Creating a sample mp3 with fade

Question

I need to know if it is possible to create a 30 second sample MP3 from a WAV file. The generated MP3 file must feature a fade at the start and end.

Currently using ffmpeg, but can not find any documentation that would support being able to do such a thing.

Could someone please provide me the name of software (CLI, *nix only) that could achieve this?

Answer 1

This will

• trim out from Position 45 sec. the next 30 seconds (0:45.0 30) and
• fade the first 5 seconds (0:5) and the last 5 seconds (0 0:5) and

• convert from wav to mp3

  sox infile.wav outfile.mp3 trim 0:45.0 30 fade h 0:5 0 0:5
  

Answer 2

Check out SoX - Sound eXchange

I have not used it myself but one of my friends speaks highly of it.

From web page (highlighted my me):

SoX is a cross-platform (Windows, Linux, MacOS X, etc.) command line utility that can convert various formats of computer audio files in to other formats. It can also apply various effects to these sound files, and, as an added bonus, SoX can play and record audio files on most platforms.