Enable 2 or 3-pass mode. It is recommended to always encode in
2 or 3-pass mode as it leads to a better bit distribution and
improves overall quality.
1 first pass
2 second pass (of two pass encoding)
3 Nth pass (second and third passes of three pass encod-
ing)
Here is how it works, and how to use it:
The first pass (pass=1) collects statistics on the video and
writes them to a file. You might want to deactivate some CPU-
hungry options, apart from the ones that are on by default.
In two pass mode, the second pass (pass=2) reads the statistics
file and bases ratecontrol decisions on it.
In three pass mode, the second pass (pass=3, that is not a typo)
does both: It first reads the statistics, then overwrites them.
You can use all encoding options, except very CPU-hungry op-
tions.
The third pass (pass=3) is the same as the second pass, except
that it has the second pass' statistics to work from. You can
use all encoding options, including CPU-hungry ones.
The first pass may use either average bitrate or constant quan-
tizer. ABR is recommended, since it does not require guessing a
quantizer. Subsequent passes are ABR, and must specify bitrate.
