[FFmpeg-devel] [PATCH] lavc/libopenh264: Drop openh264 runtime version checks

[Kalev Lember]

On Fri, Dec 8, 2023 at 9:39 AM Martin Storsjö <martin at martin.st> wrote:

> I guess this seems reasonable to me, so LGTM.
>
> The version check would be more relevant if we would be dlopening the
> OpenH264 library (which pretty much is what one has to do in order to take
> advantage of the patent offer from Cisco), but the libavcodec wrapper
> doesn't dlopen this library (and doing the dlopen dance for ffmpeg is kind
> of pointless, there's more of a point to it if individual apps want to
> integrate OpenH264 directly), so this should indeed be fine.
>

Thanks!

As for dlopening, I think instead of version checks, it would make sense to
try to dlsym() all of the actual required symbols, and error out in init if
anything is missing. That should make it all super flexible and resilient
to e.g. struct size changes that would normally be an ABI change.

In Fedora, we are planning on changing things up a bit and starting to
build packages that link with openh264 against the "noopenh264" stub
implementation and replacing it at runtime with the actual openh264 library
downloaded directly from Cisco. Flathub flatpak runtimes already use that
approach and it seems to work well there. This should hopefully let us take
advantage of the Cisco patent grant and fit well in the build system
architecture that we have.

https://gitlab.com/freedesktop-sdk/noopenh264

-- 
Kalev