You need to add the tag at least to the available BBCode tags list and add a replacement code. You should also add a new language string to the plugin's language file(s) and you also add a new icon mp3.png. Here (and attached) is a patch proposal:
Index: codebase.php
===================================================================
--- codebase.php (revision 8783)
+++ codebase.php (working copy)
@@ -188,6 +188,10 @@
$text = preg_replace("/\[youtube\].*(youtube\.com\/watch\?v=|youtu\.be\/)(.*)\[\/youtube\]/Usi", $youtube_embed_code_replacement, $text);
}
+ if (!in_array('mp3', $bbcode_tags_disabled)) {
+ $text = preg_replace("/\[mp3](.*)\[\/mp3\]/Usi", "<audio controls><source src=\"\\1\" type=\"audio/mpeg\">Your browser does not support the audio element.</audio>", $text);
+ }
+
// insert quote
if (!in_array('quote', $bbcode_tags_disabled)) {
$style = "style=\"background-image:url(plugins/bbcode_control/images/quote_show.png); background-repeat:no-repeat; background-position:top right; padding-right:40px;\"";
@@ -244,6 +248,7 @@
'url', // cpg standard
'img', // cpg standard
'youtube',
+ 'mp3',
'pid', // cpg special for internal referencing
'aid', // cpg special for internal referencing
'cid', // cpg special for internal referencing
Index: lang/english.php
===================================================================
--- lang/english.php (revision 8783)
+++ lang/english.php (working copy)
@@ -44,6 +44,7 @@
$lang_plugin_bbcode_control['size'] = 'Font size';
$lang_plugin_bbcode_control['quote'] = 'Quote';
$lang_plugin_bbcode_control['youtube'] = 'Youtube video';
+$lang_plugin_bbcode_control['mp3'] = 'MP3 audio file';
$lang_plugin_bbcode_control['tt'] = 'Teletype';
$lang_plugin_bbcode_control['hr'] = 'Horizontal rule';
$lang_plugin_bbcode_control['pid'] = 'Picture in this gallery';
Maybe I'll add this to the next plugin version. If so, the tag's name will probably be "audio" and will support all supported HTML5 audio file types (mp3, ogg, wav).