7 | 7 | FFmpeg can support four AAC-LC encoders (`aac`, `libfaac`, `libfdk_aac`, `libvo_aacenc`) and two AAC-HE encoders (`libaacplus` and `libfdk_aac`). The licenses of `libaacplus`, `libfaac`, and `libfdk_aac` are not compatible with the GPL, so the GPL does not permit distribution of binaries containing code licensed under these licenses when GPL-licensed code is also included. Therefore these encoders have been designated as "non-free", and you cannot download a pre-built ffmpeg that supports them. This can be resolved by [[CompilationGuide|compiling ffmpeg]] yourself. |