file converter m4a to mp3

{"cid":"91193355","title":"18.5 Inch Advertising Open Frame LCD Screen With 20000 Hours Long Using Life","imgUrl":"https:\/\/img.chinax.com\/nimg\/09\/a3\/764f5b440d66b10bdef2261fcd60-200x200-1.jpg","attrs":{"Price":"Negotiable","Brand Name":"Kerchan","Model Number":"SAD1850K","Minimum Order Quantity":"50 Unit\/Units","Place of Origin":"Guangdong, China","Supply Ability":"10000 Piece\/Pieces per Month shopping cart lcd display with motion sensor","Packaging Details":"1pc\/box,5pcs\/carton,carton size","Life (hrs)":"20000","Type":"TFT","Brightness":"250cd\/m2","Response Time":"5ms, 5ms","open frame monitor":"shopping cart lcd display","Input Voltage":"35W","Max Resolution":"1366 x 768","Panel Size":"18.5\" TFT LED","Display Ratio":"16:9","Pixel Pitch":"0.3(H)x0.3(V)","Viewing Angle":"160o \/ 160o","Resolution":"1366*768","Contrast Ratio":"250:1","Color":"16.7M","Brightness (nits)":"250cd\/m2","Contrast":"250:1"}}