Hi
Thanks both for the above help - I would be interested in following progress on that Louise!
I've been having a play with the https://github.com/LearningPool/adapt-contrib-responsiveIframe/ plugin (you guessed correctly) and I think I've managed to get it to work, but will share my solution here in case there is an easier way or something I'm missing - would appreciate any feedback.
So I have two embed code options I've tried with this plugin - "auto" and "iframe".
Auto:
<div id="kaltura_player_1510064935" style="width: 610px; height: 402px;" itemprop="video" itemscope itemtype="http://schema.org/VideoObject">
<span itemprop="name" content="quick_kaltura_test"></span>
<span itemprop="description" content="null"></span>
<span itemprop="duration" content="37"></span>
<span itemprop="thumbnail" content="http://cfvod.kaltura.com/p/1875011/sp/187501100/thumbnail/entry_id/1_mz34w98s/version/0"></span>
<span itemprop="width" content="610"></span>
<span itemprop="height" content="402"></span>
</div>
<script src="https://cdnapisec.kaltura.com/p/1875011/sp/187501100/embedIframeJs/uiconf_id/40937311/partner_id/1875011?autoembed=true&entry_id=1_mz34w98s&playerId=kaltura_player_1510064935&cache_st=1510064935&width=610&height=402&flashvars[streamerType]=auto"></script>
and the "iframe" one:
<iframe src="https://cdnapisec.kaltura.com/p/1875011/sp/187501100/embedIframeJs/uiconf_id/40937311/partner_id/1875011?iframeembed=true&playerId=kaltura_player_1510065173&entry_id=1_mz34w98s&flashvars[streamerType]=auto" width="610" height="402" allowfullscreen webkitallowfullscreen mozAllowFullScreen frameborder="0" style="width: 610px; height: 402px;" itemprop="video" itemscope itemtype="http://schema.org/VideoObject">
<span itemprop="name" content="quick_kaltura_test"></span>
<span itemprop="description" content="null"></span>
<span itemprop="duration" content="37"></span>
<span itemprop="thumbnail" content="http://cfvod.kaltura.com/p/1875011/sp/187501100/thumbnail/entry_id/1_mz34w98s/version/100001"></span>
<span itemprop="width" content="610"></span>
<span itemprop="height" content="402"></span>
</iframe>
In each case, using the full embed code doesn't work - and I just get a grey, blank component with no video loaded.
What I've just tried - is extracting the src link in each case by copying that out of the embed code and into the URL field of the responsive iframe plugin - the auto one didn't work (just displayed a load of code in the preview) but the iframe one worked! So that seems to be the easiest method to use to get the link.
If there is a more elegant / cleaner solution I would like to hear it! I'm not sure if this is the best way of getting this to work - and I'm not sure what the optimal breakpoints are to use with this plugin - should these match your video dimensions directly?
Thanks
Jon