[FFmpeg-trac] #10726(ffmpeg:new): SMPTE 7.1DS channel layout not usable in mappings bc of missing channel IDs

[FFmpeg]

#10726: SMPTE 7.1DS channel layout not usable in mappings bc of missing channel IDs
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             Reporter:  Martin       |                     Type:  defect
               Status:  new          |                 Priority:  minor
            Component:  ffmpeg       |                  Version:
             Keywords:               |  unspecified
  channel_layout                     |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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 Summary of the bug:

 1) The channel layout description (https://ffmpeg.org/ffmpeg-utils.html
 #Channel-Layout) lists two channel IDs ‘SDL’ = surround direct left and
 ‘SDR’ = surround direct right, but the two IDs are not used in any of the
 standard channel layout compositions. SDL/SDR map to Lsd/Lsr in E-AC-3
 (see ETSI TS 102 366 v1.4.1,
 https://www.etsi.org/deliver/etsi_ts/102300_102399/102366/01.04.01_60/ts_102366v010401p.pdf),
 Quicktime, AAC, and Mediainfo.

 2) Channel IDs are missing for "Surround Left/Right" which map to Lss/Rss
 in SMPTE, DTS-HD, AAC, and Mediainfo. Because of that there's currently no
 way to specify a '7.1DS' channel layout composition using channel IDs (see
 SMPTE ST 428-12:2013, https://ieeexplore.ieee.org/document/7291368/).

 This is not just a documentation flaw as one can check by using the
 command line below.

 How to reproduce:
 {{{
 %  ffmpeg -hide_banner -layouts | grep -e 'SD[LR]'
 ffmpeg version git-2023-11-02-ec8b8cd5c
 built on 2023-11-02
 }}}
 Patches should be submitted to the ffmpeg-devel mailing list and not this
 bug tracker.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10726>
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