[FFmpeg-devel] [PATCH] lavfi/scale: add nb_slices debug option

Michael Niedermayer michael at niedermayer.cc
Sat Dec 19 01:44:47 CET 2015


On Fri, Dec 18, 2015 at 05:31:32PM +0100, Clément Bœsch wrote:
> On Fri, Dec 18, 2015 at 04:33:18PM +0100, Nicolas George wrote:
> > L'octidi 28 frimaire, an CCXXIV, Clement Boesch a écrit :
> > > +        const int slice_h = FFMAX(1, link->h / scale->nb_slices);
> > > +        for (i = 0; i < scale->nb_slices; i++)
> > > +            scale_slice(link, out, in, scale->sws, i*slice_h, slice_h, 1, 0);
> > 
> > What happens if link->h is not a multiple of nb_slices?
> > 
> 
> That wasn't very rigorous, sorry. New patch attached.
> 
> Note: the option is not really documented since it doesn't serve any
> purpose aside from debugging slicing, and not from a threading
> perspective, but more like a locality, as in CPU cache wise apparently.
> 
> -- 
> Clément B.

>  vf_scale.c |   12 ++++++++++++
>  1 file changed, 12 insertions(+)
> ad9a7000977be97bbb57ca284ad0fdf53271beda  0001-lavfi-scale-add-nb_slices-debug-option.patch
> From 43b22797e4b549e2b3eedbfe5ee5734ed97f2521 Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?Cl=C3=A9ment=20B=C5=93sch?= <clement at stupeflix.com>
> Date: Fri, 18 Dec 2015 15:44:33 +0100
> Subject: [PATCH] lavfi/scale: add nb_slices debug option

LGTM

it seems this segfaults if NEW_FILTER is defined though (and nb_slices
is set)
(thus CCing pedro)

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The bravest are surely those who have the clearest vision
of what is before them, glory and danger alike, and yet
notwithstanding go out to meet it. -- Thucydides
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