https://www.ffmpeg.org/doxygen/2.7/group__lavu__dict.html
FFmpeg: AVDictionary
ffmpeg
https://ffmpeg.org/doxygen/2.7/group__lavu__dict.html
FFmpeg: AVDictionary
ffmpeg
https://ffmpeg.org/doxygen/8.0/structAVDictionary.html
FFmpeg: AVDictionary Struct Reference
ffmpegstructreference