On Tue, Nov 05, 2019 at 06:35:54PM +0530, Gyan wrote: > > > On 05-11-2019 03:55 pm, Michael Niedermayer wrote: > >On Tue, Nov 05, 2019 at 10:13:52AM +0530, Gyan wrote: > >> > >>On 05-11-2019 04:35 am, Michael Niedermayer wrote: > >>>On Sun, Nov 03, 2019 at 11:14:25AM +0530, Gyan wrote: > >>>>Helps better identification of expr eval failures. > >>>> > >>>>Gyan > >>>> eval.c | 21 +++++++++++++++++++++ > >>>> eval.h | 10 ++++++++++ > >>>> version.h | 4 ++-- > >>>> 3 files changed, 33 insertions(+), 2 deletions(-) > >>>>3dd142baa0144fd324eb9da8a9932cfd7ab2cd98 > >>>>0001-avutil-eval-add-function-to-track-variable-use.patch > >>>> From 19bce329464676f071707b99575f80e5abe1cd4c Mon Sep 17 00:00:00 2001 > >>>>From: Gyan Doshi <ffm...@gyani.pro> > >>>>Date: Sat, 2 Nov 2019 20:16:42 +0530 > >>>>Subject: [PATCH] avutil/eval: add function to track variable use > >>>> > >>>>Helps avoid multiple evals of cross-referenced expressions > >>>>and catch the use of non-applicable variables with respect > >>>>to eval or special mode in filters > >>>Maybe you should provide more details of the use case of this, maybe > >>>with an example. Because it seems not completely obvious > >>An example of a cross-referenced expression would be 'y=x+rand(10)'. > >>Normally in filters, X would be evaluated first, then Y, then X again. The > >>2nd eval of X will overwrite the first and can generate a different value. > >>With this func, we can avoid the 2nd eval. > >> > >>I'm in the process of modifying the scale filter to allow 'n', 't', 'pos' > >>variables in frame eval mode (it already supports dynamic output based on > >>incoming frame changes) and I would like to catch their presence in init > >>mode, since av_expr_eval will fail. Now, it can also fail due to circularly > >>referenced expressions e.g. 'x=y+10' and 'y=x+10' and there's no way to > >>detect whether it's this case or if inapplicable variables have been used. > >please add this (or similar information) to the commit message > > Done. > > Thanks, > Gyan
> eval.c | 21 +++++++++++++++++++++ > eval.h | 10 ++++++++++ > version.h | 4 ++-- > 3 files changed, 33 insertions(+), 2 deletions(-) > 740f6166ddb4b1a581aee7c34edd05d328265df1 > v2-0001-avutil-eval-add-function-to-track-variable-use.patch > From 2931fa96b8e7f80581ded280907655753e54def0 Mon Sep 17 00:00:00 2001 > From: Gyan Doshi <ffm...@gyani.pro> > Date: Sat, 2 Nov 2019 20:16:42 +0530 > Subject: [PATCH v2 1/2] avutil/eval: add function to track variable use i think the patch is ok but i think nicolas wants to wait with pushing this until there is a 2nd patch which uses the new function Thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB In fact, the RIAA has been known to suggest that students drop out of college or go to community college in order to be able to afford settlements. -- The RIAA
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