/*
  * Copyright (c) 2010 Bobby Bingham

  *

  * 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
  */
 
 /**

  * @file

  * aspect ratio modification video filters

  */
 

 #include <float.h>
 

 #include "libavutil/common.h"

 #include "libavutil/eval.h"

 #include "libavutil/mathematics.h"

 #include "libavutil/opt.h"

 #include "libavutil/parseutils.h"

 #include "libavutil/pixdesc.h"

 #include "avfilter.h"

 #include "internal.h"

 #include "video.h"

 static const char *const var_names[] = {
     "w",
     "h",
     "a", "dar",
     "sar",
     "hsub",
     "vsub",
     NULL
 };
 
 enum var_name {
     VAR_W,
     VAR_H,
     VAR_A, VAR_DAR,
     VAR_SAR,
     VAR_HSUB,
     VAR_VSUB,
     VARS_NB
 };
 

 typedef struct AspectContext {

     const AVClass *class;

     AVRational dar;
     AVRational sar;

     int max;

     char *ratio_expr;

 } AspectContext;
 

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

 {

     AspectContext *s = link->dst->priv;

     frame->sample_aspect_ratio = s->sar;

     return ff_filter_frame(link->dst->outputs[0], frame);

 }
 

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

 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

 static inline void compute_dar(AVRational *dar, AVRational sar, int w, int h)
 {
     if (sar.num && sar.den) {
         av_reduce(&dar->num, &dar->den, sar.num * w, sar.den * h, INT_MAX);
     } else {
         av_reduce(&dar->num, &dar->den, w, h, INT_MAX);
     }
 }
 

 static int get_aspect_ratio(AVFilterLink *inlink, AVRational *aspect_ratio)
 {
     AVFilterContext *ctx = inlink->dst;
     AspectContext *s = inlink->dst->priv;
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
     double var_values[VARS_NB], res;
     int ret;
 
     var_values[VAR_W]     = inlink->w;
     var_values[VAR_H]     = inlink->h;
     var_values[VAR_A]     = (double) inlink->w / inlink->h;
     var_values[VAR_SAR]   = inlink->sample_aspect_ratio.num ?
         (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
     var_values[VAR_DAR]   = var_values[VAR_A] * var_values[VAR_SAR];
     var_values[VAR_HSUB]  = 1 << desc->log2_chroma_w;
     var_values[VAR_VSUB]  = 1 << desc->log2_chroma_h;
 
     /* evaluate new aspect ratio*/

     ret = av_expr_parse_and_eval(&res, s->ratio_expr,

                                       var_names, var_values,

                                       NULL, NULL, NULL, NULL, NULL, 0, ctx);
     if (ret < 0) {
         ret = av_parse_ratio(aspect_ratio, s->ratio_expr, s->max, 0, ctx);
     } else
         *aspect_ratio = av_d2q(res, s->max);
 
     if (ret < 0) {
         av_log(ctx, AV_LOG_ERROR,

                "Error when evaluating the expression '%s'\n", s->ratio_expr);
         return ret;
     }

     if (aspect_ratio->num < 0 || aspect_ratio->den <= 0) {
         av_log(ctx, AV_LOG_ERROR,
                 "Invalid string '%s' for aspect ratio\n", s->ratio_expr);
         return AVERROR(EINVAL);
     }

     return 0;
 }
 

 #if CONFIG_SETDAR_FILTER

 static int setdar_config_props(AVFilterLink *inlink)

 {

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

     AVRational dar;

     AVRational old_dar;

     AVRational old_sar = inlink->sample_aspect_ratio;

     int ret;
 
     if ((ret = get_aspect_ratio(inlink, &s->dar)))
         return ret;

     if (s->dar.num && s->dar.den) {
         av_reduce(&s->sar.num, &s->sar.den,
                    s->dar.num * inlink->h,

                    s->dar.den * inlink->w, INT_MAX);

         inlink->sample_aspect_ratio = s->sar;
         dar = s->dar;

     } else {
         inlink->sample_aspect_ratio = (AVRational){ 1, 1 };
         dar = (AVRational){ inlink->w, inlink->h };
     }

     compute_dar(&old_dar, old_sar, inlink->w, inlink->h);
     av_log(inlink->dst, AV_LOG_VERBOSE, "w:%d h:%d dar:%d/%d sar:%d/%d -> dar:%d/%d sar:%d/%d\n",
            inlink->w, inlink->h, old_dar.num, old_dar.den, old_sar.num, old_sar.den,

            dar.num, dar.den, inlink->sample_aspect_ratio.num, inlink->sample_aspect_ratio.den);

     return 0;
 }
 

 static const AVOption setdar_options[] = {

     { "dar",   "set display aspect ratio", OFFSET(ratio_expr), AV_OPT_TYPE_STRING, { .str = "0" }, .flags = FLAGS },
     { "ratio", "set display aspect ratio", OFFSET(ratio_expr), AV_OPT_TYPE_STRING, { .str = "0" }, .flags = FLAGS },
     { "r",     "set display aspect ratio", OFFSET(ratio_expr), AV_OPT_TYPE_STRING, { .str = "0" }, .flags = FLAGS },

     { "max",   "set max value for nominator or denominator in the ratio", OFFSET(max), AV_OPT_TYPE_INT, {.i64=100}, 1, INT_MAX, FLAGS },
     { NULL }

 };
 

 AVFILTER_DEFINE_CLASS(setdar);

 static const AVFilterPad avfilter_vf_setdar_inputs[] = {
     {

         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = setdar_config_props,
         .filter_frame = filter_frame,

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

 AVFilter ff_vf_setdar = {

     .name        = "setdar",

     .description = NULL_IF_CONFIG_SMALL("Set the frame display aspect ratio."),

     .priv_size   = sizeof(AspectContext),
     .priv_class  = &setdar_class,
     .inputs      = avfilter_vf_setdar_inputs,
     .outputs     = avfilter_vf_setdar_outputs,

 };

 #endif /* CONFIG_SETDAR_FILTER */

 #if CONFIG_SETSAR_FILTER

 static int setsar_config_props(AVFilterLink *inlink)
 {

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

     AVRational old_sar = inlink->sample_aspect_ratio;
     AVRational old_dar, dar;

     int ret;
 
     if ((ret = get_aspect_ratio(inlink, &s->sar)))
         return ret;

     inlink->sample_aspect_ratio = s->sar;

     compute_dar(&old_dar, old_sar, inlink->w, inlink->h);

     compute_dar(&dar, s->sar, inlink->w, inlink->h);

     av_log(inlink->dst, AV_LOG_VERBOSE, "w:%d h:%d sar:%d/%d dar:%d/%d -> sar:%d/%d dar:%d/%d\n",
            inlink->w, inlink->h, old_sar.num, old_sar.den, old_dar.num, old_dar.den,
            inlink->sample_aspect_ratio.num, inlink->sample_aspect_ratio.den, dar.num, dar.den);
 

     return 0;
 }
 

 static const AVOption setsar_options[] = {

     { "sar",   "set sample (pixel) aspect ratio", OFFSET(ratio_expr), AV_OPT_TYPE_STRING, { .str = "0" }, .flags = FLAGS },
     { "ratio", "set sample (pixel) aspect ratio", OFFSET(ratio_expr), AV_OPT_TYPE_STRING, { .str = "0" }, .flags = FLAGS },
     { "r",     "set sample (pixel) aspect ratio", OFFSET(ratio_expr), AV_OPT_TYPE_STRING, { .str = "0" }, .flags = FLAGS },

     { "max",   "set max value for nominator or denominator in the ratio", OFFSET(max), AV_OPT_TYPE_INT, {.i64=100}, 1, INT_MAX, FLAGS },
     { NULL }

 };
 

 AVFILTER_DEFINE_CLASS(setsar);

 static const AVFilterPad avfilter_vf_setsar_inputs[] = {
     {

         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = setsar_config_props,
         .filter_frame = filter_frame,

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

 AVFilter ff_vf_setsar = {

     .name        = "setsar",

     .description = NULL_IF_CONFIG_SMALL("Set the pixel sample aspect ratio."),

     .priv_size   = sizeof(AspectContext),
     .priv_class  = &setsar_class,
     .inputs      = avfilter_vf_setsar_inputs,
     .outputs     = avfilter_vf_setsar_outputs,

 };

 #endif /* CONFIG_SETSAR_FILTER */