[FFmpeg-user] New x264 presets

Jim Worrall coniophora at gmail.com
Sat Dec 17 20:35:30 CET 2011

On Dec 17, 2011, at 9:35 AM, Anderw Gora wrote:

> Hi,
> My questions is about a canonical way of using libx264 presets
> for 2-pass encoding in the new ffmpeg 0.8.7 enviroment. There is no
> such problems with ffmpeg 0.5.
> 1. Is it enougph to put preset without changing in both passes:
> ffmpeg ... -pass 1 -vcodec libx264 -preset slow ...
> ffmpeg ... -pass 2 -vcodec libx264 -preset slow ...
> With the above settings encoding time differs just twice sometime but
> differs. Seems, this is to much efforts for the first pass...
> Some sources tell about, for example, "-preset slow_firstpass" for the
> first pass with slow preset, but in matter of fact it not working.

I don't quite understand what you're saying your problem is.  If I understand
the x264 --help, the first pass should have faster settings by default, 
unless you disable that with slow-firstpass (that is a regular option, not a
value to follow "-preset" I believe).

> 2. Is it worth to change presents between passes like:
> ffmpeg ... -pass 1 -vcodec libx264 -preset superfast ...
> ffmpeg ... -pass 2 -vcodec libx264 -preset slower ...
> 3. Is it interesting for honorable community if I share my stats of
> encoding time and quality with different presets somewhere?
> ---------
> Just info of available presets: ultrafast, superfast, veryfast,
> faster, fast, medium, slow, slower, veryslow, placebo
> ---------

I for one would be interested to see your results, including 
encoding time, file size, and quality.

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