Cut an Audio File (MP3, M4A)
Extracting a passage from a recording, making a ringtone, removing the beginning or end of a track: ffmpeg cuts an audio file in a second. Unlike video, cutting without re-encoding is precise for MP3 and AAC, because every audio frame can serve as a starting point.
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How to use it
- Install ffmpeg if you haven't already.
- Open a terminal in the folder containing your file.
- Copy the generated command, adjust the file names if needed, then run it.
- Open the resulting file to check the result.
Why the times come before the file
The start (-ss) and end (-to) options come before the source file: ffmpeg jumps straight to the right spot instead of reading through the whole beginning of the file. On a recording that's several hours long, the difference is huge.
Cutting a video
To cut a video without re-encoding, including the quirks related to keyframes, see the dedicated page.
Cut a video without re-encoding
Frequently asked questions
Is cutting without re-encoding really precise?
Almost: MP3 is split into 26-millisecond frames and AAC into 21-millisecond frames. The error is therefore less than one thirtieth of a second, which is inaudible.
Does the cut file have a "click" at the beginning or end?
It can happen if the cut lands in the middle of a sound. In that case, use the fade page to soften the intro and outro, or cut at a moment of silence.
How do I cut several pieces from the same file?
Run the command several times with different times and distinct output names. To split at regular intervals, use the page for splitting into equal parts.
Which time format should I use?
You can write 00:01:30, 1:30 or simply 90 for 90 seconds. Decimals are accepted: 12.5.