Essential Media Metadata (Video Data Sources and Applications)

Embed Global Metadata

Some level of metadata is embedded within the media stream, either as a header for use in decoding or rendering, or as an additional logical bitstream multiplexed within the media. In addition, metadata can be maintained in separate files that refer to the media file or collections of files (packages or channels) see Fig. 2.2.

Metadata is embedded with media, or stored externally.

Fig. 2.2. Metadata is embedded with media, or stored externally.

Elementary Metadata

There are several common media container formats in use on the Web today, and search engine ingest systems can parse these to extract some basic information about the media. At a minimum, the container files indicate enough global information about the media to allow decoding applications to play the file (e.g. the number of media streams in the file.) Each stream has attributes such as bitrate, frame rate, spatial resolution, etc. Typically there is at a minimum an audio stream and a video stream, but there may be multiple media streams, e.g. multirate streaming uses several video streams at different bitrates. The duration and image resolution information are required for parsing and can be of some limited practical use for search engine systems for filtering search results (e.g. “find me videos with at least a 320 by 240 resolution and 20 minutes or more in length”).


The container formats typically support the inclusion of high level descriptive information such as title. This global media metadata can be extracted from open formats using available tools and used for indexing applications. This provides some very basic information for search engines beyond the typical filesystem attributes such as size and name, but the level of detail available falls short of providing a true description of the content itself. We can think of levels of depth of information discovery about unknown media files as shown in Fig. 2.3.

Depth of discovery of metadata from media files.

Fig. 2.3. Depth of discovery of metadata from media files.

Global metadata entry dialog for a single media file

Fig. 2.4. Global metadata entry dialog for a single media file

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