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• ffmpeg replace central channel with ffmpeg

  24 mai 2020, par Rafal B

  I'm trying to replace central channel in the movie (Movie-A) with another audio stream from another movie (Movie-B).
I was able to extract stereo stream from Movie-B :

  



  ffmpeg.exe" -i "Movie-B.mkv"

Stream #0:1(pol): Audio: ac3, 48000 Hz, stereo, fltp, 320 kb/s (default)


  



  and convert it to mono stream :

  



  ffmpeg.exe" -i "Movie-B.mkv" -vn -ab 320k -ac 1 "Movie-B-Audio.ac3"
Output #0, ac3, to 'Movie-B-Audio.ac3':
Stream #0:0(pol): Audio: ac3, 48000 Hz, mono, fltp, 320 kb/s (default)


  



  For Movie-A :

  



  ffmpeg.exe" -i "Movie-B.mkv"
Stream #0:1(eng): Audio: aac (LC), 48000 Hz, 5.1, fltp (default)


  



  so Layout is 5.1 (FL+FR+FC+LFE+BL+BR), not 5.1(side) (FL+FR+FC+SL+SR)

  



  Media Info shows :

  



  Audio
ID: 2
Format: AAC
Format info: Advanced Audio Codec Low Complexity
Commercial name: AAC
Codec ID: A_AAC-2
Bit rate: 426 kb/s
Channel(s): 6 channels
Channel positions: Front: L C R, Side: L R, LFE
Channel layout: C L R Ls Rs LFE


  



  I have extracted all 6 channels into one stream with containing 6 channels :

  



  ffmpeg.exe" -i "Movie-A.mkv" -vn -ab 320k -ac 6 "Movie-A-Audio.ac3"
Output #0, ac3, to 'Movie-A-Audio.ac3':
Stream #0:0(eng): Audio: ac3, 48000 Hz, 5.1, fltp, 320 kb/s (default)


  



  But at this stage I'm getting different Layout in Movie-A-Audio.ac3 :

  



  Audio
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Commercial name                          : Dolby Digital
Duration                                 : 2 h 16 min
Bit rate mode                            : Constant
Bit rate                                 : 320 kb/s
Channel(s)                               : 6 channels
Channel layout                           : L R C LFE Ls Rs


  



  In source Movie-A.mkv it is : Channel layout : C L R Ls Rs LFE

  



  In output Movie-A-Audio.ac3 it is : Channel layout : L R C LFE Ls Rs

  



  Then I tried to extract those 6 channels into separate mono-stream files :

  



  ffmpeg.exe" -i "Movie-A-Audio.ac3" -filter_complex "channelsplit=channel_layout=5.1[FL][FR][FC][LFE][BL][BR]" -ab 320k -ac 1 -map "[FL]" extr_front_left.ac3 -ab 320k -ac 1 -map "[FR]" extr_front_right.ac3 -ab 320k -ac 1 -map "[FC]" extr_front_center.ac3 -ab 320k -ac 1 -map "[LFE]" extr_subwoofer.ac3 -ab 320k -ac 1 -map "[BL]" extr_back_left.ac3 -ab 320k -ac 1 -map "[BR]" extr_back_right.ac3


  



  With result :

  



  Stream mapping:
  Stream #0:0 (ac3) -> channelsplit
  channelsplit:FL -> Stream #0:0 (ac3)
  channelsplit:FR -> Stream #1:0 (ac3)
  channelsplit:FC -> Stream #2:0 (ac3)
  channelsplit:LFE -> Stream #3:0 (ac3)
  channelsplit:BL -> Stream #4:0 (ac3)
  channelsplit:BR -> Stream #5:0 (ac3)
Press [q] to stop, [?] for help
Output #0, ac3, to 'extr_front_left.ac3':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #0:0: Audio: ac3, 48000 Hz, mono, fltp, 320 kb/s
    Metadata:
      encoder         : Lavc58.54.100 ac3
Output #1, ac3, to 'extr_front_right.ac3':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #1:0: Audio: ac3, 48000 Hz, mono, fltp, 320 kb/s
    Metadata:
      encoder         : Lavc58.54.100 ac3
Output #2, ac3, to 'extr_front_center.ac3':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #2:0: Audio: ac3, 48000 Hz, mono, fltp, 320 kb/s
    Metadata:
      encoder         : Lavc58.54.100 ac3
Output #3, ac3, to 'extr_subwoofer.ac3':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #3:0: Audio: ac3, 48000 Hz, mono, fltp, 320 kb/s
    Metadata:
      encoder         : Lavc58.54.100 ac3
Output #4, ac3, to 'extr_back_left.ac3':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #4:0: Audio: ac3, 48000 Hz, mono, fltp, 320 kb/s
    Metadata:
      encoder         : Lavc58.54.100 ac3
Output #5, ac3, to 'extr_back_right.ac3':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #5:0: Audio: ac3, 48000 Hz, mono, fltp, 320 kb/s
    Metadata:
      encoder         : Lavc58.54.100 ac3


  



  When I'm checking channels layouts of those files extracted I see each of them is having Channel Layout marked with Central, for instant front_left.ac3 :

  



  Audio
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Commercial name                          : Dolby Digital
Duration                                 : 2 h 16 min
Bit rate mode                            : Constant
Bit rate                                 : 320 kb/s
Channel(s)                               : 1 channel
Channel layout                           : C
Sampling rate                            : 48.0 kHz


  



  Then I try to join needed channels :

  



  ffmpeg.exe" -i extr_front_left.ac3 -i extr_front_right.ac3 -i Movie-B-Audio.ac3 -i extr_back_left.ac3 -i extr_back_right.ac3 -i extr_subwoofer.ac3 -filter_complex "[0:a][1:a][2:a][3:a][4:a][5:a]join=inputs=6:channel_layout=5.1[a]" -map "[a]" "final-output.ac3


  



  But it is completely messed up : central channel (voice) is heard in front right speaker, in back right speaker is silence (or maybe it is subwoofer ?)

  



  Target is easy :

  



  

  1. convert source stereo central audio channel in Movie-B.mkv to mono channel
and

  


  2. insert it as central channel into Movie-A.mkv that have 5.1 Audio stream with layout C L R Ls Rs LFE

  


  



  So far I was able to complete 1. but I have a problem with mappings.
Can someone try to guide me how to do that ?

  


• doc/codecs : fix missing guidance in channel_layout item and remove decomissioned...

  3 janvier 2024, par Marth64

  doc/codecs : fix missing guidance in channel_layout item and remove decomissioned request_channel_layout
  Signed-off-by : Marth64 <marth64@proxyid.net>
  

  • [DH] doc/codecs.texi

• Install ffmpeg-light with cabal

  20 septembre 2016, par WirflBirfl

  I want to install the ffmpeg-light library from hackage via cabal on Windows 10 (64 bit). So I downloaded ffmpeg and extracted it to C :\FFmpeg.

  At first pkg-config was complaining that it could not find various packages. I solved this problem with .pc files.

  When I tried to use the command : cabal install ffmpeg-light cabal complained about missing C-libraries, being exactly those for which I created the .pc files.

  Then I tried the command : cabal install ffmpeg-light --extra-lib-dirs=C:\FFmpeg\lib. Now I have a different error message, which says :

  Enums.hsc:7:32: fatal error: libavcodec/avcodec.h: No such file or directory

  Edit :
  Then I tried the following command :

  cabal install ffmpeg-light --extra-lib-dirs=C:\FFmpeg\lib \
  
                             --extra-include-dirs=C:\FFmpeg\include

  Now first the compiler gives some warnings about deprecated functions in ffmpeg and redundant imports in ffmpeg-light, but compiles 11 of 11. But the build is still not successfull.

  In-place registering ffmpeg-light-0.11.1...
  
  setup-Simple-Cabal-1.22.5.0-x86_64-windows-ghc-7.10.3.exe:
  
  'C:\Haskell\bin\ghc-pkg.exe' exited with an error:
  
  ffmpeg-light-0.11.1: Warning: haddock-interfaces:
  
  C:\Users\HOLEYC~1\AppData\Local\Temp\cabal-tmp-2824\ffmpeg-light-0.11.1\dist\doc\html\ffmpeg-light\ffmpeg-light.haddock
  
  doesn't exist or isn't a file
  
  ffmpeg-light-0.11.1: Warning: haddock-html:
  
  C:\Users\HOLEYC~1\AppData\Local\Temp\cabal-tmp-2824\ffmpeg-light-0.11.1\dist\doc\html\ffmpeg-light
  
  doesn't exist or isn't a directory
  
  ffmpeg-light-0.11.1: library-dirs: C:FFmpeglib is a relative path which makes
  
  no sense (as there is nothing for it to be relative to). You can make paths
  
  relative to the package database itself by using ${pkgroot}. (use --force to
  
  override)
  
  ffmpeg-light-0.11.1: include-dirs: C:FFmpeginclude is a relative path which
  
  makes no sense (as there is nothing for it to be relative to). You can make
  
  paths relative to the package database itself by using ${pkgroot}. (use
  
  --force to override)
  
  cabal: Error: some packages failed to install:
  
  ffmpeg-light-0.11.1 failed during the building phase. The exception was:
  
  ExitFailure 1

  Some additional information :

  cabal version: cabal-install version 1.22.6.0
  
  using version 1.22.5.0 of the Cabal library
  
  gcc version of my installed Haskell platform: 5.2.0

  Example .pc file I used for pkg-config :

  Name: libavcodec
  
  Description: Library for ffmpeg
  
  Version: 57
  
  Cflags: -IC:\FFmpeg\include
  
  Libs: -LC:\FFmpeg\lib -llibavcodec