There is a need in the media industry for an API to support metadata events synchronized to audio or video media, specifically for both out-of-band event streams and in-band discrete events (e.g.,
MPD -carriage and
emsg events in MPEG DASH: http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip).
These media timed events can be used to support use cases such as ad insertion or presentation of supplemental content alongside the audio or video.
DataCue API has been previously discussed as a means to deliver in-band event data to Web applications, but this is not implemented in mainstream browser engines and is therefore not reflected in the WHATWG living HTML specification. There is previous discussion here, and an earlier liaison statement from HbbTV here. Whether
DataCue should be taken up again or another API should be developed, we believe there is a recognized need for extending the existing HTML specification to assist web applications in being able to properly process and render media-timed events.
The Media & Entertainment Interest Group has a draft use case and requirements document here. Please note that this document describes a broader range of topics, and we only propose to work on MPEG DASH MPD and
emsg events at WICG at this stage.
We ask for your support in progressing this, and look forward to working with you.