Merge pull request #11 from gwendalsimon/feat/m2ts-si-pids

feat: add m2tsSiPids field and SI table retention guidance

Author: mondain

draft-gregoire-moq-msfts.md

@@ -268,6 +268,16 @@ scrambled transport streams MUST also retain the conditional access packets
 required for descrambling; conditional access integration is application-specific
 and outside the scope of this document.
 
+The retain list above is PMT-centric.  DVB and ATSC broadcast standards carry
+service information on fixed well-known PIDs that the PMT does not reference:
+SDT/BAT (0x0011), EIT (0x0012), TDT/TOT (0x0014), and NIT (0x0010), or their
+ATSC PSIP equivalents.  The filter silently drops these tables, leaving the
+resulting track without service identity, EPG, or broadcast time.  Publishers
+targeting broadcast or IRD deployments SHOULD retain the SI tables required by
+the target standard.  When SI tables are retained, publishers SHOULD declare the
+additional PIDs using `m2tsSiPids` ({{m2ts-si-pids}}) so that subscribers can
+verify which tables are present.
+
 The `m2tsProgramNumber` field ({{m2ts-program-number}}) SHOULD be present on
 per-program tracks to identify the program carried.  When multiple per-program
 tracks are derived from the same MPTS source, the publisher SHOULD use the MSF
@@ -343,6 +353,7 @@ Table 1 lists the m2ts-specific fields defined within a track object.
 | M2TS PMT PID                  | m2tsPmtPid              | {{m2ts-pmt-pid}} |
 | M2TS PCR PID                  | m2tsPcrPid              | {{m2ts-pcr-pid}} |
 | M2TS PSI interval             | m2tsPsiInterval         | {{m2ts-psi-interval}} |
+| M2TS SI PIDs                  | m2tsSiPids              | {{m2ts-si-pids}} |
 | M2TS mux rate                 | m2tsMuxRate             | {{m2ts-mux-rate}} |
 | M2TS random access            | m2tsRandomAccess        | {{m2ts-random-access}} |
 | M2TS timestamp mode           | m2tsTimestampMode       | {{m2ts-timestamp-mode}} |
@@ -415,6 +426,16 @@ This field is advisory.  A subscriber reconstructing a constant-bit-rate
 output stream MAY use this value to restore the original mux rate when null
 packets have been removed.
 
+## M2TS SI PIDs {#m2ts-si-pids}
+
+Required: Optional    JSON Type: Array    Location: Track Object
+
+The packet identifiers of SI tables retained in the filtered track, in addition
+to those listed in the Program Map Table.  This field is advisory.  Publishers
+SHOULD include this field when they retain DVB or ATSC SI tables.  Subscribers
+MAY use this list to verify which service information tables are present without
+inspecting the packet stream.
+
 ## M2TS Random Access {#m2ts-random-access}
 
 Required: Optional    JSON Type: Boolean    Location: Track Object