[FFmpeg-user] Converting video + stereo to video + mono

[Jason Heeris]

I'm playing around with encoding video for HTML5, and I was wondering
if converting the stereo audio to mono would have any real effect on
size. So I tried using the "-ac 1" option in this invocation:

    ffmpeg -i Input.avi -vcodec libx264 -b:v 1000k -ac 1 Output.mp4

...but the resulting output still seems to have stereo audio. Leaving
aside for a moment whether this really *will* have any impact on size,
am I doing something wrong with the options here?

(I'm using ffmpeg 4:0.10.2-0ubuntu0jon1~oneiric1 under Ubuntu 11.10.)

Cheers,
Jason