Designing for worst-case signal levels wastes capacity most of the time

Evidence

Real signals often spend most of their time at low signal levels, but one has to design the quantizer to handle the maximum signal level, even if it isn’t used very often. This means that more bits are used than is strictly necessary most of the time. One way of reducing the number of bits needed to quantize an audio signal is to make the quantizer adapt to the level of the signal because loud signals mask weaker signals, as discussed in Chapter 5. This type of quantizer is known as an “adaptive quantizer,” and can save some bits. There are two main types of adaptive quantizer: 1. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2657

Categorization

• DEFINE: Defines the adaptive quantizer and links it back to psychoacoustic masking as the enabling principle.
• XREF: Ties directly to the Chapter 5 masking discussion — perception licenses a technical shortcut in compression.