I am trying to downmix 5.1 flac to stereo using ffmpeg, but getting following error

here is the command i am trying to run, i am taking the MKV file which has 5.1 FLAC as audio, and mapping the audio to a FLAC file.

%ffmpegpath% -i "%file%" -map 0:2 -vol 425 -af "pan=stereo|FL < 0.5C + 0.707L + 0.707Ls + 0.5LFE|FR < 0.5C + 0.707R + 0.707Rs + 0.5LFE" "stereo.flac"

here is the image of the error i am getting

1 Answer

There is no need to use map in this scenario. According to the ffmpeg documentation you can simply downmix the audio channels with the -ac <channels> flag.

ffmpeg -i 6channels.wav -ac 2 stereo.wav

This command would convert a surround file to stereo. You can of course use a .mkv file as input.

Your command would look like following:

%ffmpegpath% -i "%file%" -ac 2 stereo.flac