/*

  * Copyright (c) 2007 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

  * scale video filter
  */
 

 #include <stdio.h>
 #include <string.h>
 

 #include "avfilter.h"

 #include "formats.h"

 #include "internal.h"

 #include "video.h"

 #include "libavutil/avstring.h"
 #include "libavutil/eval.h"

 #include "libavutil/internal.h"

 #include "libavutil/mathematics.h"

 #include "libavutil/opt.h"

 #include "libavutil/parseutils.h"

 #include "libavutil/pixdesc.h"

 #include "libavutil/imgutils.h"

 #include "libavutil/avassert.h"

 #include "libswscale/swscale.h"
 

 static const char *const var_names[] = {

     "in_w",   "iw",
     "in_h",   "ih",
     "out_w",  "ow",
     "out_h",  "oh",

     "a",

     "sar",

     "dar",

     "hsub",
     "vsub",

     "ohsub",
     "ovsub",

     NULL
 };
 
 enum var_name {
     VAR_IN_W,   VAR_IW,
     VAR_IN_H,   VAR_IH,
     VAR_OUT_W,  VAR_OW,
     VAR_OUT_H,  VAR_OH,

     VAR_A,

     VAR_SAR,

     VAR_DAR,

     VAR_HSUB,
     VAR_VSUB,

     VAR_OHSUB,
     VAR_OVSUB,

     VARS_NB
 };
 

 typedef struct {

     const AVClass *class;

     struct SwsContext *sws;     ///< software scaler context

     struct SwsContext *isws[2]; ///< software scaler context for interlaced material

     AVDictionary *opts;

 
     /**
      * New dimensions. Special values are:
      *   0 = original width/height
      *  -1 = keep original aspect

      *  -N = try to keep aspect but make sure it is divisible by N

      */
     int w, h;

     char *size_str;

     unsigned int flags;         ///sws flags

 
     int hsub, vsub;             ///< chroma subsampling
     int slice_y;                ///< top of current output slice
     int input_is_pal;           ///< set to 1 if the input format is paletted

     int output_is_pal;          ///< set to 1 if the output format is paletted

     int interlaced;

     char *w_expr;               ///< width  expression string
     char *h_expr;               ///< height expression string

     char *flags_str;

 
     char *in_color_matrix;
     char *out_color_matrix;

 
     int in_range;
     int out_range;

 
     int out_h_chr_pos;
     int out_v_chr_pos;

     int in_h_chr_pos;
     int in_v_chr_pos;

 
     int force_original_aspect_ratio;

 } ScaleContext;
 

 static av_cold int init_dict(AVFilterContext *ctx, AVDictionary **opts)

 {
     ScaleContext *scale = ctx->priv;

     int ret;
 

     if (scale->size_str && (scale->w_expr || scale->h_expr)) {
         av_log(ctx, AV_LOG_ERROR,
                "Size and width/height expressions cannot be set at the same time.\n");
             return AVERROR(EINVAL);
     }
 

     if (scale->w_expr && !scale->h_expr)
         FFSWAP(char *, scale->w_expr, scale->size_str);
 

     if (scale->size_str) {
         char buf[32];
         if ((ret = av_parse_video_size(&scale->w, &scale->h, scale->size_str)) < 0) {
             av_log(ctx, AV_LOG_ERROR,
                    "Invalid size '%s'\n", scale->size_str);
             return ret;
         }
         snprintf(buf, sizeof(buf)-1, "%d", scale->w);
         av_opt_set(scale, "w", buf, 0);
         snprintf(buf, sizeof(buf)-1, "%d", scale->h);
         av_opt_set(scale, "h", buf, 0);
     }
     if (!scale->w_expr)
         av_opt_set(scale, "w", "iw", 0);
     if (!scale->h_expr)
         av_opt_set(scale, "h", "ih", 0);
 

     av_log(ctx, AV_LOG_VERBOSE, "w:%s h:%s flags:'%s' interl:%d\n",
            scale->w_expr, scale->h_expr, (char *)av_x_if_null(scale->flags_str, ""), scale->interlaced);

     scale->flags = 0;

     if (scale->flags_str) {
         const AVClass *class = sws_get_class();
         const AVOption    *o = av_opt_find(&class, "sws_flags", NULL, 0,
                                            AV_OPT_SEARCH_FAKE_OBJ);
         int ret = av_opt_eval_flags(&class, o, scale->flags_str, &scale->flags);
         if (ret < 0)
             return ret;

     }

     scale->opts = *opts;
     *opts = NULL;

 
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     ScaleContext *scale = ctx->priv;
     sws_freeContext(scale->sws);

     sws_freeContext(scale->isws[0]);
     sws_freeContext(scale->isws[1]);

     scale->sws = NULL;

     av_dict_free(&scale->opts);

 }
 
 static int query_formats(AVFilterContext *ctx)
 {
     AVFilterFormats *formats;

     enum AVPixelFormat pix_fmt;

     int ret;

 
     if (ctx->inputs[0]) {

         formats = NULL;

         for (pix_fmt = 0; pix_fmt < AV_PIX_FMT_NB; pix_fmt++)

             if ((sws_isSupportedInput(pix_fmt) ||
                  sws_isSupportedEndiannessConversion(pix_fmt))

                 && (ret = ff_add_format(&formats, pix_fmt)) < 0) {
                 ff_formats_unref(&formats);

                 return ret;
             }

         ff_formats_ref(formats, &ctx->inputs[0]->out_formats);

     }
     if (ctx->outputs[0]) {

         formats = NULL;

         for (pix_fmt = 0; pix_fmt < AV_PIX_FMT_NB; pix_fmt++)

             if ((sws_isSupportedOutput(pix_fmt) || pix_fmt == AV_PIX_FMT_PAL8 ||

                  sws_isSupportedEndiannessConversion(pix_fmt))

                 && (ret = ff_add_format(&formats, pix_fmt)) < 0) {
                 ff_formats_unref(&formats);

                 return ret;
             }

         ff_formats_ref(formats, &ctx->outputs[0]->in_formats);

     }
 
     return 0;
 }
 

 static const int *parse_yuv_type(const char *s, enum AVColorSpace colorspace)
 {
     if (!s)
         s = "bt601";
 
     if (s && strstr(s, "bt709")) {
         colorspace = AVCOL_SPC_BT709;
     } else if (s && strstr(s, "fcc")) {
         colorspace = AVCOL_SPC_FCC;
     } else if (s && strstr(s, "smpte240m")) {
         colorspace = AVCOL_SPC_SMPTE240M;
     } else if (s && (strstr(s, "bt601") || strstr(s, "bt470") || strstr(s, "smpte170m"))) {
         colorspace = AVCOL_SPC_BT470BG;
     }
 
     if (colorspace < 1 || colorspace > 7) {
         colorspace = AVCOL_SPC_BT470BG;
     }
 

     return sws_getCoefficients(colorspace);

 }
 

 static int config_props(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     AVFilterLink *inlink = outlink->src->inputs[0];

     enum AVPixelFormat outfmt = outlink->format;

     ScaleContext *scale = ctx->priv;

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

     const AVPixFmtDescriptor *out_desc = av_pix_fmt_desc_get(outlink->format);

     int64_t w, h;

     double var_values[VARS_NB], res;
     char *expr;
     int ret;

     int factor_w, factor_h;

 
     var_values[VAR_IN_W]  = var_values[VAR_IW] = inlink->w;
     var_values[VAR_IN_H]  = var_values[VAR_IH] = inlink->h;
     var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
     var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;

     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;

     var_values[VAR_OHSUB] = 1 << out_desc->log2_chroma_w;
     var_values[VAR_OVSUB] = 1 << out_desc->log2_chroma_h;

 
     /* evaluate width and height */
     av_expr_parse_and_eval(&res, (expr = scale->w_expr),
                            var_names, var_values,
                            NULL, NULL, NULL, NULL, NULL, 0, ctx);

     scale->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;

     if ((ret = av_expr_parse_and_eval(&res, (expr = scale->h_expr),
                                       var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
         goto fail;

     scale->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;

     /* evaluate again the width, as it may depend on the output height */
     if ((ret = av_expr_parse_and_eval(&res, (expr = scale->w_expr),
                                       var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
         goto fail;
     scale->w = res;
 
     w = scale->w;
     h = scale->h;
 

     /* Check if it is requested that the result has to be divisible by a some

      * factor (w or h = -n with n being the factor). */

     factor_w = 1;
     factor_h = 1;

     if (w < -1) {
         factor_w = -w;

     }

     if (h < -1) {
         factor_h = -h;
     }
 

     if (w < 0 && h < 0)

         scale->w = scale->h = 0;

 
     if (!(w = scale->w))
         w = inlink->w;
     if (!(h = scale->h))
         h = inlink->h;
 

     /* Make sure that the result is divisible by the factor we determined
      * earlier. If no factor was set, it is nothing will happen as the default
      * factor is 1 */

     if (w < 0)

         w = av_rescale(h, inlink->w, inlink->h * factor_w) * factor_w;

     if (h < 0)

         h = av_rescale(w, inlink->h, inlink->w * factor_h) * factor_h;

 
     /* Note that force_original_aspect_ratio may overwrite the previous set
      * dimensions so that it is not divisible by the set factors anymore. */

     if (scale->force_original_aspect_ratio) {
         int tmp_w = av_rescale(h, inlink->w, inlink->h);
         int tmp_h = av_rescale(w, inlink->h, inlink->w);
 
         if (scale->force_original_aspect_ratio == 1) {
              w = FFMIN(tmp_w, w);
              h = FFMIN(tmp_h, h);
         } else {
              w = FFMAX(tmp_w, w);
              h = FFMAX(tmp_h, h);
         }
     }
 

     if (w > INT_MAX || h > INT_MAX ||
         (h * inlink->w) > INT_MAX  ||
         (w * inlink->h) > INT_MAX)
         av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n");
 
     outlink->w = w;
     outlink->h = h;
 
     /* TODO: make algorithm configurable */
 

     scale->input_is_pal = desc->flags & AV_PIX_FMT_FLAG_PAL ||
                           desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL;

     if (outfmt == AV_PIX_FMT_PAL8) outfmt = AV_PIX_FMT_BGR8;

     scale->output_is_pal = av_pix_fmt_desc_get(outfmt)->flags & AV_PIX_FMT_FLAG_PAL ||
                            av_pix_fmt_desc_get(outfmt)->flags & AV_PIX_FMT_FLAG_PSEUDOPAL;

     if (scale->sws)

         sws_freeContext(scale->sws);

     if (scale->isws[0])
         sws_freeContext(scale->isws[0]);
     if (scale->isws[1])
         sws_freeContext(scale->isws[1]);
     scale->isws[0] = scale->isws[1] = scale->sws = NULL;

     if (inlink->w == outlink->w && inlink->h == outlink->h &&
         inlink->format == outlink->format)

         ;

     else {

         struct SwsContext **swscs[3] = {&scale->sws, &scale->isws[0], &scale->isws[1]};
         int i;
 
         for (i = 0; i < 3; i++) {
             struct SwsContext **s = swscs[i];
             *s = sws_alloc_context();
             if (!*s)
                 return AVERROR(ENOMEM);
 

             if (scale->opts) {
                 AVDictionaryEntry *e = NULL;
 
                 while ((e = av_dict_get(scale->opts, "", e, AV_DICT_IGNORE_SUFFIX))) {

                     if ((ret = av_opt_set(*s, e->key, e->value, 0)) < 0)

                         return ret;
                 }
             }
 

             av_opt_set_int(*s, "srcw", inlink ->w, 0);
             av_opt_set_int(*s, "srch", inlink ->h >> !!i, 0);
             av_opt_set_int(*s, "src_format", inlink->format, 0);
             av_opt_set_int(*s, "dstw", outlink->w, 0);
             av_opt_set_int(*s, "dsth", outlink->h >> !!i, 0);
             av_opt_set_int(*s, "dst_format", outfmt, 0);
             av_opt_set_int(*s, "sws_flags", scale->flags, 0);
 

             av_opt_set_int(*s, "src_h_chr_pos", scale->in_h_chr_pos, 0);
             av_opt_set_int(*s, "src_v_chr_pos", scale->in_v_chr_pos, 0);

             av_opt_set_int(*s, "dst_h_chr_pos", scale->out_h_chr_pos, 0);
             av_opt_set_int(*s, "dst_v_chr_pos", scale->out_v_chr_pos, 0);
 

             if ((ret = sws_init_context(*s, NULL, NULL)) < 0)
                 return ret;

             if (!scale->interlaced)
                 break;

         }

     }

     if (inlink->sample_aspect_ratio.num){
         outlink->sample_aspect_ratio = av_mul_q((AVRational){outlink->h * inlink->w, outlink->w * inlink->h}, inlink->sample_aspect_ratio);
     } else
         outlink->sample_aspect_ratio = inlink->sample_aspect_ratio;
 

     av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d fmt:%s sar:%d/%d -> w:%d h:%d fmt:%s sar:%d/%d flags:0x%0x\n",

            inlink ->w, inlink ->h, av_get_pix_fmt_name( inlink->format),

            inlink->sample_aspect_ratio.num, inlink->sample_aspect_ratio.den,

            outlink->w, outlink->h, av_get_pix_fmt_name(outlink->format),

            outlink->sample_aspect_ratio.num, outlink->sample_aspect_ratio.den,
            scale->flags);

     return 0;

 
 fail:
     av_log(NULL, AV_LOG_ERROR,

            "Error when evaluating the expression '%s'.\n"
            "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
            expr, scale->w_expr, scale->h_expr);

     return ret;

 }
 

 static int scale_slice(AVFilterLink *link, AVFrame *out_buf, AVFrame *cur_pic, struct SwsContext *sws, int y, int h, int mul, int field)

 {
     ScaleContext *scale = link->dst->priv;

     const uint8_t *in[4];
     uint8_t *out[4];

     int in_stride[4],out_stride[4];
     int i;
 
     for(i=0; i<4; i++){
         int vsub= ((i+1)&2) ? scale->vsub : 0;
          in_stride[i] = cur_pic->linesize[i] * mul;
         out_stride[i] = out_buf->linesize[i] * mul;
          in[i] = cur_pic->data[i] + ((y>>vsub)+field) * cur_pic->linesize[i];
         out[i] = out_buf->data[i] +            field  * out_buf->linesize[i];
     }

     if(scale->input_is_pal)

          in[1] = cur_pic->data[1];

     if(scale->output_is_pal)

         out[1] = out_buf->data[1];
 
     return sws_scale(sws, in, in_stride, y/mul, h,
                          out,out_stride);
 }
 

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

 {
     ScaleContext *scale = link->dst->priv;

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

     AVFrame *out;

     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
     char buf[32];

     int in_range;

     if(   in->width  != link->w
        || in->height != link->h
        || in->format != link->format) {

         int ret;
         snprintf(buf, sizeof(buf)-1, "%d", outlink->w);
         av_opt_set(scale, "w", buf, 0);
         snprintf(buf, sizeof(buf)-1, "%d", outlink->h);
         av_opt_set(scale, "h", buf, 0);

         link->dst->inputs[0]->format = in->format;

         link->dst->inputs[0]->w      = in->width;
         link->dst->inputs[0]->h      = in->height;

 
         if ((ret = config_props(outlink)) < 0)
             return ret;

     }
 

     if (!scale->sws)
         return ff_filter_frame(outlink, in);
 
     scale->hsub = desc->log2_chroma_w;
     scale->vsub = desc->log2_chroma_h;
 

     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);
     out->width  = outlink->w;
     out->height = outlink->h;

 
     if(scale->output_is_pal)
         avpriv_set_systematic_pal2((uint32_t*)out->data[1], outlink->format == AV_PIX_FMT_PAL8 ? AV_PIX_FMT_BGR8 : outlink->format);
 

     in_range = av_frame_get_color_range(in);
 

     if (   scale->in_color_matrix
         || scale->out_color_matrix
         || scale-> in_range != AVCOL_RANGE_UNSPECIFIED

         || in_range != AVCOL_RANGE_UNSPECIFIED

         || scale->out_range != AVCOL_RANGE_UNSPECIFIED) {
         int in_full, out_full, brightness, contrast, saturation;
         const int *inv_table, *table;
 
         sws_getColorspaceDetails(scale->sws, (int **)&inv_table, &in_full,
                                  (int **)&table, &out_full,
                                  &brightness, &contrast, &saturation);
 
         if (scale->in_color_matrix)
             inv_table = parse_yuv_type(scale->in_color_matrix, av_frame_get_colorspace(in));
         if (scale->out_color_matrix)
             table     = parse_yuv_type(scale->out_color_matrix, AVCOL_SPC_UNSPECIFIED);
 

         if (scale-> in_range != AVCOL_RANGE_UNSPECIFIED)
             in_full  = (scale-> in_range == AVCOL_RANGE_JPEG);

         else if (in_range != AVCOL_RANGE_UNSPECIFIED)
             in_full  = (in_range == AVCOL_RANGE_JPEG);

         if (scale->out_range != AVCOL_RANGE_UNSPECIFIED)
             out_full = (scale->out_range == AVCOL_RANGE_JPEG);
 

         sws_setColorspaceDetails(scale->sws, inv_table, in_full,
                                  table, out_full,
                                  brightness, contrast, saturation);
         if (scale->isws[0])

             sws_setColorspaceDetails(scale->isws[0], inv_table, in_full,
                                      table, out_full,
                                      brightness, contrast, saturation);

         if (scale->isws[1])

             sws_setColorspaceDetails(scale->isws[1], inv_table, in_full,
                                      table, out_full,
                                      brightness, contrast, saturation);

     }
 

     av_reduce(&out->sample_aspect_ratio.num, &out->sample_aspect_ratio.den,
               (int64_t)in->sample_aspect_ratio.num * outlink->h * link->w,
               (int64_t)in->sample_aspect_ratio.den * outlink->w * link->h,

               INT_MAX);

     if(scale->interlaced>0 || (scale->interlaced<0 && in->interlaced_frame)){

         scale_slice(link, out, in, scale->isws[0], 0, (link->h+1)/2, 2, 0);
         scale_slice(link, out, in, scale->isws[1], 0,  link->h   /2, 2, 1);

     }else{

         scale_slice(link, out, in, scale->sws, 0, link->h, 1, 0);

     }

     av_frame_free(&in);

     return ff_filter_frame(outlink, out);

 }
 

 static const AVClass *child_class_next(const AVClass *prev)
 {
     return prev ? NULL : sws_get_class();
 }
 

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

 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 
 static const AVOption scale_options[] = {

     { "w",     "Output video width",          OFFSET(w_expr),    AV_OPT_TYPE_STRING,        .flags = FLAGS },
     { "width", "Output video width",          OFFSET(w_expr),    AV_OPT_TYPE_STRING,        .flags = FLAGS },
     { "h",     "Output video height",         OFFSET(h_expr),    AV_OPT_TYPE_STRING,        .flags = FLAGS },
     { "height","Output video height",         OFFSET(h_expr),    AV_OPT_TYPE_STRING,        .flags = FLAGS },

     { "flags", "Flags to pass to libswscale", OFFSET(flags_str), AV_OPT_TYPE_STRING, { .str = "bilinear" }, .flags = FLAGS },

     { "interl", "set interlacing", OFFSET(interlaced), AV_OPT_TYPE_INT, {.i64 = 0 }, -1, 1, FLAGS },
     { "size",   "set video size",          OFFSET(size_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, FLAGS },
     { "s",      "set video size",          OFFSET(size_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, FLAGS },

     {  "in_color_matrix", "set input YCbCr type",   OFFSET(in_color_matrix),  AV_OPT_TYPE_STRING, { .str = "auto" }, .flags = FLAGS },

     { "out_color_matrix", "set output YCbCr type",  OFFSET(out_color_matrix), AV_OPT_TYPE_STRING, { .str = NULL }, .flags = FLAGS },

     {  "in_range", "set input color range",  OFFSET( in_range), AV_OPT_TYPE_INT, {.i64 = AVCOL_RANGE_UNSPECIFIED }, 0, 2, FLAGS, "range" },
     { "out_range", "set output color range", OFFSET(out_range), AV_OPT_TYPE_INT, {.i64 = AVCOL_RANGE_UNSPECIFIED }, 0, 2, FLAGS, "range" },
     { "auto",   NULL, 0, AV_OPT_TYPE_CONST, {.i64 = AVCOL_RANGE_UNSPECIFIED }, 0, 0, FLAGS, "range" },
     { "full",   NULL, 0, AV_OPT_TYPE_CONST, {.i64 = AVCOL_RANGE_JPEG}, 0, 0, FLAGS, "range" },
     { "jpeg",   NULL, 0, AV_OPT_TYPE_CONST, {.i64 = AVCOL_RANGE_JPEG}, 0, 0, FLAGS, "range" },
     { "mpeg",   NULL, 0, AV_OPT_TYPE_CONST, {.i64 = AVCOL_RANGE_MPEG}, 0, 0, FLAGS, "range" },

     { "tv",     NULL, 0, AV_OPT_TYPE_CONST, {.i64 = AVCOL_RANGE_MPEG}, 0, 0, FLAGS, "range" },
     { "pc",     NULL, 0, AV_OPT_TYPE_CONST, {.i64 = AVCOL_RANGE_JPEG}, 0, 0, FLAGS, "range" },

     { "in_v_chr_pos",   "input vertical chroma position in luma grid/256"  , OFFSET(in_v_chr_pos), AV_OPT_TYPE_INT, { .i64 = -1}, -1, 512, FLAGS },
     { "in_h_chr_pos",   "input horizontal chroma position in luma grid/256", OFFSET(in_h_chr_pos), AV_OPT_TYPE_INT, { .i64 = -1}, -1, 512, FLAGS },

     { "out_v_chr_pos",   "output vertical chroma position in luma grid/256"  , OFFSET(out_v_chr_pos), AV_OPT_TYPE_INT, { .i64 = -1}, -1, 512, FLAGS },
     { "out_h_chr_pos",   "output horizontal chroma position in luma grid/256", OFFSET(out_h_chr_pos), AV_OPT_TYPE_INT, { .i64 = -1}, -1, 512, FLAGS },

     { "force_original_aspect_ratio", "decrease or increase w/h if necessary to keep the original AR", OFFSET(force_original_aspect_ratio), AV_OPT_TYPE_INT, { .i64 = 0}, 0, 2, FLAGS, "force_oar" },
     { "disable",  NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0 }, 0, 0, FLAGS, "force_oar" },
     { "decrease", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1 }, 0, 0, FLAGS, "force_oar" },
     { "increase", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 2 }, 0, 0, FLAGS, "force_oar" },

     { NULL }

 };
 

 static const AVClass scale_class = {
     .class_name       = "scale",
     .item_name        = av_default_item_name,
     .option           = scale_options,
     .version          = LIBAVUTIL_VERSION_INT,
     .child_class_next = child_class_next,
 };

 static const AVFilterPad avfilter_vf_scale_inputs[] = {
     {

         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,

         .filter_frame = filter_frame,

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

 AVFilter ff_vf_scale = {

     .name          = "scale",

     .description   = NULL_IF_CONFIG_SMALL("Scale the input video size and/or convert the image format."),

     .init_dict     = init_dict,
     .uninit        = uninit,

     .query_formats = query_formats,

     .priv_size     = sizeof(ScaleContext),
     .priv_class    = &scale_class,
     .inputs        = avfilter_vf_scale_inputs,
     .outputs       = avfilter_vf_scale_outputs,

 };