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WIP: Composite video generator

This commit is contained in:
Jean-François DEL NERO 2023-02-20 07:58:29 +01:00
parent 65211d182a
commit ed2a200d4b
2 changed files with 184 additions and 0 deletions
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127
src/broadcast_tv/composite.c Normal file
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///////////////////////////////////////////////////////////////////////////////////
//-------------------------------------------------------------------------------//
//-------------------------------------------------------------------------------//
//-----------H----H--X----X-----CCCCC----22222----0000-----0000------11----------//
//----------H----H----X-X-----C--------------2---0----0---0----0--1--1-----------//
//---------HHHHHH-----X------C----------22222---0----0---0----0-----1------------//
//--------H----H----X--X----C----------2-------0----0---0----0-----1-------------//
//-------H----H---X-----X---CCCCC-----222222----0000-----0000----1111------------//
//-------------------------------------------------------------------------------//
//----------------------------------------------------- http://hxc2001.free.fr --//
///////////////////////////////////////////////////////////////////////////////////
// File : composite.c
// Contains: Composite video signal generator
//
// This file is part of rf-tools.
//
// Written by: Jean-François DEL NERO
//
// Copyright (C) 2023 Jean-François DEL NERO
//
// You are free to do what you want with this code.
// A credit is always appreciated if you use it into your product :)
//
// Change History (most recent first):
///////////////////////////////////////////////////////////////////////////////////
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "composite.h"
#define EQUALIZING_PULSE_LEN 2.35
#define LINE_PULSE_LEN 4.7
#define ASSERTED_LEVEL 10
#define DEASSERTED_LEVEL 100
// PAL timings
pulses_state vertical_blanking[]=
{
// First sequence of equalizing pulses
{ 5, ASSERTED_LEVEL, DEASSERTED_LEVEL, EQUALIZING_PULSE_LEN/(double)1E6 ,((COMPOSITE_LINE_PERIOD_US/2)/(double)1E6),0},
// Sequence of synchronizing pulses (Line 1 count)
{ 5, ASSERTED_LEVEL, DEASSERTED_LEVEL, 27.3/(double)1E6 ,((COMPOSITE_LINE_PERIOD_US/2)/(double)1E6),0},
// Duration of second sequence of equalizing pulses
{ 5, ASSERTED_LEVEL, DEASSERTED_LEVEL, EQUALIZING_PULSE_LEN/(double)1E6 ,((COMPOSITE_LINE_PERIOD_US/2)/(double)1E6),0},
// Lines (6 > 310)
{305, ASSERTED_LEVEL, DEASSERTED_LEVEL, LINE_PULSE_LEN/(double)1E6 ,((COMPOSITE_LINE_PERIOD_US)/(double)1E6),0},
// First sequence of equalizing pulses
{ 5, ASSERTED_LEVEL, DEASSERTED_LEVEL, EQUALIZING_PULSE_LEN/(double)1E6 ,((COMPOSITE_LINE_PERIOD_US/2)/(double)1E6),0},
// Sequence of synchronizing pulses (Line 1 count)
{ 5, ASSERTED_LEVEL, DEASSERTED_LEVEL, 27.3/(double)1E6 ,((COMPOSITE_LINE_PERIOD_US/2)/(double)1E6),0},
// Duration of second sequence of equalizing pulses
{ 5, ASSERTED_LEVEL, DEASSERTED_LEVEL, EQUALIZING_PULSE_LEN/(double)1E6 ,((COMPOSITE_LINE_PERIOD_US/2)/(double)1E6),0},
// -- end of line 318
{ 1, DEASSERTED_LEVEL, DEASSERTED_LEVEL, 0 ,(COMPOSITE_LINE_PERIOD_US/2)/(double)1E6,0},
// Lines (319 > 622)
{304, ASSERTED_LEVEL, DEASSERTED_LEVEL, LINE_PULSE_LEN/(double)1E6 ,(COMPOSITE_LINE_PERIOD_US)/(double)1E6,0},
// Line 623 - (half)
{ 1, ASSERTED_LEVEL, DEASSERTED_LEVEL, LINE_PULSE_LEN/(double)1E6 ,((COMPOSITE_LINE_PERIOD_US)/2)/(double)1E6,0},
// End
{ 0, 0, 0, 0 ,0,0}
};
void init_composite(composite_state * state, int sample_rate, int x_res, int y_res)
{
state->sample_period = (double)1 / (double)sample_rate;
state->buf_x_res = x_res;
state->buf_y_res = y_res;
state->video_buffer = malloc( x_res * y_res * sizeof(uint32_t) );
if(state->video_buffer)
memset(state->video_buffer,0,x_res * y_res * sizeof(uint32_t) );
state->step_index = 0;
state->cur_state_time = 0;
}
void gen_video_signal(composite_state * state, double * vid_signal, int buf_size)
{
int i;
double value;
value = 0;
i = 0;
while(i < buf_size)
{
if( state->cur_state_time >= vertical_blanking[state->step_index].total_duration)
{
state->cur_state_time = 0;
state->repeat_cnt++;
if( state->repeat_cnt >= vertical_blanking[state->step_index].repeat )
{
state->repeat_cnt = 0;
state->step_index++;
}
if(!vertical_blanking[state->step_index].repeat)
{
state->step_index = 0;
}
}
if( state->cur_state_time >= vertical_blanking[state->step_index].first_duration )
{
value = vertical_blanking[state->step_index].end_val;
}
else
{
value = vertical_blanking[state->step_index].start_val;
}
vid_signal[i] = value;
state->cur_state_time += state->sample_period;
i++;
}
}

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src/broadcast_tv/composite.h Normal file
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///////////////////////////////////////////////////////////////////////////////////
//-------------------------------------------------------------------------------//
//-------------------------------------------------------------------------------//
//-----------H----H--X----X-----CCCCC----22222----0000-----0000------11----------//
//----------H----H----X-X-----C--------------2---0----0---0----0--1--1-----------//
//---------HHHHHH-----X------C----------22222---0----0---0----0-----1------------//
//--------H----H----X--X----C----------2-------0----0---0----0-----1-------------//
//-------H----H---X-----X---CCCCC-----222222----0000-----0000----1111------------//
//-------------------------------------------------------------------------------//
//----------------------------------------------------- http://hxc2001.free.fr --//
///////////////////////////////////////////////////////////////////////////////////
// File : composite.h
// Contains: Composite video signal generator
//
// This file is part of rf-tools.
//
// Written by: Jean-François DEL NERO
//
// Copyright (C) 2023 Jean-François DEL NERO
//
// You are free to do what you want with this code.
// A credit is always appreciated if you use it into your product :)
//
// Change History (most recent first):
///////////////////////////////////////////////////////////////////////////////////
#define COMPOSITE_LINE_PERIOD_US 64.0
typedef struct composite_state_
{
double sample_period;
int buf_x_res;
int buf_y_res;
uint32_t * video_buffer;
int step_index;
int repeat_cnt;
double cur_state_time;
}composite_state;
typedef struct pulses_state_
{
int repeat;
double start_val;
double end_val;
double first_duration;
double total_duration;
int type;
}pulses_state;
void init_composite(composite_state * state, int sample_rate, int x_res, int y_res);
void gen_video_signal(composite_state * state, double * vid_signal, int buf_size);