| 摘要 |
A videophone includes a video camera for transducing and digitizing images at a station and connected to a video processor for compressing and encoding the digitized images into video data. The videophone also includes an audio transducer and digitizer connected to an audio processor synchronized with the video processor for compressing and encoding digitized sound. The video and audio processors are connected to a communication controller for formatting and transmitting the video data bundled with the audio data via a standard bidirectional (full duplex) telephone line in the form of a twisted pair. The communication controller can also receive and then unformat and unbundle audio and video data, and the video processor and audio processor can decode and decompress the received video and audio data, and the station further includes a display connected to the video processor for reproducing images and an electroacoustic transducer connected to the audio processor for reproducing sounds transmitted by another station. Rather than format and transmit only delayed or partial changed video data when the image changes significantly, the large amount of changed video data being stored is overwritten when the amount reaches a predetermined level, and new video data corresponding to the present appearance of the image is compressed, encoded, bundled with associated audio data, formatted, and transmitted. The image reproduced at the receiving station therefore jumps ahead to an updated image without intervening blurred images. Audio and video data can also be selectively stored and subsequently played back and/or transmitted to another station.
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