[FFmpeg-trac] #2153(avcodec:new): aac 7.1 channel layout

[FFmpeg]

#2153: aac 7.1 channel layout
-------------------------------------+-------------------------------------
             Reporter:  Crayden      |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:  avcodec      |                  Version:
             Keywords:  7.1 aac      |  unspecified
  channel layout                     |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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 Looking at the specification from
 http://developer.apple.com/library/mac/#documentation/MusicAudio/Reference/CoreAudioDataTypesRef/Reference/reference.html#//apple_ref/doc/c_ref/kAudioChannelLayoutTag_AAC_7_1
 the channels are decoded correctly for 7.1 aac files but it looks like
 they're mapped/mixed in the wrong way resulting in the following output
 behaviour:
 left -> left + center
 center -> center
 right -> right + center
 right surround -> right
 left surround -> left
 right rear surround -> right rear surround
 left rear surround -> left rear surround
 lfe -> lfe

 Since most players and audio drivers don't handle this specific layout
 correctly it may be wise to convert the layout for 7.1 channel aac files
 to a standard layout.

 This issue has already been fixed in the ffmpeg fork for LAV-Filter. Take
 a look at:
 http://git.1f0.de/gitweb?p=ffmpeg.git;a=commit;h=dfcbfd57c35bbef83df5c5256485e5bfa6f81f41

 If you need a test file:
 https://www.dropbox.com/s/csnm34xap2176sv/Channel%20Check%20Lots%20of%20Formats.mkv
 (make sure to select the 7.1 channel aac track)

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2153>
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