The way references to other specs are made could be improved. Example of problems:
Section 3.1 references "MPEG-2 TS" without linking to the reference section.
Section 3.2 references "ETSI EN 300 468" without linking to the spec.
Section 3.2 refers to Rec. ITU-R BT.188, Rec. ITU-R BT.709 and Rec ITU-R BT.2020 without them being listed in Section 2.
Section 3.2 refers to AV1 by a long name "AV1 Bitstream and Decoding Process Specification". Section 4.1 and others use "AV1 Bitstream & Decoding Process Specification" ("&" vs "and")
I suggest:
Relying on the ReSpec (or Bikeshed) framework to handle references: let the tool generate the reference section (with normative and informative subsections), let the tool generate the hyperlinks
Using the same, short words when referring to a given spec: I suggest: "MPEG-2 TS", "AV1", "BT.XXX", "ETSI EN 300 468"
The way references to other specs are made could be improved. Example of problems:
I suggest: