[FFmpeg-devel] Cleanup libswscale and reimplement GPL code under LGPL

Måns Rullgård mans
Mon Apr 7 17:30:51 CEST 2008

Luca Abeni wrote:
> Hi Ramiro,
> Ramiro Polla wrote:
>>> IMO rewriting the SIMD code because of GPL makes no sense, why would you
>>> want to do that? The code can be used without SIMD, is it so bad that
>>> non free software will be a little slower?
>>> Also i will not review any rewritten SIMD code.
>> Ok, but what about the rest of the project? Instead of rewriting SIMD
>> code, cleanly #ifdef'ing it so that swscaler can be the default scaler,
> I think the SIMD code is already #ifdef'ed (I do not know if it is
> cleanly #ifdef'ed or not, this depends on how you define "cleanly" :).
> Compiling only the non-SIMD code is quite easy.
> The problem is that the non-SIMD code (which is mainly LGPLed) depends
> on some conversion tables which are generated by GPLed code. So,
> libswscale depends on "--enable-gpl". To make the LGPLed code really
> useful without "--enable-gpl", you have to re-implement the lookup tables
> generator and release it under LGPL.

Could these tables be hardcoded?  Tables of numbers are generally not
subject to copyright law, since they contain no creative element as such.

M?ns Rullg?rd
mans at mansr.com

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