VS1053B Datasheet, PDF (61/79 Pages) List of Unclassifed Manufacturers – Ogg Vorbis/MP3/AAC/WMA/MIDI AUDIO CODEC

VLSI
Solution ^y
VS1053b preliminary
VS1053B
9. OPERATION
config1(7:6)
’00’
’01’
’10’
’11’
Usage
normal mode, process PS if it is available
process PS if it is available, but in downsampled mode
reserved
disable PS processing
AAC decoder can also increase the internal clock automatically when it detects that a file can not be de-
coded correctly with the current clock. The maximum allowed clock is configured with the SCI CLOCKF
register.
If even the highest allowed clock is too slow to decode an AAC file with SBR and PS components, the
advanced decoding features are automatically dropped one by one until the file can be played. First the
parametric stereo processing is dropped (the playback becomes mono). If that is not enough, the spectral
band replication is turned into downsampled mode (reduced bandwidth). As the last resort the spectral
band replication is fully disabled. Dropped features are restored at each song change.
9.11.4 Midi
Parameter
config1
bytesLeft
Address
0x1e03
bits [3:0]
0x1e2a/2b
Usage
Miscellaneous configuration
Reverb: 0 = auto (ON if clock >= 3.0×)
1 = off, 2 - 15 = room size
The number of bytes left in this track
The lowest 4 bits of config1 controls the reverb effect.
9.11.5 Ogg Vorbis
Parameter Address Usage
gain
0x1e2a Preferred replay-gain offset
Ogg Vorbis decoding supports Replay Gain technology. The Replay Gain technology is used to auto-
matically give all songs a matching volume so that the user does not need to adjust the volume setting
between songs. If the Ogg Vorbis decoder finds a Replay Gain tag in the song header, the tag is parsed
and the decoded gain setting can be found from the gain parameter. For a song without any Re-
play Gain tag, a default of -6 dB (gain value -12) is used. For more details about Replay Gain, see
http://en.wikipedia.org/wiki/Replay Gain and http://www.replaygain.org/.
The player software can use the gain value to adjust the volume level. Negative values mean that the
volume should be decreased, positive values mean that the volume should be increased.
For example gain = -11 means that volume should be decreased by 5.5 dB (−11/2 = −5.5), and left
and right attenuation should be increased by 11. When gain = 2 volume should be increased by 1 dB
(2/2 = 1.0), and left and right attenuation should be decreased by 2. Because volume setting can not go
above +0 dB, the value should be saturated.
Version 0.5, 2007-12-03
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