[FFmpeg-devel] [PATCH 1/2] avcodec/nvenc: Include NVENC SDK header

Andreas Cadhalpun andreas.cadhalpun at googlemail.com
Thu Dec 10 17:10:27 CET 2015

On 10.12.2015 16:49, Hendrik Leppkes wrote:
> On Thu, Dec 10, 2015 at 4:25 PM, Andreas Cadhalpun
> <andreas.cadhalpun at googlemail.com> wrote:
>> The GPL-3 requires that the 'Corresponding Source' of the distributed object code
>> is also distributed. This is defined as [1]:
>> The “Corresponding Source” for a work in object code form means all the source
>> code needed to generate, install, and (for an executable work) run the object
>> code[...]
>> For example, Corresponding Source includes [...] the source code for [...]
>> dynamically linked subprograms that the work is specifically designed to require,
>> such as by intimate data communication or control flow between those subprograms
>> and other parts of the work.
> This rule does not apply to system libraries,


> which I still am quite
> sure a hardware driver would fall under (and we can argue about that
> all day, you won't get any "proof" either way)
> If a particular system does not actually package this particular
> library, then their distribution of FFmpeg should probably just not
> enable nvenc, its of no use without the library anyway.

But if it did, it would certainly not fall under the system library exception.
If that's the only thing that allows distribution of compiled nvenc.c,
it shouldn't be enabled by default.

> You could argue the same thing for QuickSync, the only difference is
> that it depends on some sort of "dispatcher" library that sits between
> FFmpeg and the closed-source library.

Yes, that looks like a similar problem.

> Does the existence of a tiny dispatcher library suddenly "fix" these
> rules?

I don't think so, but I haven't looked at the code.

> That would be silly. Yet it is widely accepted that linking
> against libmfx for qsv is fine.

If it is 'widely accepted' that distribution of the resulting object
code is GPL compatible, then you can certainly provide links
to statements from experts saying so, e.g. from someone from the FSF.
Unless you do, 'widely accepted' is a void argument.

Best regards,

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