LV2 Categories

Standard LV2 Plug-In Categories

 * Utility.Converter
 * Utility.Analyser
 * Utility.Mixer
 * Generator.Instrument
 * Generator.Oscillator
 * Simulator.Reverb
 * Delay.Reverb
 * Modulator.Phaser
 * Modulator.Flanger
 * Modulator.Chorus
 * Filter.Lowpass
 * Filter.Highpass
 * Filter.Bandpass
 * Filter.Comb
 * Filter.Allpass
 * Filter.Equaliser
 * Filter.Equaliser.Parametric
 * Filter.Equaliser.Multiband
 * Spectral Processor.Pitch Shifter
 * Amplifier
 * Distortion.Waveshaper
 * Dynamics Processor.Compressor
 * Dynamics Processor.Expander
 * Dynamics Processor.Limiter
 * Dynamics Processor.Gate

in LV2

 * Allpass - "http://lv2plug.in/ns/lv2core#AllpassPlugin"
 * Amplifier - "http://lv2plug.in/ns/lv2core#AmplifierPlugin"
 * Analyser - "http://lv2plug.in/ns/lv2core#AnalyserPlugin"
 * Bandpass - "http://lv2plug.in/ns/lv2core#BandpassPlugin"
 * Chorus - "http://lv2plug.in/ns/lv2core#ChorusPlugin"
 * Comb - "http://lv2plug.in/ns/lv2core#CombPlugin"
 * Compressor - "http://lv2plug.in/ns/lv2core#CompressorPlugin"
 * Converter - "http://lv2plug.in/ns/lv2core#ConverterPlugin"
 * Delay - "http://lv2plug.in/ns/lv2core#DelayPlugin"
 * Distortion - "http://lv2plug.in/ns/lv2core#DistortionPlugin"
 * Dynamics Processor - "http://lv2plug.in/ns/lv2core#DynamicsPlugin"
 * Equaliser - "http://lv2plug.in/ns/lv2core#EQPlugin"
 * Expander - "http://lv2plug.in/ns/lv2core#ExpanderPlugin"
 * Filter - "http://lv2plug.in/ns/lv2core#FilterPlugin"
 * Flanger - "http://lv2plug.in/ns/lv2core#FlangerPlugin"
 * Gate - "http://lv2plug.in/ns/lv2core#GatePlugin"
 * Generator - "http://lv2plug.in/ns/lv2core#GeneratorPlugin"
 * Highpass- "http://lv2plug.in/ns/lv2core#HighpassPlugin"
 * Instrument - "http://lv2plug.in/ns/lv2core#InstrumentPlugin"
 * Limiter - "http://lv2plug.in/ns/lv2core#LimiterPlugin"
 * Lowpass - "http://lv2plug.in/ns/lv2core#LowpassPlugin"
 * Mixer - "http://lv2plug.in/ns/lv2core#MixerPlugin"
 * Modulator - "http://lv2plug.in/ns/lv2core#ModulatorPlugin"
 * Multiband - "http://lv2plug.in/ns/lv2core#MultiEQPlugin"
 * Oscillator - "http://lv2plug.in/ns/lv2core#OscillatorPlugin"
 * Parametric - "http://lv2plug.in/ns/lv2core#ParaEQPlugin"
 * Phaser - "http://lv2plug.in/ns/lv2core#PhaserPlugin"
 * Pitch Shifter -  "http://lv2plug.in/ns/lv2core#PitchPlugin"
 * Reverb - "http://lv2plug.in/ns/lv2core#ReverbPlugin"
 * Simulator - "http://lv2plug.in/ns/lv2core#SimulatorPlugin"
 * Spectral Processor - "http://lv2plug.in/ns/lv2core#SpectralPlugin"
 * Utility - "http://lv2plug.in/ns/lv2core#UtilityPlugin"
 * Waveshaper - "http://lv2plug.in/ns/lv2core#WaveshaperPlugin"

Additional Audacity-Specific Categories

 * Noise Removal - "http://audacityteam.org/namespace#NoiseRemoval"
 * Onsets - "http://audacityteam.org/namespace#OnsetDetector"
 * Pitch and Tempo "http://audacityteam.org/namespace#PitchAndTempo"
 * Time - "http://audacityteam.org/namespace#TimeAnalyser"
 * Timeline Changer - "http://audacityteam.org/namespace#TimelineChanger"

Old Discussion of New Categories

 * Do fade-in and Fade out fit in under 'Amplifier?'
 * Other possible categories (with varying degrees of suitability): Utility.Mixer, Dynamics Processor --Larsl
 * I would go with Amplifier so it sits alongside amplify, normalize and so on. --Richard
 * Gale 15Jun08 19:02 UTC: My 2p is strongly under Amplifier.
 * Something like timeline-changer is needed to cater for certain offline effects (change-speed, reverse...).
 * Can we call it "Temporal" or something that isn't hyphenated? It just seems a very cumbersome name for it. --Richard
 * Gale 15Jun08 19:02 UTC: Why is Reverse a timeline changer? Surely the user interpretation of this (if they can understand it at all) is that the length of the track will change, in which case Delay plug-ins and Change Speed would fit here as well. I'd prefer something like "Extend / Contract" (OK not great, but gets across the aim which is to  change the length of the track for its own sake, not just as a by-product of doing something  else).
 * Noise removal doesn't just consist of Fourier domain filters. In Audacity it may involve a 'compound' effect consisting of an analysis effect and an active effect combined together.
 * I don't think this matters. We can put our built-in effects in any category we want without affecting the rest of the LV2 world. --Larsl
 * James My first thought was that we should use 'Filter.Noise~Removal', however 'Filter' as a category might be too narrow. It all depends how LV2 committee define 'Filter'.
 * Larsl Talked a bit to the LV2 people, looks like 'Filter' is for filters in the DSP sense - lowpass, highpass, notch etc.


 * Richard Can anyone explain what "utility" is supposed to mean? To me it's no more helpful than having a "misc" category, and I'm loath to hide anything useful in there.
 * Larsl In lv2.ttl it has the comment "Includes things like mathematical functions and non-musical delays", and the subcategories "Converter", "Analyser", and "Mixer".
 * James I'd be inclined to lobby for Analyser being a top level category. Analyser is potentially vast!
 * Larsl Yes, but it's not going to show up in the Effects menu (unless there are pathological plugins that are categorized as Analysers but detected as effects, like some of the Generator LADSPAs) so it doesn't matter much where it is. If we want categories in the Analyse menu as well (I have that locally, with support for VAMP subcategories) we can just use the subcategories of Analyser for the top-level submenus instead of the actual top-level category (which I also have locally). There's nothing stopping us from making Analyser a top-level category in Audacity, but it shouldn't actually matter.
 * Gale 15Jun08 19:02 UTC: IMHO for built-in effects they should be in one category only, so would mean taking Normalize out of Utility and remove Change Pitch as its own top level item. Also a generic title for Noise Removal (Audio Restoration?) should IMO be a top level item; it's just too often used to be hidden in Utility.
 * James 13:24, 17 June 2008 (PDT): Gale, I disagree with you on 'one category only'. I think it's a great strength of the system that it encourages effects to be in more than one sub-menu.  When there are a very large number of effects it helps that the categories overlap.  On noise-removal - I'm partial to our promoting all the subcategories of utility to top-level categories as far as Audacity-display.  It's up to Lars though what to do - it's his call.  Unless we do that we get too embroiled in a discussion of the ideal menu structure.  That's a bit futile because this improved menu is just a stepping stone.  The important thing is that the menu is an improvement on what we had.  The future (beyond this GSoC project) is (a) a way for the user to build their own structure (b) a 'finder' that will find effects that match criteria.
 * Gale 18Jun08 05:56 UTC: I understand the advantages of plug-ins potentially being in multiple categories (e.g. "what plug-ins do I have that can do "x" ") but I was referring to the current out-of-the-box structure for built-in plug-ins. To me this implies "one category only" at present. To have first order items "Pitch and Tempo" and "Change Pitch..." (also with the same-titled effect in "Pitch and Tempo") is going to raise a lot of user questions..."Is it a mistake?"; "I wonder if the "Change Pitch" in "Pitch and "Tempo" is the same as the one at the bottom of the menu... kinda looks the same?" "Does this mean there is some way to put a plug-in from unsorted into that standalone Change Pitch?" I really think the built-in plug-ins structure should be clean, logical and common-sense, until post GSoC when some way of editing the structure is in place (maybe some way of allocating a "primary" category to a plug-in so that it displays differently when in other categories). I agree we should not get bogged down in this discussion at this stage, but there are common points here mentioned by a number of people (don't have "Utility" as a top order category; Fade-In/Out under Amplify), and I do hope Lars will consider these. A smaller number of main built-in categories would imply to me that these should have access keys, at least for now ; unsorted definitely should have in my view, as that will always be there, and when other plug-ins can be moved above "unsorted" it will be increasingly important to have a way to jump down to it. I'd just like to add an element to this discussion widely supported amongst users, but not mentioned here, which is to have a Favourites folder, or as a variant, some kind of autogenerated "recently used" folder.
 * Larsl 08:52, 26 June 2008 (PDT) A "Recent" menu would be easy to add. About optimising the categories for built-in effects - how many are actually using Audacity without any external effects at all? Do the Mac and Windows bundles come with LADSPA plggins, or do the users have to install them on their own?
 * Gale 26Jun08, 21:23 UTC: I suspect the majority of users (say two-thirds??) use built-in effects only, or with only a few extra third-party VST's . Most users are on Windows, and the LADSPA plug-in ports for both Windows and Mac are relatively recent and have to be found on the web site, then separately downloaded and installed. I think in a nutshell that until users can edit categories, there should be no plug-ins in multiple categories, no third order categories at all, and no Utility category (which means I think "Noise Removal" ("Audio Restoration"?) and "Timeline Changer" (if we can't think of anything better) should be first order categories. And though I'm strongly in favour of the full categorisation functionality when we get it, like Jan I still can't get used to the extra step(s) needed to access the built-in effects. I honestly don't believe everyone who uses a limited number of effects will welcome this. So we may actually have to consider making it optional, even though default should probably be "on". Also take a look at  - a mix of effects in the main menu and in a cascading menu where grouping makes sense (but no effects in both main and cascading menu).
 * James 04:39, 27 June 2008 (PDT) I think a preference is the right solution.

Analogies / Future Scaling
At the moment the category system is being viewed as a way to create hierarchical menus. However, it should be clear that it is a general 'tagging' mechanism, analogous to how e-mail messages and photos can be 'tagged' with arbitrary labels.

Photo sorters and finders may deal with 100,000's of photos, so the tagging and searching mechanisms are well developed there. Although it's too early for it, eventually equally sophisticated searching mechanisms may be needed for sound effects too. As the boundaries between effects, instruments and compositions starts to blur, we could reasonably anticipate a future with 100,000's of effects. Consider composite complex data-driven effects, particularly effects that change the character of a voice. Like musical compositions it's likely that in future it will be possible to create such effects without programming - and they'll be available in large numbers. We can see how the LV2 categories would scale well - the same kind of hierarchical tagging is used with photos.
 * Richard Can a plug-in have multiple tags? I assume as a result they will show up in multiple places in the menu as a result? I'd see this as distinctly useful.
 * James Yes. The structures is 'a DAG' not a tree.  A node can be on multiple branches.