Abstract: Presented herein are system(s) and method(s) for frequency domain audio speed up or slow down, while maintaining pitch. An encoded audio signal is received. Frames from the encoded audio signal are retrieved. The frames of the audio signal are transformed into a frequency domain, wherein each of said frames are associated with a plurality of initial phases, and a corresponding plurality of ending phases. The initial phases of at least one of the frames are replaced with the ending phases of another frame.

Abstract: Presented herein are system(s) and method(s) for frequency domain audio speed up or slow down, while maintaining pitch. An encoded audio signal is received. Frames from the encoded audio signal are retrieved. The frames of the audio signal are transformed into a frequency domain, wherein each of said frames are associated with a plurality of initial phases, and a corresponding plurality of ending phases. The initial phases of at least one of the frames are replaced with the ending phases of another frame.

Abstract: The invention relates to improving parameter estimation and speech synthesis. Pursuant to one aspect of the invention, a path of pitch candidates having low errors is tracked to determine a pitch estimate. Pursuant to another aspect of the invention, a number of parameters are used to classify speech segments. Pursuant to another aspect of the invention, a voicing parameter is determined using a threshold value and bands are marked voiced or unvoiced depending on two error functions that compare synthesized voiced and unvoiced spectra to an original speech spectrum. Pursuant to another aspect of the invention a voicing parameter is used to facilitate lower bits for transmitting voicing decisions. Last, pursuant to other aspects of the invention, unvoiced speech is synthesized by incorporating a random generator, and harmonics phases are initialized with a fixed set of values.

Abstract: Pursuant to one aspect of the invention, a prefilter module that incorporates an inverse filter is used in conjunction with an encoder. The inverse filter has an inverse frequency response of a frequency response of a filter that simulates speech having transmission path characteristics, such as telephone-channel bandwidth speech, and/or noisy speech. The inverse filter is used to compensate transmission path characteristics of an input signal. The inverse filter can be designed using several methods, such as, for example, an autoregressive model or a moving average model. Pursuant to a second aspect of the invention, a parameter preprocessor is used in conjunction with a decoder. The parameter preprocessor performs pitch rectification through use of a medium and linear filter, and updates spectral amplitudes and voicing parameter depending on the pitch rectification.