Am Freitag, 24. Mai 2024, 23:03:37 MESZ schrieb Michael Niedermayer:
> On Fri, May 24, 2024 at 12:33:11PM +0200, Gerion Entrup wrote:
> > Am Dienstag, 7. Mai 2024, 19:46:28 MESZ schrieb Michael Niedermayer:
> > > On Mon, May 06, 2024 at 12:30:39AM +0200, Gerion Entrup wrote:
> > > > ---
> > > > libavfilter/signature_lookup.c | 2 +-
> > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/libavfilter/signature_lookup.c
> > > > b/libavfilter/signature_lookup.c
> > > > index a0ca818a9b..b39a3e225b 100644
> > > > --- a/libavfilter/signature_lookup.c
> > > > +++ b/libavfilter/signature_lookup.c
> > > > @@ -128,7 +128,7 @@ static int get_jaccarddist(SignatureContext *sc,
> > > > CoarseSignature *first, CoarseS
> > > > int jaccarddist, i, composdist = 0, cwthcount = 0;
> > > > for (i = 0; i < 5; i++) {
> > > > if ((jaccarddist = intersection_word(first->data[i],
> > > > second->data[i])) > 0) {
> > > > - jaccarddist /= union_word(first->data[i], second->data[i]);
> > > > + jaccarddist /= FFMAX(union_word(first->data[i],
> > > > second->data[i]), 1);
> > > > }
> > >
> > > for which input data does this cause a division by 0 ?
> >
> > Sorry for the late answer. I missed your mail somehow.
> > union_word counts the amount of one bits that are created when you are
> > "or"ing
> > the course signatures. So, when the underlying videos are so different that
> > all
> > bits of the created signatures are different, the "or"-operator will always
> > return 0 and so also its sum (I have not tested this).
>
> the division only occurs if jaccarddist > 0
>
> basically what iam asking is for which A and B do we have
> (A&B) != 0 && (A|B) == 0
> or am i misreading the code ?Hmm, valid point. Then, this patch should be unnecessary. Should I send 2/2 again without 1/2 then? Gerion
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