Introduction

The MP3 mixer allows you to create, edit, and play mixed sequences of MP3 (MPEG layer 3) files. A mixed sequence is a series of entries with overlapping ends. At the overlapping end the entry that ends is will fade-out in sound amplitude, while the entry that starts will fade-in. Using the mixer you can visualy define and inspect the points where the entries overlap, define the location and slope of the fade-in and fade-out portions, view and alter the ordering of the entries within the sequence, and play the final result.

Basic Operation

As you can see in the following image, the program's main screen is divided into two areas.

The upper half of the screen displays a rendition of two successive entries. Every entry is rendered by a blue histogram that represents the sound amplitude as a function of time. The time markers at the two ends of the scrollbar indicate the visible portion of the entry. The time marker on the left each entry indicates the length of the whole entry. Above and below of the histogram the program will display the title of the song, if it appears as an ID3 tag within the MP3 file. For the top entry fade-in is represented by a green line sloping up from the left to the right, while fade-out is represented by a red line sloping down from the left to the right. The bottom entry is always represented upside down relative to the top one to enable direct comparison of amplitudes between the two entries. When the two entries are locked (as specified using the lock control on the left of their dividing line), they only scroll together. Typically entries are organised so that the end of the top entry is locked, close to the beginning of the bottom entry. To change the relative position of two entries (e.g. to synchronise their beats) you must unlock them, move them to the relative position you want, and lock them again. Using the scrollbar on the right of the visual entry display you can move between entries.

The lower half of the screen contains a table with a summary of the current mix list. The table contains the following columns:

#: Entry number
Start time: Actual time the entry will start playing
Title: Entry's title
Play time: Time the entry will be heard
End time: Actual time when entry will stop playing
Total time: Total time of the entry's file
F-I time: Length of time the fade-in will last
F-I start: Time the fade-in begins relative to the beginning of the entry file
F-I end: Time the fade-in end relative to the beginning of the entry file
F-O time: Length of time the fade-out will last
F-O start: Time the fade-out begins relative to the beginning of the entry file
F-O end: Time the fade-out ends relative to the beginning of the entry file
F-O to end: Time remaining after the fade-out ends until the end of the entry file
Filename: Filename used by this entry file

Clicking on the left grey area of an entry will make that entry appear as the top current entry in the top diagram.

Menu Commands

File

New

Create a new mix list.

Open...

Open an existing mix list.

Save

Save mix list.

Save As...

Save mix list to the file specified

Exit

Exit the program

Edit

Insert Before

Insert a new entry before the current top entry.

Replace

Replace current entry with a new entry.

Insert After

Insert a new entry after the current top entry.

Delete

Delete the current top entry.

Fade In

Specify an entry's fade-in. Click on the entry sample where the fade-in will start and drag to the point where it will end.

Fade Out

Specify an entry's fade-out. Click on the entry sample where the fade-out will start and drag to the point where it will end.

View

Top Fade-out

Scroll top entry to its fade-out point.

Bottom Fade-in

Scroll bottom entry to its fade-in point.

Play

Click Position

Click the mouse on the entry and sample position to play. The system will play about two seconds from that point onwards.

Top entry

Play the top entry from start to end. Your system must have a media player capable of playing MP3 files installed and the extension MP3 associated with it.

Bottom entry

Play the bottom entry from start to end.

Current Mix

Play the current mix between the top and bottom entry. The play starts two seconds before the bottom fade-in and ends two seconds after the top fade-out.

Verify

Verify the consistency of the mix list.

Full mix

Play the entire mix list. Before the list is played its consistency is verified. It will not be played if errors are found. Once playing commences, it can not be interrupted.

Help

Display this sorry excuse for a help file. Your system must have an Internet browser installed and the extension HTML associated with it.

About MP3 Mixer

Display program version information.

Hints and Tips

In order to obtain optimum results the following points should be taken into account:

The files should be stereo encoded at 44.1KHz.
No more than two files should be specified to play together
The mixing list file only contains references to the actual MP3 files. If yoy move the MP3 files around the list will not work.
The program was tested on a 333MHz Pentium PC with 160MB RAM. When the mixed sequence is played the CPU should be able to support the load of two MP3 decode processes, the load of the mixer, and the overhead of the audio subsystem.
The listing specification file is organized as lines containing characters with ASCII values 32-255. Some lines are very long (e.g. 30000 characters). If your editor can handle such files, feel free to play with it.

Author and Credits

(C) Copyright 2000 Diomidis D. Spinellis. All rights reserved. Permission to use, copy, and distribute this software and its documentation for non-commercial purposes and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation.

THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

The program is bundled with a Windows port of Michael Hipp's wonderful mpg123 decoder which is written and copyrighted by Michael Hipp.