On Wed, 2015-09-09 at 22:56 +0200, IOhannes m zmölnig wrote: > hi richard, paul, stefan and fellow LADders, > > the Debian folks currently are a bit at a loss of the proper > interpretation of the LADSPA_PROPERTY_REALTIME property. > > ladspa.h says: > > /* Property LADSPA_PROPERTY_REALTIME indicates that the plugin has a > > real-time dependency (e.g. listens to a MIDI device) and so its > > output must not be cached or subject to significant latency. */ > > the discussion started about a year ago (see [760758]), and it seems > that there are two opposing interpretations of that property: > > > #1 setting the property indicates to the host, that the plugin must not > be used in a non-realtime environment. > this means that a plugin that has this property set, must not be used > for batch processing, e.g. because it uses wall-clocked input (like > MIDI-devices) that simply won't deliver proper input when running at a > speed that is decoupled from wall clock. > > OR > > #2 setting the property indicates to the host, that the plugin can be > run at a lower (timing) priority; so the host can deliberately add > latency without compromising the usefulness of the full processing > chain. that would be mostly for plugins that do not do any input -> > output processing, but only take input (e.g. metering, recording).
We changed the name of this to "isLive" in LV2 to avoid confusion with the heavily overloaded term "realtime". I believe #1 is the intent. The hint serves to distinguish plugins that have some dependency on real time, from those that do not (only processing their input). The latter can be used in a more functional way, being called to process a block whenever, where the actual time run is called is irrelevant. The hint being set essentially means "if the plugin is activated, run() must be called regularly at a rate roughly corresponding to the passage of real time" Th comment says "plugin has a real-time dependency (e.g. listens to a MIDI device)" which seems pretty clear. Explanation #2, while perhaps a useful thing in some circumstances, really does not follow from the hint's definition. -- dr _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev