[LAD] Programming LV2 plugin from scratch tutorial video series

[Thomas Brand]

On 2021-10-20 14:26, David Robillard wrote:
> The main reason LV2 uses separate data files is so that hosts don't
> need to load and execute code only to discover what plugins are
> present.  This has pros and cons, like most things.


It has some merit to have all metadata in a text file separate from the 
binary plugin. The drawback is obviously that both need to be in-sync 
all the time. That however can be easily achieved by somehow automating 
the creation of metadata from the code (which otherwise a host would do 
from the binary). Whether or not the markup of text metadata is 
reasonable to be in turtle is mostly a style choice, it could have been 
XML or JSON, which have their own pros/cons, or st. else.

The beauty of a single file to contain everything also has some merit. 
Going from a scenario, where the set of available plugins on a given 
systen won't change hourly, a way to tackle this would be to leave the 
process of finding plugins and creating a metadata (~ repository) from 
queryable binary files a totally separate and even optional and 
temporally fully user-controlled process. A host could still use that 
(speced-out) central repository through 'universe' or similar, but 
should also be able to get the info directly from a given single-file 
plugin path.

Naively my imaginary plugin spec would eventually embed metadata as EBML 
at an offset to be queried by the host or the other way around, have a 
single EBML-encoded file with all metadata plus the binarie(s) inside. 
Eg. Matroska uses EBML for binary markup of video, also webp / webm is 
such dialect. Parsing seems very simple, it's a well-defined recursive 
form of <id><length><content> where id and length are encoded as 
variable size integer (first byte is giving info about following data, 
not unlike a MIDI event in some aspect). It won't solve any semantic 
issues though.

Without deep reasoning I mostly share Fons' views onto the surrounding 
topics. This of course includes also that LV2 has become a de facto 
standard with many 'compatible' plugins and hosts that work. This is 
totally separate from whining on tech / style choices :)

Greetings
Thomas