Reconstruction of a high-frequency range in low-bitrate audio coding using predictive pattern analysis

Abstract

A predictive pattern high-frequency reconstruction system and method that finds patterns in high-frequency components of an audio signal, encodes the audio signal into an encoded bitstream along with pattern information, and then uses the patterns to reconstruct the high-frequency components during decoding. The high-frequency components can be reconstructed using the pattern information alone. Embodiments of the system and method map normalized subband signals of the audio signal to a scaled representation of a time-frequency grid containing multiple tiles and perform statistical analysis on each tile to estimate subband parameters and determine whether a pattern exists. If a pattern does exist, it can be encoded in the encoded bitstream, transmitted, and used to reconstruct the high-frequency components at the decoder. A direct search technique and a fast Fourier transform (FFT) technique may be used to perform the statistical analysis.