libvo/gtf.c

   1 /*
   2  *      Copyright (C) Rudolf Marek <r.marek@sh.cvut.cz> - Aug 2002
   3  *
   4  *  You can redistribute this file under terms and conditions
   5  *  of GNU General Public licence v2.
   6  *
   7  *  GTF calculations formulas are taken from GTF_V1R1.xls
   8  *  created by ANDY.MORRISH@NSC.COM
   9  */
  10
  11 //Version 0.4
  12 #include "config.h"
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <math.h>
  16 #include "gtf.h"
  17
  18 #undef GTF_DEBUG
  19
  20 #ifdef GTF_DEBUG
  21 #define DEBUG_PRINTF(a,b) printf(a,b);
  22 #else
  23 #define DEBUG_PRINTF(a,b)
  24 #endif
  25
  26 static GTF_constants GTF_given_constants = { 3.0,550.0,1,8,1.8,8,40,20,128,600 };
  27
  28 #ifndef HAVE_ROUND
  29 static double round(double v)
  30 {
  31         return floor(v + 0.5);
  32 }
  33 #endif
  34
  35 static void GetRoundedConstants(GTF_constants *c)
  36     {
  37     c->Vsync_need = round(GTF_given_constants.Vsync_need);
  38     c->min_Vsync_BP = GTF_given_constants.min_Vsync_BP;
  39     c->min_front_porch = round(GTF_given_constants.min_front_porch);
  40     c->char_cell_granularity = GTF_given_constants.char_cell_granularity;
  41     c->margin_width = GTF_given_constants.margin_width;
  42     c->sync_width = GTF_given_constants.sync_width;
  43     c->c = ((GTF_given_constants.c - GTF_given_constants.j)*(GTF_given_constants.k / 256)) + GTF_given_constants.j;
  44     c->j = GTF_given_constants.j;
  45     c->k = GTF_given_constants.k;
  46     c->m = (GTF_given_constants.k / 256) * GTF_given_constants.m;
  47     }
  48
  49 void GTF_calcTimings(double X,double Y,double freq, int type,
  50                      int want_margins, int want_interlace,struct VesaCRTCInfoBlock *result )
  51 {
  52     GTF_constants   c;
  53     double RR, margin_top, margin_bottom, margin_left, margin_right;
  54     double estimated_H_period,sync_plus_BP,BP,interlace,V_total_lines_field;
  55     double estimated_V_field_rate,actual_H_period,actual_V_field_freq;
  56     double total_active_pixels, ideal_duty_cycle, blanking_time, H_total_pixels;
  57     double H_freq, pixel_freq,actual_V_frame_freq;
  58     double H_sync_start, H_sync_end, H_back_porch, H_front_porch, H_sync_width;
  59     double V_back_porch, V_front_porch, V_sync_start, V_sync_end,V_sync_width;
  60     double ideal_H_period;
  61     GetRoundedConstants(&c);
  62
  63
  64     pixel_freq = RR = freq;
  65
  66     /* DETERMINE IF 1/2 LINE INTERLACE IS PRESENT */
  67
  68     interlace = 0;
  69
  70     if (want_interlace) {
  71     RR = RR * 2;
  72     Y=Y/2;
  73     interlace = 0.5;
  74     }
  75
  76     result->Flags = 0;
  77
  78     if ((Y==300)||(Y==200)||(Y==240))
  79     {
  80     Y*=2;
  81     result->Flags = VESA_CRTC_DOUBLESCAN; /* TODO: check if mode support   */
  82     }
  83
  84     /* DETERMINE NUMBER OF LINES IN V MARGIN */
  85     /* DETERMINE NUMBER OF PIXELS IN H MARGIN [pixels] */
  86
  87     margin_left = margin_right = 0;
  88     margin_top = margin_bottom = 0;
  89
  90     if (want_margins) {
  91         margin_top = margin_bottom = (c.margin_width / 100) * Y;
  92         margin_left = round(( X* c.margin_width/100)/c.char_cell_granularity) \
  93                     * c.char_cell_granularity;
  94     margin_right = margin_left;
  95     DEBUG_PRINTF("margin_left_right : %f\n",margin_right)
  96     DEBUG_PRINTF("margin_top_bottom : %f\n",margin_top)
  97     }
  98
  99     /* FIND TOTAL NUMBER OF ACTIVE PIXELS (IMAGE + MARGIN) [pixels] */
 100
 101     total_active_pixels = margin_left + margin_right + X;
 102     DEBUG_PRINTF("total_active_pixels: %f\n",total_active_pixels)
 103
 104     if (type == GTF_PF)
 105     {
 106     ideal_H_period = ((c.c-100)+(sqrt(((100-c.c)*(100-c.c) )+(0.4*c.m*(total_active_pixels + margin_left + margin_right) / freq))))/2/c.m*1000;
 107
 108     DEBUG_PRINTF("ideal_H_period: %f\n",ideal_H_period)
 109
 110     /* FIND IDEAL BLANKING DUTY CYCLE FROM FORMULA [%] */
 111     ideal_duty_cycle = c.c - (c.m * ideal_H_period /1000);
 112     DEBUG_PRINTF("ideal_duty_cycle: %f\n",ideal_duty_cycle)
 113
 114     /* FIND BLANKING TIME (TO NEAREST CHAR CELL) [pixels] */
 115
 116     blanking_time = round(total_active_pixels * ideal_duty_cycle \
 117                     / (100-ideal_duty_cycle) / (2*c.char_cell_granularity))  \
 118                     * (2*c.char_cell_granularity);
 119     DEBUG_PRINTF("blanking_time : %f\n",blanking_time )
 120
 121     /* FIND TOTAL NUMBER OF PIXELS IN A LINE [pixels] */
 122     H_total_pixels = total_active_pixels + blanking_time ;
 123     DEBUG_PRINTF("H_total_pixels: %f\n",H_total_pixels)
 124     H_freq = freq / H_total_pixels * 1000;
 125     DEBUG_PRINTF("H_freq: %f\n",H_freq)
 126     actual_H_period = 1000 / H_freq;
 127     DEBUG_PRINTF("actual_H_period: %f\n",actual_H_period)
 128     sync_plus_BP = round(H_freq * c.min_Vsync_BP/1000);
 129 //   sync_plus_BP = round( freq / H_total_pixels * c.min_Vsync_BP);
 130
 131     DEBUG_PRINTF("sync_plus_BP: %f\n",sync_plus_BP)
 132
 133     } else if (type == GTF_VF)
 134     {
 135
 136     /* ESTIMATE HORIZ. PERIOD [us] */
 137
 138     estimated_H_period = (( 1/RR ) - c.min_Vsync_BP/1000000 ) /  (Y + (2 * margin_top) + c.min_front_porch + interlace) * 1000000;
 139
 140     DEBUG_PRINTF("estimated_H_period: %f\n",estimated_H_period)
 141
 142     /* FIND NUMBER OF LINES IN (SYNC + BACK PORCH) [lines] */
 143
 144     sync_plus_BP = round( c.min_Vsync_BP / estimated_H_period );
 145     DEBUG_PRINTF("sync_plus_BP: %f\n",sync_plus_BP)
 146
 147     } else if (type == GTF_HF)
 148     {
 149     sync_plus_BP = round(freq * c.min_Vsync_BP/1000);
 150     DEBUG_PRINTF("sync_plus_BP: %f\n",sync_plus_BP)
 151     }
 152
 153
 154
 155     /* FIND TOTAL NUMBER OF LINES IN VERTICAL FIELD */
 156
 157     V_total_lines_field = sync_plus_BP+interlace+margin_bottom+margin_top+Y+c.min_front_porch;
 158     DEBUG_PRINTF("V_total_lines_field : %f\n",V_total_lines_field )
 159
 160     if (type == GTF_VF)
 161     {
 162     /* ESTIMATE VERTICAL FIELD RATE [hz] */
 163
 164     estimated_V_field_rate = 1 / estimated_H_period / V_total_lines_field * 1000000;
 165     DEBUG_PRINTF(" estimated_V_field_rate: %f\n", estimated_V_field_rate)
 166     /* FIND ACTUAL HORIZONTAL PERIOD [us] */
 167
 168     actual_H_period = estimated_H_period / (RR / estimated_V_field_rate);
 169     DEBUG_PRINTF("actual_H_period: %f\n",actual_H_period)
 170     /* FIND ACTUAL VERTICAL FIELD FREQUENCY [Hz] */
 171
 172     actual_V_field_freq = 1 / actual_H_period / V_total_lines_field * 1000000;
 173     DEBUG_PRINTF("actual_V_field_freq: %f\n",actual_V_field_freq)
 174
 175     /* FIND IDEAL BLANKING DUTY CYCLE FROM FORMULA [%] */
 176     ideal_duty_cycle = c.c - (c.m * actual_H_period /1000);
 177     DEBUG_PRINTF("ideal_duty_cycle: %f\n",ideal_duty_cycle)
 178     //if (type == GTF_VF)
 179     //{
 180     //moved
 181     //}
 182     } else if (type == GTF_HF)
 183     {
 184     /* FIND IDEAL BLANKING DUTY CYCLE FROM FORMULA [%] */
 185     ideal_duty_cycle = c.c - (c.m  / freq);
 186     DEBUG_PRINTF("ideal_duty_cycle: %f\n",ideal_duty_cycle)
 187     }
 188
 189     /* FIND BLANKING TIME (TO NEAREST CHAR CELL) [pixels] */
 190
 191     if (!(type == GTF_PF))
 192     {
 193     blanking_time = round(total_active_pixels * ideal_duty_cycle \
 194                     / (100-ideal_duty_cycle) / (2*c.char_cell_granularity))  \
 195                     * (2*c.char_cell_granularity);
 196     DEBUG_PRINTF("blanking_time : %f\n",blanking_time )
 197     }
 198     else
 199 //    if (type == GTF_PF)
 200     {
 201     actual_V_field_freq = H_freq / V_total_lines_field * 1000;
 202     }
 203
 204     if (type == GTF_HF)
 205     {
 206     /* Hz */
 207     actual_V_field_freq = freq / V_total_lines_field * 1000;
 208     DEBUG_PRINTF("actual_V_field_freq: %f\n",actual_V_field_freq)
 209     }
 210
 211
 212     actual_V_frame_freq = actual_V_field_freq;
 213
 214     /* FIND ACTUAL VERTICAL  FRAME FREQUENCY [Hz]*/
 215
 216     if (want_interlace) actual_V_frame_freq = actual_V_field_freq / 2;
 217     DEBUG_PRINTF("actual_V_frame_freq: %f\n",actual_V_frame_freq)
 218
 219 //    V_freq = actual_V_frame_freq;
 220 //    DEBUG_PRINTF("V_freq %f\n",V_freq)
 221
 222
 223     if (!(type == GTF_PF))
 224     {
 225     /* FIND TOTAL NUMBER OF PIXELS IN A LINE [pixels] */
 226     H_total_pixels = total_active_pixels + blanking_time ;
 227     DEBUG_PRINTF("H_total_pixels: %f\n",H_total_pixels)
 228         if (type == GTF_VF)
 229         {
 230         /* FIND PIXEL FREQUENCY [Mhz] */
 231         pixel_freq = H_total_pixels / actual_H_period ;
 232         DEBUG_PRINTF("pixel_freq: %f\n",pixel_freq)
 233         } else if (type == GTF_HF)
 234         {
 235         /* FIND PIXEL FREQUENCY [Mhz] */
 236         pixel_freq = H_total_pixels * freq / 1000 ;
 237         DEBUG_PRINTF("pixel_freq: %f\n",pixel_freq)
 238         actual_H_period = 1000/freq;
 239         }
 240
 241         /* FIND ACTUAL HORIZONTAL FREQUENCY [KHz] */
 242
 243         H_freq = 1000 / actual_H_period;
 244         DEBUG_PRINTF("H_freq %f\n",H_freq)
 245
 246
 247     }
 248
 249     /* FIND NUMBER OF LINES IN BACK PORCH [lines] */
 250
 251     BP = sync_plus_BP - c.Vsync_need;
 252     DEBUG_PRINTF("BP: %f\n",BP)
 253
 254 /*------------------------------------------------------------------------------------------------*/
 255     /* FIND H SYNC WIDTH (TO NEAREST CHAR CELL) */
 256     H_sync_width = round(c.sync_width/100*H_total_pixels/c.char_cell_granularity)*c.char_cell_granularity;
 257     DEBUG_PRINTF("H_sync_width %f\n",H_sync_width)
 258
 259     /* FIND FRONT H PORCH(TO NEAREST CHAR CELL) */
 260     H_front_porch = (blanking_time/2) - H_sync_width;
 261     DEBUG_PRINTF("H_front_porch %f\n",H_front_porch)
 262     /* FIND BACK H PORCH(TO NEAREST CHAR CELL) */
 263     H_back_porch = H_sync_width + H_front_porch;
 264     DEBUG_PRINTF("H_back_porch%f\n",H_back_porch)
 265
 266     H_sync_start = H_total_pixels  - (H_sync_width + H_back_porch);
 267     DEBUG_PRINTF("H_sync_start %f\n",H_sync_start)
 268     H_sync_end = H_total_pixels  - H_back_porch;
 269     DEBUG_PRINTF("H_sync_end %f\n",H_sync_end)
 270
 271     V_back_porch = interlace + BP;
 272     DEBUG_PRINTF("V_back_porch%f\n",V_back_porch)
 273     V_front_porch = interlace + c.min_front_porch;
 274     DEBUG_PRINTF("V_front_porch%f\n",V_front_porch)
 275
 276     V_sync_width = c.Vsync_need;
 277     V_sync_start = V_total_lines_field  - (V_sync_width + V_back_porch);
 278     DEBUG_PRINTF("V_sync_start %f\n",V_sync_start)
 279     V_sync_end = V_total_lines_field  - V_back_porch;
 280     DEBUG_PRINTF("V_sync_end %f\n",V_sync_end)
 281
 282     result->hTotal = H_total_pixels;
 283     result-> hSyncStart  = H_sync_start;  /* Horizontal sync start in pixels */
 284     result-> hSyncEnd = H_sync_end;   /* Horizontal sync end in pixels */
 285     result-> vTotal= V_total_lines_field;     /* Vertical total in lines */
 286     result-> vSyncStart = V_sync_start; /* Vertical sync start in lines */
 287     result-> vSyncEnd = V_sync_end;   /* Vertical sync end in lines */
 288     result->  Flags = (result->Flags)|VESA_CRTC_HSYNC_NEG;      /* Flags (Interlaced, Double Scan etc) */
 289
 290     if (want_interlace)
 291     {
 292     result->Flags = (result->Flags) | VESA_CRTC_INTERLACED;
 293     }
 294
 295     result->  PixelClock = pixel_freq*1000000; /* Pixel clock in units of Hz */
 296     result-> RefreshRate = actual_V_frame_freq*100;/* Refresh rate in units of 0.01 Hz*/
 297
 298     }
 299
 300