On Tue, 25 Sep 2012, John Van Sickle wrote:

> On Tue, Sep 25, 2012 at 2:12 PM, Luca Barbato <[email protected]> wrote:
> > On 09/25/2012 06:29 PM, John Van Sickle wrote:
> >> -    x4->params.rc.f_ip_factor             = 1 / 
> >> fabs(avctx->i_quant_factor);
> >> +    if (avctx->i_quant_factor >= 0)
> >> +        x4->params.rc.f_ip_factor         = avctx->i_quant_factor;
> >
> > Looks strange to me. before it was 1/qf...
>
> As discussed on irc, I have no idea why it was previously: 1 /
> fabs(avctx->i_quant_factor);
>
> With my patch the option now behaves the same way as x264cli. The
> default is 1.40, and using "-tune grain" correctly sets ipratio to
> 1.10. If you set --ipratio .80 using x264cli, that's what you get. Not
> 1/.80 like avconv is currently doing. Do this make sense?

The meaning that x264 assigns to f_ip_factor is the reciprocal of the
meaning that libav codecs assign to i_quant_factor.

--Loren Merritt
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