$ brew install ffmpeg$ git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg
$ cd ffmpeg
$ ./configure --enable-libmp3lame
$ make
$ make install
$ ffmpeg -version
ffmpeg version N-83262-gb9f2f93 Copyright (c) 2000-2017 the FFmpeg developers
built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
configuration: --enable-libmp3lame
libavutil      55. 45.100 / 55. 45.100
libavcodec     57. 75.100 / 57. 75.100
libavformat    57. 65.100 / 57. 65.100
libavdevice    57.  2.100 / 57.  2.100
libavfilter     6. 71.100 /  6. 71.100
libswscale      4.  3.101 /  4.  3.101
libswresample   2.  4.100 /  2.  4.100$ ffmpeg -i input.mp3 -codec:a libmp3lame -filter:a "atempo=1.5" -vn output.mp3http://stackoverflow.com/questions/35937403/error-libmp3lame-3-98-3-not-found
$ tar -zxvf lame-3.99.5.tar.gz 
$ cd lame-3.99.5
$ ./configure
$ make
$ make installhttp://superuser.com/questions/656313/ffmpeg-says-unknown-encoder-mp3
$ cd ffmpeg
$ ./configure --enable-libmp3lame
$ make
$ make install$ brew install yasm