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/* hacktv - Analogue video transmitter for the HackRF */
/*=======================================================================*/
/* Copyright 2019 Philip Heron <phil@sanslogic.co.uk> */
/* */
/* This program is free software: you can redistribute it and/or modify */
/* it under the terms of the GNU General Public License as published by */
/* the Free Software Foundation, either version 3 of the License, or */
/* (at your option) any later version. */
/* */
/* This program 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 General Public License for more details. */
/* */
/* You should have received a copy of the GNU General Public License */
/* along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* -=== ACP / Macrovision encoder ===- */
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "video.h"
int acp_init(acp_t *s, vid_t *vid)
{
double left;
double spacing;
double psync_width;
int i;
memset(s, 0, sizeof(acp_t));
if(vid->conf.lines == 625)
{
left = 8.88e-6;
spacing = 5.92e-6;
psync_width = 2.368e-6;
}
else
{
left = 8.288e-6;
spacing = 8.288e-6;
psync_width = 2.222e-6;
}
/* Calculate the levels */
s->psync_level = vid->sync_level + round((vid->white_level - vid->sync_level) * 0.06);
s->pagc_level = vid->sync_level + round((vid->white_level - vid->sync_level) * 1.10);
/* Calculate the width of each pulse */
s->psync_width = round(vid->sample_rate * psync_width);
s->pagc_width = round(vid->sample_rate * 2.7e-6);
/* Left position of each pulse */
for(i = 0; i < 6; i++)
{
s->left[i] = round(vid->sample_rate * (left + spacing * i));
}
return(VID_OK);
}
void acp_free(acp_t *s)
{
if(s == NULL) return;
memset(s, 0, sizeof(acp_t));
}
int acp_render_line(vid_t *s, void *arg, int nlines, vid_line_t **lines)
{
acp_t *a = arg;
int i, x;
vid_line_t *l = lines[0];
i = 0;
if(l->line == 1)
{
/* Vary the AGC pulse level, clipped sawtooth waveform */
i = abs(l->frame * 4 % 1712 - 856) - 150;
if(i < 0) i = 0;
else if(i > 255) i = 255;
i = s->yiq_level_lookup[i << 16 | i << 8 | i].y;
a->pagc_level = s->sync_level + round((i - s->sync_level) * 1.10);
}
i = 0;
if(s->conf.lines == 625)
{
/* For 625-line modes, ACP is rendered on lines 9-18 and 321-330 */
if(l->line >= 9 && l->line <= 18) i = 1;
if(l->line >= 321 && l->line <= 330) i = 1;
}
else
{
/* For 525-line modes, ACP is rendered on lines 12-19 and 275-282 */
if(l->line >= 12 && l->line <= 19) i = 1;
if(l->line >= 275 && l->line <= 282) i = 1;
}
if(i == 0 || l->vbialloc) return(1);
/* Render the P-Sync / AGC pulse pairs */
for(i = 0; i < 6; i++)
{
/* Render the P-Sync pulse */
for(x = a->left[i]; x < a->left[i] + a->psync_width; x++)
{
l->output[x * 2] = a->psync_level;
}
/* Render the AGC pulse */
for(; x < a->left[i] + a->psync_width + a->pagc_width; x++)
{
l->output[x * 2] = a->pagc_level;
}
}
l->vbialloc = 1;
return(1);
}
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