[FFmpeg-devel] [PATCH] libavfilter: constify filter list

[Muhammad Faiz]

On Tue, Jan 30, 2018 at 7:50 PM, Michael Niedermayer
<michael at niedermayer.cc> wrote:
> On Tue, Jan 30, 2018 at 02:24:12PM +0700, Muhammad Faiz wrote:
>> Move REGISTER_FILTER to FILTER_TABLE in configure.
>> Auto generate filter extern and filter table.
>> Sort filter table, use bsearch on avfilter_get_by_name.
>> Define next pointer at filter extern, no need to initialize
>> next pointer at run time, so AVFilter can be set to const.
>
>> Make avfilter_register always return error.
>
> That breaks API

No. Because with current API, it is impossible to implement external filter.


> Its also a step away from supporting plugins.
> Why plugins matter ? Because having plugin
> support is a big advantage, it allows a much wider
> community to work on, write and maintain filters.
>
> With plugins, people can write filters that are
> written in languages other than C. Or filters which
> some developer in FFmpeg doesnt want. Or they can be
> maintained externally by people who just do not like us.
> Or by people who perfer a FOSS license different from
> LGPL/GPL/BSD. Iam sure others can come up with more
> reasons ...
>
> Of course avfilter_register() isnt enough for plugins
> but it or something equivalent is needed for plugins.
>
> So i would prefer if avfilter_register() stays supported
> indefinitly or in case a different system is written for
> plugins then until that system is in place.

It just returns error and logs error message that currently external
filter is unsupported. If someone wants to implement support for
external filter, it can be easily added later using separate
list/table.