| Message ID | df67a789-79e7-937e-5111-96181239af5f@googlemail.com |
|---|---|
| State | Accepted |
| Headers | show |
On Wed, Nov 09, 2016 at 08:52:54PM +0100, Andreas Cadhalpun wrote: > On 09.11.2016 02:27, Michael Niedermayer wrote: > > On Tue, Nov 08, 2016 at 10:36:01PM +0100, Andreas Cadhalpun wrote: > >> Since the loop goes down to i = 0 the number of iterations (variable > >> count) is the original i, not i - 1. > >> In the case of i originally being 1, this miscalculation resulted in > >> a division by zero. > >> > >> This problem was introduced in commit > >> 4b90dcb8493552c17a811c8b1e6538dae4061f9d. > >> > >> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> > >> --- > >> libavcodec/dvbsubdec.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/libavcodec/dvbsubdec.c b/libavcodec/dvbsubdec.c > >> index e9f4765..31898ea 100644 > >> --- a/libavcodec/dvbsubdec.c > >> +++ b/libavcodec/dvbsubdec.c > >> @@ -810,7 +810,7 @@ static void compute_default_clut(AVSubtitleRect *rect, int w, int h) > >> list_inv[ i ] = bestv; > >> } > >> > >> - count = i - 1; > >> + count = i; > >> for (i--; i>=0; i--) { > >> int v = i*255/count; > >> AV_WN32(rect->data[1] + 4*list_inv[i], RGBA(v/2,v,v/2,v)); > > > > with this a 2 color text would be 50% and 100% transparent > > it should be transparent background and opaque text, > > count = FFMAX(i - 1, 1); > > seems better to me > > OK, patch doing that is attached. > > Best regards, > Andreas > > dvbsubdec.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > 10b117a15971daf75d61efe486b961d3cc59d480 0001-dvbsubdec-fix-division-by-zero-in-compute_default_cl.patch > From 436318575abf482e1ea144f651c47bc2730e41a2 Mon Sep 17 00:00:00 2001 > From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> > Date: Tue, 8 Nov 2016 22:32:42 +0100 > Subject: [PATCH] dvbsubdec: fix division by zero in compute_default_clut > > This problem was introduced in commit > 4b90dcb8493552c17a811c8b1e6538dae4061f9d. > > Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> > --- > libavcodec/dvbsubdec.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) LGTM thx [...]
On 10.11.2016 17:42, Michael Niedermayer wrote: > On Wed, Nov 09, 2016 at 08:52:54PM +0100, Andreas Cadhalpun wrote: >> dvbsubdec.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> 10b117a15971daf75d61efe486b961d3cc59d480 0001-dvbsubdec-fix-division-by-zero-in-compute_default_cl.patch >> From 436318575abf482e1ea144f651c47bc2730e41a2 Mon Sep 17 00:00:00 2001 >> From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> >> Date: Tue, 8 Nov 2016 22:32:42 +0100 >> Subject: [PATCH] dvbsubdec: fix division by zero in compute_default_clut >> >> This problem was introduced in commit >> 4b90dcb8493552c17a811c8b1e6538dae4061f9d. >> >> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> >> --- >> libavcodec/dvbsubdec.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) > > LGTM Pushed. Best regards, Andreas
From 436318575abf482e1ea144f651c47bc2730e41a2 Mon Sep 17 00:00:00 2001 From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> Date: Tue, 8 Nov 2016 22:32:42 +0100 Subject: [PATCH] dvbsubdec: fix division by zero in compute_default_clut This problem was introduced in commit 4b90dcb8493552c17a811c8b1e6538dae4061f9d. Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> --- libavcodec/dvbsubdec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/dvbsubdec.c b/libavcodec/dvbsubdec.c index e9f4765..bf3b1a1 100644 --- a/libavcodec/dvbsubdec.c +++ b/libavcodec/dvbsubdec.c @@ -810,7 +810,7 @@ static void compute_default_clut(AVSubtitleRect *rect, int w, int h) list_inv[ i ] = bestv; } - count = i - 1; + count = FFMAX(i - 1, 1); for (i--; i>=0; i--) { int v = i*255/count; AV_WN32(rect->data[1] + 4*list_inv[i], RGBA(v/2,v,v/2,v)); -- 2.10.2