| 摘要 |
Provided are an apparatus for and a method of determining a transmission rate in speech transcoding. An input frame is classified as speech or silence based on a first threshold value that is predetermined for at least one of a fixed code-book gain value, an adaptive code-book gain value, a noise to signal rate, and a pitch delay that correspond to an input parameter of a coded bit stream. An input frame classified as voiced is classified as stationary or non-stationary based on a third threshold value that is predetermined for the amount of change in the ACBG value or a difference between the minimum and maximum pitch delays. An input frame, classified as voiced by a voiced/unvoiced classifying portion, is classified as voiced or non-stationary based on a class of a previous frame. An input frame, classified as voiced by a voiced/non-stationary classifying portion, is classified as stationary or non-stationary based on a third threshold value that is predetermined for the amount of change in the ACBG value or a difference between the minimum and maximum pitch delays. A transmission rate and a type of the determined rate for the input frame are determined based on transmission rates and types of the transmission rates that are predetermined for a class of the input frame corresponding to the result of classification.
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