Method and apparatus for reducing synchronization delay in packet-based voice terminals by resynchronizing during talk spurts
First Claim
1. A method for operating a media subsystem when playing audio data for reducing synchronization delay, comprising:
- when a frame comprising audio data is sent to a decoder, measuring the synchronization delay;
determining by how much the synchronization delay should be adjusted; and
adjusting the synchronization delay in a content-aware manner by adding or removing one or more audio samples in a selected current frame or in a selected subsequent frame so as not to significantly degrade the quality of the played back audio data.
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Accused Products
Abstract
Circuitry, embodied in a media subsystem (10A), reproduces a speech or other type of audio signal, and is operable when playing back audio data for reducing synchronization delay. A method operates by, when a frame containing audio data is sent to a decoder (20), measuring the synchronization delay; determining by how much the synchronization delay should be adjusted; and adjusting the synchronization delay in a content-aware manner by adding or removing one or more audio samples in a selected current frame or in a selected subsequent frame so as not to significantly degrade the quality of the played back audio data. When the synchronization delay is adjusted by more than one audio sample, the adjustment can be made by all of the determined audio samples in one adjustment, or the adjustment is made by less than all of the determined audio samples by a plurality of adjustments. The step of adjusting selects, if possible, an unvoiced frame and discriminates against a transient frame. The step of determining includes measuring an average amount of time that a frame resides in a jitter buffer (18), and adjusting the synchronization delay so that the average duration approaches a desired jitter buffer residency duration.
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Citations
36 Claims
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1. A method for operating a media subsystem when playing audio data for reducing synchronization delay, comprising:
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when a frame comprising audio data is sent to a decoder, measuring the synchronization delay;
determining by how much the synchronization delay should be adjusted; and
adjusting the synchronization delay in a content-aware manner by adding or removing one or more audio samples in a selected current frame or in a selected subsequent frame so as not to significantly degrade the quality of the played back audio data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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- 9. Apparatus for reproducing a speech signal, comprising buffer circuitry for storing data from a packet that contains data representing a speech signal prior to the data being sent to a decoder, further comprising control circuitry operable when a frame comprising audio data is sent to the decoder, for measuring a synchronization delay, for determining by how much the synchronization delay should be adjusted and for adjusting the synchronization delay in a content-aware manner by adding or removing one or more audio samples in a selected current frame or in a selected subsequent frame so as not to significantly degrade the quality of the played back audio data.
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24. A method for operating a communication device while synthesizing speech from speech data, the method operating to reduce synchronization delay and comprising:
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for a received frame comprising encoded speech data to be sent to a speech decoder, measuring the synchronization delay;
determining by how much the synchronization delay should be adjusted; and
adjusting the synchronization delay by adding or removing one or more speech samples in a selected frame so as not to significantly degrade the quality of the reproduced speech, where the frame is selected based on at least one speech decoder-related parameter so as to select, if possible, an unvoiced frame over a voiced frame, while discriminating against selecting a transient frame. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification