MumboJumbo 0.1 beta Readme

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What is MumboJumbo?

MumboJumbo is a Java applet that is capable of playing sound files. It is useful when you don't want your users to have to download a special plugin to play sound files that you would like to use in your page. You simply specify the sound file to be played as a parameter to the applet.

MumboJumbo could be used:

The applet plays sound by first converting the file to an 8 bit, 8Khz, Ulaw stream. The JVM supports this sound format natively, so the Ulaw stream is sent to an internal audio player. At this point the supported formats are: I'm adding to this admittedly short list of supported formats as time permits. If you have a format that you would really like to see here, write to me and let me know.

MumboJumbo runs in one of three different modes:

The zip file contains the following:

File / DirectoryDescription
Readme.htmlThis file.
index.*Examples showing how to use MumboJumbo.
classes/Contains all the Java packages and source code for MumboJumbo.
samples/Sample wav files that demostrate the capabilities of this applet.
MakefileUsed to compile all the source code.


You can download MumboJumbo from the projects sourceforge page.

Installation and Use

Move the MumboJumbo directory to a place where it is accessible from your web server. The sound files that you want to play should also be accessible from the same webserver.

In your HTML file add an applet tag like this:

<applet code=com.voxeo.mumbojumbo.MumboJumbo codebase="/applets/MumboJumbo/classes/" width=200 height=100>
      <param name=soundfile value="/media/msg3.wav">
      <param name=mode value=console>
      <param name=autoplay value=true>
The codebase should be a valid reference to where you installed the applet.
The width and height values will determine the size of the console if it is turned on. Normally, if the console is turned off, i.e., you don't want to see the Play/Stop buttons, then you should set the height and width values to 0.
The soundfile parameter should refer to a valid file in the supported format.
The mode parameter can be either "console" (default) or "noconsole".
The autoplay parameter can be either "true" or "false" (default).

See the examples section for more details on using this applet.


Understanding the source code

This is for those of you who would like to read or modify the source code:

All the source is in the classes/ directory. There are three packages in this directory:

package com.voxeo.mumbojumbo: Contains the applet, a Utility class, and a TriggerWatcher thread class. The TriggerWatcher exists to listen for Javascript calls. This thread was necessary because of what seems to be a bug in both IE and Netscape browsers. In either case, if the Javascript function directly called the playAudio() function in the applet, the browsers would catch this as an access violation. Instead, if the Javascript function only called a function in the applet which set a flag or a trigger, and a seperate thread was watching this trigger, then everything would work fine.

package com.voxeo.mumbojumbo.player: Contains the Ulaw stream player, and its supporting objects. The Ulaw player sends the Ulaw stream to an internal AudioPlayer which talks to the local sound device.

package com.voxeo.mumbojumbo.decoders: Contains the various decoders which convert the various supported data formats into a Ulaw stream. The WAVDecoder object, uses the WAVHeader object to determine the type of WAV file, and then sends the input stream to the appropriate decoder. contains a single table that is used in converting PCM to Ulaw data.

To do List

Here is whats next on my list of things to do for MumboJumbo (roughly in order of priority):


Last but not least I owe my deepest thanks to the following people:

Jutta Degener: I ported a part of her GSM library to create the GSM decoder in MumboJumbo. Jutta was also a tremendous help in trying to debug the GSM decoding code, and her great website of GSM resources helped me a lot in understanding GSM.

Christopher Edwards: Christopher wrote the first version of this applet which was initially intended to decode raw GSM.

Francois Souchay: I'm not that thankful about it anymore, but Francois is the one who gave me my first introduction to DSP.

Written by Omi Chandiramani
while working for Voxeo Corporation