Plugin API Reference

Lifecycle — required by all plugin types

Export	Signature	Notes
amp_plugin_info	const AmpPluginInfo* (void)	Static metadata; api_version must equal 2.
amp_plugin_init	int (const AmpHostContext*)	Return 0 = OK. Receives sample rate, channels, buffer size, data dir, log.
amp_plugin_shutdown	void (void)	Cleanup before the library is unloaded.

DSP — type 1 (AMP_PLUGIN_DSP)

Export	Signature	Thread
amp_plugin_dsp_process required	void (float* samples, int frames, int channels)	audio — realtime-safe, in place, interleaved PCM [-1,1]

Input — type 2 (AMP_PLUGIN_INPUT)

Export	Signature	Returns
amp_plugin_input_can_decode	int (const char* ext)	1 if you handle this extension
amp_plugin_input_open	void* (const char* path, int* sr, int* ch)	opaque handle (sets sample rate + channels)
amp_plugin_input_read	int (void* h, float* buf, int maxFrames)	frames produced (0 = EOF)
amp_plugin_input_close	void (void* h)	—

Visualization — type 3 (AMP_PLUGIN_VISUALIZATION)

Export	Signature	Thread
amp_plugin_vis_push required	void (const float* samples, int frames, int channels)	audio — copy to a lock-free buffer, render off-thread

Crossfader — type 4 (AMP_PLUGIN_CROSSFADER)

Export	Signature	Notes
amp_plugin_crossfader_blend required	void (const float* a, const float* b, float* out, int frames, int ch, float position)	position 0=A · 0.5=equal · 1=B. Realtime-safe.

Parameter API — optional (DSP + Crossfader)

Export	Signature
amp_plugin_set_param	void (const char* name, double value)
amp_plugin_get_param	double (const char* name)
amp_plugin_get_param_count	int (void)
amp_plugin_get_param_info	const AmpParamInfo* (int index)

Provide these and the host builds a generic parameter UI (sliders/dropdowns) automatically — no Qt required. AmpParamInfo carries name, label, unit, min, max, default, is_enum, enum_names.

Custom Qt UI — optional (shared Qt runtime only)

Export	Signature
amp_plugin_create_ui	void* (void* parent_qwidget) → returns QWidget*
amp_plugin_destroy_ui	void (void* widget)

Symbol-name constants

The header defines string constants for every export (e.g. AMP_SYM_INFO "amp_plugin_info", AMP_SYM_DSP_PROCESS, AMP_SYM_CROSSFADER_BLEND) for safe dlsym/ GetProcAddress probing. The host rejects any plugin whose api_version ≠ 2.