Hi there, latly i realised a compile error in the arm code of synth_filter_neon.S. For AARCH64 the syntax of the BIC opcode is a bit different if i read the docs correct. For AARCH64 and 64bit GP Registers the syntax is BIC Xd, Xn, Xm{, shift #amount} ; 64-bit general registers Indeed i get a compile error when using xcode6.2 :32:21: error: invalid operand for instruction bic x7, x7,#63 <https://github.com/FFmpeg/FFmpeg/pull/63> Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn) Target: x86_64-apple-darwin13.4.0 Thread model: posix It seems to compile fine on Xcode7 and its clang but i have no clue why ... Working syntax would be: bic x7, x7, x7, lsl#63 <https://github.com/FFmpeg/FFmpeg/pull/63> Not sure if the semantics are still correct. I have not the slightest clue of arm assembler i have to admit. Sorry couldn't reply to the commit which introduced this because i wasn't subscribed to the list at that time. For further reference i also commented on your github mirror about that already (and wonder why Janne Grunau doesn't get those emails from github...): https://github.com/FFmpeg/FFmpeg/commit/705f5e5e155f6f280a360af220fc5b30cfce... Any comment would be great. Kind Regards Memphiz