| Along with the arrival of the digital era. digital audio coding technology has gained rapid development, the improvement of living standards spurred the desire to enjoy a better quality of audio services, the increasing demand for multi-channel audio services, stereo and multi-channel audio codecthe technology has become an important support technology, one of the value-added services of high-quality audio.The traditional multichannel audio coding is encoded separately for each channel, bit rate linear growth with the number of channels. Spatial audio coding technology through downmix input signal, and to extract the parameters of the characterization of spatial information to solve the bit rate with the number of channels is approximately linear growth defects, stereo/surround sound at lower bit rates, has become the field of audio technology in research focus. However, due to the short time of the study of spatial audio coding theory spatial audio parameter representation and extraction model is not yet perfect. Existing spatial audio coding technology is still stuck in the perception of the human auditory system space parameters in principle and theoretical level, can not be used in the actual spatial audio coding impact key element to improve the quality of the audio signal reconstruction.The face of a lack of core technology of digital audio and video industry, the plight of long-term high fees subject to European and American standards, and users increasingly urgent demand for high-quality multi-channel audio business the traditional multichannel audio coding theory more and more difficult to meet the developmentneeds. As a multi-channel audio encoding mainstream spatial audio coding technology, the representation of spatial audio parameters and extraction model is not perfect, does not consider the perceptual characteristics of the human ear space parameters.The topics of research programs is based on the physical phenomena of human ears listening, based on the physiological characteristics of the auditory system, the existing theory of spatial hearing, critical band is divided thinking, Breebaart delay attenuation network as well as channel capacity and letter entropy concept and scientific achievements of theBased on the research strategy to develop and structure model, experimental data acquisition and validation of the theoretical results based on a large number of subjective listening tests. Whole topic of scientific theory as a precondition to the experimental analysis based on a combination of theory and practice, progressive layers, a chain with strong feasibility, specific analysis is as follows:(1) Establishing the binaural cues space from the physical layer to the physiological layer perceptual model.Based on existing theories and models of spatial hearing, the topic through building the experimental system, the production has a certain spatial information specific sequence, by a large number of subjective listening tests, access to the binaural cues space perception characteristics, perceived characteristic curve depicting spatial cues use of the mathematical analysis of the relationship of the the abstract various spatial cues ears positioning functions and spatial cues binaural positioning function, the establishment of a the physiological layer one-dimensional, two-dimensional and three-dimensional model. This shows that the use of scientific and objective attitude observed subjective test results, and found that the law and the establishment of the model are feasible.(2) Measurement model based perceptual entropy-based spatial information.Critical sub-band filtering techniques used in the study, delay network attenuation and noise superimposed technology able to achieve physiological layer simulation, and loss of spatial information for the listening process parameters superimposed noise on the output space to reflect the sound source positioning between interference limited accuracy as well as the inherent noise in the auditory system. Visible, thus building measure spatial information model is consistent with the results of theoretical studies and human listening characteristics.In addition, the purpose of this study is to measure by modeling the spatial information and then guide the application of the audio signal, only a qualitative description is not enough, also need space parameters of each band, their limited resolution and the effective perception amount of parameters between interaction quantitative analysis and description. Therefore, this topic on the basis of the measurement model based on the experimental results, starting from the concept of just perceptible differences, study how to characterize effective perceived amount, and draw on the concept of channel capacity formula and entropy space information metric formula eventually put forward the theory of spatial entropy. The entire research ideas are built on the basis of the results of scientific theory, a reasonable experimental program, and a lot of listening tests, follow the principles of the theory to guide the experimental results of testing theory. (3) Establishing audio coding in space perception entropy Application Framework. The topics in the theoretical level of binaural cues space perception model and spatial information metrics model building, and on this basis to explore how this theory to enhance and expands the application level. Binaural perception model based on psychoacoustic theory to establish parameters frequency perceptual characteristics, as the judgment basis of parameter extraction strategy to design fixed model parameter extraction; spatial perceptual entropy is used to measure the amount of information of the spatial information, can be calculated the various parameters of the intra-frame spatial perception of the size of the amount of information to determine the perception of the importance of the frame rate with different parameters to calculate the spatial parameters in different frequency bands mean square error of the judge parameter changes the law, based on the above theory to design real-time mode parameter extraction strategy. Through the establishment of a new framework of encoding the multi-model parameter extraction strategies applied in the actual coding, testing the effectiveness and practicality of the algorithm. By the above analysis, all research results from the theory are gradually carrying out scientific experiments and data analysis, the study is feasible in theory.Audio perception of this topic for the space key technologies of the measurement model to study the perceptual characteristics of the spatial parameters based on the human ear, binaural cues spatial perception model; proposed using perceptual entropy metric perceived amount of space information, the establishment of spatial information measuremodel; proposed measurement model based on the spatial information coding framework for efficient spatial audio coding. |
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