HbbTV 1.5 experiments [via Multi-device Timing Community Group]

Hi all,

In collaboration with Vicometch-IK4, we did some tests of HbbTV 1.5 to see if we
could manage to exploit Shared Motions to add sync capabilities to existing
smart TVs.  The HbbTV 1.5 does not have any explicit support for
synchronization, and while HbbTV 2.0 will bring this, lots of existing SmartTVs
will not get these upgrades.  If you are interested and have knowledge about
HbbTV, we welcome any input on this initial experiment.

We quickly discovered that the media element of the TV (as well as other weaker
devices, like Chromecasts) are unable to provide a good user experience when
slaving after a Shared Motion.  They typically lack variable playback rate, and
skip operations tend to be very slow.  Our approach was therefore to request
the media element to play from a given position.  It will not be very correct,
but instead of trying to correct the playback on the TV, we rather adjust the
Shared Motion to match what the TV does.  In this way, we've re-created a
master-slave relation, with one master (the TV/Chromecast) and however many
slaves you want.

Here is a film we made from our experiment with a Panasonic TV:



Interestingly, we see that the currentTime reported by this TV fluctuates
within around 250ms.  We are however able to select the better samples and in
that way provide a consistent experience.  The TV we tested did need
calibration, but this seemed to be hardware specific and consistent for skips,
reloads and other content.

This test is of course IP based.  We asked for some input on this for
broadcasted content.  It appears that we only would have streamevents to
provide an estimated time (possibly to within a second), but perhaps even
relatively rough estimates of the current position could be extracted and make
for user friendly transitions between broadcasted and IP delivered content?

Of course, HbbTV 2.0 devices should be much better at all of this, and provide
local synchronization to boot.  However, we believe this experiment opens for
an interesting transition phase, where current SmartTVs can provide at least
some additional functionality for a vast number of users.

If there is any interest in testing other HbbTVs, we're very willing to provide
a simple web application for testing, including manual calibration.  Please let
us know!

Regards, Njål



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'HbbTV 1.5 experiments'

https://www.w3.org/community/webtiming/2016/04/04/hbbtv-1-5-experiments/



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Received on Monday, 4 April 2016 19:27:01 UTC