I'm using Mac OS X 10.5 and am looking for a free video converter software which supports mp4, avi, and wmv files (and perhaps rmvb, too). I want to convert avi, wmv, and rmvb files to mp4 to be able to play them on my iPod. I've already searched but could only find quite expensive shareware. Do you know any software available for free, please?
I don't know about wmv and rmvb files, but Handbrake does quite a good job with avi, mpg and mov and has a built-in iPod and iPhone/iPod Touch preset to help you easily convert your videos.
Take a look at ffmpegX.
I have never tried it but as it is based on the very powerful ffmpg I think you should give it a try.
Further reading on the webpage (thanks John T) reveals that you have to install ffmpeg separately, but they do provide a link, but only to the ffmpg source. Unfortunately binary distributions for ffmpeg are hard to find and not everyone is up to building things from scratch.
So my advice is to see if it's simpler to use mpeg2enc, or mencoder as a backend instead. (links found in John T's answer)
Another free program (which I'm running now in the background) to edit videos is MPEG Streamclip, which reads mostly everything that can be read through Quicktime with Perian and can generate mp4 files that can be dragged into iTunes to be synced to your iPod/iPhone.
The only thing I'm not sure it reads is rmvb.
Check out Video Monkey, it's VisualHub re-incarnated.