Methods, Encoder And Decoder For Linear Predictive Encoding And Decoding Of Sound Signals Upon Transition Between Frames Having Different Sampling Rates

A method implemented in a sound signal decoder for converting received linear predictive (LP) filter parameters from a sound signal sampling rate S1 to a sound signal sampling rate S2, the method comprising:

• computing, at the sampling rate S1, a power spectrum of a LP synthesis filter using the received LP filter parameters;
• modifying the power spectrum of the LP synthesis filter to convert it from the sampling rate S1 to the sampling rate S2;
• inverse transforming the modified power spectrum of the LP synthesis filter to determine autocorrelations of the LP synthesis filter at the sampling rate S2;
• and
• using the autocorrelations to compute the LP filter parameters at the sampling rate S2.

A device for use in a sound signal encoder for converting linear predictive (LP) filter parameters from a sound signal sampling rate S1 to a sound signal sampling rate S2, device comprising:

• a processor configured to:
• compute, at the sampling rate S1, a power spectrum of a LP synthesis filter using the LP filter parameters,
• modify the power spectrum of the LP synthesis filter to convert it from the sampling rate S1 to the sampling rate S2,
• inverse transform the modified power spectrum of the LP synthesis filter to determine autocorrelations of the LP synthesis filter at the sampling rate S2, and
• use the autocorrelations to compute the LP filter parameters at the sampling rate S2.

A device for use in a sound signal decoder for converting received linear predictive (LP) filter parameters from a sound signal sampling rate S1 to a sound signal sampling rate S2, the device comprising:

• a processor configured to:
• compute, at the sampling rate S1, a power spectrum of a LP synthesis filter using the received LP filter parameters,
• modify the power spectrum of the LP synthesis filter to convert it from the sampling rate S1 to the sampling rate S2,
• inverse transform the modified power spectrum of the LP synthesis filter to determine autocorrelations of the LP synthesis filter at the sampling rate S2, and
• use the autocorrelations to compute the LP filter parameters at the sampling rate S2.