| Message ID | 411427cc-6dec-62cc-4795-0b7c57b47004@googlemail.com |
|---|---|
| State | Accepted |
| Headers | show |
On Fri, Nov 25, 2016 at 12:31:28AM +0100, Andreas Cadhalpun wrote: > On 24.11.2016 18:29, Michael Niedermayer wrote: > > On Thu, Nov 24, 2016 at 01:15:54AM +0100, Andreas Cadhalpun wrote: > >> On 23.11.2016 03:22, Michael Niedermayer wrote: > >>> On Sun, Nov 13, 2016 at 09:29:11PM +0100, Andreas Cadhalpun wrote: > >>>> It causes division by zero crashes. > >>>> > >>>> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> > >>>> --- > >>>> libavcodec/aacsbr_fixed.c | 4 ++++ > >>>> 1 file changed, 4 insertions(+) > >>>> > >>>> diff --git a/libavcodec/aacsbr_fixed.c b/libavcodec/aacsbr_fixed.c > >>>> index b26314a..d2a7027 100644 > >>>> --- a/libavcodec/aacsbr_fixed.c > >>>> +++ b/libavcodec/aacsbr_fixed.c > >>>> @@ -429,6 +429,10 @@ static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr, > >>>> av_add_sf(FLOAT_1, sbr->e_curr[e][m]), > >>>> av_add_sf(FLOAT_1, sbr->q_mapped[e][m])))); > >>>> } > >>>> + if (sbr->gain[e][m].mant == 0) { > >>>> + sbr->gain[e][m] = FLOAT_1; > >>>> + sbr->gain[e][m].exp = MIN_EXP; > >>>> + } > >>> > >>> Why is this not not needed for the float code ? > >> > >> Because float can represent smaller absolute values than normalized SoftFloat. > >> > >>> is there a shortcomming in the SoftFloat code ? > >> > >> In a way, because the SoftFloat gets normalized, e.g.: > >> * float: 2.16840434e-19 * 2.77555756e-17 / 10337.5293 = 5.82201677e-40 > >> * SoftFloat: av_div_sf(av_mul_sf({mant = 536870912, exp = -61}, {mant = 536870912, exp = -54}), > >> {mant = 677439305, exp = 14}) = {mant = 850858499, exp = -130} = FLOAT_0 > > > > hmm > > does increasing the limits for SoftFloats exponent solve this ? > > Yes, patch is attached. > > > If that works and doesnt break anything it would be good to have > > SoftFloat cover the range float has > > I'm not entirely sure about not breaking anything. For example the output of > the softfloat test changes, but for some reason that test is not enabled anyway. > > Best regards, > Andreas > softfloat.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > 17b9929a3b2f3b064cc1f96c7ed48dfe377f191a 0001-softfloat-decrease-MIN_EXP-to-cover-full-float-range.patch > From e28c5828a62c583152834f661f9a15b572b07eee Mon Sep 17 00:00:00 2001 > From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> > Date: Fri, 25 Nov 2016 00:26:51 +0100 > Subject: [PATCH] softfloat: decrease MIN_EXP to cover full float range > > floats are not necessarily normalized, so a normalized softfloat needs > MIN_EXP lowered by 23 to cover that range. > > Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> > --- > libavutil/softfloat.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) LGTM thx [...]
On 25.11.2016 01:12, Michael Niedermayer wrote: > On Fri, Nov 25, 2016 at 12:31:28AM +0100, Andreas Cadhalpun wrote: >> softfloat.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> 17b9929a3b2f3b064cc1f96c7ed48dfe377f191a 0001-softfloat-decrease-MIN_EXP-to-cover-full-float-range.patch >> From e28c5828a62c583152834f661f9a15b572b07eee Mon Sep 17 00:00:00 2001 >> From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> >> Date: Fri, 25 Nov 2016 00:26:51 +0100 >> Subject: [PATCH] softfloat: decrease MIN_EXP to cover full float range >> >> floats are not necessarily normalized, so a normalized softfloat needs >> MIN_EXP lowered by 23 to cover that range. >> >> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> >> --- >> libavutil/softfloat.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) > > LGTM Pushed. Best regards, Andreas
From e28c5828a62c583152834f661f9a15b572b07eee Mon Sep 17 00:00:00 2001 From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> Date: Fri, 25 Nov 2016 00:26:51 +0100 Subject: [PATCH] softfloat: decrease MIN_EXP to cover full float range floats are not necessarily normalized, so a normalized softfloat needs MIN_EXP lowered by 23 to cover that range. Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> --- libavutil/softfloat.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavutil/softfloat.h b/libavutil/softfloat.h index 48d0d59..fa91d1e 100644 --- a/libavutil/softfloat.h +++ b/libavutil/softfloat.h @@ -27,7 +27,7 @@ #include "avassert.h" #include "softfloat_tables.h" -#define MIN_EXP -126 +#define MIN_EXP -149 #define MAX_EXP 126 #define ONE_BITS 29 -- 2.10.2