Audio channel layout mapping between AAC, AC-3, E-AC-3, TrueHD, Atmos, DTS, DTS-HD, USAC, BS 2051, IEC 62574, QuickTime, WAVE...

We try at MediaArea to have a common output whatever is the format, in order to be able to compare formats.
Unfortunately, each audio format "vendor" has its own method for naming channels, and worse it sometimes change over time.
Below is an attempt to map each names of channels for each audio format specification to a common name in MediaInfo and other tools developed by MediaArea.

Disclaimer: nothing "official" from any standardization body, this attempt is just for us but may be useful for someone else so we make the mapping public. As every standardization body and format vendor has different point of view on channel location, there are definitely some disagreements but if you think that there is an issue with an obvious fix don't hesitate to contact us for debating about it.

This page contains:

  • A table with for each channel a generic description, its classicly used azimuth and elevation, the expected mapping from each format specification, the channel name used in channel layout field by MediaInfo 18.08 and later
  • An image showing how we split the space surround the user (names used are the one from MediaInfo 18.08 and later)
  • Some remarks about the mapping, when the mapping is not obvious and/or has some known issues
  • Some references / links

Audio channel layout mapping

Generic
Descriptive
Name		 ↕ ↔ ST
428-12
2013		 BS
2051-0
System H
+ IEC
62574		 TS
102
366
v1.4.1
(E-AC-3)		 TS
103
420
v1.1.1
(JOC)		 TS
103
190-1
v1.3.1
(AC-4)		 TS
102
366
v1.4.2
(E-AC-3)
draft		 TS
103
420
v1.2.1
(JOC)
draft		 TS
103
190-1
v1.4.1
(AC-4)
draft		 Quick
Time		 TS
102
114
v1.4.1
(DTS)		 TS
102
114
v1.4.1
(DTS
-HD)		 Micro
soft
WAV		 MPEG
(AAC,
USAC)		 MediaInfo
Name
Bottom Front Centre -30 0 BtFC Bfc CI Cb Bfc
Bottom Front Left -30 45 BtFL Bfl LI Lb Bfl
Bottom Front Right -30 -45 BtFR Bfr RI Rb Bfr
Low-frequency Effects -30 60 LFE LFE1 LFE LFE LFE LFE LFE LFE LFE LFE LFE LFE LFE LFE
Low-frequency Effects 2 -30 -60 LFE2 LFE2 LFE2 LFE2 LFE2 LFE2 LFE2 LFE2 LFE2 LFE2 LFE2
Half-way left screen 0 N/A Hwbcal
Half-way right screen 0 N/A Hwbcalr
Left Screen 0 N/A Lscr Lscr Leos Lscr
Right Screen 0 N/A Rscr Rscr Reos Rscr
Center 0 0 C FC C C C C C C C C C FC C C
Center Left 0 15 Lc Lc Lc N/A N/A Lc Lc Lc
0 22 FLc FLC Lc
Center Right 0 -15 Rc Rc Rc N/A N/A Rc Rc Rc
0 -22 FRc FRC Rc
Left 0 30 L L L L L L L L L L L
0 45 FL FL L
Right 0 -30 R R R R R R R R R R R
0 -45 FR FR R
Left Front Wide 0 60 FLw Lw Lw Lw Lw Lw Lw Lw Lw Lw Lw
Right Front Wide 0 -60 FRw Rw Rw Rw Rw Rw Rw Rw Rw Rw Rw
Left Side Surround 0 90 Lss SiL Lss Lss Lss
Right Side Surround 0 -90 Rss SiR Rss Rss Rss
Left Surround 0 110 Ls LS Ls Ls Ls Ls Ls Ls CL Ls SL Ls Ls
Right Surround 0 -110 Rs RS Rs Rs Rs Rs Rs Rs CR Rs SR Rs Rs
Left Surround Direct 0 N/A LSd Lsd N/A Lsd Lsd Lsd
Right Surround Direct 0 N/A RSd Rsd N/A Rsd Rsd Rsd
Left Rear Surround 0 135 BL BL Lsr Lb
0 150 Lrs Lrs Lrs Lrs Lb Lb Lb Lrs SL Lsr
Right Rear Surround 0 -135 BR BR Rsr Rb
0 -150 Rrs Rrs Rrs Rrs Rb Rb Rb Rrs SR Rsr
Back Centre 0 -180 Cs BC Cs Cs Cb Cb Cs S Cs BC Cs Cb
Top Front Centre 45 0 TpFC Vhc Vhc Tfc Tfc Vhc Ch TFC Cv Tfc
Vertical Height Left 45 N/A Vhl N/A Vhl
Vertical Height Right 45 N/A Vhr N/A Vhr
Left Front High 45 45 TpFL Lvh Lfh Tfl Tfl Vhl Lh TFL Lv Tfl
Right Front High 45 -45 TpFR Rvh Rfh Tfr Tfr Vhr Rh TFR Rv Tfr
Left Top Middle 45 90 TpSiL Lts Ltm Tsl Tsl Lhs Lvss Tsl
Right Top Middle 45 -90 TpSiR Rts Rtm Tsr Tsr Rhs Rvss Tsr
Left Top Surround 45 110 TpLS Lvs Lvs
Right Top Surround 45 -110 TpRS Rvs Rvs
Left Rear High 45 135 TpBL Lrh Tbl Tbl Lhr TBL Lvr Tbl
Right Rear High 45 -135 TpBR Rrh Tbr Tbr Rhr TBR Rvr Tbr
Top Back Centre 45 180 TpBC Tbc Tbc Chr TBC Cvr Tbc
Top Centre -90 N/A TpC Ts Ts Tc Tc Ts Oh TC Ts Tc
Left Matrix Total Lt Lt Lt
Right Matrix Total Rt Rt Rt
Mono 1 M
Mono 2 M

How we split the space surround the user

Outer circle: bottom layer. Middle circle: middle layer. Inner circles: up layer. Blue rectangle: the screen. Black rectangles: LFE.

Audio channel Layout graphic

Remarks

  • Positive Azimuth is on the left (counterclockwise), negative azimuth is on the right (clockwise)
  • Azimuth values are arbitrary choosen from our understanding of the most suitable location of corresponding hypothetical loudspeakers, specs may have a range (sometimes conflicting with another spec) or may have a slightly different location
  • MediaInfo column is about names used by MediaInfo 18.08 and later
  • Microsoft WAV: SL/SR is displayed as -90/+90 ("Side Surround") in several docs but they are usually used for -110/+110 ("Surround")
  • BS 2051-0 System H: FL/FR is noted with "60" but Table 3 indicates that +/-45° is in tolerated range & Table 7 displays them at +/-45°. IEC 62574:2011 maps FL/FR to L/R (usually between 30° and 45°)
  • AC-4: L/R are mapped to FLc/FRc and Lw/Rw to FL/FR in table A.42 but it appears that this mapping is conflicting with USAC specifications which maps Lw/Rw to new FRw/FLw; additionally, Lw/Rw are intended to be at +/-60°
  • AC-4: vhl/Vhr are synonym of Tfl and are deprecated

References / links