What is the ffmpeg command to merge two mono audio streams into one stereo?

[Iced Coffee]

I'm talking about transcoding DNxHD from MXF containers, which traditionally separate the video stream and each audio channel into totally separate files. So what I need to do is basically say

- Input 'video.mxf'
- Input 'Audioleft_mono.mxf'
- Input 'Audioright_mono.mxf'
- Output a new file with a stereo audio stream, in which audioleft is panned 100% to the left and audioright is panned 100% to the right.

Sounds simple, but the syntax of the -amerge command is just inscrutable to me. I have no idea how to work it.

If someone could just throw out the correct syntax for a command like this, I'd be grateful.

[poisondeathray]

http://ffmbc.wordpress.com/2011/01/15/monotracks-to-stereo-ii/