[FFmpeg-devel] [PATCH] lavc: drop VDA

[Hendrik Leppkes]

On Fri, Sep 29, 2017 at 7:08 PM, Clément Bœsch <u at pkh.me> wrote:
> On Fri, Sep 29, 2017 at 06:15:57PM +0200, Hendrik Leppkes wrote:
>> On Fri, Sep 29, 2017 at 2:40 PM, Clément Bœsch <u at pkh.me> wrote:
>> > On Fri, Sep 29, 2017 at 11:38:42AM +0200, Hendrik Leppkes wrote:
>> >> On Fri, Sep 29, 2017 at 11:11 AM, Clément Bœsch <u at pkh.me> wrote:
>> >> > From: Clément Bœsch <cboesch at gopro.com>
>> >> >
>> >> > Deprecated (aka removed) in OSX 10.11, and we have a replacement for it
>> >> > (VideoToolbox).
>> >> > ---
>> >> > Changes since RFC: rebase, ifdefery depreciation dance for the pix fmt,
>> >> > Changelog entry.
>> >> >
>> >>
>> >> vda.h is an installed header with public API in it, removing it
>> >> entirely would be an API and ABI break.
>> >>
>> >
>> > vda.h may be exposed unconditionally, but its associated object vda.o
>> > isn't. Since it depends on vda to be assembled, the vda stub itself
>> > doesn't seem to be present ever. So we're basically exposing a header for
>> > functions we can never link against.
>> >
>> > So should I somehow fix VDA while dropping it by providing a stub that was
>> > never present?
>> >
>>
>> vda is autodetected so a "naive" build would have it, so I would argue
>> the ABI of such a "naive" build should probably remain constant?
>
> Just to be clear (sorry if I make you repeat yourself), we currently have
> the following:
>
> - Systems without VDA (that is, almost all of them) do not have access to
>   either VDA or the stub: for them, we are exposing a header with FFmpeg
>   symbols not accessible.
>
> - Systems with VDA have access to the VDA code (assuming it still build)
>
> What you suggest:
>
> - Both systems (with and without VDA) should now use the existing stub we
>   currently never build so the ABI for systems with VDA will be kept.
>
> Is that correct?
>
> If so, this means we will start introducing a deprecated API stub for VDA
> on all systems.
>
> Or should I start exposing the stub only for VDA systems, meaning I'll
> need to keep the VDA detection in the configure?
>

Obivously including the stub everywhere is much easier and far saner,
does it really harm to do that?

- Hendrik