[FFmpeg-user] 7.1 Audio support in ffmpeg

[Varsha Godage]

Hi ,



I am using ffmpeg version "ffmpeg-20150415-git-fbdaebb-win64-shared" on
windows.

I am not able to transcode 7.1 channel audio files, it gets converted into
5.1 audio.

pasting console output and command line :

 C:\ffmpeg\ffmpeg-20150415-git-fbdaebb-win64-shared\bin>ffmpeg.exe -i
v:Content\multichannel_content\WAV\8_Channel_ID_48.wav -acodec ac3

8_channel_ac3.mkv

ffmpeg version N-71455-gfbdaebb Copyright (c) 2000-2015 the FFmpeg
developers

  built with gcc 4.9.2 (GCC)

  configuration: --disable-static --enable-shared --enable-gpl
--enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib -

-enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv
--enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca -

-enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm
--enable-libilbc --enable-libmodplug --enable-libmp3lame --enable

-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg
--enable-libopus --enable-librtmp --enable-libschroedinger --enable-l

ibsoxr --enable-libspeex --enable-libtheora --enable-libtwolame
--enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enab

le-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp
--enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --

enable-lzma --enable-decklink --enable-zlib

  libavutil      54. 22.101 / 54. 22.101

  libavcodec     56. 34.100 / 56. 34.100

  libavformat    56. 30.100 / 56. 30.100

  libavdevice    56.  4.100 / 56.  4.100

  libavfilter     5. 14.100 /  5. 14.100

  libswscale      3.  1.101 /  3.  1.101

  libswresample   1.  1.100 /  1.  1.100

  libpostproc    53.  3.100 / 53.  3.100

Guessed Channel Layout for  Input Stream #0.0 : 7.1

Input #0, wav, from
'v:Content\multichannel_content\WAV\8_Channel_ID_48.wav':

  Duration: 00:00:12.06, bitrate: 6144 kb/s

    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, 8
channels, s16, 6144 kb/s

Output #0, matroska, to '8_channel_ac3.mkv':

  Metadata:

    encoder         : Lavf56.30.100

    Stream #0:0: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, 5.1(side),
fltp, 448 kb/s

    Metadata:

      encoder         : Lavc56.34.100 ac3

Stream mapping:

  Stream #0:0 -> #0:0 (pcm_s16le (native) -> ac3 (native))

Press [q] to stop, [?] for help

size=     663kB time=00:00:12.05 bitrate= 450.3kbits/s

video:0kB audio:660kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: 0.481805%



Here input stream has 8channels but resultant output stream has 6 channels.

 Is there any way to transcode 7.1 audio using ffmpeg?



Regards,

Varsha.