diff --git a/draft-gregoire-moq-msfts.md b/draft-gregoire-moq-msfts.md
index 1d4a786..d6b4b77 100644
--- a/draft-gregoire-moq-msfts.md
+++ b/draft-gregoire-moq-msfts.md
@@ -250,6 +250,12 @@ each track contains only:
 * All packets whose PID is listed in the Program Map Table of the selected
   program, including the PCR_PID and the PIDs of all elementary streams.
 
+Removing null packets changes the inter-packet byte spacing that
+constant-bit-rate receivers use to recover the mux clock.  A subscriber
+wishing to reconstruct a constant-bit-rate output stream cannot derive the
+original rate from the stream alone; publishers that remove null packets
+SHOULD declare the source mux rate using `m2tsMuxRate` ({{m2ts-mux-rate}}).
+
 These rules apply to unscrambled transport stream sources.  Publishers filtering
 scrambled transport streams MUST also retain the conditional access packets
 required for descrambling; conditional access integration is application-specific
@@ -312,6 +318,7 @@ 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 mux rate                 | m2tsMuxRate             | {{m2ts-mux-rate}} |
 | M2TS random access            | m2tsRandomAccess        | {{m2ts-random-access}} |
 | M2TS timestamp mode           | m2tsTimestampMode       | {{m2ts-timestamp-mode}} |
 | M2TS SCTE-35 PID              | m2tsScte35Pid           | {{m2ts-scte35-pid}} |
@@ -367,6 +374,15 @@ the Program Association Table and Program Map Table in the packet stream.  When
 present, publishers SHOULD repeat PSI at an interval no larger than this value
 for live content.  Subscribers MAY use this value to estimate join latency.
 
+## M2TS Mux Rate {#m2ts-mux-rate}
+
+Required: Optional    JSON Type: Number    Location: Track Object
+
+The nominal source mux rate of the transport stream in bits per second.
+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 Random Access {#m2ts-random-access}
 
 Required: Optional    JSON Type: Boolean    Location: Track Object