Many video storage devices were designed for just video and audio, without
any expectation of a need to store additional enhancement data. Some
enhancements require only recording of simple triggers within the closed caption channel. Others require data storage and devices not available to the
consumer and broadcaster.
Click On Other Layers
Broadcast TV
ATVEFTransport A - (Line 21 Triggers, Internet access to enhancement
content.)
Virtually any consumer or professional video recorder or PVR can record the
closed-caption channel on line 21 and preserve ATVEF triggers located in Text
Channel 2.
ATVEF Transport B - (Broadcast delivery of enhancement triggers and content.)
There is no consumer video tape recorder or PVR that can store enhancement content
accompanying a program. While most professional digital video tape recorders
have the capability to record over 300,000 bps within the vertical interval,
there is no hardware available to inject enhancement data into this stream.
The single method today for storing ATVEF content for later broadcast is
within a separate ATVEF data server that is synchronized to the video playback
server or tape recorder.
PC Synchronous enhancements are incompatible with recording. Since the
content is pushed to the user PC in sync with the broadcast, it will be out of
sync with any playback from a home VCR or PVR. This problem seems to have no
solution.
PC streaming technologies that offer enhanced TV features have been
extended so the storage can accommodate enhancements on both the provider and
consumer hard drives. It is easy to extend a computer file format to encompass
new data channels by a routine upgrade of the server and player software and no
modification to the rigid parts of the system.
