Yes, it's normal. Now you know why people want the biggest fastest 64-bit CPU they can afford.
I've had video encoding projects run for days. Just transcoding a DVD on my AMD64 3200+ will take about 8 hours.
Video processing takes considerable patience. You quickly learn to run test samples first to insure that the encode will run as you expect. There's nothing more annoying that encoding for two days to find out the aspect ratio was wrong...