Some more explanatory comments to enforce checkin

srtcore/srt.h

@@ -300,13 +300,19 @@ typedef enum SRT_TRANSTYPE
 // This is for MPEG TS and it's a default SRTO_PAYLOADSIZE for SRTT_LIVE.
 static const int SRT_LIVE_DEF_PLSIZE = 1316; // = 188*7, recommended for MPEG TS
 
-// This is the maximum payload size for Live mode, should you have a different
-// payload type than MPEG TS.
+// DEPRECATED. Use one of these below instead.
 SRT_ATR_DEPRECATED_PX static const int SRT_LIVE_MAX_PLSIZE SRT_ATR_DEPRECATED = 1456; // MTU(1500) - UDP.hdr(28) - SRT.hdr(16)
 
+// These constants define the maximum size of the payload
+// in a single UDP packet, depending on the IP version, and
+// with the default socket options, that is:
+// * default 1500 bytes of MTU (see SRTO_MSS)
+// * without FEC packet filter (see SRTO_PACKETFILTER)
+// * without AEAD through AES-GCM (see SRTO_CRYPTOMODE)
 static const int SRT_MAX_PLSIZE_AF_INET = 1456; // MTU(1500) - IPv4.hdr(20) - UDP.hdr(8) - SRT.hdr(16)
 static const int SRT_MAX_PLSIZE_AF_INET6 = 1444; // MTU(1500) - IPv6.hdr(32) - UDP.hdr(8) - SRT.hdr(16)
 
+// A macro for these above in case when the IP family is passed as a runtime value.
 #define SRT_MAX_PLSIZE(famspec) ((famspec) == AF_INET ? SRT_MAX_PLSIZE_AF_INET : SRT_MAX_PLSIZE_AF_INET6)
 
 // Latency for Live transmission: default is 120