Esrender's mod_audio requires ffmpeg, mencoder and flvtool2 to provide support for different input and output media-formats.
Please configure mod_audio with the correct locations of the executables.
<?php define('PHPVIDEOTOOLKIT_FFMPEG_BINARY', '/path/to/ffmpeg'); define('PHPVIDEOTOOLKIT_FLVTOOLS_BINARY', '/path/to/flvtool2'); define('PHPVIDEOTOOLKIT_MENCODER_BINARY', '/path/to/mencoder');