Vector quantization of decorrelated spectral coefficients
AssigneeApple Inc.
InventorsVenkatraman ATTI, Dipanjan SEN
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Abstract
Aspects of the present disclosure provide improved techniques for coding audio signal with a transient audio sound. Improved techniques include parsing a frame of predetermined length of audio samples into a series of windows of a smaller size, and transforming the windows of time-domain samples into a series of windows of frequency-domain samples. In an aspect coding of the frequency-domain samples may include vector quantization of vectors formed of frequency-domain samples selected from across the frame.
Claims20
An audio encoding method, comprising:
- parsing a sequence of audio samples contained within a frame of a predetermined size into a plurality of windows of smaller size,
- transforming the audio samples in the windows into respective sets of frequency-domain coefficients,
- developing a plurality of vectors, each vector containing frequency-domain coefficients selected from a plurality of the windows,
- quantizing vectors of the plurality of vectors according to a vector codebook, and
- coding the quantized vectors as an encoded audio signal.
A system for audio encoding, comprising:
- a processor;
- and
- a memory storing instructions, that when executed by the processor, cause the system to:
- parse a sequence of audio samples contained within a frame of a predetermined size into a plurality of windows of smaller size,
- transform the audio samples in the windows into respective sets of frequency-domain coefficients,
- develop a plurality of vectors, each vector containing frequency-domain coefficients selected from a plurality of the windows,
- quantize vectors of the plurality of vectors according to a vector codebook, and coding the quantized vectors as an encoded audio signal.
A non-transitory computer readable memory storing instructions for encoding audio that, when executed by a processor, cause the processor to:
- parse a sequence of audio samples contained within a frame of a predetermined size into a plurality of windows of smaller size,
- transform the audio samples in the windows into respective sets of frequency-domain coefficients,
- develop a plurality of vectors, each vector containing frequency-domain coefficients selected from a plurality of the windows,
- quantize the vectors according to a vector codebook, and
- coding the quantized vectors as an encoded audio signal.
An audio decoding method, comprising:
- decoding a frame of coded audio data with reference to a quantization codebook, the decoding recovering, for each of a plurality of codebook indices received in coded audio data, a vector representing transform coefficients of the audio data;
- transforming recovered coefficients of the frame from a domain of transform coefficients to a domain of time samples;
- wherein the transforming occurs on a window granularity at a smaller size than a size of the frame, and the decoding assigns recovered transform coefficients to coefficient positions according to a pattern in which transform coefficients recovered from a single vector are assigned to coefficient positions of a plurality of windows.
A system for audio decoding, comprising:
- a processor;
- and
- a memory storing instructions, that when executed by the processor, cause the system to:
- decode a frame of coded audio data with reference to a quantization codebook, the decoding recovering, for each of a plurality of codebook indices received in coded audio data, a vector representing transform coefficients of the audio data;
- transform recovered coefficients of the frame from a domain of transform coefficients to a domain of time samples;
- wherein the transforming occurs on a window granularity at a smaller size than a size of the frame, and the decoding assigns recovered transform coefficients to transform coefficient positions according to a pattern in which frequency coefficients recovered from a single vector are assigned to transform coefficient positions of a plurality of windows.
A non-transitory computer readable memory storing instructions for decoding audio that, when executed by a processor, cause the processor to:
- decode a frame of coded audio data with reference to a quantization codebook, the decoding recovering, for each of a plurality of codebook indices received in coded audio data, a vector representing transform coefficients of the audio data;
- transform recovered coefficients of the frame from a domain of transform coefficients to a domain of time samples;
- wherein the transforming occurs on a window granularity at a smaller size than a size of the frame, and the decoding assigns recovered transform coefficients to transform coefficient positions according to a pattern in which frequency coefficients recovered from a single vector are assigned to transform coefficient positions of a plurality of windows.
Dependencies are inferred from the claim text.