Merge pull request #12 from gwendalsimon/feat/m2ts-cc-pid-preservation

feat: add CC/PID preservation MUST NOTs and PCR timing note

Author: mondain

draft-gregoire-moq-msfts.md

@@ -189,6 +189,11 @@ Stream semantics.  Continuity counters, adaptation fields, PCR, PTS, DTS,
 Program Specific Information (PSI), and other transport-stream syntax remain
 inside the source packets.
 
+A publisher MUST NOT modify the continuity counter of any source packet, and
+MUST NOT remap packet identifiers when forwarding a source transport stream.
+Either modification silently breaks program decoding or conditional access at
+the receiver.
+
 A publisher SHOULD place an independently usable random access point at the
 first media Object of each MOQT Group.  For single-program video tracks, this
 normally means that the Group begins at or before the transport-stream packets
@@ -296,6 +301,13 @@ MUST signal it by setting the discontinuity_indicator bit (ISO 13818-1
 Section 2.4.3.5) in the adaptation field of the first TS packet carrying PCR
 in the new Group.
 
+Note: Hardware IRDs recover the mux clock from the rate at which PCR-bearing
+packets arrive, not only from their encoded values.  MOQT does not guarantee
+that Object delivery preserves the inter-packet timing of the source stream.
+Deployments targeting such receivers should account for this constraint and may
+require a rate-controlled egress that re-paces packets according to the source
+mux rate.
+
 Note: The 33-bit PCR base field wraps around after approximately 26.5 hours of
 continuous stream time.  For long-running live streams this is a normal event;
 receivers should handle it as a continuous timeline continuation rather than a