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| author | Clément Bœsch <ubitux@gmail.com> | 2012-12-07 00:36:29 +0100 |
|---|---|---|
| committer | Anton Khirnov <anton@khirnov.net> | 2013-03-28 07:59:04 +0100 |
| commit | 2d66fc543b01995d6146fc132a778d3e722ca665 (patch) | |
| tree | 22aadf11effb0a211c7f10461baf1fa238ba4da3 /libavfilter/x86 | |
| parent | 8b9a153ef3673d5847291987fa0dcddeac4a640b (diff) | |
| download | ffmpeg-2d66fc543b01995d6146fc132a778d3e722ca665.tar.gz | |
lavfi/gradfun: fix rounding in MMX code.
Current code divides before increasing precision.
Also reduce upper bound for strength from 255 to 64. This will prevent
an overflow in the SSSE3 and MMX filter_line code: delta is expressed as
an u16 being shifted by 2 to the left. If it overflows, having a
strength not above 64 will make sure that m is set to 0 (making the
m*m*delta >> 14 expression void).
A value above 64 should not make any sense unless gradfun is used as
a blur filter.
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Diffstat (limited to 'libavfilter/x86')
| -rw-r--r-- | libavfilter/x86/vf_gradfun.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/libavfilter/x86/vf_gradfun.c b/libavfilter/x86/vf_gradfun.c index b4ca86c617..75c117a9a2 100644 --- a/libavfilter/x86/vf_gradfun.c +++ b/libavfilter/x86/vf_gradfun.c @@ -62,8 +62,8 @@ static void gradfun_filter_line_mmxext(uint8_t *dst, uint8_t *src, uint16_t *dc, "pminsw %%mm7, %%mm2 \n" // m = -max(0, 127-m) "pmullw %%mm2, %%mm2 \n" "paddw %%mm4, %%mm0 \n" // pix += dither - "pmulhw %%mm2, %%mm1 \n" "psllw $2, %%mm1 \n" // m = m*m*delta >> 14 + "pmulhw %%mm2, %%mm1 \n" "paddw %%mm1, %%mm0 \n" // pix += m "psraw $7, %%mm0 \n" "packuswb %%mm0, %%mm0 \n" |