Encoding and decoding of digital audio signals using difference data
First Claim
1. An encoding system, comprising:
- a processor; and
a memory device storing instructions executable by the processor, the instructions being executable by the processor to perform a method for encoding an audio signal, the method comprising;
receiving a digital audio signal;
parsing the digital audio signal into a plurality of frames, each frame including a specified number of audio samples;
performing a transform of the audio samples of each frame to produce a plurality of frequency-domain coefficients for each frame;
partitioning the plurality of frequency-domain coefficients for each frame into a plurality of bands for each frame;
allocating a specified number of bits for each band in each frame;
computing a difference value for each band in each frame, the difference value representing a difference between the number of bits allocated for each band in each frame and a corresponding estimated number of bits allocatable for each band in each frame;
encoding a bit stream to include;
data representing the digital audio signal, anddata representing the difference values, but notdata directly representing the number of bits allocated for each band in each frame; and
outputting the bit stream.
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Accused Products
Abstract
An audio encoder can parse a digital audio signal into a plurality of frames, each frame including a specified number of audio samples, perform a transform of the audio samples of each frame to produce a plurality of frequency-domain coefficients for each frame, partition the plurality of frequency-domain coefficients for each frame into a plurality of bands for each frame, each band having bit data that represents a number of bits allocated for the band, and encode the digital audio signal and difference data to a bit stream (e.g., an encoded digital audio signal). The difference data can produce the full bit data when combined with estimate data that can be computed from data present in the bit stream. The difference data can be compressed to a smaller size than the full bit data, which can reduce the space required in the bit stream.
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Citations
20 Claims
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1. An encoding system, comprising:
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a processor; and a memory device storing instructions executable by the processor, the instructions being executable by the processor to perform a method for encoding an audio signal, the method comprising; receiving a digital audio signal; parsing the digital audio signal into a plurality of frames, each frame including a specified number of audio samples; performing a transform of the audio samples of each frame to produce a plurality of frequency-domain coefficients for each frame; partitioning the plurality of frequency-domain coefficients for each frame into a plurality of bands for each frame; allocating a specified number of bits for each band in each frame; computing a difference value for each band in each frame, the difference value representing a difference between the number of bits allocated for each band in each frame and a corresponding estimated number of bits allocatable for each band in each frame; encoding a bit stream to include; data representing the digital audio signal, and data representing the difference values, but not data directly representing the number of bits allocated for each band in each frame; and outputting the bit stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14)
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10. The encoding system of 1, wherein each frame includes exactly 1024 samples.
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15. A decoding system, comprising:
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a processor; and a memory device storing instructions executable by the processor, the instructions being executable by the processor to perform a method for decoding an encoded audio signal, the method comprising; receiving a bit stream, the bit stream including a plurality of frames, each frame partitioned into a plurality of bands; extracting from the bit stream a quantized norm of each band in each frame; based on the extracted quantized norms, determining an estimated number of bits allocatable for each band in each frame; for each band of each frame, extracting difference values from the bit stream, the difference values representing a difference between a number of bits allocated for each band in each frame and the corresponding estimated number of bits allocatable for each band in each frame; combining the difference values with the corresponding estimated number of bits allocatable for each band in each frame, to determine a number of bits allocated for each band in each frame; allocating the determined number of bits for each band in each frame; and decoding the bit stream using the determined number of bits for each band in each frame to generate a decoded digital audio signal. - View Dependent Claims (16, 17, 18)
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19. An encoding system, comprising:
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a receiver circuit to receive a digital audio signal; a framer circuit to parse the digital audio signal into a plurality of frames, each frame including a specified number of audio samples; a transformer circuit to perform a transform of the audio samples of each frame to produce a plurality of frequency-domain coefficients for each frame; a frequency band partitioner circuit to partition the plurality of frequency-domain coefficients for each frame into a plurality of bands for each frame; a frame bit allocation circuit to allocate a specified number of bits for each band in each frame; a difference calculation circuit to compute a difference value for each band in each frame, the difference value representing a difference between the number of bits allocated for each band in each frame and a corresponding estimated number of bits allocatable for each band in each frame; an encoder circuit to encode a bit stream to include; data representing the digital audio signal, and data representing the difference values, but not data directly representing the number of bits allocated for each band in each frame; and an output circuit to output the bit stream. - View Dependent Claims (20)
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Specification