glitchless switch between mono and stereo

I am thinking about a video selector application that shows videos in 3D space.

The sound of the videos is moved with the visual content (with some boosted Doppler effect) so you can hear the videos sliding in and out of scope. When a video is selected then it can be watched full screen. If the video has stereo sound then the channels are mixed directly to the left and right channel of the earphone. So I need to change playback from mono source in 3D to stereo source without 3D audio engine without stopping playback.

What do you think? Is it possible with OpenAL API?