[FFmpeg-user] dshow 2 mono audio input to 1 stereo right/left output

[Tim Hiles]

I've tried a few different things but I can't seem to get this right.  So,
the question becomes, is it possible?  I tried the -amix filter but as I'm
sure you are all aware that just combines the two streams into one. I'd
like to keep them separated one input signal on the right one input signal
on the left.

C:\ffmpeg\ffmpeg\bin\ffmpeg.exe -f dshow -ac 1 -i "audio=Internal Mic (IDT
High Definiti" -f dshow
-ac 1 -i "audio=Stereo Mix (IDT High Definition" -ar 22050 -ac 2 -map 0:0
-map 1:0 test.mp3
ffmpeg version N-76123-g002b049 Copyright (c) 2000-2015 the FFmpeg
developers
  built with gcc 5.2.0 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads
--enable-avisynth --enable-bzlib --enable-fontconfi
g --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-libm
p3lame --enable-libopencore-amrnb --enable-libopencore-amrwb
--enable-libopenjpeg --enable-libopus --enable-librtmp --en
able-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora
--enable-libtwolame --enable-libvidstab --ena
ble-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx
--enable-libwavpack --enable-libwebp --enabl
e-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma
--enable-decklink --enable-zlib
  libavutil      55.  4.100 / 55.  4.100
  libavcodec     57.  7.100 / 57.  7.100
  libavformat    57.  8.102 / 57.  8.102
  libavdevice    57.  0.100 / 57.  0.100
  libavfilter     6. 11.100 /  6. 11.100
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.100 /  2.  0.100
  libpostproc    54.  0.100 / 54.  0.100
Guessed Channel Layout for  Input Stream #0.0 : mono
Input #0, dshow, from 'audio=Internal Mic (IDT High Definiti':
  Duration: N/A, start: 182761.002000, bitrate: 705 kb/s
    Stream #0:0: Audio: pcm_s16le, 44100 Hz, 1 channels, s16, 705 kb/s
Guessed Channel Layout for  Input Stream #1.0 : mono
Input #1, dshow, from 'audio=Stereo Mix (IDT High Definition':
  Duration: N/A, start: 182762.604000, bitrate: 705 kb/s
    Stream #1:0: Audio: pcm_s16le, 44100 Hz, 1 channels, s16, 705 kb/s
File 'test.mp3' already exists. Overwrite ? [y/N] y
[mp3 @ 00477e80] Invalid audio stream. Exactly one MP3 audio stream is
required.
Output #0, mp3, to 'test.mp3':
  Metadata:
    encoder         : Lavf57.8.102
    Stream #0:0: Audio: mp3 (libmp3lame), 22050 Hz, stereo, s16p
    Metadata:
      encoder         : Lavc57.7.100 libmp3lame
    Stream #0:1: Audio: mp3 (libmp3lame), 22050 Hz, stereo, s16p
    Metadata:
      encoder         : Lavc57.7.100 libmp3lame
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s16le (native) -> mp3 (libmp3lame))
  Stream #1:0 -> #0:1 (pcm_s16le (native) -> mp3 (libmp3lame))
Could not write header for output file #0 (incorrect codec parameters ?):
Invalid argument

Thanks for any help!