| 词条 | Radio with Pictures system for use with DVB |
| 释义 |
}} Radio with Pictures (System for use with DVB transmission)Radio is frequently broadcast using the DVB (Digital Video Broadcasting) transmission standard on satellite, cable and terrestrial transmitters but normally those receiving will only view a blank TV screen. There exists the MHEG international standards for transmission of basic still images but these do not have universal receiver compatibility and are usually tied to and configured around a particular transmission operator's specific receivers (or a design of set-top box). In theory, it should not be a problem to create graphic images using the DVB television standards in order to allow text and graphics to accompany audio. However those who have attempted to do this discovered that the minimum bandwidth required for all set-top boxes to display graphics is not a great deal less than that needed for normal television (i.e. about 1.5 Mbit/s). This makes its use uneconomic for radio. Software developers thus devised proprietary ways in which low bandwidth images can be transmitted and yet still be received on all standard DVB receivers. Since 2002, such systems have been employed for transmission of still images on satellite services where it is the image that is of primary importance and the sound is secondary. The UK company WRN Broadcast adapted the systems so they can provide images that better support radio broadcasts and named the system "Radio with Pictures". Several such services are in current use by international radio broadcasters such as "Huna Amsterdam" for Radio Netherlands Worldwide to the Middle East, and "VOA24" for Voice of America to Africa. The principal features of "Radio with Pictures", according to information from WRN Broadcast, are: 1. 100% compatibility with existing DVB receivers used worldwide 2. Operates with bandwidths from 50 to 250kbit/s 3. Supports a 'live' mode where pictures and text are synchronised with the audio, and controlled from the radio studio 4. Supports interactity such that the audience may submit text and pictures to the screen (after broadcaster mediation) via SMS, email, Twitter etc. 5. The channel is located alongside TV services where most audience browsing takes place 6. Web pages may be placed on the screen and cannot be easily subject to censorship 7. Radio programming can be turned into a full-time 24/7 channel 8. The sources for visuals can be totally automated 9. Visuals may embrace information accompanying a radio broadcast e.g. album cover, or weather map, or advertising. ReferencesExternal linksPress Release 1 : Digital Video Broadcasting |
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