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tube: reuse history buffers, clean up buffer size

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Connor Olding 2014-02-05 21:17:30 -08:00
parent 4de1731d93
commit 7cfeef142d
1 changed files with 23 additions and 17 deletions
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40
crap_tube.h
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@ -16,9 +16,12 @@
#define COPYRIGHT "MIT" #define COPYRIGHT "MIT"
#define PARAMETERS 0 #define PARAMETERS 0
#define HIST_SIZE 36
#define HIST_SIZE_2 18
typedef struct { typedef struct {
double history_L[64]; double history_L[HIST_SIZE];
double history_R[64]; double history_R[HIST_SIZE];
} personal; } personal;
static void static void
@ -35,19 +38,20 @@ distort(double x)
return (27*x + 9) / (9*x*x + 6*x + 19) - 9/19.; return (27*x + 9) / (9*x*x + 6*x + 19) - 9/19.;
} }
#define BQSHIFT(i) \
h[i*2 + 1] = h[i*2 + 0]; \
h[i*2 + 0] = x;
// b2 is always b0 with lowpasses // b2 is always b0 with lowpasses
// a0 is already factored into the rest of the coefficients // a0 is already factored into the rest of the coefficients
#define LOWPASS(i, b0, b1, a1, a2) \ #define LOWPASS(i, b0, b1, a1, a2) \
y = b0*x + b1*xn[i*2] + b0*xn[i*2 + 1] \ y = b0*x + b1*h[i*2 + 0] + b0*h[i*2 + 1] \
- a1*yn[i*2] - a2*yn[i*2 + 1]; \ - a1*h[i*2 + 2] - a2*h[i*2 + 3]; \
xn[i*2 + 1] = xn[i*2]; \ BQSHIFT(i); \
xn[i*2] = x; \
yn[i*2 + 1] = yn[i*2]; \
yn[i*2] = y; \
x = y; x = y;
static double static double
upsample(double xn[16], double yn[16], double x) upsample(double h[HIST_SIZE_2], double x)
{ {
double y; double y;
LOWPASS(0, +0.71327159,+0.00688573,-0.45391337,+0.88734229); LOWPASS(0, +0.71327159,+0.00688573,-0.45391337,+0.88734229);
@ -58,11 +62,12 @@ upsample(double xn[16], double yn[16], double x)
LOWPASS(5, +0.37268890,+0.47433865,+0.08224090,+0.13747554); LOWPASS(5, +0.37268890,+0.47433865,+0.08224090,+0.13747554);
LOWPASS(6, +0.33241251,+0.56148939,+0.16727062,+0.05904378); LOWPASS(6, +0.33241251,+0.56148939,+0.16727062,+0.05904378);
LOWPASS(7, +0.31079382,+0.60975767,+0.21392163,+0.01742368); LOWPASS(7, +0.31079382,+0.60975767,+0.21392163,+0.01742368);
BQSHIFT(8);
return y; return y;
} }
static double static double
downsample(double xn[16], double yn[16], double x) downsample(double h[HIST_SIZE_2], double x)
{ {
double y; double y;
LOWPASS(0, +0.62136966,-0.87573986,-1.56336581,+0.93036527); LOWPASS(0, +0.62136966,-0.87573986,-1.56336581,+0.93036527);
@ -73,17 +78,18 @@ downsample(double xn[16], double yn[16], double x)
LOWPASS(5, +0.24269774,-0.06242297,-0.85492245,+0.27789496); LOWPASS(5, +0.24269774,-0.06242297,-0.85492245,+0.27789496);
LOWPASS(6, +0.16673206,+0.11379847,-0.72421195,+0.17147454); LOWPASS(6, +0.16673206,+0.11379847,-0.72421195,+0.17147454);
LOWPASS(7, +0.12199271,+0.21811002,-0.64769184,+0.10978728); LOWPASS(7, +0.12199271,+0.21811002,-0.64769184,+0.10978728);
BQSHIFT(8);
return y; return y;
} }
static double static double
process_one(double h[64], double x) process_one(double h[HIST_SIZE], double x)
{ {
double y; double y;
y = downsample(h+32, h+48, distort(4*upsample(h, h+16, x))); y = downsample(h + HIST_SIZE_2, distort(4*upsample(h, x)));
downsample(h+32, h+48, distort(4*upsample(h, h+16, 0))); downsample(h + HIST_SIZE_2, distort(4*upsample(h, 0)));
downsample(h+32, h+48, distort(4*upsample(h, h+16, 0))); downsample(h + HIST_SIZE_2, distort(4*upsample(h, 0)));
downsample(h+32, h+48, distort(4*upsample(h, h+16, 0))); downsample(h + HIST_SIZE_2, distort(4*upsample(h, 0)));
return y*0.71; return y*0.71;
} }
@ -113,8 +119,8 @@ process_double(personal *data,
static void static void
resume(personal *data) { resume(personal *data) {
memset(data->history_L, 0, 64); memset(data->history_L, 0, HIST_SIZE*sizeof(double));
memset(data->history_R, 0, 64); memset(data->history_R, 0, HIST_SIZE*sizeof(double));
} }
static void static void