[FFmpeg-devel] [PATCH] add phqm filter and img_hash

[Jan Ekström]

Hi,

On Sat, Oct 26, 2019 at 4:35 PM Christopher Kennedy
<ckennedy at ellation.com> wrote:
> The C OpenCV API is not recommended so this does the OpenCV part
> in C++ which allows it to be fully utilized and supported. So that seems
> better to me than using the API OpenCV won't really support and doesn't
> allow usage of img_hash (it is NOT in the C API of OpenCV, impossible to use).

Just noting my two cents about the OpenCV C API as I've noticed
regarding people trying to utilize the opencv capabilities already in
FFmpeg on the user IRC channel:

It seems like upstream OpenCV actively has broken it quite a long time
ago, and the earlier code we have utilizing OpenCV doesn't even
compile with current OpenCV versions.
https://github.com/opencv/opencv/issues/8438#issuecomment-288638915

Thus, unless the OpenCV project's view on C APIs changes, I don't see
it being worthwhile adding any new code utilizing the C APIs that only
work with old versions of OpenCV. One way of possibly changing this is
to advocate for C interfaces at OpenCV, but for that the actual
advocates/users of OpenCV usage should raise on the walls regarding
that.

So while we heavily dislike having C++ APIs as dependencies, I think
if we want to have (current) OpenCV usage around, then modules
utilizing C++ should be permitted (pretty sure we already have some of
those in the code base for other libraries that have been deemed
important enough by someone).

Jan