[LAD] LV2 Beat reporting?

[Jeremy]

I would lean towards trigger "events" as well, but I'd probably want some
input from DAW developers before I just wrote an extension myself.

Jeremy

On Tue, Dec 28, 2010 at 3:00 PM, Paul Giblock <pgiblox at gmail.com> wrote:

> It sounds to me like the generic "Beat" Event would be a "TriggerEvent".
> Triggers could be for clock, gates, envelopes, etc..  At least I think this
> would model the way old modulars would interact fairly well.  But: Is it
> modeled as an audio-port with peaks to denote the triggers, or as an event
> port with timed events?  I'm leaning towards events personally.
>
> -Paul
>
>
> On Tue, Dec 28, 2010 at 2:29 PM, JohnLM <johnlm at apollo.lv> wrote:
>
>> Well I think the idea is quite good! I could think of few more uses,
>> including real-time DJ "crossfade/mix" sync by beats, and such.
>>
>> I haven't looked into LV2 much yet, but one thing is sure. You can't
>> make the plugin universal. Any host dealing with such plugin must be
>> aware of it's purpose whether the output is simply audio clicks or some
>> kind of event interface.
>>
>> As much as I understand LV2 does not mandate universal-use "filter"
>> plugins as LADSPA did, so you're good with extending it as you see fit.
>> Host code modifications will be required, but if you make it generic
>> enough, the interface could be picked up by various projects.
>>
>>
>> On Sun, 26 Dec 2010 01:58:13 -0500
>> Jeremy <jeremybubs at gmail.com> wrote:
>>
>> > Hi all,
>> >
>> > So I'm writing some LV2 plugins to wrap up the Aubio audio analysis
>> > library<http://aubio.org/>,
>> > and I'm not sure exactly how to handle functions like "onset"
>> > detection. Currently, it just outputs clicks to an audio port (0 when
>> > no beat, 1 when beat is detected).  However, this doesn't take
>> > advantage of the power of LV2.  It is unclear to hosts and other
>> > plugins exactly what sort of data is coming out.
>> >
>> > I was thinking that maybe it would output MIDI, as midi matches the
>> > "event based" aspect of beat detection.  Perhaps sending out MIDI
>> > beat clock signals <http://en.wikipedia.org/wiki/MIDI_beat_clock>?
>> > However, that doesn't really match the sort of data that the Aubio
>> > functions detect. Maybe it could just send a midi note on event?
>> >
>> > It seems like maybe some sort of LV2 specific extension might be in
>> > order? The Event Port <http://lv2plug.in/ns/ext/event/#EventPort>
>> > extension seems to define everything I need: sending timestamped
>> > events with no extra information attached.  The question is: does it
>> > require some sort of further extension to define what a beat port is
>> > in the way the MidiEvent extension does?
>> >
>> > Of course, this raises the question: Is a port specific for "beats"
>> > even necessary?  I can think of a few cases:
>> >
>> >    - DAW uses beat signals to set up markers on a track
>> >    - DAW uses beat signals to break a percussive track up into beats.
>> >    - Delay effect uses beat signals to have a timed delay
>> >    - Automatic drummer adds on a percussion part to audio with
>> > varying tempo
>> >    - ? other beat-synchronous effects?
>> >
>> > Anyway, I'm wondering what you all think would be the best option, or
>> > whether you think functionality like this is even warranted in an LV2
>> > plugin (should analysis plugins stick to VAMP?).  So let me know what
>> > you think.
>> >
>> > Jeremy Salwen
>>
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