[Ffmpeg-devel] (L)GPLed yuv2rgb code

Benjamin Larsson banan
Fri Dec 22 16:53:16 CET 2006


Luca Abeni skrev:
> Hi all,
>
> so, I disabled the compilation of libswscale under LGPL.
>
> At this point, I do not think there is anything to do: if a table must
> map i in (cy*(((i - YTABLE_MIN)<<16) - oy) + (1<<31))>>32, I can rewrite
> the code 100 times, but I will alway end up writing
> value = (cy*(((i - YTABLE_MIN)<<16) - oy) + (1<<31))>>32;
> or an equivalent expression.
> Idem, if table_b[i] must contain a value shifted right by 3 and then
> shifted left by 11 if bpp=16 or by 10 if bpp=15, I will always end up by
> writing something equivalent to
> value = ytable[i + YTABLE_MIN] >> 3;
> if (!isBGR(c->dstFormat)) {
>     value <<= ((fmt_depth(c->dstFormat) == 16) ? 11 : 10);
> }
> ((uint16_t *)table_b)[i] = value;
>
>
> So, at this point I think libswscale cannot be LGPLed (I would have
> preferred knowing this from the beginning, before spending too much time
> on this, but...)
>
>
> Unless someone proves me wrong again, I'll remove yuv2rgb_init.c from
> the subversion repository in few days.
>   

Well describe the process in words (not to detailed) and then let 
someone else reimplement it. That should be safe enough.

>
> 			Sorry,
> 				Luca
>
>   

MvH
Benjamin Larsson




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