Method and apparatus for reducing synchronization delay in packet-based voice terminals by resynchronizing during talk spurts
First Claim
1. A method comprising:
- when a frame comprising active speech data is sent to a decoder, measuring synchronization delay;
determining by how much the synchronization delay should be adjusted;
selecting a frame of the active speech data in dependence on characteristics of the active speech data reflected in the frame; and
adjusting the synchronization delay during a period of active speech by adding or removing one or more audio samples in the selected frame so as not to significantly degrade the quality of the played back active speech 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 comprising:
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when a frame comprising active speech data is sent to a decoder, measuring synchronization delay; determining by how much the synchronization delay should be adjusted; selecting a frame of the active speech data in dependence on characteristics of the active speech data reflected in the frame; and adjusting the synchronization delay during a period of active speech by adding or removing one or more audio samples in the selected frame so as not to significantly degrade the quality of the played back active speech data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Apparatus comprising:
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buffer circuitry for storing active speech data from a packet prior to the active speech data being sent to a decoder; and control circuitry operable when a frame comprising active speech data is sent to the decoder, the control circuitry configured to measure synchronization delay;
to determine by how much the synchronization delay should be adjusted;
to select a frame of the active speech data in dependence on characteristics of the active speech data reflected in the frame; and
to adjust the synchronization delay by adding or removing one or more audio samples in the selected frame so as not to significantly degrade the quality of the played back audio data. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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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 active 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 of the active speech data 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