Silence compression for recorded voice messages
First Claim
1. A silence compression method, comprising:
- retrieving a previously stored compressed speech message from memory;
analyzing said previously stored compressed speech message to determine a spectral property of said previously stored compressed speech message;
modifying said previously stored compressed speech message based on said spectral property to produce a silence compressed speech message; and
storing said silence compressed speech message to said memory.
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Accused Products
Abstract
A silence compression system that improves data compression in a digital speech storage device, such as a digital telephone answering machine, without undue clipping of voice signals. Instead of employing only real-time compression, the inventive silence system analyzes and compresses or re-compresses digital speech samples stored previously, when the voice messaging system is off-line or otherwise in a low priority state. A method of silence compression comprises receiving real-time speech samples, storing the same in memory, and analyzing the stored speech samples at a later time to determine thresholds for periods of silence. The periods of silence are then compressed, and the silence compressed voice message is restored in memory. In this fashion, the processor is not required to make a silence period determination on-the-fly simultaneous with encoding and compression of the real-time voice message, and thus is not subjected to heavy processor loads typically encountered in real time. This enables more efficient compression of speech samples, lighter duty processors, and improved voice quality upon reproduction by eliminating undesired clipping of the voice signal encountered in prior systems after periods of silence. The silence compressed speech samples are stored in a storage device for subsequent playback.
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Citations
35 Claims
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1. A silence compression method, comprising:
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retrieving a previously stored compressed speech message from memory; analyzing said previously stored compressed speech message to determine a spectral property of said previously stored compressed speech message; modifying said previously stored compressed speech message based on said spectral property to produce a silence compressed speech message; and storing said silence compressed speech message to said memory. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A voice messaging system including off-line speech compression, comprising:
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an input to receive real-time digital speech samples based on a real-time analog speech message; a speech encoder to generate compressed digital speech samples by compressing said real-time digital speech samples received by said input; a storage device connected to said speech encoder to store said compressed digital speech samples; and a module to retrieve said stored compressed digital speech samples from said storage device, to analyze said retrieved compressed digital speech samples to determine a spectral property of said real-time analog speech message, to modify periods of silence of said retrieved compressed digital speech samples based on said determined spectral property to generate silence compressed digital speech samples, and to store said silence compressed digital speech samples in said storage device. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A telephone answering device, comprising:
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an input to receive real-time digital speech samples based on a real-time analog speech message; a speech encoder to generate compressed digital speech samples by compressing said real-time digital speech samples received by said input; a storage device connected to said speech encoder to store said compressed digital speech samples; and a module to retrieve said stored compressed digital speech samples from said storage device, to analyze said retrieved compressed digital speech samples to determine a spectral property of said real-time analog speech message, to modify periods of silence of said retrieved compressed digital speech samples based on said determined spectral property to generate silence compressed digital speech samples, and to store said silence compressed digital speech samples in said storage device. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification