How can I combine two audio tracks within the same .mov file?

Question

I used Skype and Ecamm Call Recorder to record a podcast. Based on my last experience where I had a problem with echoing from my computer speakers into the mic, I decided to use headphones and a USB mic in order to record the call. However, when I play the .mov file back the conversation was recorded on two separate audio tracks. So my voice is on audio stream 1 and the guest is on audio stream 2. Is there a way for me to combine these two tracks without having to re-record the entire thing? When I converted the file into a .mp3 it seems that only the guest's side is captured.

Answer 1

You can use Audacity, its free all you have to do is import both files into one audio track and export them.

Answer 2

I had the same problem (my Skype recorded to a .mov file that had two separate audio "streams" or tracks)

I used Ffmpeg to convert to a .mp4 file with a single stereo audio track that was merged from the original audio tracks.

I was fine with one Skype user's voice being in the left speaker and the other Skype user's voice being in the right speaker.

This is the command that worked for me:

ffmpeg -i "input.mov" -filter_complex "[0:v]format=yuv420p[v];[0:a]amerge=inputs=$(ffprobe -loglevel error -select_streams a -show_entries stream=codec_type -of csv=p=0 "input.mov" | wc -l)[a]" -map "[v]" -map "[a]" -c:a libmp3lame output.mp4

And it was inspired by LordNeckbeard.

If you'd rather merge further so that both voices are in the same (mono) channel so that they come out of both left and right speakers, add -ac 1 as shown here.