diff --git a/codec/mjpeg/jpeg.go b/codec/mjpeg/jpeg.go
index 1cd7b92b..b2d5b149 100644
--- a/codec/mjpeg/jpeg.go
+++ b/codec/mjpeg/jpeg.go
@@ -73,15 +73,15 @@ const (
 
 // SOF0 (start of frame) header fields.
 const (
-	sofLen            = 17
-	sofPrecision      = 8
-	sofNoOfComponents = 3
+	sofLen            = 17 // Length of SOF0 segment excluding marker.
+	sofPrecision      = 8  // Data precision in bits/sample.
+	sofNoOfComponents = 3  // Number of components (1 = grey scaled, 3 = color YcbCr or YIQ 4 = color CMYK)
 )
 
 // SOS (start of scan) header fields.
 const (
-	sosLen              = 12
-	sosComponentsInScan = 3
+	sosLen              = 12 // Length of SOS segment excluding marker.
+	sosComponentsInScan = 3  // Number of components in scan.
 )
 
 var (