How to split an MP3 file without re-encoding it

audioaudio conversionmp3

I have a 400 MB MP3 file at 96 kbps, taken from a CD.
I want to split this into many files.

Is there any way to do that without affecting the quality of audio,
or maybe without re-encoding the file?

Best Answer

There is a program called mp3splt - I specify start and end time of the part I am interested in. It is also possible to split automatically with silence detection.

Use Variable Bit Rate (VBR)

You can use the -q:a option in ffmpeg to create a variable bitrate (VBR) MP3 output:

ffmpeg -i input.m4a -c:v copy -c:a libmp3lame -q:a 4 output.mp3

What `-q:a` values to use

From FFmpeg Wiki: MP3:

Control quality with -q:a (or the alias -qscale:a). Values are encoder specific, so for libmp3lame the range is 0-9 where a lower value is a higher quality.

0-3 will normally produce transparent results

4 (default) should be close to perceptual transparency

6 usually produces an "acceptable" quality.

The option -q:a is mapped to the -V option in the standalone lame command-line interface tool.

You'll have to experiment to see what value is acceptable for you. Also see Hydrogen Audio: Recommended LAME Encoder Settings.

Encoding multiple files

In Linux and macOS you can use a Bash "for loop" to encode all files in a directory:

$ mkdir newfiles
$ for f in *.m4a; do ffmpeg -i "$f" -codec:v copy -codec:a libmp3lame -q:a 2 newfiles/"${f%.m4a}.mp3"; done

Best Answer

Related Solutions

Split MonkeyAudio (.ape + .cue + .log) of whole audio CD into MP3 of individual tracks

FFMPEG: Convert m4a to mp3 without significant loss

Use Variable Bit Rate (VBR)

What -q:a values to use

Encoding multiple files

Related Question

What `-q:a` values to use