07-12-2011, 01:04 AM
When you set either an average bit-rate or a target file-size:
- the first pass determines the locations of the most complex parts of the video
- the second pass does the encoding, ensuring that the average bit-rate stays where you set it, increasing the bit-rate where needed, and lowering it where it's not needed.
The preferred Handbrake settings now are Constant Quality, which does not benefit from 2-pass encoding, as opposed to average bit-rate or target file-size methods.
If you are using a Constant Quality setting, no need/no benefit from a second pass.