codec/h264/h264dec: made absi faster and more readable

codec/h264/h264dec/helpers.go

@@ -9,7 +9,6 @@ package h264dec
 
 import (
 	"errors"
-	"math"
 )
 
 // binToSlice is a helper function to convert a string of binary into a
@@ -57,6 +56,9 @@ func mini(a, b int) int {
 	return b
 }
 
-func absi(i int) int {
-	return int(math.Abs(float64(i)))
+func absi(a int) int {
+	if a < 0 {
+		return -a
+	}
+	return a
 }