Content delivery system
First Claim
1. A method of controlling a telecommunications terminal in a packet switched system, wherein the method comprises:
- the terminal in the packet switched system transmits to a server a playback-rate-indication signal indicative of the rate at which the terminal plays an audio output,the server determines a playback offset value by comparison of the playback-rate-indication signal received from the terminal with a playback-rate set by the server,the server transmits the playback offset value to the terminal; and
the terminal applies the playback offset value to its audio output so that the rate at which the output is played becomes synchronised to the rate set by the server.
1 Assignment
0 Petitions
Accused Products
Abstract
The audio outputs 29 of each of a plurality of telecommunications terminals in a packet switched system are synchronized by having each terminal transmit a stream of packets whose rate, and therefore duration is determined according to a clock generator 25, and is thus indicative of the rate at which the terminal is generating its audio output. The signals from each terminal are transmitted to a common server. For each terminal, the server uses a master dock to compare the duration of the packet stream with an expected duration, and calculates an offset value which is returned to the respective terminal. Each terminal stores the offset value it receives (20) and uses it to adjust the output of its clock generator 25 so that its operations can be synchronized to the server. This allows all the terminals'"'"' digital-to-analog conversion processes to be synchronized such that all their analog outputs are coordinated, allowing co-located acoustic outputs to be synchronous. A second embodiment maintains synchronization by maintaining the volume of the data buffer 23 serving the audio output 29 within predetermined limits.
20 Citations
16 Claims
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1. A method of controlling a telecommunications terminal in a packet switched system, wherein the method comprises:
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the terminal in the packet switched system transmits to a server a playback-rate-indication signal indicative of the rate at which the terminal plays an audio output, the server determines a playback offset value by comparison of the playback-rate-indication signal received from the terminal with a playback-rate set by the server, the server transmits the playback offset value to the terminal; and the terminal applies the playback offset value to its audio output so that the rate at which the output is played becomes synchronised to the rate set by the server. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A telecommunications terminal for connection to a packet switched system, the terminal comprising
an internal clock having a predetermined clocking value; -
an audio output controlled by the clocking value; a signal generator for generating a playback-rate-indication signal indicative of the rate at which the terminal plays an audio output; a transmitter for transmitting the playback-rate-indication signal to a server; a receiver for receiving playback offset value from the server; and a clock adjustment processor for adjusting the clocking value of the internal clock according to the playback offset value. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A server for connection to a packet switched telecommunications system for controlling one or more telecommunications terminals connected to the system, the server comprising:
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a master clock; a receiver for receiving a playback-rate-indication signal from each terminal indicative of the playback rate at which each respective terminal plays an audio output, a processor for calculating, for each terminal, a respective playback offset value derived from the playback-rate-indication signal received from the terminal, and a transmitter for transmitting the playback offset values to the respective terminals so that the playback offset values can be used by the terminals to control the audio output. - View Dependent Claims (14, 15, 16)
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Specification