[FFmpeg-user] After reading x264 Encoding Guide, some questions

Carl Eugen Hoyos cehoyos at ag.or.at
Fri Dec 7 13:27:08 CET 2012

Francois Visagie <francois.visagie <at> gmail.com> writes:

> 3. I'm trying to understand the relationship between x264opts 
> and other "libx264 AVOptions" in ffmpeg -h. If I understand 
> correctly, x264opts are passed to libx264 for parsing and 
> others are parsed by ffmpeg before being passed to libx264, if 
> I could put it that way? But then, what does it mean
> when http://www.ffmpeg.org/ffmpeg.html#Options-4 says
> "'passlogfile filename'
> Specify filename for 2 pass stats. Deprecated in favor of 
> x264opts (see stats libx264 option)."

It means that when using -vcodec libx264, using "passlogfile" 
is deprecated, you should use -x264opts stats instead.

> - this makes x264opts and libx264 options sound like
> the same thing?

Well, x264opts sets libx264 options, so one could probably 
say they are the same things...

> 4. Both the Encoding Guide and the ffmpeg documentation refer to 'x264
> -fullhelp', but ffmpeg does not recognise such a parameter

That is because it is a x264 parameter, ie you need the x264 
executable to see the fullhelp.

I am not trying to say here that I don't understand this is 
not easy to use. The reason is though that with this design 
new x264 features can be used without changing FFmpeg.

Carl Eugen

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