In one of our Drupal site, we have integrated a music section as client requirement. From this section client can add audio files (mainly mp3 files), from the back end and stored files listing will show in the front-end with a music player i.e., the audio files will run in the embedded player from the browser.
To fulfill client requirement we installed a Drupal module named swftools (http://drupalmodules.com/module/swf-tools). Once, this module is enabled its created a content type from where administrator can add audio files and some configuration settings links added in administrative menu.
From this administrative menu we have chosen the default player named Generic MP3 Player for mp3 files. The link to choose the default player is administrative menu/swftools/file handling.
Now, when mp3 files are viewed from the front end the default player is embedded in the browser. The location of the default mp3 player is module swftools/shared/generic/generic_mp3.swf. To change this player with our custom player we have just replace this file with a same file name. As this file is embedding by default in the browser to play the audio, now our customer player will embed automatically because we have just replaced with same file name.