1). Zapping Support - OV
§ Any streamed service may be complemented by associated zapping support content.
§ The zapping support content may be used to bridge the service switching time at the terminal.
§ During this time, the content, which is associated with the zapping support, will be presented to the user until the content of the selected service becomes available to the terminal.
§ Therefore the user has the possibility to get a first impression of the content that is transmitted for the selected service.
§ The datatypes that can be used for zapping support depend on whether the zapping support is static or dynamic.
2). Zapping Support in ESG Acquisition Fragment provided to the user with two options:
a) Dynamic Zapping, where the Zapping Support is provided not as part of the ESG data so it can be dynamically changing.
b) Static Zapping, where the Zapping Support is provided inlined.
3). The main differences between dynamic zapping and static zapping
§ Major differences are the transport mechanism and timeliness.
§ The switching times between the zapping information and the content channel itself depends on the terminal architecture. For instance the switching time might depend on the capability of the terminal to determine random access point in the AV content in parallel to the decoding of the zapping information.
3.1). Transport mechanism:
§ Dynamic zapping content is transported as a separate IP flow in burst separate from that of the selected service.
§ Static zapping content is transported as part of the ESG.
3.2). Timeliness:
§ Dynamic zapping content contains continuously updated snapshots of the service.
§ Static zapping content contains one single
3.3). Timely manner:
§ Dynamic zapping content is aligned with the content of the selected service.
§ Static zapping is transported significantly in advance to the streaming service.
4). Dynamic zapping
§ The dynamic zapping support is provided as a stream, which contains content to support the zapping to the sessions described by this Acquisition Fragment, e.g. a copy of the audio/video content with reduced performance, a still picture showing the latest snapshot out of the current video or dynamic text such as subtitles.
§ Also a combination of the aforementioned is possible.
§ The zapping support can provide data of different types. The type or types of zapping data can be obtained from the Zapping Support Classification Scheme.
§ The session description of the Zapping Support Session can be obtained from the ZappingSupportSessionDescription Element.
§ A dynamic zapping service is a streaming service on a separate IP flow in a separate zapping burst, which contains complementary content about the selected streaming service. The content within every received zapping service burst will be continuously updated.
§ The following datatypes are available for dynamic zapping:
- Video: This is a reduced quality copy of the selected service's video component. The video is transported with the same protocol stack and restrictions as specified for the selected service.
- Audio: This is an reduced quality copy of the selected service's audio component. The audio is transported with the same protocol stack and restrictions as specified for the selected service.
- DynamicText: The dynamic text may contain content related to the progress of the selected AV service, such as sub-titling, or other textual content
5). Static Zapping
§ The static zapping support is provided in form of inlined data, which contains content to support the zapping to the sessions described by this Acquisition Fragment, such as a still picture giving the impression of the current A/V service, graphics or simple text.
§ Availability of a complementing static zapping support for a particular streaming session is signalled in the Acquisition Fragment by the presence of the MediaLocator element.
§ The type or types of zapping data can be obtained from the Zapping Support Classification Scheme.
§ A static zapping service has its content transmitted as ESG auxiliary data or inlined within the ESG using the MediaLocatorType.
§ The following two datatypes are declared as classification scheme terms for static zapping support.
- Static picture
- Static text
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