滤器the_content ond/或the_excerpt 并替换已经不是属性值的音频URL。

示例：

add_filter( \'the_content\', \'wpse_82336_audio_url_to_shortcode\', 1 );
add_filter( \'the_excerpt\', \'wpse_82336_audio_url_to_shortcode\', 1 );

function wpse_82336_audio_url_to_shortcode( $content )
{
    # See http://en.wikipedia.org/wiki/Audio_file_format
    # Adjust the list to your needs
    $suffixes = array (
        \'3gp\', \'aa3\', \'aac\', \'aiff\', \'ape\', \'at3\', \'au\',  \'flac\', \'m4a\', \'m4b\',
        \'m4p\', \'m4r\', \'m4v\', \'mpc\',  \'mp3\', \'mp4\', \'mpp\', \'oga\',  \'ogg\', \'oma\',
        \'pcm\', \'tta\', \'wav\', \'wma\',  \'wv\',
    );

    $formats = join( \'|\', $suffixes );
    $regex   = \'~
    (([^"\\\'])|^)            # start of string or attribute delimiter -> match 1
    (https?                 # http or https
        ://                 # separator
        .+/                 # domain plus /
        .+                  # file name at least one character
        \\.                  # a dot
        (\' . $formats . \')  # file suffixes
    )                       # complete URL -> match 3
    (([^"\\\'])|$)?           # end of string or attribute delimiter -> match 5
    ~imUx\';                 # case insensitive, multi-line, ungreedy, commented

    return preg_replace( $regex, \'\\1[audio src="\\3"]\\5\', $content );
}