[LAD] Suitable peak/RMS/etc. data for UI metering

Hello, A new/upcoming LV2 extension (from Lars Luthman) includes facilities for sending host-calculated metric data for audio ports to a UI, for metering and such. This is intended as a sane replacement for the currently used kludge of having plugin control output ports provide this information. So, more DSP-minded folks, my question is: what data is required, and is a reasonable compromise between overhead and expressiveness? The current revision has the following: /** A data type that is used to pass peak and RMS values for a period of audio data at an input or output port to an UI, using port_event. See the documentation for pui:floatPeakRMS for details about how and when this should be done. */ typedef struct _LV2_PUI_Peak_RMS_Data { /** The start of the measurement period. This is just a running counter that must not be interpreted as any sort of global frame position. It should only be interpreted relative to the starts of other measurement periods in port_event() calls to the same plugin instance. This counter is allowed to overflow, in which case it should just wrap around. */ uint32_t period_start; /** The size of the measurement period, in the same units as period_start. */ uint32_t period_size; /** The peak value for the measurement period. This should be the maximal value for abs(sample) over all the samples in the period. */ float peak; /** The RMS value for the measurement period. This should be the root mean square value of the samples in the period, equivalent to sqrt((pow(sample1, 2) + pow(sample2, 2) + ... + pow(sampleN, 2)) / N) where N is period_size. */ float rms; } LV2_PUI_Peak_RMS_Data; Thanks, -dr