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Old 04-02-2019, 09:35 AM   #36
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Join Date: Dec 2012
Location: Germany
Posts: 1,902

found it

here's the command line allowing to capture 2x stereo audio from two audio sources into the same video:
"D:\Programme\ffmpeg x64\bin\ffmpeg.exe" -n -rtbufsize 2000M -f gdigrab -r 25 -video_size 1920x1080 -draw_mouse 1 -i desktop -f dshow -i audio="SPDIF/ADAT (1+2) (RME Babyface)" -f dshow -i audio="ADAT (5+6) (RME Babyface)" -map 0:v -map 1:a -map 2:a -c:v libx264 -r 25 -preset faster -x264-params keyint=25 -tune zerolatency -crf 12 -pix_fmt yuv420p -ac 2 -c:a:1 aac -b:a:1 320k -c:a:2 aac -b:a:2 192k -ar 48K "G:\Screen-Videos\Screenvideo_.mkv"
As always, you'll have to adjust the code to your paths and audio devices.

additional notes:
  • I'm using FreeAudioVideoPack to extract both audio streams from the captured video to be able to insert them into two audio tracks in Reaper
  • For some unknown reasons, resulting audio streams are different from what I'm declaring in the command line! Stream 1 is recorded as vorbis 112 kbps and stream 2 is recorded as aac 256 kbps. I can't seem to figure out why atm. At least it is possible to capture 2x streo simultaneously, further reducing my need for OBS or other apps
  • audio streams seem to not be totally in sync with the video. I'm nudging them manually in Reaper.
I'm currently looking for solutions to the above issues.
[Check out my free VST plugin collection here.]
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