/*
  * Copyright (c) 2003 Michael Niedermayer
  * 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 hue/saturation filter to the input video
  * Ported from MPlayer libmpcodecs/vf_hue.c.
  */
 

 #include <float.h>

 #include "libavutil/eval.h"

 #include "libavutil/imgutils.h"

 #include "libavutil/opt.h"

 #include "libavutil/pixdesc.h"
 
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 

 #define HUE_DEFAULT_VAL 0
 #define SAT_DEFAULT_VAL 1
 

 #define HUE_DEFAULT_VAL_STRING AV_STRINGIFY(HUE_DEFAULT_VAL)
 #define SAT_DEFAULT_VAL_STRING AV_STRINGIFY(SAT_DEFAULT_VAL)
 
 #define SAT_MIN_VAL -10
 #define SAT_MAX_VAL 10
 
 static const char *const var_names[] = {
     "n",   // frame count
     "pts", // presentation timestamp expressed in AV_TIME_BASE units
     "r",   // frame rate
     "t",   // timestamp expressed in seconds
     "tb",  // timebase
     NULL
 };
 
 enum var_name {
     VAR_N,
     VAR_PTS,
     VAR_R,
     VAR_T,
     VAR_TB,
     VAR_NB
 };
 

 typedef struct {

     const    AVClass *class;
     float    hue_deg; /* hue expressed in degrees */
     float    hue; /* hue expressed in radians */

     char     *hue_deg_expr;
     char     *hue_expr;
     AVExpr   *hue_deg_pexpr;
     AVExpr   *hue_pexpr;

     float    saturation;

     char     *saturation_expr;
     AVExpr   *saturation_pexpr;

     int      hsub;
     int      vsub;
     int32_t hue_sin;
     int32_t hue_cos;

     int      flat_syntax;
     double   var_values[VAR_NB];

 } HueContext;
 

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

 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

 static const AVOption hue_options[] = {

     { "h", "set the hue angle degrees expression", OFFSET(hue_deg_expr), AV_OPT_TYPE_STRING,
       { .str = NULL }, .flags = FLAGS },
     { "H", "set the hue angle radians expression", OFFSET(hue_expr), AV_OPT_TYPE_STRING,
       { .str = NULL }, .flags = FLAGS },
     { "s", "set the saturation expression", OFFSET(saturation_expr), AV_OPT_TYPE_STRING,
       { .str = NULL }, .flags = FLAGS },

     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(hue);
 

 static inline void compute_sin_and_cos(HueContext *hue)
 {
     /*
      * Scale the value to the norm of the resulting (U,V) vector, that is
      * the saturation.
      * This will be useful in the process_chrominance function.
      */
     hue->hue_sin = rint(sin(hue->hue) * (1 << 16) * hue->saturation);
     hue->hue_cos = rint(cos(hue->hue) * (1 << 16) * hue->saturation);
 }
 

 #define SET_EXPRESSION(attr, name) do {                                           \
     if (hue->attr##_expr) {                                                       \

         if ((ret = av_expr_parse(&hue->attr##_pexpr, hue->attr##_expr, var_names, \
                                  NULL, NULL, NULL, NULL, 0, ctx)) < 0) {          \
             av_log(ctx, AV_LOG_ERROR,                                             \
                    "Parsing failed for expression " #name "='%s'",                \
                    hue->attr##_expr);                                             \
             hue->attr##_expr  = old_##attr##_expr;                                \
             hue->attr##_pexpr = old_##attr##_pexpr;                               \
             return AVERROR(EINVAL);                                               \
         } else if (old_##attr##_pexpr) {                                          \

             av_freep(&old_##attr##_expr);                                         \

             av_expr_free(old_##attr##_pexpr);                                     \

             old_##attr##_pexpr = NULL;                                            \

         }                                                                         \

     } else {                                                                      \
         hue->attr##_expr = old_##attr##_expr;                                     \
     }                                                                             \
 } while (0)

 static inline int set_options(AVFilterContext *ctx, const char *args)

 {
     HueContext *hue = ctx->priv;

     int ret;

     char   *old_hue_expr,  *old_hue_deg_expr,  *old_saturation_expr;
     AVExpr *old_hue_pexpr, *old_hue_deg_pexpr, *old_saturation_pexpr;

     static const char *shorthand[] = { "h", "s", NULL };

     old_hue_expr        = hue->hue_expr;
     old_hue_deg_expr    = hue->hue_deg_expr;
     old_saturation_expr = hue->saturation_expr;
 
     old_hue_pexpr        = hue->hue_pexpr;
     old_hue_deg_pexpr    = hue->hue_deg_pexpr;
     old_saturation_pexpr = hue->saturation_pexpr;
 
     hue->hue_expr     = NULL;
     hue->hue_deg_expr = NULL;
     hue->saturation_expr = NULL;
 
     if ((ret = av_opt_set_from_string(hue, args, shorthand, "=", ":")) < 0)
         return ret;
     if (hue->hue_expr && hue->hue_deg_expr) {
         av_log(ctx, AV_LOG_ERROR,
                "H and h options are incompatible and cannot be specified "
                "at the same time\n");
         hue->hue_expr     = old_hue_expr;
         hue->hue_deg_expr = old_hue_deg_expr;
 
         return AVERROR(EINVAL);
     }
 
     SET_EXPRESSION(hue_deg, h);
     SET_EXPRESSION(hue, H);
     SET_EXPRESSION(saturation, s);
 
     hue->flat_syntax = 0;
 
     av_log(ctx, AV_LOG_VERBOSE,
            "H_expr:%s h_deg_expr:%s s_expr:%s\n",
            hue->hue_expr, hue->hue_deg_expr, hue->saturation_expr);

 
     compute_sin_and_cos(hue);
 

     return 0;
 }
 
 static av_cold int init(AVFilterContext *ctx, const char *args)
 {
     HueContext *hue = ctx->priv;
 
     hue->class = &hue_class;
     av_opt_set_defaults(hue);
 

     hue->saturation    = SAT_DEFAULT_VAL;
     hue->hue           = HUE_DEFAULT_VAL;
     hue->hue_deg_pexpr = NULL;
     hue->hue_pexpr     = NULL;
     hue->flat_syntax   = 1;

     return set_options(ctx, args);

 }
 

 static av_cold void uninit(AVFilterContext *ctx)
 {
     HueContext *hue = ctx->priv;
 
     av_opt_free(hue);

 
     av_free(hue->hue_deg_expr);
     av_expr_free(hue->hue_deg_pexpr);
     av_free(hue->hue_expr);
     av_expr_free(hue->hue_pexpr);
     av_free(hue->saturation_expr);
     av_expr_free(hue->saturation_pexpr);

 }
 

 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_YUVA420P,
         AV_PIX_FMT_NONE

     };
 
     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
 
     return 0;
 }
 
 static int config_props(AVFilterLink *inlink)
 {
     HueContext *hue = inlink->dst->priv;

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

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

 
     hue->var_values[VAR_N]  = 0;
     hue->var_values[VAR_TB] = av_q2d(inlink->time_base);
     hue->var_values[VAR_R]  = inlink->frame_rate.num == 0 || inlink->frame_rate.den == 0 ?
         NAN : av_q2d(inlink->frame_rate);

 
     return 0;
 }
 
 static void process_chrominance(uint8_t *udst, uint8_t *vdst, const int dst_linesize,
                                 uint8_t *usrc, uint8_t *vsrc, const int src_linesize,
                                 int w, int h,
                                 const int32_t c, const int32_t s)
 {
     int32_t u, v, new_u, new_v;
     int i;
 
     /*
      * If we consider U and V as the components of a 2D vector then its angle
      * is the hue and the norm is the saturation
      */
     while (h--) {
         for (i = 0; i < w; i++) {
             /* Normalize the components from range [16;140] to [-112;112] */
             u = usrc[i] - 128;
             v = vsrc[i] - 128;
             /*
              * Apply the rotation of the vector : (c * u) - (s * v)
              *                                    (s * u) + (c * v)
              * De-normalize the components (without forgetting to scale 128
              * by << 16)
              * Finally scale back the result by >> 16
              */
             new_u = ((c * u) - (s * v) + (1 << 15) + (128 << 16)) >> 16;
             new_v = ((s * u) + (c * v) + (1 << 15) + (128 << 16)) >> 16;
 
             /* Prevent a potential overflow */
             udst[i] = av_clip_uint8_c(new_u);
             vdst[i] = av_clip_uint8_c(new_v);
         }
 
         usrc += src_linesize;
         vsrc += src_linesize;
         udst += dst_linesize;
         vdst += dst_linesize;
     }
 }
 

 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
 #define TS2T(ts, tb) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts) * av_q2d(tb))
 

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

 {
     HueContext *hue = inlink->dst->priv;
     AVFilterLink *outlink = inlink->dst->outputs[0];

     AVFilterBufferRef *outpic;

     outpic = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
     if (!outpic) {
         avfilter_unref_bufferp(&inpic);

         return AVERROR(ENOMEM);

     }
     avfilter_copy_buffer_ref_props(outpic, inpic);

 
     if (!hue->flat_syntax) {
         hue->var_values[VAR_T]   = TS2T(inpic->pts, inlink->time_base);
         hue->var_values[VAR_PTS] = TS2D(inpic->pts);
 
         if (hue->saturation_expr) {
             hue->saturation = av_expr_eval(hue->saturation_pexpr, hue->var_values, NULL);
 
             if (hue->saturation < SAT_MIN_VAL || hue->saturation > SAT_MAX_VAL) {
                 hue->saturation = av_clip(hue->saturation, SAT_MIN_VAL, SAT_MAX_VAL);
                 av_log(inlink->dst, AV_LOG_WARNING,
                        "Saturation value not in range [%d,%d]: clipping value to %0.1f\n",
                        SAT_MIN_VAL, SAT_MAX_VAL, hue->saturation);
             }
         }
 
         if (hue->hue_deg_expr) {
             hue->hue_deg = av_expr_eval(hue->hue_deg_pexpr, hue->var_values, NULL);
             hue->hue = hue->hue_deg * M_PI / 180;
         } else if (hue->hue_expr) {
             hue->hue = av_expr_eval(hue->hue_pexpr, hue->var_values, NULL);
         }
 
         av_log(inlink->dst, AV_LOG_DEBUG,
                "H:%0.1f s:%0.f t:%0.1f n:%d\n",
                hue->hue, hue->saturation,
                hue->var_values[VAR_T], (int)hue->var_values[VAR_N]);
 
         compute_sin_and_cos(hue);
     }
 
     hue->var_values[VAR_N] += 1;
 

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

                         inlink->w, inlink->h);
 

     process_chrominance(outpic->data[1], outpic->data[2], outpic->linesize[1],
                         inpic->data[1],  inpic->data[2],  inpic->linesize[1],

                         inlink->w >> hue->hsub, inlink->h >> hue->vsub,
                         hue->hue_cos, hue->hue_sin);
 

     avfilter_unref_bufferp(&inpic);
     return ff_filter_frame(outlink, outpic);

 }
 

 static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
                            char *res, int res_len, int flags)
 {

     if (!strcmp(cmd, "reinit"))
         return set_options(ctx, args);
     else

         return AVERROR(ENOSYS);
 }
 

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

         .filter_frame = filter_frame,

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

 AVFilter avfilter_vf_hue = {
     .name        = "hue",
     .description = NULL_IF_CONFIG_SMALL("Adjust the hue and saturation of the input video."),
 
     .priv_size = sizeof(HueContext),
 
     .init          = init,

     .uninit        = uninit,

     .query_formats = query_formats,

     .process_command = process_command,

     .inputs          = hue_inputs,
     .outputs         = hue_outputs,
     .priv_class      = &hue_class,

 };