How to change a video resolution?

Can I change a video resolution (say, from 640x480 to 320x240)?

UPDATE:

At ubuntuforums there's a thread talking about avidemux, I did a search in the wiki for "resolution" but I found nothing about how to change it. Does anyone use it?


Solution 1:

ffmpeg

FFmpeg (or avconv if ffmpeg was not available) can do this easily

ffmpeg -i input.mpeg -s 320x240 output.mpeg

There are felt one million additional options to change the output format. These can also be combined

ffmpeg -i input.mp4 -s 320x240 output.mpeg