[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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