No, I have spent more time in the past dealing with ffmpeg
compatibility. It may be that your version of avconv is older than the
ffmpeg version you are trying to use. As well if you run avconv as
"ffmpeg" you get a very old version of fffmpeg that avconv shipped for
compatibility. If you are using a recent version of ffmpeg from
ffmpeg.org, or a recent version of avconv, you should be using SVN:
http://tovid.wikia.com/wiki/Installing_tovid#Subversion
Please post if you still find something not working in SVN, I have not
received any reports of problems but have not checked myself in a while.
cheers,
Robert (aka grepper)