[LAD] the role of lv2 extensions

Steve Harris steve at plugin.org.uk
Mon Aug 10 10:48:10 UTC 2009


On 10 Aug 2009, at 10:41, Fons Adriaensen wrote:

> On Mon, Aug 10, 2009 at 10:26:34AM +0200, Jörn Nettingsmeier wrote:
>
>> from a design standpoint, i totally agree with all your points, and  
>> what
>> little i've so far grokked of lv2 looks very nice indeed. *but*:  
>> it's a
>> moving target, and few host authors have committed themselves to
>> implement those extensions.
>>
>> the problem i see: the extensions mentioned on the lv2 website are of
>> very different maturity, it's absolutely not clear which of those  
>> should
>> be considered "canonical" and hence a *must-implement* feature, nor  
>> has
>> there been any public discussion about any canonical set of core
>> extensions (excuse that weird expression, but i can't think of  
>> anything
>> better).
>
>
>
>> crooked analogy alert... as it is now, lv2 resembles XML: you can do
>> anything in principle, but there is almost no common semantics. we
>> should move it to XHTML: define a set of mandatory extensions that
>> everybody can expect to work pretty much everywhere (to the extent  
>> that
>> it makes sense - i understand a synth host might have different
>> priorities than, say, ardour).
>
> The evolutive process described and advocated by Dave is
> certainly one that can work - it is the way e.g. natural
> languages get defined and change over time. It's also why
> they tend to be inconsistent and why you need to study a
> lot more grammar than would be required otherwise.

Sure. The original intention was that LV2 1.x would "bless" certain  
extensions as being required for that version, but that's not been  
necessary so far.

> This should be compared to the (in most cases) quite
> consistent syntax of computer programming languages.
> And in the end, a plugin interface is a language that
> has to be understood by both the host and the plugin.

Or at least some of it does. There are some (many?) cases where a  
plugin is still fully usable by the host, even if it doesn't  
comprehend the extension. Port groups is an example of this.

- Steve


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