util/error: refactor error handling

src/codec/decoder/audio.rs

@@ -16,7 +16,7 @@ impl Audio {
 			let mut got: c_int = 0;
 
 			match avcodec_decode_audio4(self.ptr, out.ptr, &mut got, &packet.val) {
-				e if e < 0 => Err(Error::new(e)),
+				e if e < 0 => Err(Error::from(e)),
 				_          => Ok(got != 0)
 			}
 		}