/
analogtv.c
2202 lines (1857 loc) · 64.9 KB
/
analogtv.c
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/* analogtv, Copyright (c) 2003, 2004 Trevor Blackwell <tlb@tlb.org>
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation. No representations are made about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*/
/*
This is the code for implementing something that looks like a conventional
analog TV set. It simulates the following characteristics of standard
televisions:
- Realistic rendering of a composite video signal
- Compression & brightening on the right, as the scan gets truncated
because of saturation in the flyback transformer
- Blooming of the picture dependent on brightness
- Overscan, cutting off a few pixels on the left side.
- Colored text in mixed graphics/text modes
It's amazing how much it makes your high-end monitor look like at large
late-70s TV. All you need is to put a big "Solid State" logo in curly script
on it and you'd be set.
In DirectColor or TrueColor modes, it generates pixel values
directly from RGB values it calculates across each scan line. In
PseudoColor mode, it consider each possible pattern of 5 preceding
bit values in each possible position modulo 4 and allocates a color
for each. A few things, like the brightening on the right side as
the horizontal trace slows down, aren't done in PseudoColor.
I originally wrote it for the Apple ][ emulator, and generalized it
here for use with a rewrite of xteevee and possibly others.
A maxim of technology is that failures reveal underlying mechanism.
A good way to learn how something works is to push it to failure.
The way it fails will usually tell you a lot about how it works. The
corollary for this piece of software is that in order to emulate
realistic failures of a TV set, it has to work just like a TV set.
So there is lots of DSP-style emulation of analog circuitry for
things like color decoding, H and V sync following, and more. In
2003, computers are just fast enough to do this at television signal
rates. We use a 14 MHz sample rate here, so we can do on the order
of a couple hundred instructions per sample and keep a good frame
rate.
Trevor Blackwell <tlb@tlb.org>
*/
#ifdef HAVE_COCOA
# include "jwxyz.h"
#else /* !HAVE_COCOA */
# include <X11/Xlib.h>
# include <X11/Xutil.h>
#endif
#include <assert.h>
#include "utils.h"
#include "resources.h"
#include "analogtv.h"
#include "yarandom.h"
#include "grabscreen.h"
/* #define DEBUG 1 */
#ifdef DEBUG
/* only works on linux + freebsd */
#include <machine/cpufunc.h>
#define DTIME_DECL u_int64_t dtimes[100]; int n_dtimes
#define DTIME_START do {n_dtimes=0; dtimes[n_dtimes++]=rdtsc(); } while (0)
#define DTIME dtimes[n_dtimes++]=rdtsc()
#define DTIME_SHOW(DIV) \
do { \
double _dtime_div=(DIV); \
printf("time/%.1f: ",_dtime_div); \
for (i=1; i<n_dtimes; i++) \
printf(" %0.9f",(dtimes[i]-dtimes[i-1])* 1e-9 / _dtime_div); \
printf("\n"); \
} while (0)
#else
#define DTIME_DECL
#define DTIME_START do { } while (0)
#define DTIME do { } while (0)
#define DTIME_SHOW(DIV) do { } while (0)
#endif
#define FASTRND (fastrnd = fastrnd*1103515245+12345)
static void analogtv_ntsc_to_yiq(analogtv *it, int lineno, double *signal,
int start, int end);
static double puramp(analogtv *it, double tc, double start, double over)
{
double pt=it->powerup-start;
double ret;
if (pt<0.0) return 0.0;
if (pt>900.0 || pt/tc>8.0) return 1.0;
ret=(1.0-exp(-pt/tc))*over;
if (ret>1.0) return 1.0;
return ret*ret;
}
/*
There are actual standards for TV signals: NTSC and RS-170A describe the
system used in the US and Japan. Europe has slightly different systems, but
not different enough to make substantially different screensaver displays.
Sadly, the standards bodies don't do anything so useful as publish the spec on
the web. Best bets are:
http://www.ee.washington.edu/conselec/CE/kuhn/ntsc/95x4.htm
http://www.ntsc-tv.com/ntsc-index-02.htm
In DirectColor or TrueColor modes, it generates pixel values directly from RGB
values it calculates across each scan line. In PseudoColor mode, it consider
each possible pattern of 5 preceding bit values in each possible position
modulo 4 and allocates a color for each. A few things, like the brightening on
the right side as the horizontal trace slows down, aren't done in PseudoColor.
I'd like to add a bit of visible retrace, but it conflicts with being able to
bitcopy the image when fast scrolling. After another couple of CPU
generations, we could probably regenerate the whole image from scratch every
time. On a P4 2 GHz it can manage this fine for blinking text, but scrolling
looks too slow.
*/
/* localbyteorder is MSBFirst or LSBFirst */
static int localbyteorder;
static const double float_low8_ofs=8388608.0;
static int float_extraction_works;
typedef union {
float f;
int i;
} float_extract_t;
static void
analogtv_init(void)
{
int i;
{
unsigned int localbyteorder_loc = (MSBFirst<<24) | (LSBFirst<<0);
localbyteorder=*(char *)&localbyteorder_loc;
}
if (1) {
float_extract_t fe;
int ans;
float_extraction_works=1;
for (i=0; i<256*4; i++) {
fe.f=float_low8_ofs+(double)i;
ans=fe.i&0x3ff;
if (ans != i) {
#ifdef DEBUG
printf("Float extraction failed for %d => %d\n",i,ans);
#endif
float_extraction_works=0;
break;
}
}
}
}
void
analogtv_set_defaults(analogtv *it, char *prefix)
{
char buf[256];
sprintf(buf,"%sTVTint",prefix);
it->tint_control = get_float_resource(it->dpy, buf,"TVTint");
sprintf(buf,"%sTVColor",prefix);
it->color_control = get_float_resource(it->dpy, buf,"TVColor")/100.0;
sprintf(buf,"%sTVBrightness",prefix);
it->brightness_control = get_float_resource(it->dpy, buf,"TVBrightness") / 100.0;
sprintf(buf,"%sTVContrast",prefix);
it->contrast_control = get_float_resource(it->dpy, buf,"TVContrast") / 100.0;
it->height_control = 1.0;
it->width_control = 1.0;
it->squish_control = 0.0;
it->powerup=1000.0;
it->hashnoise_rpm=0;
it->hashnoise_on=0;
it->hashnoise_enable=1;
it->horiz_desync=frand(10.0)-5.0;
it->squeezebottom=frand(5.0)-1.0;
#ifdef DEBUG
printf("analogtv: prefix=%s\n",prefix);
printf(" use: shm=%d cmap=%d color=%d\n",
it->use_shm,it->use_cmap,it->use_color);
printf(" controls: tint=%g color=%g brightness=%g contrast=%g\n",
it->tint_control, it->color_control, it->brightness_control,
it->contrast_control);
printf(" freq_error %g: %g %d\n",
it->freq_error, it->freq_error_inc, it->flutter_tint);
printf(" desync: %g %d\n",
it->horiz_desync, it->flutter_horiz_desync);
printf(" hashnoise rpm: %g\n",
it->hashnoise_rpm);
printf(" vis: %d %d %d\n",
it->visclass, it->visbits, it->visdepth);
printf(" shift: %d-%d %d-%d %d-%d\n",
it->red_invprec,it->red_shift,
it->green_invprec,it->green_shift,
it->blue_invprec,it->blue_shift);
printf(" size: %d %d %d %d xrepl=%d\n",
it->usewidth, it->useheight,
it->screen_xo, it->screen_yo, it->xrepl);
printf(" ANALOGTV_V=%d\n",ANALOGTV_V);
printf(" ANALOGTV_TOP=%d\n",ANALOGTV_TOP);
printf(" ANALOGTV_VISLINES=%d\n",ANALOGTV_VISLINES);
printf(" ANALOGTV_BOT=%d\n",ANALOGTV_BOT);
printf(" ANALOGTV_H=%d\n",ANALOGTV_H);
printf(" ANALOGTV_SYNC_START=%d\n",ANALOGTV_SYNC_START);
printf(" ANALOGTV_BP_START=%d\n",ANALOGTV_BP_START);
printf(" ANALOGTV_CB_START=%d\n",ANALOGTV_CB_START);
printf(" ANALOGTV_PIC_START=%d\n",ANALOGTV_PIC_START);
printf(" ANALOGTV_PIC_LEN=%d\n",ANALOGTV_PIC_LEN);
printf(" ANALOGTV_FP_START=%d\n",ANALOGTV_FP_START);
printf(" ANALOGTV_PIC_END=%d\n",ANALOGTV_PIC_END);
printf(" ANALOGTV_HASHNOISE_LEN=%d\n",ANALOGTV_HASHNOISE_LEN);
#endif
}
extern Bool mono_p; /* shoot me */
static void
analogtv_free_image(analogtv *it)
{
if (it->image) {
if (it->use_shm) {
#ifdef HAVE_XSHM_EXTENSION
destroy_xshm_image(it->dpy, it->image, &it->shm_info);
#endif
} else {
XDestroyImage(it->image);
}
it->image=NULL;
}
}
static void
analogtv_alloc_image(analogtv *it)
{
if (it->use_shm) {
#ifdef HAVE_XSHM_EXTENSION
it->image=create_xshm_image(it->dpy, it->xgwa.visual, it->xgwa.depth, ZPixmap, 0,
&it->shm_info, it->usewidth, it->useheight);
#endif
if (!it->image) it->use_shm=0;
}
if (!it->image) {
it->image = XCreateImage(it->dpy, it->xgwa.visual, it->xgwa.depth, ZPixmap, 0, 0,
it->usewidth, it->useheight, 8, 0);
it->image->data = (char *)malloc(it->image->height * it->image->bytes_per_line);
}
memset (it->image->data, 0, it->image->height * it->image->bytes_per_line);
}
static void
analogtv_configure(analogtv *it)
{
int oldwidth=it->usewidth;
int oldheight=it->useheight;
int wlim,hlim,height_diff;
/* If the window is very small, don't let the image we draw get lower
than the actual TV resolution (266x200.)
If the aspect ratio of the window is within 15% of a 4:3 ratio,
then scale the image to exactly fill the window.
Otherwise, center the image either horizontally or vertically,
padding on the left+right, or top+bottom, but not both.
If it's very close (2.5%) to a multiple of VISLINES, make it exact
For example, it maps 1024 => 1000.
*/
float percent = 0.15; /* jwz: 20% caused severe top/bottom clipping
in Pong on 1680x1050 iMac screen. */
float min_ratio = 4.0 / 3.0 * (1 - percent);
float max_ratio = 4.0 / 3.0 * (1 + percent);
float ratio;
float height_snap=0.025;
hlim = it->xgwa.height;
wlim = it->xgwa.width;
ratio = wlim / (float) hlim;
if (wlim < 266 || hlim < 200)
{
wlim = 266;
hlim = 200;
# ifdef DEBUG
fprintf (stderr,
"size: minimal: %dx%d in %dx%d (%.3f < %.3f < %.3f)\n",
wlim, hlim, it->xgwa.width, it->xgwa.height,
min_ratio, ratio, max_ratio);
# endif
}
else if (ratio > min_ratio && ratio < max_ratio)
{
# ifdef DEBUG
fprintf (stderr,
"size: close enough: %dx%d (%.3f < %.3f < %.3f)\n",
wlim, hlim, min_ratio, ratio, max_ratio);
# endif
}
else if (ratio > max_ratio)
{
wlim = hlim*max_ratio;
# ifdef DEBUG
fprintf (stderr,
"size: center H: %dx%d in %dx%d (%.3f < %.3f < %.3f)\n",
wlim, hlim, it->xgwa.width, it->xgwa.height,
min_ratio, ratio, max_ratio);
# endif
}
else /* ratio < min_ratio */
{
hlim = wlim/min_ratio;
# ifdef DEBUG
fprintf (stderr,
"size: center V: %dx%d in %dx%d (%.3f < %.3f < %.3f)\n",
wlim, hlim, it->xgwa.width, it->xgwa.height,
min_ratio, ratio, max_ratio);
# endif
}
height_diff = ((hlim + ANALOGTV_VISLINES/2) % ANALOGTV_VISLINES) - ANALOGTV_VISLINES/2;
if (height_diff != 0 && fabs(height_diff) < hlim * height_snap)
{
hlim -= height_diff;
}
/* Most times this doesn't change */
if (wlim != oldwidth || hlim != oldheight) {
it->usewidth=wlim;
it->useheight=hlim;
it->xrepl=1+it->usewidth/640;
if (it->xrepl>2) it->xrepl=2;
it->subwidth=it->usewidth/it->xrepl;
analogtv_free_image(it);
analogtv_alloc_image(it);
}
it->screen_xo = (it->xgwa.width-it->usewidth)/2;
it->screen_yo = (it->xgwa.height-it->useheight)/2;
it->need_clear=1;
}
void
analogtv_reconfigure(analogtv *it)
{
XGetWindowAttributes (it->dpy, it->window, &it->xgwa);
analogtv_configure(it);
}
analogtv *
analogtv_allocate(Display *dpy, Window window)
{
XGCValues gcv;
analogtv *it=NULL;
int i;
analogtv_init();
it=(analogtv *)calloc(1,sizeof(analogtv));
if (!it) return 0;
it->dpy=dpy;
it->window=window;
it->shrinkpulse=-1;
it->n_colors=0;
#ifdef HAVE_XSHM_EXTENSION
it->use_shm=1;
#else
it->use_shm=0;
#endif
XGetWindowAttributes (it->dpy, it->window, &it->xgwa);
it->screen=it->xgwa.screen;
it->colormap=it->xgwa.colormap;
it->visclass=it->xgwa.visual->class;
it->visbits=it->xgwa.visual->bits_per_rgb;
it->visdepth=it->xgwa.depth;
if (it->visclass == TrueColor || it->visclass == DirectColor) {
if (get_integer_resource (it->dpy, "use_cmap", "Integer")) {
it->use_cmap=1;
} else {
it->use_cmap=0;
}
it->use_color=!mono_p;
}
else if (it->visclass == PseudoColor || it->visclass == StaticColor) {
it->use_cmap=1;
it->use_color=!mono_p;
}
else {
it->use_cmap=1;
it->use_color=0;
}
it->red_mask=it->xgwa.visual->red_mask;
it->green_mask=it->xgwa.visual->green_mask;
it->blue_mask=it->xgwa.visual->blue_mask;
it->red_shift=it->red_invprec=-1;
it->green_shift=it->green_invprec=-1;
it->blue_shift=it->blue_invprec=-1;
if (!it->use_cmap) {
/* Is there a standard way to do this? Does this handle all cases? */
int shift, prec;
for (shift=0; shift<32; shift++) {
for (prec=1; prec<16 && prec<40-shift; prec++) {
unsigned long mask=(0xffffUL>>(16-prec)) << shift;
if (it->red_shift<0 && mask==it->red_mask)
it->red_shift=shift, it->red_invprec=16-prec;
if (it->green_shift<0 && mask==it->green_mask)
it->green_shift=shift, it->green_invprec=16-prec;
if (it->blue_shift<0 && mask==it->blue_mask)
it->blue_shift=shift, it->blue_invprec=16-prec;
}
}
if (it->red_shift<0 || it->green_shift<0 || it->blue_shift<0) {
if (0) fprintf(stderr,"Can't figure out color space\n");
goto fail;
}
for (i=0; i<ANALOGTV_CV_MAX; i++) {
int intensity=pow(i/256.0, 0.8)*65535.0; /* gamma correction */
if (intensity>65535) intensity=65535;
it->red_values[i]=((intensity>>it->red_invprec)<<it->red_shift);
it->green_values[i]=((intensity>>it->green_invprec)<<it->green_shift);
it->blue_values[i]=((intensity>>it->blue_invprec)<<it->blue_shift);
}
}
gcv.background=get_pixel_resource(it->dpy, it->colormap,
"background", "Background");
it->gc = XCreateGC(it->dpy, it->window, GCBackground, &gcv);
XSetWindowBackground(it->dpy, it->window, gcv.background);
XClearWindow(dpy,window);
analogtv_configure(it);
return it;
fail:
if (it) free(it);
return NULL;
}
void
analogtv_release(analogtv *it)
{
if (it->image) {
if (it->use_shm) {
#ifdef HAVE_XSHM_EXTENSION
destroy_xshm_image(it->dpy, it->image, &it->shm_info);
#endif
} else {
XDestroyImage(it->image);
}
it->image=NULL;
}
if (it->gc) XFreeGC(it->dpy, it->gc);
it->gc=NULL;
if (it->n_colors) XFreeColors(it->dpy, it->colormap, it->colors, it->n_colors, 0L);
it->n_colors=0;
}
/*
First generate the I and Q reference signals, which we'll multiply
the input signal by to accomplish the demodulation. Normally they
are shifted 33 degrees from the colorburst. I think this was convenient
for inductor-capacitor-vacuum tube implementation.
The tint control, FWIW, just adds a phase shift to the chroma signal,
and the color control controls the amplitude.
In text modes (colormode==0) the system disabled the color burst, and no
color was detected by the monitor.
freq_error gives a mismatch between the built-in oscillator and the
TV's colorbust. Some II Plus machines seemed to occasionally get
instability problems -- the crystal oscillator was a single
transistor if I remember correctly -- and the frequency would vary
enough that the tint would change across the width of the screen.
The left side would be in correct tint because it had just gotten
resynchronized with the color burst.
If we're using a colormap, set it up.
*/
int
analogtv_set_demod(analogtv *it)
{
int y_levels=10,i_levels=5,q_levels=5;
/*
In principle, we might be able to figure out how to adjust the
color map frame-by-frame to get some nice color bummage. But I'm
terrified of changing the color map because we'll get flashing.
I can hardly believe we still have to deal with colormaps. They're
like having NEAR PTRs: an enormous hassle for the programmer just
to save on memory. They should have been deprecated by 1995 or
so. */
cmap_again:
if (it->use_cmap && !it->n_colors) {
if (it->n_colors) {
XFreeColors(it->dpy, it->colormap, it->colors, it->n_colors, 0L);
it->n_colors=0;
}
{
int yli,qli,ili;
for (yli=0; yli<y_levels; yli++) {
for (ili=0; ili<i_levels; ili++) {
for (qli=0; qli<q_levels; qli++) {
double interpy,interpi,interpq;
double levelmult=700.0;
int r,g,b;
XColor col;
interpy=100.0 * ((double)yli/y_levels);
interpi=50.0 * (((double)ili-(0.5*i_levels))/(double)i_levels);
interpq=50.0 * (((double)qli-(0.5*q_levels))/(double)q_levels);
r=(int)((interpy + 1.04*interpi + 0.624*interpq)*levelmult);
g=(int)((interpy - 0.276*interpi - 0.639*interpq)*levelmult);
b=(int)((interpy - 1.105*interpi + 1.729*interpq)*levelmult);
if (r<0) r=0;
if (r>65535) r=65535;
if (g<0) g=0;
if (g>65535) g=65535;
if (b<0) b=0;
if (b>65535) b=65535;
#ifdef DEBUG
printf("%0.2f %0.2f %0.2f => %02x%02x%02x\n",
interpy, interpi, interpq,
r/256,g/256,b/256);
#endif
col.red=r;
col.green=g;
col.blue=b;
col.pixel=0;
if (!XAllocColor(it->dpy, it->colormap, &col)) {
if (q_levels > y_levels*4/12)
q_levels--;
else if (i_levels > y_levels*5/12)
i_levels--;
else
y_levels--;
if (y_levels<2)
return -1;
goto cmap_again;
}
it->colors[it->n_colors++]=col.pixel;
}
}
}
it->cmap_y_levels=y_levels;
it->cmap_i_levels=i_levels;
it->cmap_q_levels=q_levels;
}
}
return 0;
}
#if 0
unsigned int
analogtv_line_signature(analogtv_input *input, int lineno)
{
int i;
char *origsignal=&input->signal[(lineno+input->vsync)
%ANALOGTV_V][input->line_hsync[lineno]];
unsigned int hash=0;
/* probably lame */
for (i=0; i<ANALOGTV_PIC_LEN; i++) {
int c=origsignal[i];
hash = hash + (hash<<17) + c;
}
hash += input->line_hsync[lineno];
hash ^= hash >> 2;
/*
hash += input->hashnoise_times[lineno];
hash ^= hash >> 2;
*/
return hash;
}
#endif
/* Here we model the analog circuitry of an NTSC television.
Basically, it splits the signal into 3 signals: Y, I and Q. Y
corresponds to luminance, and you get it by low-pass filtering the
input signal to below 3.57 MHz.
I and Q are the in-phase and quadrature components of the 3.57 MHz
subcarrier. We get them by multiplying by cos(3.57 MHz*t) and
sin(3.57 MHz*t), and low-pass filtering. Because the eye has less
resolution in some colors than others, the I component gets
low-pass filtered at 1.5 MHz and the Q at 0.5 MHz. The I component
is approximately orange-blue, and Q is roughly purple-green. See
http://www.ntsc-tv.com for details.
We actually do an awful lot to the signal here. I suspect it would
make sense to wrap them all up together by calculating impulse
response and doing FFT convolutions.
*/
static void
analogtv_ntsc_to_yiq(analogtv *it, int lineno, double *signal,
int start, int end)
{
enum {MAXDELAY=32};
int i;
double *sp;
int phasecorr=(signal-it->rx_signal)&3;
struct analogtv_yiq_s *yiq;
int colormode;
double agclevel=it->agclevel;
double brightadd=it->brightness_control*100.0 - ANALOGTV_BLACK_LEVEL;
double delay[MAXDELAY+ANALOGTV_PIC_LEN], *dp;
double multiq2[4];
{
double cb_i=(it->line_cb_phase[lineno][(2+phasecorr)&3]-
it->line_cb_phase[lineno][(0+phasecorr)&3])/16.0;
double cb_q=(it->line_cb_phase[lineno][(3+phasecorr)&3]-
it->line_cb_phase[lineno][(1+phasecorr)&3])/16.0;
colormode = (cb_i * cb_i + cb_q * cb_q) > 2.8;
if (colormode) {
double tint_i = -cos((103 + it->color_control)*3.1415926/180);
double tint_q = sin((103 + it->color_control)*3.1415926/180);
multiq2[0] = (cb_i*tint_i - cb_q*tint_q) * it->color_control;
multiq2[1] = (cb_q*tint_i + cb_i*tint_q) * it->color_control;
multiq2[2]=-multiq2[0];
multiq2[3]=-multiq2[1];
}
}
#if 0
if (lineno==100) {
printf("multiq = [%0.3f %0.3f %0.3f %0.3f] ",
it->multiq[60],it->multiq[61],it->multiq[62],it->multiq[63]);
printf("it->line_cb_phase = [%0.3f %0.3f %0.3f %0.3f]\n",
it->line_cb_phase[lineno][0],it->line_cb_phase[lineno][1],
it->line_cb_phase[lineno][2],it->line_cb_phase[lineno][3]);
printf("multiq2 = [%0.3f %0.3f %0.3f %0.3f]\n",
multiq2[0],multiq2[1],multiq2[2],multiq2[3]);
}
#endif
dp=delay+ANALOGTV_PIC_LEN-MAXDELAY;
for (i=0; i<5; i++) dp[i]=0.0;
assert(start>=0);
assert(end < ANALOGTV_PIC_LEN+10);
dp=delay+ANALOGTV_PIC_LEN-MAXDELAY;
for (i=0; i<24; i++) dp[i]=0.0;
for (i=start, yiq=it->yiq+start, sp=signal+start;
i<end;
i++, dp--, yiq++, sp++) {
/* Now filter them. These are infinite impulse response filters
calculated by the script at
http://www-users.cs.york.ac.uk/~fisher/mkfilter. This is
fixed-point integer DSP, son. No place for wimps. We do it in
integer because you can count on integer being faster on most
CPUs. We care about speed because we need to recalculate every
time we blink text, and when we spew random bytes into screen
memory. This is roughly 16.16 fixed point arithmetic, but we
scale some filter values up by a few bits to avoid some nasty
precision errors. */
/* Filter Y with a 4-pole low-pass Butterworth filter at 3.5 MHz
with an extra zero at 3.5 MHz, from
mkfilter -Bu -Lp -o 4 -a 2.1428571429e-01 0 -Z 2.5e-01 -l
Delay about 2 */
dp[0] = sp[0] * 0.0469904257251935 * agclevel;
dp[8] = (+1.0*(dp[6]+dp[0])
+4.0*(dp[5]+dp[1])
+7.0*(dp[4]+dp[2])
+8.0*(dp[3])
-0.0176648*dp[12]
-0.4860288*dp[10]);
yiq->y = dp[8] + brightadd;
}
if (colormode) {
dp=delay+ANALOGTV_PIC_LEN-MAXDELAY;
for (i=0; i<27; i++) dp[i]=0.0;
for (i=start, yiq=it->yiq+start, sp=signal+start;
i<end;
i++, dp--, yiq++, sp++) {
double sig=*sp;
/* Filter I and Q with a 3-pole low-pass Butterworth filter at
1.5 MHz with an extra zero at 3.5 MHz, from
mkfilter -Bu -Lp -o 3 -a 1.0714285714e-01 0 -Z 2.5000000000e-01 -l
Delay about 3.
*/
dp[0] = sig*multiq2[i&3] * 0.0833333333333;
yiq->i=dp[8] = (dp[5] + dp[0]
+3.0*(dp[4] + dp[1])
+4.0*(dp[3] + dp[2])
-0.3333333333 * dp[10]);
dp[16] = sig*multiq2[(i+3)&3] * 0.0833333333333;
yiq->q=dp[24] = (dp[16+5] + dp[16+0]
+3.0*(dp[16+4] + dp[16+1])
+4.0*(dp[16+3] + dp[16+2])
-0.3333333333 * dp[24+2]);
}
} else {
for (i=start, yiq=it->yiq+start; i<end; i++, yiq++) {
yiq->i = yiq->q = 0.0;
}
}
}
void
analogtv_setup_teletext(analogtv_input *input)
{
int x,y;
int teletext=ANALOGTV_BLACK_LEVEL;
/* Teletext goes in line 21. But I suspect there are other things
in the vertical retrace interval */
for (y=19; y<22; y++) {
for (x=ANALOGTV_PIC_START; x<ANALOGTV_PIC_END; x++) {
if ((x&7)==0) {
teletext=(random()&1) ? ANALOGTV_WHITE_LEVEL : ANALOGTV_BLACK_LEVEL;
}
input->signal[y][x]=teletext;
}
}
}
void
analogtv_setup_frame(analogtv *it)
{
int i,x,y;
it->redraw_all=0;
if (it->flutter_horiz_desync) {
/* Horizontal sync during vertical sync instability. */
it->horiz_desync += -0.10*(it->horiz_desync-3.0) +
((int)(random()&0xff)-0x80) *
((int)(random()&0xff)-0x80) *
((int)(random()&0xff)-0x80) * 0.000001;
}
for (i=0; i<ANALOGTV_V; i++) {
it->hashnoise_times[i]=0;
}
if (it->hashnoise_enable && !it->hashnoise_on) {
if (random()%10000==0) {
it->hashnoise_on=1;
it->shrinkpulse=random()%ANALOGTV_V;
}
}
if (random()%1000==0) {
it->hashnoise_on=0;
}
if (it->hashnoise_on) {
it->hashnoise_rpm += (15000.0 - it->hashnoise_rpm)*0.05 +
((int)(random()%2000)-1000)*0.1;
} else {
it->hashnoise_rpm -= 100 + 0.01*it->hashnoise_rpm;
if (it->hashnoise_rpm<0.0) it->hashnoise_rpm=0.0;
}
if (it->hashnoise_rpm > 0.0) {
int hni;
int hnc=it->hashnoise_counter; /* in 24.8 format */
/* Convert rpm of a 16-pole motor into dots in 24.8 format */
hni = (int)(ANALOGTV_V * ANALOGTV_H * 256.0 /
(it->hashnoise_rpm * 16.0 / 60.0 / 60.0));
while (hnc < (ANALOGTV_V * ANALOGTV_H)<<8) {
y=(hnc>>8)/ANALOGTV_H;
x=(hnc>>8)%ANALOGTV_H;
if (x>0 && x<ANALOGTV_H - ANALOGTV_HASHNOISE_LEN) {
it->hashnoise_times[y]=x;
}
hnc += hni + (int)(random()%65536)-32768;
}
hnc -= (ANALOGTV_V * ANALOGTV_H)<<8;
}
if (it->rx_signal_level != 0.0)
it->agclevel = 1.0/it->rx_signal_level;
#ifdef DEBUG2
printf("filter: ");
for (i=0; i<ANALOGTV_GHOSTFIR_LEN; i++) {
printf(" %0.3f",it->ghostfir[i]);
}
printf(" siglevel=%g agc=%g\n", siglevel, it->agclevel);
#endif
}
void
analogtv_setup_sync(analogtv_input *input, int do_cb, int do_ssavi)
{
int i,lineno,vsync;
signed char *sig;
int synclevel = do_ssavi ? ANALOGTV_WHITE_LEVEL : ANALOGTV_SYNC_LEVEL;
for (lineno=0; lineno<ANALOGTV_V; lineno++) {
vsync=lineno>=3 && lineno<7;
sig=input->signal[lineno];
i=ANALOGTV_SYNC_START;
if (vsync) {
while (i<ANALOGTV_BP_START) sig[i++]=ANALOGTV_BLANK_LEVEL;
while (i<ANALOGTV_H) sig[i++]=synclevel;
} else {
while (i<ANALOGTV_BP_START) sig[i++]=synclevel;
while (i<ANALOGTV_PIC_START) sig[i++]=ANALOGTV_BLANK_LEVEL;
while (i<ANALOGTV_FP_START) sig[i++]=ANALOGTV_BLACK_LEVEL;
}
while (i<ANALOGTV_H) sig[i++]=ANALOGTV_BLANK_LEVEL;
if (do_cb) {
/* 9 cycles of colorburst */
for (i=ANALOGTV_CB_START; i<ANALOGTV_CB_START+36; i+=4) {
sig[i+1] += ANALOGTV_CB_LEVEL;
sig[i+3] -= ANALOGTV_CB_LEVEL;
}
}
}
}
static void
analogtv_sync(analogtv *it)
{
int cur_hsync=it->cur_hsync;
int cur_vsync=it->cur_vsync;
int lineno = 0;
int i,j;
double osc,filt;
double *sp;
double cbfc=1.0/128.0;
sp = it->rx_signal + lineno*ANALOGTV_H + cur_hsync;
for (i=-32; i<32; i++) {
lineno = (cur_vsync + i + ANALOGTV_V) % ANALOGTV_V;
sp = it->rx_signal + lineno*ANALOGTV_H;
filt=0.0;
for (j=0; j<ANALOGTV_H; j+=ANALOGTV_H/16) {
filt += sp[j];
}
filt *= it->agclevel;
osc = (double)(ANALOGTV_V+i)/(double)ANALOGTV_V;
if (osc >= 1.05+0.0002 * filt) break;
}
cur_vsync = (cur_vsync + i + ANALOGTV_V) % ANALOGTV_V;
for (lineno=0; lineno<ANALOGTV_V; lineno++) {
if (lineno>5 && lineno<ANALOGTV_V-3) { /* ignore vsync interval */
sp = it->rx_signal + ((lineno + cur_vsync + ANALOGTV_V)%ANALOGTV_V
)*ANALOGTV_H + cur_hsync;
for (i=-8; i<8; i++) {
osc = (double)(ANALOGTV_H+i)/(double)ANALOGTV_H;
filt=(sp[i-3]+sp[i-2]+sp[i-1]+sp[i]) * it->agclevel;
if (osc >= 1.005 + 0.0001*filt) break;
}
cur_hsync = (cur_hsync + i + ANALOGTV_H) % ANALOGTV_H;
}
it->line_hsync[lineno]=(cur_hsync + ANALOGTV_PIC_START +
ANALOGTV_H) % ANALOGTV_H;
/* Now look for the colorburst, which is a few cycles after the H
sync pulse, and store its phase.
The colorburst is 9 cycles long, and we look at the middle 5
cycles.
*/
if (lineno>15) {
sp = it->rx_signal + lineno*ANALOGTV_H + (cur_hsync&~3);
for (i=ANALOGTV_CB_START+8; i<ANALOGTV_CB_START+36-8; i++) {
it->cb_phase[i&3] = it->cb_phase[i&3]*(1.0-cbfc) +
sp[i]*it->agclevel*cbfc;
}
}
{
double tot=0.1;
double cbgain;
for (i=0; i<4; i++) {
tot += it->cb_phase[i]*it->cb_phase[i];
}
cbgain = 32.0/sqrt(tot);
for (i=0; i<4; i++) {
it->line_cb_phase[lineno][i]=it->cb_phase[i]*cbgain;
}
}
#ifdef DEBUG
if (0) printf("hs=%d cb=[%0.3f %0.3f %0.3f %0.3f]\n",
cur_hsync,
it->cb_phase[0], it->cb_phase[1],
it->cb_phase[2], it->cb_phase[3]);
#endif
/* if (random()%2000==0) cur_hsync=random()%ANALOGTV_H; */
}
it->cur_hsync = cur_hsync;
it->cur_vsync = cur_vsync;
}
static double
analogtv_levelmult(analogtv *it, int level)
{
static const double levelfac[3]={-7.5, 5.5, 24.5};
return (40.0 + levelfac[level]*puramp(it, 3.0, 6.0, 1.0))/256.0;
}
static int
analogtv_level(analogtv *it, int y, int ytop, int ybot)
{
int level;
if (ybot-ytop>=7) {
if (y==ytop || y==ybot-1) level=0;
else if (y==ytop+1 || y==ybot-2) level=1;
else level=2;
}
else if (ybot-ytop>=5) {
if (y==ytop || y==ybot-1) level=0;
else level=2;
}
else if (ybot-ytop>=3) {
if (y==ytop) level=0;
else level=2;