Browser FFmpeg recipe

Combine Audio Files Online with FFmpeg

Append two audio files into one MP3 output.

Command

Run this FFmpeg command

ffmpeg -i audio1.mp3 -i audio2.mp3 -filter_complex [0:a][1:a]concat=n=2:v=0:a=1[a] -map [a] -b:a 192k combined.mp3

When to use it

  • voice notes
  • podcast segments
  • music drafts

How it works

  1. Upload both audio files.
  2. Update audio2.mp3 if the second file has a different name.
  3. Run FFmpeg and download the combined MP3.

Option reference

OptionWhat it does
concat=n=2:v=0:a=1Concatenates two audio inputs and no video.
-map [a]Writes the concatenated audio stream.
-b:a 192kSets the MP3 output bitrate.

Practical notes

  • For many files, build a larger concat filter or use a concat list.
  • Re-encoding makes it easier to join audio with different source formats.

FAQ

Can the inputs be different audio formats?

Often yes, because FFmpeg decodes and re-encodes the joined output.

Can I make the output M4A?

Yes. Change the output filename and audio codec to AAC.