The speech transmission index (STI) is a popular simple metric for the prediction of speech intelligibility when speech is passed through a transmission channel. Computation of STI from acoustic measurements is described in the IEC 60268-16:2020 standard. Though, reliable implementations of STI are not publicly accessible and are frequently limited to the use with a proprietary measurement hardware. We present a Matlab STI implementation of both the direct and indirect approaches according to the standard, including the shortened STIPA protocol. The suggested implementation meets prescribed requirements, as evidenced by tests on reference signals. Additionally, we conducted a verification measurement in comparison to a commercial measurement device. Our software comes with open source code.

翻译：语音传输指数（STI）是一种广泛使用的简单度量指标，用于预测语音通过传输通道后的可懂度。根据IEC 60268-16:2020标准，描述了从声学测量中计算STI的方法。然而，可靠的STI实现方案并未公开，且通常仅限于与专有测量硬件配合使用。我们提出了一种符合该标准的MATLAB STI实现，涵盖了直接和间接两种计算方法，包括缩短的STIPA协议。通过对参考信号的测试证明，该实现满足规定要求。此外，我们还与商用测量设备进行了对比验证测量。我们的软件提供开源代码。