Lame

Lame Header

Extended Lame Header

Octet↓, Bit→	0	1	2	3	4	5	6	7
0	revision				vbr_method
1	lowpass_filter
2	track_peak
3
4
5
6	track_gain Replay Gain Data Format
7
8	album_gain Replay Gain Data Format
9
10	album_gain_adj
11	encoding_flags				ath_type
12	bitrate
13	encoder_delay_start
14	encoder_delay_start				encoder_padding_end
15	encoder_padding_end
16	source_sample_frequency_enum		unwise_setting_used	stereo_mode			noise_shaping
17	mp3_gain_sign	mp3_gain
18			surround_info			preset_used
19	preset_used
20	music_length
21
22
23
24	music_crc
25	header_crc
26

vbr_method

In case of Lame, the meaning is the following:

value	VBR method
2	abr
3	vbr old / vbr rh
4	vbr mtrh
5	vbr mt

encoding_flags

Flag	Description
000?	LAME uses --nspsytune
00?0	LAME uses --nssafejoint
0?00	This track is --nogap continued in a next track, is true for all but the last track in a --nogap album
?000	This track is the --nogap continuation of an earlier one is true for all but the first track in a --nogap album

Flag value	Description
0	false
1	true

References:

• http://gabriel.mp3-tech.org/mp3infotag.html
• https://github.com/quodlibet/mutagen/blob/abd58ee58772224334a18817c3fb31103572f70e/mutagen/mp3/_util.py#L112