Table 2 Subjective and objective grades for audio quality measurement
From: An imperceptible and robust audio watermarking algorithm
Audio quality | Subjective difference grade (SDG) | Objective difference grade (ODG) |
|---|---|---|
Imperceptible | 5 | 0 |
Perceptible, but not annoying | 4 | −1.0 |
Slightly annoying | 3 | −2.0 |
Annoying | 2 | −3.0 |
Very annoying | 1 | −4.0 |