MP3 file too short

When i add an audio mp3 file to the timeline on long files the audio is cut and not same length as the file played on Winamp - I do commentary on football reviews and i always lose the end of the commentary on Timeline so when i export to mp4 the audio is incomplete

What version of Shotcut are you using?

I do not see this problem on any of my MP3 files, and I have a lot of them. It is perhaps a problem with how this mp3 was recorded/written. You need to share the mp3 with us, but I doubt there is anything we can do because this is what the FFmpeg library tells us is the duration. You can try to override the Duration in Properties. Or, you can convert the file to WAV before bringing it into Shotcut.