diff options
Diffstat (limited to 'src/common/emphasis.c')
| -rw-r--r-- | src/common/emphasis.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/src/common/emphasis.c b/src/common/emphasis.c index 3e753e7..c4a8242 100644 --- a/src/common/emphasis.c +++ b/src/common/emphasis.c @@ -26,10 +26,9 @@ #define PI M_PI -#define CUT_OFF_E 300.0 /* cut-off frequency for emphasis filters */ -#define CUT_OFF_H 300.0 /* cut-off frequency for high-pass filters */ +#define CUT_OFF_H 200.0 /* cut-off frequency for high-pass filters */ -int init_emphasis(emphasis_t *state, int samplerate) +int init_emphasis(emphasis_t *state, int samplerate, double cut_off) { double factor, rc, dt; @@ -40,13 +39,15 @@ int init_emphasis(emphasis_t *state, int samplerate) } /* exp (-2 * PI * CUT_OFF * delta_t) */ - factor = exp(-2.0 * PI * CUT_OFF_E / samplerate); /* 1/samplerate == delta_t */ + factor = exp(-2.0 * PI * cut_off / samplerate); /* 1/samplerate == delta_t */ PDEBUG(DDSP, DEBUG_DEBUG, "Emphasis factor = %.3f\n", factor); state->p.factor = factor; - state->p.amp = samplerate / 6350.0; + state->p.amp = samplerate / 6400.0; state->d.d_factor = factor; - state->d.amp = 1.0 / (samplerate / 5550.0); + state->d.amp = 1.0 / (samplerate / 5750.0); + /* high-pass filter prevents low frequency noise and dc level + * from being amplified by de-emphasis */ rc = 1.0 / (CUT_OFF_H * 2.0 *3.14); dt = 1.0 / samplerate; state->d.h_factor = rc / (rc + dt); |