bw_sampler

Very basic sampler with variable playback speed.

Examples

Here you can download one or more example VST3 plugins for Windows, macOS and Linux. Source code of the audio engine(s) is included in the archive(s).

VST® is a trademark of Steinberg Media Technologies GmbH, registered in Europe and other countries.

API

Module type: DSP

bw_sampler_coeffs

typedef struct bw_sampler_coeffs bw_sampler_coeffs;

Coefficients and related.

bw_sampler_state

typedef struct bw_sampler_state bw_sampler_state;

Internal state and related.

bw_sampler_phase

typedef enum {
	bw_sampler_phase_before,
	bw_sampler_phase_playing,
	bw_sampler_phase_done
} bw_sampler_phase;

Sampler playback phase:

• bw_sampler_phase_before: playback has not yet started;
• bw_sampler_phase_playing: playback ongoing;
• bw_sampler_phase_done: playback finished.

bw_sampler_init()

static inline void bw_sampler_init(
	bw_sampler_coeffs * BW_RESTRICT coeffs);

Initializes input parameter values in coeffs.

bw_sampler_set_sample_rate()

static inline void bw_sampler_set_sample_rate(
	bw_sampler_coeffs * BW_RESTRICT coeffs,
	float                           sample_rate);

Sets the sample_rate (Hz) value in coeffs.

bw_sampler_reset_coeffs()

static inline void bw_sampler_reset_coeffs(
	bw_sampler_coeffs * BW_RESTRICT coeffs);

Resets coefficients in coeffs to assume their target values.

bw_sampler_reset_state()

static inline float bw_sampler_reset_state(
	const bw_sampler_coeffs * BW_RESTRICT coeffs,
	bw_sampler_state * BW_RESTRICT        state,
	const float * BW_RESTRICT             sample,
	size_t                                sample_length,
	float                                 pos_0);

Resets the given state to its initial values using the given coeffs, the audio sample and its corresponding sample_length, and the initial and the initial playback position pos_0.

Returns the corresponding initial output value.

sample_length must be strictly positive.

bw_sampler_reset_state_multi()

static inline void bw_sampler_reset_state_multi(
	const bw_sampler_coeffs * BW_RESTRICT              coeffs,
	bw_sampler_state * BW_RESTRICT const * BW_RESTRICT state,
	const float * BW_RESTRICT const * BW_RESTRICT      sample,
	const size_t * BW_RESTRICT                         sample_length,
	const float *                                      pos_0,
	float *                                            y_0,
	size_t                                             n_channels);

Resets each of the n_channels states to its initial values using the given coeffs, the n_channels audio samples and their corresponding sample_lengths, and the corresponding initial playback positions in the pos_0 array.

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

All values in sample_length must be strictly positive.

bw_sampler_update_coeffs_ctrl()

static inline void bw_sampler_update_coeffs_ctrl(
	bw_sampler_coeffs * BW_RESTRICT coeffs);

Triggers control-rate update of coefficients in coeffs.

bw_sampler_update_coeffs_audio()

static inline void bw_sampler_update_coeffs_audio(
	bw_sampler_coeffs * BW_RESTRICT coeffs);

Triggers audio-rate update of coefficients in coeffs.

bw_sampler_process1()

static inline float bw_sampler_process1(
	const bw_sampler_coeffs * BW_RESTRICT coeffs,
	bw_sampler_state * BW_RESTRICT        state,
	const float * BW_RESTRICT             sample,
	size_t                                sample_length);

Computes and returns the next output sample from the input audio sample of length sample_length using coeffs, while using and updating state (audio rate only).

sample_length must be strictly positive.

bw_sampler_process()

static inline void bw_sampler_process(
	bw_sampler_coeffs * BW_RESTRICT coeffs,
	bw_sampler_state * BW_RESTRICT  state,
	const float * BW_RESTRICT       sample,
	size_t                          sample_length,
	float * BW_RESTRICT             y,
	size_t                          n_samples);

Computes and fills the first n_samples of the output buffer y from the input audio sample of length sample_length, while using and updating both coeffs and state (control and audio rate).

sample_length must be strictly positive.

bw_sampler_process_multi()

static inline void bw_sampler_process_multi(
	bw_sampler_coeffs * BW_RESTRICT                    coeffs,
	bw_sampler_state * BW_RESTRICT const * BW_RESTRICT state,
	const float * BW_RESTRICT const * BW_RESTRICT      sample,
	const size_t * BW_RESTRICT                         sample_length,
	float * BW_RESTRICT const * BW_RESTRICT            y,
	size_t                                             n_channels,
	size_t                                             n_samples);

Computes and fills the first n_samples of the n_channels output buffers y using the given n_channels input audio samples and their corresponding sample_lengths, while using and updating both the common coeffs and each of the n_channels states (control and audio rate).

All values in sample_length must be strictly positive.

bw_sampler_set_rate()

static inline void bw_sampler_set_rate(
	bw_sampler_coeffs * BW_RESTRICT coeffs,
	float                           value);

Sets the playback rate value in coeffs.

value must be non-negative.

Default value: 1.f.

bw_sampler_get_phase()

static inline bw_sampler_phase bw_sampler_get_phase(
	const bw_sampler_state * BW_RESTRICT state);

Returns the current playback phase as stored in state.

bw_sampler_coeffs_is_valid()

static inline char bw_sampler_coeffs_is_valid(
	const bw_sampler_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_sampler_coeffs.

bw_sampler_state_is_valid()

static inline char bw_sampler_state_is_valid(
	const bw_sampler_coeffs * BW_RESTRICT coeffs,
	const bw_sampler_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 BW_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_sampler_state.

C++ wrapper

Brickworks::Sampler

template<size_t N_CHANNELS = 1>
class Sampler {
public:
	Sampler();

	void setSampleRate(
		float sampleRate);

	void reset(
		const float * BW_RESTRICT const * BW_RESTRICT sample,
		const size_t * BW_RESTRICT                    sampleLength,
		float                                         pos0 = 0.f,
		float * BW_RESTRICT                           y0 = BW_NULL);

# ifndef BW_CXX_NO_ARRAY
	void reset(
		std::array<const float * BW_RESTRICT, N_CHANNELS> sample,
		std::array<size_t, N_CHANNELS>                    sampleLength,
		float                                             pos0 = 0.f,
		std::array<float, N_CHANNELS> * BW_RESTRICT       y0 = BW_NULL);
# endif

	void reset(
		const float * BW_RESTRICT const * BW_RESTRICT sample,
		const size_t * BW_RESTRICT                    sampleLength,
		const float *                                 pos0,
		float *                                       y0 = BW_NULL);

# ifndef BW_CXX_NO_ARRAY
	void reset(
		std::array<const float * BW_RESTRICT, N_CHANNELS> sample,
		std::array<size_t, N_CHANNELS>                    sampleLength,
		std::array<float, N_CHANNELS>                     pos0,
		std::array<float, N_CHANNELS> * BW_RESTRICT       y0 = BW_NULL);
# endif

	void process(
		const float * BW_RESTRICT const * BW_RESTRICT sample,
		const size_t * BW_RESTRICT                    sampleLength,
		float * const *                               y,
		size_t                                        nSamples);

# ifndef BW_CXX_NO_ARRAY
	void process(
		std::array<const float * BW_RESTRICT, N_CHANNELS> sample,
		std::array<size_t, N_CHANNELS>                    sampleLength,
		std::array<float *, N_CHANNELS>                   y,
		size_t                                            nSamples);
# endif

	void setRate(
		float value);

	bw_sampler_phase getPhase(
		size_t channel);
...
}

Changelog

• Version 1.0.0:
  • First release.