cmake fetchcontent support

[Neurofibromin]

Hi,
Great project! I was wondering if cmake FetchContent integration is planned? I think it would make it easier to include this library in other projects. Currently it sort of works, but the header include path is not picked up by default.

include(FetchContent)
FetchContent_Declare(
        avcpp
        GIT_REPOSITORY https://github.com/h4tr3d/avcpp.git
        GIT_TAG        v2.7.1
)
FetchContent_MakeAvailable(avcpp)
message(STATUS "headers: ${avcpp_SOURCE_DIR}/src")

Thanks!

[mmomtchev]

For this to be really useful, all of the dependencies must support it. And ffmpeg in particular.

At the moment, conan is the way to go if you need this feature.

I have a dependant project (https://github.com/mmomtchev/ffmpeg) and I use conan to bring all the dependencies, including ffmpeg, and then just include avcpp as a git subproject.

[Neurofibromin]

Thanks for the answer!

Yes, automatic provision of transitive dependencies would be ideal, but I think even without that it would be a nice feature. I am using system libraries for ffmpeg, but there is no system package for avcpp, so FetchContent for avcpp would be the next best thing.

[h4tr3d]

I define the FetchContent support but currently it is not well-checked. In the near future I will deal with such case of usage and completely debug it. Thanks for interesting!

[KKhanhH]

We do use fetchcontent with avcpp here along with a system provided package of ffmpeg for one of the platforms we support. This is an older version so there was some patches that needed to be applied that might not be necessary anymore.
https://github.com/CommitteeOfZero/impacto/blob/1971894401aae1d32159a055649b52c545c00e96/CMakeLists.txt#L1101
https://github.com/CommitteeOfZero/impacto/blob/master/vendor/patches/avcpp.patch
We did have to manually add the include directories for ${AvCpp_SOURCE_DIR}/src, so that could be automated.