LOW-LATENCY, LOW-FREQUENCY EFFECTS CODEC

1 . A method of encoding a low-frequency effect (LFE) channel, comprising:

receiving, using one or more processors, a time-domain LFE channel signal;

filtering, using a low-pass filter, the time-domain LFE channel signal to produce a filtered time-domain LFE channel signal, wherein the low-pass filter has a cut-off frequency;

converting, using the one or more processors, the filtered time-domain LFE channel signal into a frequency-domain representation of the time-domain LFE channel signal that includes a number of coefficients representing a frequency spectrum of the time-domain LFE channel signal;

arranging, using the one or more processors, the coefficients into two or more subband groups corresponding to different frequency bands of the time-domain LFE channel signal, wherein the different frequency bands include a primary LFE frequency band that is below a cut-off frequency of an LFE speaker and at least one other LFE frequency band that is higher than the cut-off frequency of the LFE speaker, where each subband group has a width, and a sum of the widths of the subband groups includes the primary LFE frequency band and the at least one other LFE frequency band;

generating a scaling shift factor based on a maximum number of quantization points available and a sum of the absolute values of the coefficients;

quantizing, using the one or more processors, the coefficients in each subband group according to a frequency response curve of the low-pass filter and using the scaling shift factor to produce quantized coefficients;

encoding, using the one or more processors, the quantized coefficients in each subband group using an entropy coder tuned for the subband group; and

generating, using the one or more processors, a bitstream including the encoded quantized coefficients.

2 . A low-latency, low-frequency effect (LFE) encoder, comprising:

one or more processors; and

a non-transitory computer-readable medium storing instructions that, upon execution by the one or more processors, cause the one or more processors to perform operations of method claim 1 .

3 . A non-transitory, computer-readable medium storing instructions that, upon execution by one or more processors, cause the one or more processors to perform operations of claim 1 .

4 . A method of decoding a low-frequency effect (LFE) channel, comprising:

receiving, using one or more processors, an LFE channel bitstream, the LFE channel bitstream including entropy coded quantized coefficients representing a frequency spectrum of a time-domain LFE channel signal;

decoding, using the one or more processors, the entropy coded quantized coefficients using an entropy decoder;

inverse quantizing, using the one or more processors, the quantized coefficients, wherein the coefficients were quantized in subband groups corresponding to frequency bands according to a frequency response curve of a low-pass filter used to filter the time-domain LFE channel signal in an encoder;

converting, using the one or more processors, the inverse quantized coefficients to a time-domain LFE channel signal; and

filtering, using a low-pass filter, the time-domain LFE channel signal.

5 . A low-latency, low-frequency effect (LFE) decoder, comprising:

one or more processors; and

a non-transitory computer-readable medium storing instructions that, upon execution by the one or more processors, cause the one or more processors to perform operations of method claim 4 .

6 . A non-transitory, computer-readable medium storing instructions that, upon execution by one or more processors, cause the one or more processors to perform operations of claim 4 .