h.264 2-pass vs 3-pass encoding

[DarkNeutron]

What is the quality/time trade off between 2-pass and 3-pass h.264 encoding in MeGUI?

I am sure that I am missing a page or post somewhere, but this is the first time Google has failed me.

I am going to re-encode a HDTV video (1280x1080) and thought I would ask before starting a 2 week job.:o

[killerhex]

h.265 exists

[DarkNeutron]

Oops!

Darn typos...

[Adub]

The difference is mostly negligible. Usually you want to use a 3rd pass only when you are having trouble reaching a specific size, otherwise, there is little to no quality difference.

Plus it can save you hours of encoding time.

[foxyshadis]

Also, if you push the codec too hard - such as if your stats file is full of 50s and 51s (or your max quant) - then you'll need a 3rd pass to smooth out the rate control, or motion scenes will look terrible. (Worse than they have to, anyway, which isn't saying much at those bitrates.)

[akupenguin]

If your movie needs to be encoded entirely at max quant to get your bitrate, then ratecontrol has no flexibility, and running another pass won't change it.
And if you ever see qp=51 (whether or not it's the majority of the movie), the solution is to downscale, not just tweak ratecontrol.