feat: add CC/PID preservation MUST NOTs and PCR timing note - #12
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* Add MUST NOT modify continuity counters and MUST NOT remap PIDs in §5.2; either modification silently breaks program decoding or conditional access at the receiver * Add non-normative note in §5.5 that MOQT does not guarantee inter-packet PCR timing; deployments targeting hardware IRDs may require a rate-controlled egress to re-pace packets Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Summary
Two related clarifications for contribution and IRD deployments, addressing fidelity concerns raised in #7.
§5.2 — continuity counter and PID preservation
The existing text describes continuity counters, PIDs, and other transport-stream syntax as "remaining inside the source packets" — a description of what is carried, not a prohibition on modification. A publisher forwarding a source transport stream could technically rewrite continuity counters or remap PIDs while complying with the current text. Both modifications are silent disqualifiers for IRD receivers: a broken continuity counter sequence triggers decoder errors; PID remapping breaks demultiplexing and conditional access without warning. This PR adds explicit MUST NOTs to match the byte-faithful carriage requirement described in #7.
§5.5 — PCR arrival timing
The PCR and Timing section correctly handles PCR value continuity and discontinuity signaling but says nothing about inter-packet timing. Hardware IRDs derive 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 inter-packet timing; packets arrive in bursts shaped by QUIC rather than at source mux rate. A non-normative note acknowledges this constraint, addressing the second option raised in point 4 of #7 — a statement that PCR is authoritative and that the egress should pace to it.
Changes
§5.2 Object Boundaries — add MUST NOT modify continuity counters and MUST NOT remap PIDs when forwarding a source transport stream.
§5.5 PCR and Timing — add non-normative note on inter-packet PCR timing and IRD mux-clock recovery.