Reply
 
Thread Tools Display Modes
  #1   Report Post  
Posted to rec.audio.tech
Dieter Britz[_3_] Dieter Britz[_3_] is offline
external usenet poster
 
Posts: 9
Default Concatenating mp3 files

I use Audacity and want to concatenate mp3 files with it.
There are instructions for that - import the (e.g. two)
files, click on the second, CTRL C, go to the end of file 1
and CTRL V, and export that. Even when I wipe the second
before exporting the concatenated top one, it turns out too
big. E.g. file 1, 12 Mb, file 2, 4 Mb, but the result is 22 Mb.

What am I doing wrong, or how should I do it?

--
Dieter Britz
  #2   Report Post  
Posted to rec.audio.tech
Dave Platt[_2_] Dave Platt[_2_] is offline
external usenet poster
 
Posts: 12
Default Concatenating mp3 files

In article ,
Dieter Britz wrote:
I use Audacity and want to concatenate mp3 files with it.
There are instructions for that - import the (e.g. two)
files, click on the second, CTRL C, go to the end of file 1
and CTRL V, and export that. Even when I wipe the second
before exporting the concatenated top one, it turns out too
big. E.g. file 1, 12 Mb, file 2, 4 Mb, but the result is 22 Mb.

What am I doing wrong, or how should I do it?


If you're using Audacity, then what's happening is that Audacity is
decoding (decompressing) the MP3 file when it loads then, turning them
back into normal audio samples. After you concatenate them, the
"save" operation is then re-encoding the combined file, at whatever
compression or bit-rate setting that Audacity is set up to use.

That's going to have two effects:

- You'll lose audio quality, compared to the original MP3 files,
because of the extra decode/re-encode step (decoding is lossless,
but the re-encoding step is lossy).

- The combined file size may be either more or less than the sum of
the two separate encoded file sizes, because Audacity's compression
settings are probably different than whatever did the MP3 encodings
of the original files.

A better way to do this is to use a tool which is capable of parsing
the MP3 data and catenating the two streams, without having to decode
and re-encode the audio. As far as I'm aware, Audacity cannot do this.

If you have a Linux system, you could use "mp3wrap" (Debian and Ubuntu
have it and it's probably available for other distributions as well).
It can combine the streams, and still preserve MP3 tagging ("crossing
the streams" isn't always bad :-) )

If you're using Windows there are very probably similar utilities
available.

  #3   Report Post  
Posted to rec.audio.tech
Dieter Britz[_3_] Dieter Britz[_3_] is offline
external usenet poster
 
Posts: 9
Default Concatenating mp3 files

On Sat, 04 Jan 2020 15:27:41 -0800, Dave Platt wrote:

In article ,
Dieter Britz wrote:
I use Audacity and want to concatenate mp3 files with it. There are
instructions for that - import the (e.g. two)
files, click on the second, CTRL C, go to the end of file 1 and CTRL V,
and export that. Even when I wipe the second before exporting the
concatenated top one, it turns out too big. E.g. file 1, 12 Mb, file 2,
4 Mb, but the result is 22 Mb.

What am I doing wrong, or how should I do it?


If you're using Audacity, then what's happening is that Audacity is
decoding (decompressing) the MP3 file when it loads then, turning them
back into normal audio samples. After you concatenate them, the "save"
operation is then re-encoding the combined file, at whatever compression
or bit-rate setting that Audacity is set up to use.

That's going to have two effects:

- You'll lose audio quality, compared to the original MP3 files,
because of the extra decode/re-encode step (decoding is lossless, but
the re-encoding step is lossy).

- The combined file size may be either more or less than the sum of
the two separate encoded file sizes, because Audacity's compression
settings are probably different than whatever did the MP3 encodings
of the original files.

A better way to do this is to use a tool which is capable of parsing the
MP3 data and catenating the two streams, without having to decode and
re-encode the audio. As far as I'm aware, Audacity cannot do this.

If you have a Linux system, you could use "mp3wrap" (Debian and Ubuntu
have it and it's probably available for other distributions as well). It
can combine the streams, and still preserve MP3 tagging ("crossing the
streams" isn't always bad :-) )

If you're using Windows there are very probably similar utilities
available.


Thanks! I just installed mp3wrap, didn't know it existed. Good stuff!

--
Dieter Britz
  #4   Report Post  
Posted to rec.audio.tech
Randy Yates[_2_] Randy Yates[_2_] is offline
external usenet poster
 
Posts: 221
Default Concatenating mp3 files

Dieter Britz writes:

I use Audacity and want to concatenate mp3 files with it.
There are instructions for that - import the (e.g. two)
files, click on the second, CTRL C, go to the end of file 1
and CTRL V, and export that. Even when I wipe the second
before exporting the concatenated top one, it turns out too
big. E.g. file 1, 12 Mb, file 2, 4 Mb, but the result is 22 Mb.

What am I doing wrong, or how should I do it?


It may be some of the (re)encoding parameters you are using
in Audacity are not as lax as the originally-encoded files.
--
Randy Yates, DSP/Embedded Firmware Developer
Digital Signal Labs
http://www.digitalsignallabs.com
Reply
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Concatenating Audio Files in with Perl on a Mac Gary Morrison Pro Audio 4 March 28th 06 01:45 AM
More files Peter Hill Pro Audio 1 October 7th 05 11:15 AM
VOI Files Michael Pro Audio 0 October 12th 04 03:16 AM
SRI files Freddo Pro Audio 0 April 1st 04 02:36 PM
Logic 5 Files to AIFF Files LeBaron & Alrich Pro Audio 5 October 27th 03 04:58 PM


All times are GMT +1. The time now is 02:13 PM.

Powered by: vBulletin
Copyright ©2000 - 2023, Jelsoft Enterprises Ltd.
Copyright 2004-2023 AudioBanter.com.
The comments are property of their posters.
 

About Us

"It's about Audio and hi-fi"