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