How does one join MP3 files?
Is there any software that can join several MP3 files into one MP3 file, without having to decode and encode again?
"On the web, people advise to just concatenate the files"
I've wondered this too. It's a legitimate question because - if there *were* such a thing as a file header and you concatenated files in this manner, some MP3 players may work around the multiple headers and play it, and others may not.
I have been reading about ID3 tags recently. It appears the ID3 v1.x tags are the last 128 bytes of the file and ID3 v2 tags are at the beginning of the file and can be variable in length (usually a file can have both). Taking a little time, it would be quite easy to strip these out and then concatenate the files with a little bit of programming. I would imagine the player would otherwise just interpret the ID3 as music if encountered in the middle of a file.
MP3 files are made up of several blocks, each of which has its own header. There is no MP3 header for the whole file. It was designed with streaming in mind so you can pick up in the middle of the stream and not have to worry about having missed the header.
MP3 files consists of frames that all have their own header. So, you can just concatenate them. Almost all readers will automatically skip over meta-data (like ID3 tags) while playing the music. When they look for meta-data, though, they might be confused if they do not find it in the beginning (for most ID3v2) or in the end (for all ID3v1).
Francis Van Aeken
I use a small utility called Id3Remover to remove all v1 and v2 tags from my files.
Stickytape or glue usually does the trick.
Another, only slightly more labor-intensive way to do it is to import the files into an audio editing program, copy the waveforms from one of the MP3s, and paste it onto the end of the other, then save as a new MP3.
You'll want to do what Brad does to add audiable breaks and transitions anyway.
Not to mention volume normalization. Some of peaks and valleys will just drive you nuts.
Yes if you join two clips that aren't silent at the break point, you'll get an audible "pop" at the instantaneous transition between the two sounds.
I think AlbumWrap might do what you want:
"you'll get an audible "pop" at the instantaneous transition between the two sounds"
Let's try 'cat' and see
What happens if the two mp3 files are different bitrates and frequencies?
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