
 

 static int set_expr(AVExpr **pexpr, const char *expr, const char *option, void *log_ctx)
 {
     int ret;
     AVExpr *old = NULL;
 
     if (*pexpr)
         old = *pexpr;

     ret = av_expr_parse(pexpr, expr, var_names, NULL, NULL, NULL, NULL, 0, log_ctx);

     if (ret < 0) {
         av_log(log_ctx, AV_LOG_ERROR,

                "Error when parsing the expression '%s' for %s\n",

                expr, option);
         *pexpr = old;
         return ret;
     }
 
     av_expr_free(old);
     return 0;
 }
 

 static int initialize(AVFilterContext *ctx)
 {
     EQContext *eq = ctx->priv;

     int ret;

 
     eq->process = process_c;
 

     if ((ret = set_expr(&eq->contrast_pexpr,     eq->contrast_expr,     "contrast",     ctx)) < 0 ||
         (ret = set_expr(&eq->brightness_pexpr,   eq->brightness_expr,   "brightness",   ctx)) < 0 ||
         (ret = set_expr(&eq->saturation_pexpr,   eq->saturation_expr,   "saturation",   ctx)) < 0 ||
         (ret = set_expr(&eq->gamma_pexpr,        eq->gamma_expr,        "gamma",        ctx)) < 0 ||
         (ret = set_expr(&eq->gamma_r_pexpr,      eq->gamma_r_expr,      "gamma_r",      ctx)) < 0 ||
         (ret = set_expr(&eq->gamma_g_pexpr,      eq->gamma_g_expr,      "gamma_g",      ctx)) < 0 ||
         (ret = set_expr(&eq->gamma_b_pexpr,      eq->gamma_b_expr,      "gamma_b",      ctx)) < 0 ||
         (ret = set_expr(&eq->gamma_weight_pexpr, eq->gamma_weight_expr, "gamma_weight", ctx)) < 0 )
         return ret;
 

     if (ARCH_X86)
         ff_eq_init_x86(eq);
 

     if (eq->eval_mode == EVAL_MODE_INIT) {
         set_gamma(eq);
         set_contrast(eq);
         set_brightness(eq);
         set_saturation(eq);
     }

 
     return 0;
 }
 

 static void uninit(AVFilterContext *ctx)
 {
     EQContext *eq = ctx->priv;
 
     av_expr_free(eq->contrast_pexpr);     eq->contrast_pexpr     = NULL;
     av_expr_free(eq->brightness_pexpr);   eq->brightness_pexpr   = NULL;
     av_expr_free(eq->saturation_pexpr);   eq->saturation_pexpr   = NULL;
     av_expr_free(eq->gamma_pexpr);        eq->gamma_pexpr        = NULL;
     av_expr_free(eq->gamma_weight_pexpr); eq->gamma_weight_pexpr = NULL;
     av_expr_free(eq->gamma_r_pexpr);      eq->gamma_r_pexpr      = NULL;
     av_expr_free(eq->gamma_g_pexpr);      eq->gamma_g_pexpr      = NULL;
     av_expr_free(eq->gamma_b_pexpr);      eq->gamma_b_pexpr      = NULL;
 }
 

 static int config_props(AVFilterLink *inlink)
 {
     EQContext *eq = inlink->dst->priv;
 
     eq->var_values[VAR_N] = 0;
     eq->var_values[VAR_R] = inlink->frame_rate.num == 0 || inlink->frame_rate.den == 0 ?
         NAN : av_q2d(inlink->frame_rate);
 
     return 0;
 }
 

 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pixel_fmts_eq[] = {
         AV_PIX_FMT_GRAY8,
         AV_PIX_FMT_YUV410P,
         AV_PIX_FMT_YUV411P,
         AV_PIX_FMT_YUV420P,
         AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV444P,
         AV_PIX_FMT_NONE
     };

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

 }
 

 #define TS2T(ts, tb) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts) * av_q2d(tb))
 

 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = inlink->dst->outputs[0];
     EQContext *eq = ctx->priv;
     AVFrame *out;

     int64_t pos = av_frame_get_pkt_pos(in);

     const AVPixFmtDescriptor *desc;
     int i;
 
     out = ff_get_video_buffer(outlink, inlink->w, inlink->h);
     if (!out)
         return AVERROR(ENOMEM);
 
     av_frame_copy_props(out, in);
     desc = av_pix_fmt_desc_get(inlink->format);
 

     eq->var_values[VAR_N]   = inlink->frame_count;
     eq->var_values[VAR_POS] = pos == -1 ? NAN : pos;
     eq->var_values[VAR_T]   = TS2T(in->pts, inlink->time_base);
 
     if (eq->eval_mode == EVAL_MODE_FRAME) {
         set_gamma(eq);
         set_contrast(eq);
         set_brightness(eq);
         set_saturation(eq);
     }
 

     for (i = 0; i < desc->nb_components; i++) {
         int w = inlink->w;
         int h = inlink->h;
 
         if (i == 1 || i == 2) {

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

         }
 
         if (eq->param[i].adjust)
             eq->param[i].adjust(&eq->param[i], out->data[i], out->linesize[i],
                                  in->data[i], in->linesize[i], w, h);
         else
             av_image_copy_plane(out->data[i], out->linesize[i],
                                 in->data[i], in->linesize[i], w, h);
     }
 

     av_frame_free(&in);

     return ff_filter_frame(outlink, out);
 }

 static inline int set_param(AVExpr **pexpr, const char *args, const char *cmd,
                             void (*set_fn)(EQContext *eq), AVFilterContext *ctx)
 {
     EQContext *eq = ctx->priv;
     int ret;
     if ((ret = set_expr(pexpr, args, cmd, ctx)) < 0)
         return ret;

     if (eq->eval_mode == EVAL_MODE_INIT)
         set_fn(eq);

     return 0;
 }
 

 static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
                            char *res, int res_len, int flags)
 {
     EQContext *eq = ctx->priv;
 

 #define SET_PARAM(param_name, set_fn_name)                              \
     if (!strcmp(cmd, #param_name)) return set_param(&eq->param_name##_pexpr, args, cmd, set_##set_fn_name, ctx);
 
          SET_PARAM(contrast, contrast)
     else SET_PARAM(brightness, brightness)
     else SET_PARAM(saturation, saturation)
     else SET_PARAM(gamma, gamma)
     else SET_PARAM(gamma_r, gamma)
     else SET_PARAM(gamma_g, gamma)
     else SET_PARAM(gamma_b, gamma)
     else SET_PARAM(gamma_weight, gamma)
     else return AVERROR(ENOSYS);

 }
 

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

         .config_props = config_props,

     },
     { NULL }
 };
 
 static const AVFilterPad eq_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
 #define OFFSET(x) offsetof(EQContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
 static const AVOption eq_options[] = {
     { "contrast",     "set the contrast adjustment, negative values give a negative image",

         OFFSET(contrast_expr),     AV_OPT_TYPE_STRING, {.str = "1.0"}, CHAR_MIN, CHAR_MAX, FLAGS },

     { "brightness",   "set the brightness adjustment",

         OFFSET(brightness_expr),   AV_OPT_TYPE_STRING, {.str = "0.0"}, CHAR_MIN, CHAR_MAX, FLAGS },

     { "saturation",   "set the saturation adjustment",

         OFFSET(saturation_expr),   AV_OPT_TYPE_STRING, {.str = "1.0"}, CHAR_MIN, CHAR_MAX, FLAGS },

     { "gamma",        "set the initial gamma value",

         OFFSET(gamma_expr),        AV_OPT_TYPE_STRING, {.str = "1.0"}, CHAR_MIN, CHAR_MAX, FLAGS },

     { "gamma_r",      "gamma value for red",

         OFFSET(gamma_r_expr),      AV_OPT_TYPE_STRING, {.str = "1.0"}, CHAR_MIN, CHAR_MAX, FLAGS },

     { "gamma_g",      "gamma value for green",

         OFFSET(gamma_g_expr),      AV_OPT_TYPE_STRING, {.str = "1.0"}, CHAR_MIN, CHAR_MAX, FLAGS },

     { "gamma_b",      "gamma value for blue",

         OFFSET(gamma_b_expr),      AV_OPT_TYPE_STRING, {.str = "1.0"}, CHAR_MIN, CHAR_MAX, FLAGS },

     { "gamma_weight", "set the gamma weight which reduces the effect of gamma on bright areas",

         OFFSET(gamma_weight_expr), AV_OPT_TYPE_STRING, {.str = "1.0"}, CHAR_MIN, CHAR_MAX, FLAGS },

     { "eval", "specify when to evaluate expressions", OFFSET(eval_mode), AV_OPT_TYPE_INT, {.i64 = EVAL_MODE_INIT}, 0, EVAL_MODE_NB-1, FLAGS, "eval" },
          { "init",  "eval expressions once during initialization", 0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_INIT},  .flags = FLAGS, .unit = "eval" },
          { "frame", "eval expressions per-frame",                  0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_FRAME}, .flags = FLAGS, .unit = "eval" },

     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(eq);
 
 AVFilter ff_vf_eq = {

     .name            = "eq",
     .description     = NULL_IF_CONFIG_SMALL("Adjust brightness, contrast, gamma, and saturation."),
     .priv_size       = sizeof(EQContext),
     .priv_class      = &eq_class,
     .inputs          = eq_inputs,
     .outputs         = eq_outputs,
     .process_command = process_command,
     .query_formats   = query_formats,
     .init            = initialize,
     .uninit          = uninit,

 };