On 15/10/2024 21:23, Frank Plowman wrote: > On 14/10/2024 23:26, Michael Niedermayer wrote: >> On Sat, Oct 05, 2024 at 03:38:05PM -0700, Frank Plowman wrote: >>> The first branch of this ternary expression was intended to avoid >>> having two shift operations in the case the RHS is not known at >>> compile time. It only works if the LHS has a signed type however, >>> otherwise the result is invalid. >> >> If the expression is faster, why not check if its signed ? >> >> if its not faster, then the argument could be that its not >> faster and removes complexity >> >> thx >> > > In a quick microbenchmark (clang 16, AArch64), the bithack is 10% faster > with -O0 but there is no significant difference with -O1 and up.
It has been drawn to my attention that this is causing a failure for VVC_HDR_UHDTV1_OpenGOP_3840x2160_50fps_HLG10_mosaic from the DVB VVC test suite, due to the macro's use at libavcodec/cbs_h266_syntax_template.c:1206 In light of the lack of performance difference between the two implementations and the simplicity of the proposed change, I think the bithack should be removed. Cheers, -- Frank _______________________________________________ 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".
