In a number of scenarios, ancillary timed content can be made available that enhances the experience of consuming some primary content. Examples include not only accessibility optional sub-titling or captions, but also content that enhances the user’s experience in other ways.
It is desirable that the availability and alignment of this ancillary media for the primary media be signaled using standard techniques and terms, in a uniform way, with only the manner in which it is stored in the formats varying.
Delivery of multimedia services using a combination of different transport protocols and formats is currently being investigated by many broadcasters (for example as part of HbbTV 2.0 requirements), and has been under discussion at MPEG during the 102nd (see contribution m26903 ) and the 103rd (m28136) MPEG meetings.
This exploration proposes to investigate this signaling, and how it may be embedded in a number of common formats, particularly those under MPEG control. The document integrates some ideas from contribution m31448.