[FFmpeg-devel] [PATCH 10/11] avfilter/vf_ssim: use log10 instead of log()/log(10)

[Ganesh Ajjanagadde]

On Thu, Oct 29, 2015 at 2:33 PM, Ronald S. Bultje <rsbultje at gmail.com> wrote:
> Hi,
>
> On Thu, Oct 29, 2015 at 2:07 PM, Ganesh Ajjanagadde <gajjanag at mit.edu>
> wrote:
>
>> On Thu, Oct 29, 2015 at 1:37 PM, Michael Niedermayer
>> <michael at niedermayer.cc> wrote:
>> > On Thu, Oct 29, 2015 at 12:20:08AM -0400, Ganesh Ajjanagadde wrote:
>> >> This is likely more precise and conveys the intent better.
>> >>
>> >> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
>> >> ---
>> >>  libavfilter/vf_ssim.c | 2 +-
>> >>  1 file changed, 1 insertion(+), 1 deletion(-)
>> >>
>> >> diff --git a/libavfilter/vf_ssim.c b/libavfilter/vf_ssim.c
>> >> index ce1e3db..6b2a8d7 100644
>> >> --- a/libavfilter/vf_ssim.c
>> >> +++ b/libavfilter/vf_ssim.c
>> >> @@ -176,7 +176,7 @@ static float ssim_plane(SSIMDSPContext *dsp,
>> >>
>> >>  static double ssim_db(double ssim, double weight)
>> >>  {
>> >> -    return 10 * (log(weight) / log(10) - log(weight - ssim) / log(10));
>> >> +    return 10 * (log10(weight) - log10(weight - ssim));
>> >
>> > LGTM
>> >
>> > note, this can be simplified further but thats maybe off topic in
>> > relation to switching to log10
>>
>> I did note that you can rewrite as log10(weight/(weight-ssim)), but
>> avoided it deliberately as I did not know what people want with
>> respect to it. Since you brought it up and think it may be good, I
>> will change it.
>>
>> I personally don't consider it too off topic, and prefer this over
>> sending a separate patch for the simplification and dealing with
>> another wm4 rant about it.
>> Will push all later, once everything is reviewed and ok'ed.
>
>
> Now, now, let's stay friendly and professional...

I referred to it as a "rant" because that is what it was, and I want
to make it sufficiently clear that the reason patches I send often
result in a ton of noise is often not technical, but simply a
knee-jerk reaction and associated bickering over it.

I do not enjoy dealing with such things, but I can almost surely
guarantee that is what would happen if I send a separate patch for it.
I (and most people here) want work to be done at minimal noise cost,
and hence I gave my rationale for changing without sending a separate
patch.

Your point is taken though, and I will attempt to refrain from such things.

>
> Ronald
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