[FFmpeg-devel] Load FDK AAC at run-time

Paul B Mahol onemda at gmail.com
Thu Feb 21 22:13:06 CET 2013

On 2/21/13, Kyle Schwarz <zeranoe at gmail.com> wrote:
> On 2/19/2013 4:56 PM, Reimar Doeffinger wrote:
>> On Tue, Feb 19, 2013 at 01:15:17AM -0500, Kyle Schwarz wrote:
>>> On 2/17/2013 11:40 AM, Carl Eugen Hoyos wrote:
>>>> Kyle Schwarz <zeranoe <at> gmail.com> writes:
>>>>> There is a demand for FDK AAC, but FDK AAC cannot
>>>>> be compiled into a FFmpeg binary and remain
>>>>> compatible with the GPL. FDK AAC can however be
>>>>> redistributed as a binary alongside a FFmpeg copy
>>>>> that is GPL.
>>>> Ianal, but imo, that would (exactly) contradict the
>>>> (essence of the) GPL and we should therefore not
>>>> support it.
>>>> Whoever needs a better GPL-compatible AAC encoder
>>>> should consider to either improve or support
>>>> improving FFmpeg's native AAC encoder.
>>> I don't want to start any arguments, but are there any other people
>>> with an opinion?
>> Well, I see advantages in dynamic loading (for example distributions
>> can make it an optional dependency, thus reducing bloat).
>> However I am strongly against doing it in any way that might
>> make people believe this changes anything with concern to
>> licensing, I find it likely that these kind of "tricks"
>> will at best work in a select few jurisdictions if at all.
>> There is also the point that dynamic loading in a way that
>> works across operating systems without opening security holes
>> is very tricky to do from a library.
>> For example, Windows by default loads libraries from the
>> current working directory, which is a security concern.
>> The solution to that is to disable that behaviour,
>> however doing that inside libavcodec seems inappropriate
>> since libraries should avoid changing global program state.
> If FFmpeg is compiled as a shared build, for Windows it loads the .dll
> files in the working directory.
> Please explain how you think this would expose a security hole?
> If I was to submit a patch that works cross platform that loads fdk-aac
> at runtime, will it be applied?

Unfortunately I can not answer that, first patch (or link to repo with patch)
need to be posted on mailing list.

> Best regards,
>    Kyle Schwarz
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