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IMBE Tone Insertion Algorithm

IP.com Disclosure Number: IPCOM000013174D
Original Publication Date: 2003-Jun-17
Included in the Prior Art Database: 2003-Jun-17
Document File: 1 page(s) / 42K

Publishing Venue

Motorola

Related People

Erik S. Perrins: AUTHOR

Abstract

This paper describes an algorithm for inserting tone frames into the IMBE encoder output stream. The algorithm works in tandem with a tone detection algorithm, and will insert IMBE tone frames based on the decisions of the detector. The algorithm takes into account the attributes of the IMBE encoder when inserting the tone frames in order to achieve the best audio quality possible. Specifically, it accounts for the delay of the encoder, and attempts to smooth out any transient effects in connection with starting and stopping the insertion of pre-defined IMBE frames.

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IMBE Tone Insertion Algorithm

by Erik S. Perrins

This paper describes an algorithm for inserting tone frames into the IMBE encoder output stream.� The algorithm works in tandem with a tone detection algorithm, and will insert IMBE tone frames based on the decisions of the detector.� The algorithm takes into account the attributes of the IMBE encoder when inserting the tone frames in order to achieve the best audio quality possible.� Specifically, it accounts for the delay of the encoder, and attempts to smooth out any transient effects in connection with starting and stopping the insertion of pre-defined IMBE frames.

The insertion algorithm operates from the standpoint that the tone decision has been made, and a history of recent decisions is available.� Once a decision has been made, the algorithm inserts the tone frames with some delay D (D is an integer number of 20 ms frames, D >= 0).� For example, if D = 1, and the detect decision at frame n was Tone X, then at frame n+1 the algorithm would insert the frame corresponding to Tone X.� In addition, when the algorithm transitions from any detect decision to undetect, it repeats the previous decision R additional frame before undetecting (R >= 0).� For example, suppose R = 2 and at frame n the algorithm does not detect any tone of interest, but at frame n-1 it detected Tone X.� Then for frames n+D and n+D+1 the algorithm will continue to insert the frame corresponding to Tone X.� This repeat mechanism is aborted if the algor...