Video search engine systems can make use of redirector (or “metafiles”) to provide increased functionality when initiating video playback. Instead of the user interface containing links directly to the media files, the links point to media metafiles which are small text markup files issued by the HTTP server with a particular MIME type that is mapped to the client media player.
At this point the browser has done its job and control of the streaming session is passed to the media player which connects to a media server. This arrangement provides several advantages:
– Response time: the small files download instantly and the media player application can launch quickly and begin video playback using progressive download or streaming.
– Failover / Loadbalancing: The redirector files can include alternative URLs for retrieving the media and media players support a failover mechanism where connection to servers indicated by a list of URLs is attempted in sequence. Applications can also generate metafiles dynamically with URLs pointing to lightly loaded streaming servers if the desired media is avalible on multiple media servers.
– Playtime offsets / clipping: the media play time start and duration can be encoded in the metafile. The ability to seek into the media is critical for directing users to relevant segments in long-form content.
– Playlists / Ad insertion: sets of media files matching user quieres can be represented as a play list and interfaces supported by the media player can be used to navigate amoung them. Preroll or interstitial advertizing can be supported using this mechanism – where essentially one or more clips in the playlist are ads. Much to users chagrin, these clips can be marked so that the ability to skip or fastforward are disabled during playback of ads.
– Additional features: Optionally, directives for including media captions (similar to closed captions) are supported. Also, metadata specific to the session can be included, e.g. the title can be set to “Results for your query for the term: NASA.” This mechanism can be used to effectivly override any metadata embedded in the media itself.