text: /*
   * 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;
  #if FF_API_OLD_FILTER_OPTS
      float aspect_den;
  #endif
      char *ratio_expr;
  } AspectContext;
  
  static av_cold int init(AVFilterContext *ctx)
  {
      AspectContext *s = ctx->priv;
      int ret;
  
  #if FF_API_OLD_FILTER_OPTS
      if (s->ratio_expr && s->aspect_den > 0) {
          double num;
          av_log(ctx, AV_LOG_WARNING,
                 "num:den syntax is deprecated, please use num/den or named options instead\n");
          ret = av_expr_parse_and_eval(&num, s->ratio_expr, NULL, NULL,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx);
          if (ret < 0) {
              av_log(ctx, AV_LOG_ERROR, "Unable to parse ratio numerator \"%s\"\n", s->ratio_expr);
              return AVERROR(EINVAL);
          }
          s->sar = s->dar = av_d2q(num / s->aspect_den, s->max);
      }
  #endif
  
      return 0;
  }
  
  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 FF_API_OLD_FILTER_OPTS
      if (!(s->ratio_expr && s->aspect_den > 0)) {
  #endif
      if ((ret = get_aspect_ratio(inlink, &s->dar)))
          return ret;
  #if FF_API_OLD_FILTER_OPTS
      }
  #endif
  
      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 },
  #if FF_API_OLD_FILTER_OPTS
      { "dar_den", NULL, OFFSET(aspect_den), AV_OPT_TYPE_FLOAT, { .dbl = 0 }, 0, FLT_MAX, FLAGS },
  #endif
      { "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."),
      .init        = init,
      .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 FF_API_OLD_FILTER_OPTS
      if (!(s->ratio_expr && s->aspect_den > 0)) {
  #endif
      if ((ret = get_aspect_ratio(inlink, &s->sar)))
          return ret;
  #if FF_API_OLD_FILTER_OPTS
      }
  #endif
  
      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 },
  #if FF_API_OLD_FILTER_OPTS
      { "sar_den", NULL, OFFSET(aspect_den), AV_OPT_TYPE_FLOAT, { .dbl = 0 }, 0, FLT_MAX, FLAGS },
  #endif
      { "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."),
      .init        = init,
      .priv_size   = sizeof(AspectContext),
      .priv_class  = &setsar_class,
      .inputs      = avfilter_vf_setsar_inputs,
      .outputs     = avfilter_vf_setsar_outputs,
  };
  
  #endif /* CONFIG_SETSAR_FILTER */
  