To encode click URL once: 
${URL_ENC(${CLICK_URL},1)} 
If http://Pontiac.media is passed as the click URL,  
using ${URL_ENC(${CLICK_URL},1)} to single encode the URL would result in http%3A%2F%2FPontiac.media populating the creative. 

To encode media URL once: 
${URL_ENC(${MEDIA_URL},1)} 

To encode media URL twice: 
${URL_ENC(${MEDIA_URL},2)} 

To encode a custom macro called ADFORMAT once: 
${URL_ENC(#{ADFORMAT},1)}