/*

  * 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
  */
 
 #include "libavutil/rational.h"
 

 #include "mpeg12.h"
 #include "mpeg12data.h"
 

 const AVRational ff_mpeg12_frame_rate_tab[16] = {
     {    0,    0},
     {24000, 1001},
     {   24,    1},
     {   25,    1},
     {30000, 1001},
     {   30,    1},
     {   50,    1},
     {60000, 1001},
     {   60,    1},
   // Xing's 15fps: (9)
     {   15,    1},
   // libmpeg3's "Unofficial economy rates": (10-13)
     {    5,    1},
     {   10,    1},
     {   12,    1},
     {   15,    1},
     {    0,    0},
 };

 
 void ff_mpeg12_find_best_frame_rate(AVRational frame_rate,
                                     int *code, int *ext_n, int *ext_d,
                                     int nonstandard)
 {
     int mpeg2 = ext_n && ext_d;
     int max_code = nonstandard ? 12 : 8;
     int c, n, d, best_c, best_n, best_d;
     AVRational best_error = { INT_MAX, 1 };
 
     // Default to NTSC if the inputs make no sense.
     best_c = 4;
     best_n = best_d = 1;
 
     for (c = 1; c <= max_code; c++) {
         if (av_cmp_q(frame_rate, ff_mpeg12_frame_rate_tab[c]) == 0) {
             best_c = c;
             goto found;
         }
     }
 
     for (c = 1; c <= max_code; c++) {
         for (n = 1; n <= (mpeg2 ? 4 : 1); n++) {
             for (d = 1; d <= (mpeg2 ? 32 : 1); d++) {
                 AVRational test, error;
                 int cmp;
 
                 test = av_mul_q(ff_mpeg12_frame_rate_tab[c],
                                 (AVRational) { n, d });
 
                 cmp = av_cmp_q(test, frame_rate);
                 if (cmp == 0) {
                     best_c = c;
                     best_n = n;
                     best_d = d;
                     goto found;
                 }
 
                 if (cmp < 0)
                     error = av_div_q(frame_rate, test);
                 else
                     error = av_div_q(test, frame_rate);
 
                 cmp = av_cmp_q(error, best_error);
                 if (cmp < 0 || (cmp == 0 && n == 1 && d == 1)) {
                     best_c = c;
                     best_n = n;
                     best_d = d;
                     best_error = error;
                 }
             }
         }
     }
 
 found:
     *code = best_c;
     if (mpeg2) {
         *ext_n = best_n - 1;
         *ext_d = best_d - 1;
     }
 }