Screen Capture/Recording with ffmpeg

My attempt to record a video tutorial was failing with the error 'x11grab AVParameters don't have video size and/or rate. Use -s and -r'. This was in response to typing in the following command as based on an example in the ffmpeg man page.

ffmpeg -f x11grab -s 1280x1024 -i :0.0 -r 25 -sameq /tmp/test.mpg

After several failed tries, I determined that the error could be coming from the -r option. I moved it to immediately after the -s option so that both -s and -r options followed the x11grab specification. This time, it worked great. The final command is shown below.

ffmpeg -f x11grab -r 25 -s 1280x1024 -i :0.0 -sameq /tmp/test.mpg