This specification defines a direct mapping between CMAF Tracks ( [CMAF] Sect 3.2.1) and MOQT tracks ([MoQTransport] Sect 2.3).
CMAF switching sets are a set of one or more CMAF tracks (3.2.1), where each track is an alternative encoding of the same source content and are constrained to enable seamless track switching (3.3.9).
Each CMAF track in a switching set MUST be transmitted as a separate MOQT Track. The catalog entry for each of these tracks in the switching set MUST carry a Alternate group (altGroup) key with a common value.
The MOQT Group numbers within these switching set tracks MUST be media time-aligned. Mandating the track being media time-aligned requires that the presentation time of the first media sample contained within the first MOQT Object of each MOQT Group is identical.