[MPlayer-users] mencoder: effective use of qp, crf params for x264?

[Loren Merritt]

On Mon, 29 Jan 2007, matthew.garman at gmail.com wrote:

> -x264encopts crf=18:bitrate=2000:...

crf is an alternative to bitrate. You can't specify both. Like any other 
option, the latter took precedence, so your encode was just a 2000kbps 
average bitrate encode.

> Before learning about the crf param, I did a two-pass encode, with
> these x264encopts for passes one and two (respectively):
> [...]
> That took about the same time, resulting file size was 2.1 GB.

A two pass encode took the same time as a one pass encode with the same 
settings? No way. Even if the first pass is turbo, it's not free. And 
mencoder has to filter the video twice (spp is slow).

--Loren Merritt