libvo/gtf.c

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