[FFmpeg-user] Creating surround sound from mono wav files

[Paul B Mahol]

On 12/23/18, CherylJosie <exwyeorzee-at-yahoo.com at ffmpeg.org> wrote:
> Hi all,
> I am trying to merge a surround sound file from discrete mono files with
> ffmpeg.
> The -map_channel function does not accept multiple audio input streams, and
> so far I have only managed to create stereo with -filter_complex amerge.
> amerge seems to ignore additional channels beyond stereo at the output, even
> though it parses them as inputs.

It does not parses them all.
Read manual and you will notice that amerge needs option that set
number of inputs.