“…(ii) Contrast test objects: PCA-based codec signal that transmits two channels separately, PCA-based codec signal with traditional parametric stereo, PCA-based codec signal with improved parametric stereo, G719 codec signal with traditional parametric stereo [24], HE-AACv2 codec signal, anchor signal, and original signal. In the algorithm proposed in this paper, the relationship between the quality of the restored signal and bitrate is not linear, as Figure 17 shows, which uses a simple subjective test with different bitrate allocation; therefore, the test chooses a case in which the qualities of restored signal and bitrate are both acceptable.…”