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

[Ganesh Ajjanagadde]

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.

>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
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