diff --git a/stream/mts/psi/psi.go b/stream/mts/psi/psi.go
index cc9dc8f9..c93d3011 100644
--- a/stream/mts/psi/psi.go
+++ b/stream/mts/psi/psi.go
@@ -32,11 +32,10 @@ import (
 	"github.com/Comcast/gots/psi"
 )
 
-const (
-	PacketSize = 184 // packet size of a psi.
-)
+// PacketSize of psi (without mpegts header)
+const PacketSize = 184
 
-// Lengths of section definitions
+// Lengths of section definitions.
 const (
 	ESSDDefLen = 5
 	DescDefLen = 2
@@ -46,15 +45,14 @@ const (
 	PSIDefLen  = 3
 )
 
-// Table Type IDs
+// Table Type IDs.
 const (
 	patID = 0x00
 	pmtID = 0x02
 )
 
-const TotalSyntaxSecLen = 180
-
 // Consts relating to time description
+// TODO: remove this, we don't do metadata like this anymore.
 const (
 	TimeDescTag  = 234
 	TimeTagIndx  = 13
@@ -63,6 +61,7 @@ const (
 )
 
 // Consts relating to location description
+// TODO: remove this, we don't do metadata like this anymore.
 const (
 	LocationDescTag  = 235
 	LocationTagIndx  = 23
@@ -70,35 +69,32 @@ const (
 	LocationDataSize = 32 // bytes
 )
 
-// Other misc consts
+// crc hassh Size
+const crcSize = 4
+
+// Consts relating to syntax section.
 const (
+	TotalSyntaxSecLen = 180
 	SyntaxSecLenIdx1  = 2
 	SyntaxSecLenIdx2  = 3
 	SyntaxSecLenMask1 = 0x03
-	crcSize           = 4
-)
-
-const (
-	SectionLenIdx1 = 2
-	SectionLenIdx2 = 3
-)
-
-const (
-	SectionLenMask1 = 0x03
+	SectionLenMask1   = 0x03
 )
 
+// Consts relating to program info len.
 const (
 	ProgramInfoLenIdx1  = 11
 	ProgramInfoLenIdx2  = 12
 	ProgramInfoLenMask1 = 0x03
 )
 
-const (
-	DescriptorsIdx = ProgramInfoLenIdx2 + 1
-)
+// DescriptorsIdx is the index that the descriptors start at.
+const DescriptorsIdx = ProgramInfoLenIdx2 + 1
 
+// MetadataTag is the descriptor tag used for metadata.
 const MetadataTag = 0x26
 
+// TODO: get rid of these - not a good idea.
 type (
 	PSIBytes   []byte
 	Descriptor []byte