Wanted: Mono capable windows command line mp3/mp2 -> ogg converter, One that doesn't require installation. Options

[sonytp50]

Hi,

I'm looking for a simple mp3/mp2 -> ogg encoder recommendation for windows that
does not require installation and can encode a single file (or folder). The resulting ogg
file should be mono, to get it as small as possible.

I know that normally mp3->ogg conversions are a big No-No due to the loss of quality.

In my usage scenario this is not an issue: I want to convert radio (speech) programs so
that I can get as much as possible on a 2GB Ipod Nano (Rockbox) and don't mind if the
quality suffers a lot. I'll delete the files after listening to them anyway.
I plan to keep the encoder on the Ipod - to run without installation whenever needed.

The conversion has to be directly from mp3/mp2 to ogg - I normally do not have the 2GB
free hard disc space required to unpack the radio shows to WAV before encoding them.

The best thing I have so far is ffmpeg, called like this:
ffmpeg -i input.mp3 -acodec vorbis -aq 20 -ar 22050 output.ogg

Alas it only seems to do ogg in stereo, not mono.

Any recommendations?