LAME -q switch

Internal Variables

-q n	huffman search	full_outer_loop	sv_qnt.substep_shaping	subblock gain	noise shaping	amplification	stopping	description
0	best	1	2	1	1	2	1	Use slowest & best possible version of all algorithms.
1	best	0	2	1	1	2	1
2	best	0	2	1	1	1	1	Recommended. Same as -h. -q 0 and -q 1 are slow and may not produce significantly higher quality.
3	best	0	?	1	1	1	1	Default value. Good speed, good quality.
4	best	0	?	1	1	0	0
5-6	normal	0	?	1	1	0	0
7-8	normal	0	?	-1	0	0	0	Same as -f. Very fast, ok quality. (psycho acoustics are used for pre-echo & M/S, but no noise shaping is done.
9	normal	0	?	-1	0	0	0	Disables almost all algorithms including psy-model. Poor quality.

VBR

-q n	description
0-4	Default value. Use the best algorithm.
5-6	Use the not so good algorithm
7-9

Observations

• -q 5-6 Output Same Results. LAME header will indicate the different quality parameter. But the files are otherwise a perfect match.
• -q 7-8 Is always mapped to -q 7 and thus outputs identical files, including the LAME header.
• -q 9 Output is same as -q 7. But official doc describes it as a different quality. LAME header will be different for CBR/ABR and identical for VBR.