$ 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.mp3
http://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 install
http://superuser.com/questions/656313/ffmpeg-says-unknown-encoder-mp3
$ cd ffmpeg
$ ./configure --enable-libmp3lame
$ make
$ make install
$ brew install yasm