Today, Oz Linden delivered an in-world opinion on the ability of third-party Second Life viewers to use the LLKDU JPEG2000 decoding library that has shipped with Linden Lab’s official viewers to-date.

Now, bear in mind, this was in voice and wasn’t presented as an official statement – so it’s not what I’d consider official Lab policy yet, and since I had to get it second-hand might not be quite the same message. I gather that it is pretty close, though.

So, here’s the skinny.

Firstly, KDU is a commercial JPEG2000 library that is used for decoding textures in Second Life viewers. Linden Lab ships it as LLKDU (which is the KDU library built inside a simplified wrapper). Due to a number of intellectual property issues, it is noticeably faster than the open-source alternatives.

It gives a third-party viewer an edge in speed, but the LLKDU library isn’t licensed for distribution by anyone other than Linden Lab.

Despite this, a few third-party viewers have (at times) distributed LLKDU bundled with their viewers. Others are okay to use it if it is copied into their installation directories, or have an installer that finds the library in your official viewer directory and copies it across to the third-party viewer.

Oz has now weighed in on this, presumably on behalf of Linden Lab, and things are going to change:

  • Linden Lab considers the ability of third-party viewers to use LLKDU to be a GPL violation. This applies to any other proprietary library. Therefore no third-party viewer under the GPL license (that’s the viewer 1.x codebase) will be permitted to do so.
  • New viewers that have the ability to load LLKDU and use it will not be added to the viewer directory.
  • Viewers that are already on the viewer directory will have some unspecified grace-period to remove that functionality, before the Lab gets surly about it and starts taking action.
  • Viewers that are under the LGPL (meaning, using the new viewer 2.x codebase) will be able to link to and use their own version of KDU, if they’ve spent the money to license KDU for distribution.
  • Future versions of Linden Lab’s official viewers won’t have KDU included as a separate library file at all. It’ll be built into the executable (ie: statically linked). Linden Lab may make some arrangement to allow Snowstorm contributors to submit their code to be compiled with KDU for testing purposes.

It’s an interesting change, certainly.

The fastest viewers currently available are the ones that use late-model Snowglobe (1.x) code as a base, and (somehow) incorporate LLKDU (if available). Those are generally the speed-demons of the Second Life viewer world.

So, viewer developers have several options:

  • Strip out the ability to use LLKDU.
  • Purchase a license for KDU and migrate to the viewer 2.x codebase. I believe the cheapest is about US$1,000 for a single-developer license, last I looked.
  • Get hammered by the Lab.

Once again, I’ll stress that this does not yet constitute official policy from Linden Lab yet. The Lab traditionally only considers official policy to be statements that come through cleared channels, or that are presented as an official statement by a staff-member. In-world statements by Lab staff – absent any such statement – are not considered to be official declarations of policy, or even to be necessarily correct as official Lab statements frequently contradict in-world statements made by Lab staff.

Nevertheless, I’m expecting some sort of official statement to follow.



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