Evaluation of spatial audio quality in non-standardized test environments

长期以来，音质感知一直是各种评价的主题。特别是近年来在多声道音频领域的发展，理论上可以实现真实的音频再现，但其实际应用质量仍有待评估。尽管对空间音频质量进行了广泛的研究，但仍有一些方面尚未完全理解，例如质量参数的组成。质量评价一般在标准化的测试环境中进行，以下简称实验室。此外，主要采用标准化的评估方法，通常将基本音频质量与参考信号进行比较。这些方法的单维定量结果仅在标准化测试环境中具有可比性和可重复性。它们既没有考虑到音频质量的多维性，也没有考虑到实际的使用环境。此外，不考虑受试者的个体质量量表，并对所有受试者的质量评分进行平均。另一个关键方面是参考信号并不总是已知或定义的。最近的研究试图理解音质感知的多维性，使用描述性评价方法。这些方法允许在没有参考和参与者自己的描述的情况下进行个人质量评级。不同的研究已经表明，音色和空间是空间音质的两个非常重要的方面。但是，对于质量要素的类型、权重及其对整体质量的影响，目前还存在一定的分歧。除了在音乐厅进行的一些评价外，在现有的评价中尚未对其使用环境进行评价。然而，主观音质很大程度上取决于房间的声学效果，不能简单地转移到其他房间。在这个项目中，有效和可重复的评估和分析方法将被开发出来，以更好地理解人类的质量感知，并对感知到的空间音频质量进行评级。该项目的目标是分析音频质量感知的维度，并评估测试环境对音频质量感知的影响。结果将显示依赖于使用环境的不同质量参数的权重和影响。它们可以直接用于开发客观的质量评价方法和改进编码算法。

Audio quality perception is already subject of different evaluation for a long time. Especially developments in the last few years in the domain of multichannel audio theoretically enable a realistic audio reproduction, but its quality for practical applications still needs to be evaluated. Despite extensive research on spatial audio quality there are still aspects that are not yet fully understood, for example the composition of the quality parameters. Quality evaluations are generally done in standardized test environments, hereinafter referred to as laboratory. Furthermore, mainly standardized evaluation methods are used, which usually measure the basic audio quality compared to a reference signal. The unidimensional, quantitative results of these methods are only comparable and repeatable in standardized test environments. They neither take into account the multidimensionality of audio quality nor the actual context of use. Furthermore, individual quality scales of subjects are not considered and quality ratings are averaged over all subjects. Another critical aspect is that the reference signal is not always known or defined. Recent research that tries to understand the multidimensionality of audio quality perception uses descriptive evaluation methods. These methods allow an individual quality rating often without a reference and participants own descriptions. Different studies already showed that timbre and spaciousness are two very important aspects of spatial audio quality. However, there is still some disagreement on the type and weighting of the quality elements and their influence on the overall quality. Except some evaluations in concert halls, the context of use it not evaluated in existing evaluations so far. Though, the subjective audio quality very much depends on the room acoustics and cannot be transferred simply to other rooms. In this project valid and repeatable evaluation and analysis methods will be developed to better understand human quality perception and to rate the perceived spatial audio quality. The goal of the project is to analyze the dimensions of audio quality perception as well as to evaluate the influence of the test environment on quality perception. The results will show the weighting and influence of the different quality parameters dependent on the context of use. They can be used directly for the development of objective quality evaluation methods and to improve coding algorithms.