Re: [FFmpeg-devel] [PATCH] swscale: Remove duplicated code
On Mon, Mar 25, 2019 at 12:36:24PM +0100, Hendrik Leppkes wrote: > On Mon, Mar 25, 2019 at 11:35 AM Lauri Kasanen wrote: > > > > On Mon, 25 Mar 2019 11:17:38 +0100 > > Michael Niedermayer wrote: > > > > > On Sun, Mar 24, 2019 at 01:04:51PM +0200, Lauri Kasanen wrote: > > > > In this function, the exact same clamping happens both in the if and > > > > unconditionally. > > > > > > > > Signed-off-by: Lauri Kasanen > > > > --- > > > > libswscale/output.c | 14 -- > > > > 1 file changed, 14 deletions(-) > > > > > > The removed code is the one that should stay, the other should be > > > removed. > > > one check for a rarely true condition should be faster than 4 checks > > > > Yes, I thought so too, but the commit that added the unconditional code > > says it fixes a bug... > > > > Could it overflow so high that other bits then the one being checked > for are set? in realistic cases this should not happen. It may be possible to construct a case with crafted scale parameters where this happens > Perhaps another bit pattern with more high bits set would > solve that. yes, actually i thought we did use a different pattern ... [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Observe your enemies, for they first find out your faults. -- Antisthenes signature.asc Description: PGP signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] swscale: Remove duplicated code
On Mon, Mar 25, 2019 at 12:37:37PM +0200, Lauri Kasanen wrote: > On Mon, 25 Mar 2019 11:17:38 +0100 > Michael Niedermayer wrote: > > > On Sun, Mar 24, 2019 at 01:04:51PM +0200, Lauri Kasanen wrote: > > > In this function, the exact same clamping happens both in the if and > > > unconditionally. > > > > > > Signed-off-by: Lauri Kasanen > > > --- > > > libswscale/output.c | 14 -- > > > 1 file changed, 14 deletions(-) > > > > The removed code is the one that should stay, the other should be > > removed. > > one check for a rarely true condition should be faster than 4 checks > > Yes, I thought so too, but the commit that added the unconditional code > says it fixes a bug... yes, but its parent did not had the other cliping code, it should have been a bugfix only as long as the other code wasnt there [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Those who are too smart to engage in politics are punished by being governed by those who are dumber. -- Plato signature.asc Description: PGP signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] swscale: Remove duplicated code
On Mon, Mar 25, 2019 at 11:35 AM Lauri Kasanen wrote: > > On Mon, 25 Mar 2019 11:17:38 +0100 > Michael Niedermayer wrote: > > > On Sun, Mar 24, 2019 at 01:04:51PM +0200, Lauri Kasanen wrote: > > > In this function, the exact same clamping happens both in the if and > > > unconditionally. > > > > > > Signed-off-by: Lauri Kasanen > > > --- > > > libswscale/output.c | 14 -- > > > 1 file changed, 14 deletions(-) > > > > The removed code is the one that should stay, the other should be > > removed. > > one check for a rarely true condition should be faster than 4 checks > > Yes, I thought so too, but the commit that added the unconditional code > says it fixes a bug... > Could it overflow so high that other bits then the one being checked for are set? Perhaps another bit pattern with more high bits set would solve that. - Hendrik ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] swscale: Remove duplicated code
On Mon, 25 Mar 2019 11:17:38 +0100 Michael Niedermayer wrote: > On Sun, Mar 24, 2019 at 01:04:51PM +0200, Lauri Kasanen wrote: > > In this function, the exact same clamping happens both in the if and > > unconditionally. > > > > Signed-off-by: Lauri Kasanen > > --- > > libswscale/output.c | 14 -- > > 1 file changed, 14 deletions(-) > > The removed code is the one that should stay, the other should be > removed. > one check for a rarely true condition should be faster than 4 checks Yes, I thought so too, but the commit that added the unconditional code says it fixes a bug... - Lauri ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH] swscale: Remove duplicated code
On Sun, Mar 24, 2019 at 01:04:51PM +0200, Lauri Kasanen wrote: > In this function, the exact same clamping happens both in the if and > unconditionally. > > Signed-off-by: Lauri Kasanen > --- > libswscale/output.c | 14 -- > 1 file changed, 14 deletions(-) The removed code is the one that should stay, the other should be removed. one check for a rarely true condition should be faster than 4 checks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB While the State exists there can be no freedom; when there is freedom there will be no State. -- Vladimir Lenin signature.asc Description: PGP signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
[FFmpeg-devel] [PATCH] swscale: Remove duplicated code
In this function, the exact same clamping happens both in the if and
unconditionally.
Signed-off-by: Lauri Kasanen
---
libswscale/output.c | 14 --
1 file changed, 14 deletions(-)
diff --git a/libswscale/output.c b/libswscale/output.c
index d7c53e6..8441ddd 100644
--- a/libswscale/output.c
+++ b/libswscale/output.c
@@ -846,13 +846,6 @@ yuv2422_1_c_template(SwsContext *c, const int16_t *buf0,
int U = (ubuf0[i] +64) >> 7;
int V = (vbuf0[i] +64) >> 7;
-if ((Y1 | Y2 | U | V) & 0x100) {
-Y1 = av_clip_uint8(Y1);
-Y2 = av_clip_uint8(Y2);
-U = av_clip_uint8(U);
-V = av_clip_uint8(V);
-}
-
Y1 = av_clip_uint8(Y1);
Y2 = av_clip_uint8(Y2);
U = av_clip_uint8(U);
@@ -868,13 +861,6 @@ yuv2422_1_c_template(SwsContext *c, const int16_t *buf0,
int U = (ubuf0[i] + ubuf1[i]+128) >> 8;
int V = (vbuf0[i] + vbuf1[i]+128) >> 8;
-if ((Y1 | Y2 | U | V) & 0x100) {
-Y1 = av_clip_uint8(Y1);
-Y2 = av_clip_uint8(Y2);
-U = av_clip_uint8(U);
-V = av_clip_uint8(V);
-}
-
Y1 = av_clip_uint8(Y1);
Y2 = av_clip_uint8(Y2);
U = av_clip_uint8(U);
--
2.6.2
___
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
