Set the bitrate to use for encoding. Acceptable values for RATE are any which are allowed by the MP3 format. According to the manual for LAME, this means:

For sampling frequencies of 32, 44.1, and 48 kHz, RATE can be among 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, and 320.

For sampling frequencies of 16, 22.05, and 24 kHz, RATE can be among 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, and 160.

When in doubt, it is recommended to choose a bitrate among 96, 112, 128, 160, 192, 224, 256, and 320. If not specified, RATE defaults to 128.

Enable debug output. This will result in a large quantity of diagnostic information being printed to stderr as the program runs. This option will normally not be used. It implies -f.

Set mode to use for interpreting ReplayGain tags. The allowed values for MODE are:

0 - Ignore all ReplayGain tags.

1 - Prefer album gain tag, but fall back to track gain if album gain is not present.

2 - Use track gain if present.

Set the reference loudness in decibels to adjust ReplayGain tags. ReplayGain software usually defaults to a loudness of 89 dB, but if this is too quiet, a higher value can be set here, causing adjustment of ReplayGain values in tags.

Run in foreground instead of detaching from the terminal.

Print usage information.

Set quality for encoding, as understood by LAME. The slowest and best quality is 0, while 9 is the fastest and worst quality. The default value is 5, although according to the LAME manual, 2 is recommended.

Force single-threaded operation.

Output version information.