how to trim x seconds from the end of an audio track

Written by John Riselvato - original link

Note: Trimming at this point should be easily understood but for a refresher refer to answers in How to trim ‘x’ seconds from the start of an audio track?. 

Trimming a couple of seconds off the end of a track is easy but again requires a different thinking of how time works in FFMPEG. Like trimming from the start of an audio track, trimming from the end of a track uses the argument -t or duration with no seeking.

In this example, the input file is 1 minute long with the requirement of 10 seconds removed from the end:

  $ ffmpeg -t 00:00:50 -i input.mp3 -async 1 output.mp3

By setting a smaller time than the actual audio duration, FFMPEG will automatically trim the audio. Now the benefit of manually setting the duration instead of FFMPEG automatically handling it is understandable.