[FFmpeg-devel] [PATCH] AC3 LGPL relicense/split

Justin Ruggles justin.ruggles
Sun Mar 22 02:34:30 CET 2009

Jason Garrett-Glaser wrote:
> On Sat, Mar 21, 2009 at 10:19 AM, Justin Ruggles
> <justin.ruggles at gmail.com> wrote:
>> Hi,
>> In my opinion, just one function could still be considered as derivative
>> of liba52, ac3_decode_transform_coeffs_ch().  The thing that makes it
>> very much like liba52 is that it uses pre-calculated tables to ungroup
>> the mantissa codes after encountering the first bap in a group.
> Is "similar algorithm" really justification for considering the
> function to be GPL?
> By that logic, since we have a bunch of functions in ffmpeg that
> almost directly rip off the algoirthms used in Certain Proprietary
> Software, those functions must be restricted to nonfree.

It wasn't just the algorithm that was used originally, it was a direct
copy of liba52, which was then modified incrementally over the past
couple years so that now that function only resembles the original in
the basic algorithm.  If enough people here feel confident that it
constitutes a rewrite as-is then I won't argue too much, but to me the
code looks very similar.


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