| 摘要 |
A comprehensive mechanism is provided for broadcasting and accessing multiple audio sources in connection with the viewing of a television program. In the preferred embodiment, the first step in providing audio is collecting the audio through the use of standard audio capture techniques. Next, the audio is distributed by either of in-band via broadcast or out-of-band techniques. In-band audio is preferably provided via an MPEG stream associated with the current television program. Out-of-band (OOB) audio can be broadcast as well, although it is preferable to select which channel is distributed upstream first, rather than broadcast all channels downstream and consume bandwidth for unselected audio. Thus, it is preferred that only the desired audio channel(s) are sent over the OOB channel. The audio is preferably tagged with metadata, such that information describing the audio accompanies each audio channel. This allows, for example, a description of the audio to be provided to the viewer as part of a selection mechanism (see below), and/or provides control information that is used by the system, for example to configure the system for a particular type of audio processing, e.g. DTS; display accompanying graphic information; such as an ad; or engage a viewer authentication/billing mechanism, for example to provide upstream information concerning the viewer's selections. With either system, the viewer operates a set top box to select the appropriate audio channel(s) and route the television audio to a television or to a separate amplifier and speakers for reproduction.
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