H.264 – A video coding format that uses a block-oriented, motion-compensation-based video compression standard. H.264/MPEG-4 AVC is one of the most common formats used for recording, compressing, and distributing video content.
For more information see: https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC

HLS – An acronym for HTTP Live Streaming is an HTTP-based media streaming communications protocol implemented by Apple Inc. It works by breaking the overall stream into a sequence of small HTTP-based file downloads, each download loading one short chunk of an overall potentially unbounded transport stream. As the stream is played, the client may select from a number of different alternate streams containing the same material encoded at a variety of data rates, allowing the streaming session to adapt to the available data rate. At the start of the streaming session, it downloads an extended M3U playlist containing the metadata for the various sub-streams [that] are available. See http://en.wikipedia.org/wiki/HTTP_Live_Streamingfor more information.

Host-initiated – Any activity that is auto-initiated.

Host-initiated sub-load – The additional file limit allowed for rich media and Rising Star units that is auto-initiated one second after the domContentLoadedEventEnd occurs (web page content has been loaded) on the host computer or device.

Hot Spot– A “hot spot” is an area of an ad unit, which when rolled-over/rolled-on by the user’s cursor, such rollover triggers an event (i.e. expand ad). The hotspot should never be larger than 1/4th the size of the original (collapsed) ad unit. The trigger event should not occur unless the user’s cursor rests in the hotspot zone for at least 1-second. Hotspots should never initiate audio (audio should only be initiated by a click). When hotspots are used, the trigger event should stop immediately upon the user’s cursor leaving the hotspot zone (i.e. ad collapses), and the ad unit should return to its original state.

HTML5 – An acronym for Hypertext Markup Language, version 5. HTML5 extends earlier versions to include tags for processing video, audio, canvas, an other embedded audio and video items without requiring proprietary plug-ins and APIs. HTML5 has been used as an alternative to developing and executing interactions similar to those using Adobe Flash but with very different technology.