Specific outcomes from the project
Application and evaluation
Practical low bit-rate codec measurement technique
The method described above to analyse the performance of reproduction systems can also be modified to analyse the performance of various low bit-rate codecs.
A number of standardised methods have been derived to give an objective measurement that predicts the perceived quality of audio low bit-rate codecs. However, these methods are mono only, and do not consider spatial aspects of the sound. The binaural hearing model that has been developed can be used in a comparative manner to test the degradations in spatial quality caused by the low bit-rate codecs compared to the input signal. In addition to this, the properties of the codecs can be tested more thoroughly by using an adapted version of the test signals created for use in 2-channel reproduction systems. This can provide a more rapid and critical absolute test than if a large range of musical samples are used in a comparative test. This requires further research to develop fully, and could be added to the existing standardised measurement methods.
[To be reported