Arithmetic encoding/decoding of a digital information signal
AssigneeU.S. Philips Corporation
InventorsAlphons A. M. L. Bruekers, Adriaan J. Rijnberg
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Abstract
Audio signals are converted from analog into digital using the well-known sigma-delta modulation techniques. The digital signal then consists of a sequence of 1-bit samples at a frequency of e.g. 2822400 Hz (=64*44100 Hz). Lossless coding techniques are used to reduce the required storage- or transmission-capacity for these 1-bit oversampled audio signals. The performance (compression ratio) of the lossless coder for 1-bit oversampled audio signals is improved by sometimes overruling the probability signal for the lossless coder.
Claims26
Apparatus for arithmetically encoding a digital information signal, comprising:
- input means for receiving the digital information signal;
- arithmetic coder means having a first input for receiving the information signal as an input signal, a second input for receiving a probability signal, and an output for supplying an output signal, the arithmetic coder means compressing the input signal in response to the probability signal so as to obtain the output signal;
- probability signal generation means for generating the probability signal for the arithmetic coder means;
- and
- means for switching the arithmetic coder means into an encoding mode, the switching means including overruling means for overruling the probability signal to the arithmetic coder means and applying a predetermined and fixed probability signal to the arithmetic coder means, for encoding the one or more symbols of the input signal, which are substantially identical to the symbols of the input signal.
A method for arithmetically encoding a digital information signal, comprising the steps of:
- receiving the digital information signal;
- providing the digital information signal to an input as an input signal;
- arithmetically encoding the input signal in response to a probability signal so as to obtain a data compressed version of the input signal;
- supplying the data compressed version of the input signal as an output signal;
- generating the probability signal for the arithmetic encoding;
- and
- switching into an encoding mode, including the step of overruling the probability signal to the arithmetic encoding and applying a predetermined and fixed probability signal to the arithmetic encoding, for encoding the one or more symbols of the input signal, which are substantially identical to the symbols of the input signal.
An apparatus, comprising:
- a record carrier, the record carrier storing an encoded digital information signal, the digital information signal encoded by:
- providing the digital information signal to an input as an input signal;
- arithmetically encoding the input signal in response to a probability signal so as to obtain a data compressed version of the input signal;
- supplying the data compressed version of the input signal as an output signal;
- generating the probability signal for the arithmetic encoding;
- and
- switching into an encoding mode, including the step of overruling the probability signal to the arithmetic encoding and applying a predetermined and fixed probability signal to the arithmetic encoding, for encoding the one or more symbols of the input signal, which are substantially identical to the symbols of the input signal.
Apparatus for arithmetically decoding an arithmetically encoded digital information signal, comprising:
- input means for receiving an arithmetically encoded digital information signal;
- arithmetic decoder means having a first input for receiving the arithmetically encoded information signal as an input signal, a second input for receiving a probability signal, and an output for supplying an output signal, the arithmetic decoder means expanding the input signal in response to the probability signal so as to obtain the output signal;
- probability signal generation means for generating the probability signal for the arithmetic decoder means;
- output means for supplying the digital information signal;
- and
- means for switching the arithmetic decoder means into a decoding mode, the switching means including overruling means for overruling the probability signal to the arithmetic decoder means and applying a predetermined and fixed probability signal to the arithmetic decoder means, for decoding the one or more symbols of the arithmetically encoded digital information signal, which are substantially identical to the symbols of the arithmetically encoded digital information signal.
Dependencies are inferred from the claim text.