Onda is a Java Swing and console application that compresses 16-bit and 24-bit AIFF and WAVE audio files using the Onda lossless audio compression (LAC) algorithm. The Onda algorithm doesn't perform as well as some other open-source LAC algorithms in terms of either speed or compression ratio; its virtue, if it can be said to have one, is that it is easy to understand and to implement, involving no mathematics beyond a bit of arithmetic.

The motivation for publishing the Onda algorithm is that there may be circumstances in which a mediocre but simple LAC algorithm that's easy to implement is preferable to a good but complex algorithm. There is a diminishing return on the complexity of LAC algorithms; each extra percentage point of compression becomes increasingly difficult to achieve. The Onda algorithm is content with the easy pickings: it gives up the struggle for extra compression when the going gets tough, with the expectation that its less-than-stellar performance will be sufficient for some purposes.

Features

• It can compress 16-bit and 24-bit AIFF and WAVE audio files, and can validate and expand files that it has compressed.
• It can be used as a command-line (console) application or with a graphical user interface (GUI).
• It can operate on single files or on all the files in a directory, with optional recursion. Input files and directories can be specified directly or as a list of pathnames in a text file.
• When it is run as a GUI application, input files and directories can be specified by drag-and-drop on systems that support it.
• It can preserve the ancillary chunks of AIFF and WAVE files (eg, the bext chunk used in BWF files), using a filter to specify the chunks that should be included in or excluded from a compressed file.

Links

• Source code
• Manual  (Single HTML file)
  (JavaScript must be enabled in your browser in order to generate the manual's table of contents.)
• Screenshot of Onda
• Details of the Onda algorithm and Onda file formats  (Single HTML file)
  (JavaScript must be enabled in your browser in order to generate the document's table of contents.)

Licence

• The contents of the uk.blankaspect.onda package (including resources) may be used under the terms of version 3 of the GNU General Public License.
• All other contents of the blankaspect/onda repository may be used under the terms of the MIT License.