Rate Control Based on Quality

If quality is more important to you than file size, then try out the 1-pass quality-based mode. Using this option you get to pick a target quantizer. Sound nifty? The quantizer is just a number between 1 and 31. Opting for a lower number will give you better picture quality but you'll also get larger files. Larger numbers reduce the file size but give you worse quality.

In practice, a quantizer of 4 is good quality with reasonable file size. You may want to move it down to 3, but anything less than that won't make much visible difference for most people.