Glossary

From Media Fragments Working Group Wiki
Jump to: navigation, search

Please put terms used in the realm of the Media Fragments WG (and their definitions) here


URI and URI Fragment

URI

URI Fragment

  • URI Fragment from Wikipedia: http://en.wikipedia.org/wiki/Fragment_identifier
  • RFC3986 defines that the meaning of <something#somebit> depends on what <something> is, which in turn depends on the URI scheme. For the 'http' scheme the RFC2616 tells us that in order to find out what <something> is, a 'HTTP GET' has to be performed, yielding a certain 'Content-Type' in the response (i.e. telling about the mime-type of <something>). The mime-type registry defines what <#somebit> means within a document of the <something>-type. For example, for e.g. 'text/html' [RFC2854] defines that <#somebit> is actually a part of the document identified by an anchor.
  • Basic axioms from from http://www.w3.org/DesignIssues/Fragment.html:
    • The significance of the fragment identifier is a function of the MIME type of the object
    • The fragment ID spec for a new MIME type should be part of the MIME type registration process
  • The meaning of fragment identifiers is defined by the media type and not by the protocol

MIME Type

Video Resource

  • Assumption: a video is something with a single unified timeline, as the image below currently suggests (see comment)
  • Description of a video resource: https://wiki.mozilla.org/images/thumb/4/40/Model_Video_Resource.jpg/800px-Model_Video_Resource.jpg Describes the following:
    • track = data of one codec type encapsulated into a media container
    • video resource header = information that applies to all tracks
    • track header = header that applies to the data in one encapsulated codec track only
    • frame = a image from a video stream
    • video track = track with frames in a constant frame rate (e.g. 25 fps)
    • audio track = track with audio samples at a constant sampling rate (e.g. 44100 Hz)
    • text track = track with time-aligned text segments; text segments may overlap in time and may be discontinuous (i.e. have gaps in time)
    • image track = track with images (e.g. slide show); images may overlap in time and may be discontinuous (i.e. have gaps in time)

Other Principles

  • Follow-your-nose