On Fri, Feb 09, 2018 at 02:03:24AM +0900, Nekopanda wrote: > - Fix field selection for skipped macroblocks > > For B field pictures, the spec says, > > > The prediction shall be made from the field of the same parity as the field > > being predicted. > > I did it. > > - Fix motion vector rounding for chroma components > > In 16x8 motion compensation, for lower 16x8 region, the input to > mpeg_motion() for motion_y was "motion_y + 16", which causes wrong rounding. > For 4:2:0, chroma scaling for y is dividing by two and rounding toward zero. > When motion_y < 0 and motion_y + 16 > 0, the rounding direction of "motion_y" > and "motion_y + 16" is different and rounding "motion_y + 16" would be > incorrect. > > We should input "motion_y" as is to round correctly. I add "is_16x8" flag to > do that. > --- > libavcodec/mpeg12dec.c | 2 ++ > libavcodec/mpegvideo_motion.c | 30 ++++++++++++++++-------------- > 2 files changed, 18 insertions(+), 14 deletions(-)
How did you find this bug ? do you have a testcase / file which shows artifacts without this change ? assuming the change is correct then the patch needs to update several fate checksums. As is it would break make fate thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB "Nothing to hide" only works if the folks in power share the values of you and everyone you know entirely and always will -- Tom Scott
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