[MEncoder-users] B-frames and GOP with MPEG-2 for DVD

[RC]

On Thu, 07 Jun 2007 16:40:52 -0400
Nicolas Hesler <nicolas.hesler at sheridanc.on.ca> wrote:

> So why have a b frames option in the first place, if it only degrades 
> the quality?  For smaller encodes?  So as a rule, never use B-Frames 
> unless you're concerned with space?

B-frames are a tricky issue.  At lower bitrates they help significantly
with gradual scene transitions (fades), but they can hurt the overall
quality even more in some cases.

It seems they mainly exists in (hardware) encoders for
simple, single-pass ratecontrol, and so lots of standards mandate their
use.