Mix down 5.1 AC3 to Stereo WAV?

Question

I wonder if I can mix down a 5.1 AC3 file to Stereo WAV file, i.e. 6-channel > 2-channel. I'd like to know how to do this with via terminal with ffmpeg (or avconv, because it says ffmpeg is deprecated).

Answer 1

From man avconv, Audio Options section:

-ac[:stream_specifier] channels (input/output,per-stream)
           Set the number of audio channels. For output streams it is set by
           default to the number of input audio channels. For input streams
           this option only makes sense for audio grabbing devices and raw
           demuxers and is mapped to the corresponding demuxer options.

So you basic command line would be:

avconv -i <input file> -ac 2 <output file>.wav

You may also play with downmixing settings for the AC3 decoder, ie, the options where you can configure how the 6 channels from 5.1 will be merged (downmixed) into the 2 of stereo. Check for -dmix_mode and the -*mixlev* family of options under the Audio Encoders / ac3 section of the manual

Answer 2

You may refer to the following step by step guide on how to change audio channel between 6 channel, 5.1 channel, 2 channel stereo, mono and etc at How to Convert Video Audio Channel to 2 Channel, 5.1 Channel, or Mono?

It can easily help to: Convert 5.1 to 2 channel stereo like convert H.264 MP4 5.1 audio to 2-channel stereo source so as to play MP4 with 5.1-channel on Xbox 360. Convert 6 channel to 2 channels like convert 6 channel AC3 to 2 channel MP2 or convert an MKV 6 channel audio to 2 channel stereo without affecting video quality. Convert 2 channel to 5.1 channel like turn a dual channel wav file into 5.1 AC3 format; convert MP3 2 channel to 5.1 channel, convert 2 channel stereo to 5.1 surround sound Convert 2 channel audio into 6 channel to get surround sound in order to listen surround sound from home theater. Convert 6 channel to stereo like converting 6 channel CAF, OGG, AAC to stereo wave files or 2 channel AC3 Convert multiple-channel to mono like 5.1/6 channel to mono, 2 channel stereo to mono and etc.