Concatenating MP3 files

Question

Seeing as how MP3 frames are (mostly) independent units, I thought it would work well to simply concatenate several tagless MP3 files together in order to merge them losslessly.

However, as it seems, many player programs (including mplayer and mpd) seem to be detecting the file length in some way that I cannot find documentation for, and only see and play the part corresponding to the first of the files I concatenated.

Whatever this information is, I'm sure it can't be too hard to write a program to remove and then rebuild it, but I have no clue what it is. Does anyone know?

Just to make sure: Yes, I removed the ID3 tags of all the files.

Well, it's more a question of file formats than an A/V question, so I figured SO would be more appropriate. — Dolda2000, Jul 22 '12 at 03:35
The MP3 format is quite complex. It is not just a piece of cake to decode. — Cole Tobin, Jul 22 '12 at 03:37
possible duplicate of [What is the best way to merge mp3 files?](http://stackoverflow.com/questions/62618/what-is-the-best-way-to-merge-mp3-files) — Greg Hewgill, Jul 22 '12 at 03:46
@GregHewgill: Not really. I'm not so much interested in the most practical way to merge MP3 files, but rather what specifically is preventing me from merging them in this way. — Dolda2000, Jul 22 '12 at 03:51
@Dolda2000: If that is the case, you will need to describe exactly how you are merging them — Steve, Jul 22 '12 at 03:52
@steve: I am describing it, am I not? I simply concatenate them (having removed ID3 tags). — Dolda2000, Jul 22 '12 at 03:53
@arxanas: `cat 1.mp3 2.mp3 3.mp3 >result.mp3`, quite simply. — Dolda2000, Jul 22 '12 at 03:55
@Dolda2000 I just tried `cat 1.mp3 2.mp3 >3.mp3` — with ID3 tags —, and to my astonishment, it worked! Worked in VLC and iTunes. — Waleed Khan, Jul 22 '12 at 04:02

Dolda2000 · Accepted Answer · 2012-07-22T04:41:25.230

Ah. I found the mp3val program, which I tried running at the resultant file after concatenation, and it told me that the file contains a "Xing header" which, while masquerading as an empty data chunk, apparently contains redundant information about the number of frames and length of the file.

It seems to be made for VBR files, but these CBR files contain it nonetheless. Either way, Google does point to a lot of information about the Xing header, which appears to be what I need.

Concatenating MP3 files

1 Answers1

Linked