Resize all files before transfering to your recorder. I did that and things are fine.
Err... you
are following the conversation, right? Perhaps you mean re-encode (aka "transcode"), for a simple "resize" will more than likely break things worse than they were before.
For OP: You might be able to use something like
AVIDemux here, to
copy video and re-encode the audio, downmixing to 2 channel?
Best wishes,
Rick.