ffmpeg integration

[Tildaar]

ffmpeg support for heif is something that is still missing. There were a few discussions since the release of iOS 11 which introduced heic photos. Nobody was willing to implement ffmpeg support for heif since then. Maybe this library might be a candidate to fill this gab. What do you think?

[farindk]

Technically, that should be well possible. Would you be willing to write that ffmpeg adapter code? I've done several projects with ffmpeg, but I don't have the time to dive that deep into ffmpeg to implement this. However, I would be willing to assist with answering questions that might arise.