Joining MP3s

July 18, 2007 10:29 PM

How can I join multiple MP3s into one?

I have a couple of Librivox books that I want to join as one huge MP3 file for my player. How can I do this using either freeware or FOSS?

posted by enriquem to Technology (12 answers total)

Audacity.
posted by The Esteemed Doctor Bunsen Honeydew at 10:34 PM on July 18, 2007

Audacity would work, but it would decode and reencode the mp3 data which is pretty much the worst thing you can do, quality wise.

You'll get better quality if you don't reencode but use something like Mp3 Splitter Joiner Pro (I am not really vouching for this - I just tried it and it does seem to do what you need though) This will work best if all your mp3s have the same encoding settings.
posted by aubilenon at 10:52 PM on July 18, 2007

mp3wrap (it's in the Ubuntu, and I guess Debian, repos. Or they have source and a windows version at the site).

Just do:
mp3wrap outputfile input1.mp3 input2.mp3 .....

or
mp3wrap outputfile *.mp3
posted by markr at 11:00 PM on July 18, 2007

That's a better answer than mine.
posted by aubilenon at 11:55 PM on July 18, 2007

I had to do this in a hurry once, and I just concatenated the files. The spare MP3 headers turned into a not very noticeable click.
posted by flabdablet at 11:57 PM on July 18, 2007

I'd avoid concatenating the mp3's if you can - it causes havok with a lot of players who report that the track is only 3 minutes long and then get "surprised" when it isn't. It also means that you cannot seek to a particular section of the music beyond the first song as the progress bar assumes the track to be only the length of the first song.

It'll work as a stop-gap solution, but not in the long term. I've used MP3 Splitter and Joiner - which does the trick but isn't free.
posted by mr_silver at 12:50 AM on July 19, 2007

flabdablet: The spare mp3 headers should be no click at all; stuff that's not valid framedata ought be be ignored by any reasonable player. However, the encoder looks at the surrounding two frames of data when encoding a given frame, so cutting and splicing frames together will cause discontinuities, which sound like small clicks.
posted by aubilenon at 1:00 AM on July 19, 2007

Acoustica Audio MP3 Mixer

Oh look, here's a torrent

Here's a couple examples of what I've accomplished with it.
posted by Mach3avelli at 1:05 AM on July 19, 2007

mp3directcut is the best tool for this. if the mp3s are constant bitrate, you'll have no problems. if they're variable bit rate, you may have some issues, but equally - you may not!
posted by ascullion at 2:55 AM on July 19, 2007

i should say, even though it's called mp3directcut, it can be used to join files as well..
posted by ascullion at 2:56 AM on July 19, 2007

I've used mp3cat to join VBR mp3s, and while iTunes reports the wrong length, my iPod shuffle doesn't seem to care.
posted by Utilitaritron at 4:46 AM on July 19, 2007

alternatively, you could just create a playlist....
posted by jaded at 5:38 AM on July 19, 2007