Re: [FFmpeg-devel] [PATCH] vf_blend: Use integers for divide mode

2016-02-22 Thread Martin Vignali 
2016-02-23 0:22 GMT+01:00 Ganesh Ajjanagadde :

> On Fri, Feb 19, 2016 at 1:06 PM, Martin Vignali
>  wrote:
> > Hello,
> >
> > Is it necessary to clip value, if B == 0 ?
>
> Well, integer division by 0 is undefined...
>
> >
> >
> > Martin
> >
> > 2016-02-19 18:47 GMT+01:00 Timothy Gu :
> >
> [...]
>

Yes, but in that case, zero division can't happen, because B == 0 is tested.

For now, this is the line

av_clip_uint8(B == 0 ? 255 : 255 * A / B))


I think something like this can be enough :

B == 0 ? 255 : av_clip_uint8(255 * A / B))


Martin
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Re: [FFmpeg-devel] [PATCH] vf_blend: Use integers for divide mode

2016-02-22 Thread Ganesh Ajjanagadde 
On Fri, Feb 19, 2016 at 1:06 PM, Martin Vignali
 wrote:
> Hello,
>
> Is it necessary to clip value, if B == 0 ?

Well, integer division by 0 is undefined...

>
>
> Martin
>
> 2016-02-19 18:47 GMT+01:00 Timothy Gu :
>
[...]
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Re: [FFmpeg-devel] [PATCH] vf_blend: Use integers for divide mode

2016-02-19 Thread Martin Vignali 
Hello,

Is it necessary to clip value, if B == 0 ?


Martin

2016-02-19 18:47 GMT+01:00 Timothy Gu :

> On Sun, Feb 14, 2016 at 10:41:04AM +0100, Paul B Mahol wrote:
> >
> > ok
>
> Pushed (last week). Thanks.
>
> Timothy
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Re: [FFmpeg-devel] [PATCH] vf_blend: Use integers for divide mode

2016-02-19 Thread Timothy Gu 
On Sun, Feb 14, 2016 at 10:41:04AM +0100, Paul B Mahol wrote:
> 
> ok

Pushed (last week). Thanks.

Timothy
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Re: [FFmpeg-devel] [PATCH] vf_blend: Use integers for divide mode

2016-02-14 Thread Paul B Mahol 
On 2/14/16, Timothy Gu  wrote:
> 2.5x faster for 8-bit mode without autovectorization in GCC, 2x
> slower with it on x86. However, since the platforms we enable GCC
> autovectorization on most probably has support for SSE2
> optimization (added in the subsequent commit), this commit should
> in general do good.
> ---
>  libavfilter/vf_blend.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/libavfilter/vf_blend.c b/libavfilter/vf_blend.c
> index 2b734b4..b9e5add 100644
> --- a/libavfilter/vf_blend.c
> +++ b/libavfilter/vf_blend.c
> @@ -240,7 +240,7 @@ DEFINE_BLEND8(hardlight,  (B < 128) ? MULTIPLY(2, B, A)
> : SCREEN(2, B, A))
>  DEFINE_BLEND8(hardmix,(A < (255 - B)) ? 0: 255)
>  DEFINE_BLEND8(darken, FFMIN(A, B))
>  DEFINE_BLEND8(lighten,FFMAX(A, B))
> -DEFINE_BLEND8(divide, av_clip_uint8(((float)A / ((float)B) * 255)))
> +DEFINE_BLEND8(divide, av_clip_uint8(B == 0 ? 255 : 255 * A / B))
>  DEFINE_BLEND8(dodge,  DODGE(A, B))
>  DEFINE_BLEND8(burn,   BURN(A, B))
>  DEFINE_BLEND8(softlight,  (A > 127) ? B + (255 - B) * (A - 127.5) / 127.5 *
> (0.5 - fabs(B - 127.5) / 255): B - B * ((127.5 - A) / 127.5) * (0.5 - fabs(B
> - 127.5)/255))
> @@ -280,7 +280,7 @@ DEFINE_BLEND16(hardlight,  (B < 32768) ? MULTIPLY(2, B,
> A) : SCREEN(2, B, A))
>  DEFINE_BLEND16(hardmix,(A < (65535 - B)) ? 0: 65535)
>  DEFINE_BLEND16(darken, FFMIN(A, B))
>  DEFINE_BLEND16(lighten,FFMAX(A, B))
> -DEFINE_BLEND16(divide, av_clip_uint16(((float)A / ((float)B) * 65535)))
> +DEFINE_BLEND16(divide, av_clip_uint16(B == 0 ? 65535 : 65535 * A / B))
>  DEFINE_BLEND16(dodge,  DODGE(A, B))
>  DEFINE_BLEND16(burn,   BURN(A, B))
>  DEFINE_BLEND16(softlight,  (A > 32767) ? B + (65535 - B) * (A - 32767.5) /
> 32767.5 * (0.5 - fabs(B - 32767.5) / 65535): B - B * ((32767.5 - A) /
> 32767.5) * (0.5 - fabs(B - 32767.5)/65535))
> --
> 2.1.4
>
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ok
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[FFmpeg-devel] [PATCH] vf_blend: Use integers for divide mode

2016-02-13 Thread Timothy Gu 
2.5x faster for 8-bit mode without autovectorization in GCC, 2x
slower with it on x86. However, since the platforms we enable GCC
autovectorization on most probably has support for SSE2
optimization (added in the subsequent commit), this commit should
in general do good.
---
 libavfilter/vf_blend.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavfilter/vf_blend.c b/libavfilter/vf_blend.c
index 2b734b4..b9e5add 100644
--- a/libavfilter/vf_blend.c
+++ b/libavfilter/vf_blend.c
@@ -240,7 +240,7 @@ DEFINE_BLEND8(hardlight,  (B < 128) ? MULTIPLY(2, B, A) : 
SCREEN(2, B, A))
 DEFINE_BLEND8(hardmix,(A < (255 - B)) ? 0: 255)
 DEFINE_BLEND8(darken, FFMIN(A, B))
 DEFINE_BLEND8(lighten,FFMAX(A, B))
-DEFINE_BLEND8(divide, av_clip_uint8(((float)A / ((float)B) * 255)))
+DEFINE_BLEND8(divide, av_clip_uint8(B == 0 ? 255 : 255 * A / B))
 DEFINE_BLEND8(dodge,  DODGE(A, B))
 DEFINE_BLEND8(burn,   BURN(A, B))
 DEFINE_BLEND8(softlight,  (A > 127) ? B + (255 - B) * (A - 127.5) / 127.5 * 
(0.5 - fabs(B - 127.5) / 255): B - B * ((127.5 - A) / 127.5) * (0.5 - fabs(B - 
127.5)/255))
@@ -280,7 +280,7 @@ DEFINE_BLEND16(hardlight,  (B < 32768) ? MULTIPLY(2, B, A) 
: SCREEN(2, B, A))
 DEFINE_BLEND16(hardmix,(A < (65535 - B)) ? 0: 65535)
 DEFINE_BLEND16(darken, FFMIN(A, B))
 DEFINE_BLEND16(lighten,FFMAX(A, B))
-DEFINE_BLEND16(divide, av_clip_uint16(((float)A / ((float)B) * 65535)))
+DEFINE_BLEND16(divide, av_clip_uint16(B == 0 ? 65535 : 65535 * A / B))
 DEFINE_BLEND16(dodge,  DODGE(A, B))
 DEFINE_BLEND16(burn,   BURN(A, B))
 DEFINE_BLEND16(softlight,  (A > 32767) ? B + (65535 - B) * (A - 32767.5) / 
32767.5 * (0.5 - fabs(B - 32767.5) / 65535): B - B * ((32767.5 - A) / 32767.5) 
* (0.5 - fabs(B - 32767.5)/65535))
-- 
2.1.4

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