Brickworks > API documentation > bw_hs2

bw_hs2

Description

Second-order high shelf filter (12 dB/oct) with unitary DC gain.

Info

Module type: dsp

Version: 1.0.0

Requires:

API

bw_hs2_coeffs

typedef struct bw_hs2_coeffs bw_hs2_coeffs;

Coefficients and related.

bw_hs2_state

typedef struct bw_hs2_state bw_hs2_state;

Internal state and related.

bw_hs2_init()

static inline void bw_hs2_init(
	bw_hs2_coeffs * BW_RESTRICT coeffs);

Initializes input parameter values in coeffs.

bw_hs2_set_sample_rate()

static inline void bw_hs2_set_sample_rate(
	bw_hs2_coeffs * BW_RESTRICT coeffs,
	float                       sample_rate);

Sets the sample_rate (Hz) value in coeffs.

bw_hs2_reset_coeffs()

static inline void bw_hs2_reset_coeffs(
	bw_hs2_coeffs * BW_RESTRICT coeffs);

Resets coefficients in coeffs to assume their target values.

bw_hs2_reset_state()

static inline float bw_hs2_reset_state(
	const bw_hs2_coeffs * BW_RESTRICT coeffs,
	bw_hs2_state * BW_RESTRICT        state,
	float                             x_0);

Resets the given state to its initial values using the given coeffs and the quiescent/initial input value x_0.

Returns the corresponding quiescent/initial output value.

bw_hs2_reset_state_multi()

static inline void bw_hs2_reset_state_multi(
	const bw_hs2_coeffs * BW_RESTRICT              coeffs,
	bw_hs2_state * BW_RESTRICT const * BW_RESTRICT state,
	const float *                                  x_0,
	float *                                        y_0,
	size_t                                         n_channels);

Resets each of the n_channels states to its initial values using the given coeffs and the corresponding initial input value in the x_0 array.

The corresponding initial output values are written into the y_0 array, if not NULL.

bw_hs2_update_coeffs_ctrl()

static inline void bw_hs2_update_coeffs_ctrl(
	bw_hs2_coeffs * BW_RESTRICT coeffs);

Triggers control-rate update of coefficients in coeffs.

bw_hs2_update_coeffs_audio()

static inline void bw_hs2_update_coeffs_audio(
	bw_hs2_coeffs * BW_RESTRICT coeffs);

Triggers audio-rate update of coefficients in coeffs.

bw_hs2_process1()

static inline float bw_hs2_process1(
	const bw_hs2_coeffs * BW_RESTRICT coeffs,
	bw_hs2_state * BW_RESTRICT        state,
	float                             x);

Processes one input sample x using coeffs, while using and updating state. Returns the corresponding output sample.

bw_hs2_process()

static inline void bw_hs2_process(
	bw_hs2_coeffs * BW_RESTRICT coeffs,
	bw_hs2_state * BW_RESTRICT  state,
	const float *               x,
	float *                     y,
	size_t                      n_samples);

Processes the first n_samples of the input buffer x and fills the first n_samples of the output buffer y, while using and updating both coeffs and state (control and audio rate).

bw_hs2_process_multi()

static inline void bw_hs2_process_multi(
	bw_hs2_coeffs * BW_RESTRICT                    coeffs,
	bw_hs2_state * BW_RESTRICT const * BW_RESTRICT state,
	const float * const *                          x,
	float * const *                                y,
	size_t                                         n_channels,
	size_t                                         n_samples);

Processes the first n_samples of the n_channels input buffers x and fills the first n_samples of the n_channels output buffers y, while using and updating both the common coeffs and each of the n_channels states (control and audio rate).

bw_hs2_set_cutoff()

static inline void bw_hs2_set_cutoff(
	bw_hs2_coeffs * BW_RESTRICT coeffs,
	float                       value);

Sets the cutoff frequency value (Hz) in coeffs.

value must be finite and positive.

By the time bw_hs2_reset_coeffs(), bw_hs2_update_coeffs_ctrl(), bw_hs2_update_coeffs_audio(), bw_hs2_process1(), bw_hs2_process(), or bw_hs2_process_multi() is called, cutoff * bw_sqrtf(bw_sqrtf(high_gain)) must be in [1e-6f, 1e12f].

Default value: 1e3f.

bw_hs2_set_Q()

static inline void bw_hs2_set_Q(
	bw_hs2_coeffs * BW_RESTRICT coeffs,
	float                       value);

Sets the quality factor to the given value in coeffs.

Valid range: [1e-6f, 1e6f].

Default value: 0.5f.

bw_hs2_set_prewarp_at_cutoff()

static inline void bw_hs2_set_prewarp_at_cutoff(
	bw_hs2_coeffs * BW_RESTRICT coeffs,
	char                        value);

Sets whether bilinear transform prewarping frequency should match the cutoff frequency (non-0) or not (0).

Default value: non-0 (on).

bw_hs2_set_prewarp_freq()

static inline void bw_hs2_set_prewarp_freq(
	bw_hs2_coeffs * BW_RESTRICT coeffs,
	float                       value);

Sets the prewarping frequency value (Hz) in coeffs.

Only used when the prewarp_at_cutoff parameter is off and however internally limited to avoid instability.

Valid range: [1e-6f, 1e12f].

Default value: 1e3f.

bw_hs2_set_high_gain_lin()

static inline void bw_hs2_set_high_gain_lin(
	bw_hs2_coeffs * BW_RESTRICT coeffs,
	float                       value);

Sets the high-frequency gain parameter to the given value (linear gain) in coeffs.

Valid range: [1e-30f, 1e30f].

By the time bw_hs2_reset_coeffs(), bw_hs2_update_coeffs_ctrl(), bw_hs2_update_coeffs_audio(), bw_hs2_process1(), bw_hs2_process(), or bw_hs2_process_multi() is called, cutoff * bw_sqrtf(bw_sqrtf(high_gain)) must be in [1e-6f, 1e12f].

Default value: 1.f.

bw_hs2_set_high_gain_dB()

static inline void bw_hs2_set_high_gain_dB(
	bw_hs2_coeffs * BW_RESTRICT coeffs,
	float                       value);

Sets the high-frequency gain parameter to the given value (dB) in coeffs.

Valid range: [-600.f, 600.f].

By the time bw_hs2_reset_coeffs(), bw_hs2_update_coeffs_ctrl(), bw_hs2_update_coeffs_audio(), bw_hs2_process1(), bw_hs2_process(), or bw_hs2_process_multi() is called, cutoff * bw_sqrtf(bw_sqrtf(high_gain)) must be in [1e-6f, 1e12f].

Default value: 0.f.

bw_hs2_coeffs_is_valid()

static inline char bw_hs2_coeffs_is_valid(
	const bw_hs2_coeffs * BW_RESTRICT coeffs);

Tries to determine whether coeffs is valid and returns non-0 if it seems to be the case and 0 if it is certainly not. False positives are possible, false negatives are not.

coeffs must at least point to a readable memory block of size greater than or equal to that of bw_hs2_coeffs.

bw_hs2_state_is_valid()

static inline char bw_hs2_state_is_valid(
	const bw_hs2_coeffs * BW_RESTRICT coeffs,
	const bw_hs2_state * BW_RESTRICT  state);

Tries to determine whether state is valid and returns non-0 if it seems to be the case and 0 if it is certainly not. False positives are possible, false negatives are not.

If coeffs is not NULL extra cross-checks might be performed (state is supposed to be associated to coeffs).

state must at least point to a readable memory block of size greater than or equal to that of bw_hs2_state.

C++ wrapper

Brickworks::HS2
template<size_t N_CHANNELS>
class HS2 {
public:
	HS2();

	void setSampleRate(
		float sampleRate);

	void reset(
		float               x0 = 0.f,
		float * BW_RESTRICT y0 = nullptr);

	void reset(
		float                                       x0,
		std::array<float, N_CHANNELS> * BW_RESTRICT y0);

	void reset(
		const float * x0,
		float *       y0 = nullptr);

	void reset(
		std::array<float, N_CHANNELS>               x0,
		std::array<float, N_CHANNELS> * BW_RESTRICT y0 = nullptr);

	void process(
		const float * const * x,
		float * const *       y,
		size_t                nSamples);

	void process(
		std::array<const float *, N_CHANNELS> x,
		std::array<float *, N_CHANNELS>       y,
		size_t                                nSamples);

	void setCutoff(
		float value);

	void setQ(
		float value);

	void setPrewarpAtCutoff(
		bool value);

	void setPrewarpFreq(
		float value);

	void setHighGainLin(
		float value);

	void setHighGainDB(
		float value);
...
}

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