5 name => '<abbr title="MPEG-1 Audio Layer III">MP3</abbr>',
17 name => '<abbr title="Advanced Audio Coding">AAC</abbr>',
21 name => '<abbr title="Adaptive Transform Acoustic Coding">ATRAC</abbr>',
27 children => [qw( quality limits royalties support )],
30 name => 'compression quality',
31 children => [qw( quality_music quality_speech quality_ll )],
61 children => [qw( channels bitrate latency peeling )],
67 mp3 => [3, 6, 'stereo, extended to upto 5.1'],
73 name => 'bitrate peeling',
75 vorbis => [3, undef, 'yes but "unusable" quality'],
82 name => 'frame size (ms)',
84 mp3 => [3, 26, 'typical version and layer has 1152 samples at 44kHz'],
89 name => 'minimal bitrate',
97 mp3 => [5, undef, 'expired'],
99 opus => [4, undef, 'open and free design'],
100 atrac => [2, undef, 'proprietary, but the original patents have expired'],