In subpel_avg_variance functions, code similar to the following
punpkldq m2, [addr]
actually reads 8 bytes. For functions that are supposed to work on
buffers only have less 8 bytes a line, this caused valgrind error
of reading uninitialized memory.
Change-Id: I2a4c079dbdbc747829bd9e2ed85f0018ad2a3a34
Encoding of bus @ 1500kbps (first 50 frames) goes from 3min57 to
3min35, i.e. approximately a 10.5% speedup. Note that the SIMD versions
which use a bilinear filter (x_offset & 7 || y_offset & 7) aren't
perfectly interleaved, and can probably be improved further in the
future. I've marked this with a few TODOs/FIXMEs in the code.
Change-Id: I5c9e900c0f0d32e431a50fecae213b510b2549f9
