-q n   Algorithm quality selection

Bitrate is of course the main influence on quality. The higher the bitrate, the higher the quality. But for a given bitrate, we have a choice of algorithms to determine the best scalefactors and Huffman encoding (noise shaping).

n = 0

Use slowest and best possible version of all algorithms. "-q 0" and "-q 1" are slow and may not produce significantly higher quality.

n = 2

Recommended. Same as -h.

n = 5

Default value. Good speed, reasonable quality.

n = 7

Same as -f. Very fast, OK quality. (psychoacoustics are used for pre-echo & mid/side, but no noise shaping is done).

n = 9

Disables almost all algorithms including psychoacoustic model. Poor quality.