[FFmpeg-user] libx264 very bad scaling with 4 real CPU cores (no HT)
barsnick at gmx.net
Fri Dec 4 12:52:16 CET 2015
On Fri, Dec 04, 2015 at 12:06:24 +0100, D wrote:
> mailing list or forum (they link to doom10 which doesn't exist, LOL) or
> The other thing I find weird with -preset is that one can use -crf
> setting with it. I thought a preset would cover this and no -crf setting
> would be needed/allowed. But because it is, the question is what other
> settings are allowed/needed? Confusing.
As far as my experience tells me, the presets control speed versus
size, at (approximately) constant quality. So "-preset veryslow" and
"-preset ultrafast" should show the same image quality. There are test
measurements out there to prove it, IIRC. You then use "-crf" to vary
the requested quality.
Indeed, asking x264 folk would be better. :)
More information about the ffmpeg-user