Sorry for the trouble. I will look at it as soon as I can.

In R286:3415015e3d45ce485c5cdb1bc47698729deb8d98#3662845, @romangg wrote:

On Neon (Xenial based) FFmpeg version is 2.8.14. It still doesn't fail on CMake. It maybe compares 3.1 with the version numbers of the FFmpeg modules. Their major versions are >50. Then it fails on build, because AVCodecParameters is not defined (fails since 037208a787e0).

I am trying to modify FindFFmpeg.cmake to do version checks.
I did not yet succeeded because I want to check the version for one component at a time. I will ask a review once I am done.

The FindFFmpeg CMake module uses pkg-config modversions to determine the overall version. These don't match the notion of "FFmpeg release 3.1" because the libraries are versioned separately. For instance:

libavdevice 58.3.100
libavfilter 7.16.100
libavformat 58.12.100
libavutil 56.14.100
libpostproc 55.1.100
libswresample 3.1.100
libavcodec 58.18.100
libswscale 5.1.100

So what you really need to do is check for ffmpeg components with version-numbering corresponding to the API / library version that introduces them -- and/or check for the specific API you need via CheckSymbolExists

In R286:3415015e3d45ce485c5cdb1bc47698729deb8d98#3663659, @adridg wrote:

The FindFFmpeg CMake module uses pkg-config modversions to determine the overall version. These don't match the notion of "FFmpeg release 3.1" because the libraries are versioned separately. For instance:

libavdevice 58.3.100
libavfilter 7.16.100
libavformat 58.12.100
libavutil 56.14.100
libpostproc 55.1.100
libswresample 3.1.100
libavcodec 58.18.100
libswscale 5.1.100

So what you really need to do is check for ffmpeg components with version-numbering corresponding to the API / library version that introduces them -- and/or check for the specific API you need via CheckSymbolExists

I have pushed D13302 to show you what I am trying to do. Still, the check for the structure member does not yet work.