int AFsetSpeaker(const char String[])
Set loudspeaker spatial positions
This routine sets the mapping of output channels to speaker positions. The spatial positions of the loudspeakers are specified as a list of comma and/or white-space separated locations from the list below.
Name IEC 62574 AES 22.2 WAVE Ext
FL - Front Left 1 1/1 1 0x1
FR - Front Right 2 1/2 2 0x2
FC - Front Center 3 2/1 3 0x4
LFE1 - Low Frequency Effects-1 4 2/2 4 0x8
BL - Back Left 5 3/1 5 0x10
BR - Back Right 6 3/2 6 0x20
FLc - Front Left center 7 4/1 7 0x40
FRc - Front Right center 8 4/2 8 0x80
BC - Back Center 9 5/1 9 0x100
LFE2 - Low Frequency Effects-2 10 5/2
SiL - Side Left 11 6/1 10 0x200
SiR - Side Right 12 6/2 11 0x400
TpFL - Top Front Left 13 7/1 12 0x800
TpFR - Top Front Right 14 7/2 13 0x1000
TpFC - Top Front Center 15 8/1 14 0x2000
TpC - Top Center 16 8/2 15 0x4000
TpBL - Top Back Left 17 9/1 16 0x8000
TpBR - Top Back Right 18 9/2 17 0x10000
TpSiL - Top Side Left 19 10/1
TpSiR - Top Side Right 20 10/2
TpBC - Top Back Center 21 11/1 18 0x20000
BtFC - Bottom Front Center 22 11/2
BtFL - Bottom Front Left 23 12/1
BtFR - Bottom Front Right 24 12/2
FLw - Front Left wide 25
FRw - Front Right wide 26
LS - Left Surround 27
RS - Right Surround 28
LSd - Left Surround direct 29
RSd - Right Surround direct 30
TpLS - Top Left Surround 31
TpRS - Top Right Surround 32
- - No speaker assigned
A speaker position can be associated with only one channel. For compatibility with previous usage, some synonyms are applicable. For instance
LF -> LFE1 SL/SR -> SiL/SiR TFL/TFR -> TpFL/TpFR TBL/TFR -> TpBL/TpBR
The following names can be used to set a speaker location configuration.
"1.0-mono" -> "FC" "2.0-stereo" -> "FL FR" "4.0-quad" -> "FL FR BL BR" "5.1-surround" -> "FL FR FC LFE1 BL BR" "5.1+4-surround" -> "FL FR FC LFE1 BL BR TpFL TpFR TpBL TpBR" "7.1-surround" -> "FL FR FC LFE1 BL BR SiL SiR" "7.1+4-surround" -> "FL FR FC LFE1 BL BR SiL SiR TpFL TpFR TpBL TpBR"
These files can store the speaker locations in the file header if certain constraints are in place.
Available speaker locations:
"FL FR FC LFE1 BL BR FLc FRc BC SiL SiR TpC TpFL TpFC TpFR,
TpBL, TpBC, TpBR"
Channels:
If M speaker locations are specified, they must be associated with the
first M audio channels.
Speaker Location Order:
The speaker locations must be in the same order as the list, but locations
can be skipped. As an example, the order "FL FR TpC" is valid, but
"FL FC FR" is not.
Speaker locations are implicit in AIFC-C audio files.
Stereo: "FL FR" 3 channel: "FL FR FC" Quadraphonic" "FR FR BL BR" 4 channel surround: "FL FC FR BC" 6 channel surround: "FL FLc FC FR FRc BC"
Speaker locations appear as an information record of the form,
"loudspeakers: FL FR LFE1"
This speaker location record is one of the standard information records which appear in the file header.
P. Kabal / Revision 1.29 2023-03-23