In the variance calculations the difference is summed and later squared.
When the sum exceeds sqrt(2^31) the value is treated as a negative when
it is shifted which gives incorrect results.
To fix this we cast the result of the multiplication as unsigned.
The alternative fix is to shift sum down by 4 before multiplying.
However that will reduce precision.
For 16x16 blocks the maximum sum is 65280 and sqrt(2^31) is 46340 (and
change).
PPC change is untested.
Change-Id: I1bad27ea0720067def6d71a6da5f789508cec265
Storing vp8_bilinear_filters_mmx in an mmx file and using it in an sse2
file is bad
Moving towards allowing --disable-mmx
Change-Id: I20493b35bdedcdcfc0915e6f05fdbe6c81a4a742
The encoder defined about 4 set of similar functions to calculate sum,
variance or sse or a combination of them. This commit removed one set
of these functions, get8x8var and get16x16var, where calls to the later
function are replaced with var16x16 by using the fact on a 16x16 MB:
variance == sse - sum*sum/256
Change-Id: I803eabd1fb3ab177780a40338cbd596dffaed267
This declaration did not match the prototype_sad() prototype, but was
unused in this translation unit, so it is removed instead. Fixes
issue 290.
Change-Id: I168854f88a85f73ca9aaf61d1e5dc0f43fc3fdb3
A large number of functions were defined with external linkage, even
though they were only used from within one file. This patch changes
their linkage to static and removes the vp8_ prefix from their names,
which should make it more obvious to the reader that the function is
contained within the current translation unit. Functions that were
not referenced were removed.
These symbols were identified by:
$ nm -A libvpx.a | sort -k3 | uniq -c -f2 | grep ' [A-Z] ' \
| sort | grep '^ *1 '
Change-Id: I59609f58ab65312012c047036ae1e0634f795779
This patch fixes the system dependent entries for the half-pixel
variance functions in both the RTCD and non-RTCD cases:
- The generic C versions of these functions are now correct.
Before all three cases called the hv code.
- Wire up the ARM functions in RTCD mode
- Created stubs for x86 to call the optimized subpixel functions
with the correct parameters, rather than falling back to C
code.
Change-Id: I1d937d074d929e0eb93aacb1232cc5e0ad1c6184
These functions should never change their input, and there's no
reason not to declare that.
This allows them to be passed static const data.
Change-Id: Ia49fe4b01e80e9afcb24b4844817694d4da5995c
Changes 'The VP8 project' to 'The WebM project', for consistency
with other webmproject.org repositories.
Fixes issue #97.
Change-Id: I37c13ed5fbdb9d334ceef71c6350e9febed9bbba
When the license headers were updated, they accidentally contained
trailing whitespace, so unfortunately we have to touch all the files
again.
Change-Id: I236c05fade06589e417179c0444cb39b09e4200d
