An audio code rate control method and system

Abstract

The embodiment of the present invention discloses an audio code rate control method and system. The method includes: determining a subband for initial coding according to the number of available bits; calculating an initial value of an effective scale factor of the subband according to a masking threshold of the subband; Adjust the effective scale factor so that the quantization noise of the subband frequency domain coefficients is smaller than the masking threshold, quantize the subband according to the effective scale factor, encode the quantized frequency domain coefficients, and determine the encoding Number of bits required; when the number of bits required for encoding is greater than the number of available bits, adjust the number of bits required for encoding by adjusting the effective scale factor of the subband in steps, so that the number of bits required for encoding is less than or equal to the number of available bits number. It can take into account the sound quality on the basis of reducing the complexity of the algorithm.

Description

technical field [0001] The present invention mainly relates to the field of audio coding and decoding, in particular to an audio code rate control method and system. Background technique [0002] The traditional digital audio compression technology mainly uses waveform coding to achieve data compression by reducing the entropy redundancy of data. This method does not take into account the subjective characteristics of the human hearing effect, the algorithm compression rate is low, and the sound quality is also poor. It is mainly used for the compression of narrowband audio signals, such as A-law coding. In order to transmit better sound quality on a limited network bandwidth, an audio compression technology based on the subjective perception characteristics of the human ear has been developed. Related parties have formulated MPEG-1 Audio, MPEG-2 Audio, MPEG-2 AAC ( Advanced Audio Coding, Dolby (AC-3), MPEG-4AAC and other audio compression standards. This audio data compre...

AI Technical Summary

Problems solved by technology

[0004] The inventor found in the process of realizing the present invention that the prior art has at least the following disadvantages: the prior art requires a large number of calculations, and the calculation is complicated

The inner loop quantizes and encodes the frequency domain coefficients. Each scale factor band is traversed once, and the calculation is complicated; the outer loop calculates the quantization noise of each scale factor band. As long as one subband does not meet the requirements, the inner layer will be called again Loop, resulting in an increase in the number of times the inner loop runs, and an increase in the amount of calculation of the algorithm

Images