Tasks
For an introduction to term definitions and architecture, please consult
The MTCG will concern itself with the following tasks.
T1. TimingObject
TimingObjects are local objects, mediating access to local or online timing resources. The TimingObject is essentially an ideal clock/stop-watch, advancing deterministically in accordance with a system clock. So, for a mediacontroller based on a TimingObject it should take exactly 2.0 seconds for the currentTime property to advance from 3.0 to 5.0, given that playbackRate is 1.0. This deterministic behavior is required for reliable distributed synchronization. Note however that this assumption is currently not valid for HTMLMediaElements, as playback is often too slow or too fast measured relative to the local system clock. This task will draft a specification for a common API for the TimingObject, using the Shared Motion API as a starting point.
https://www.w3.org/community/webtiming/timingobject/
T.2 Timed Media
Currently HTMLMediaElements accept external timing control through the association with the HTMLMediaController. MTCG will work to facilitate similar integration with the HTMLTimingObject. MTCG initially targets precise timing of HTMLMediaElements through JavaScript extension libraries, but will also discuss possible benefits of native browser support for timed media. This task shall review the current spec and implementation of the HTMLMediaElement. The task output includes bug reports, suggestions for API modifications, as well as a reference implementation of JavaScript integration with the TimingObject. This task shall also propose a test suite for the HTMLMediaElement with respect to precise timing.
https://www.w3.org/community/webtiming/timedmedia/
T.3 Timed Data
MTCG aims to facilitate the integration of timed data with multi-device timing by defining the TimingTextTrack, based on the established concept of TextTrack. TimingTextTrack will not take direction from a HTMLMediaElement (as is currently the case for text tracks), but integrate directly with the TimingObject. This task shall review the current spec and implementation of the TextTrack and TimingTextTrack. The task output includes bug reports, suggestions for API modifications, as well as a reference implementation in JavaScript, integrating with multi-device timing proxies.
https://www.w3.org/community/webtiming/timeddata/
T.4 Timing Providers
Timing services implement a protocol allowing TimingObjects to connect, synchronize and interact with server side timing resources. As a first approach the Multi-device Timing Community Group proposes to NOT standardize such a protocol, but instead introducing the concept of a Timing Provider, allowing third party implementations of such protocols.
https://www.w3.org/community/webtiming/timingprovider/
