[FFmpeg-user] FFmpeg and libx264 presets and Constant Rate Factor (CRF)

[Def Etienne]

> 
> On 7 Aug 2021, at 10:12, Bill Crockett <wsc4 at optusnet.com.au> wrote:
> 
> First of all, I am not doing 2 pass encoding.  I am using the CRF option.
> 
> They say for constant quality encoding, you will save bitrate by choosing a slower preset.   A slower preset will provide better compression.
> 
> ultrafast
> superfast
> veryfast
> faster
> fast
> medium – default preset
> slow
> slower
> veryslow
> placebo
> 
> I do not care about compression or files size.  But I do care about quality.
> 
> If I choose a CRF of 20, and I use the "veryslow" preset, the quality will still be the same if I choose a CRF of 20 and use the "superfast" preset?
> 

Yes. I think  It will be the same by the documentation. 

> The same with this.  If I choose a CRF of 10, and I use the "veryslow" preset, the quality will still be the same if I choose a CRF of 10 and use the "superfast" preset?
> 

> Is this correct about the quality please?