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WebP-Lossless encoding improvements.

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Lossy (with Alpha) image compression gets 2.3X speedup.
Compressing lossless images is 20%-40% faster now.

Change-Id: I41f0225838b48ae5c60b1effd1b0de72fecb3ae6
This commit is contained in:
Vikas Arora
2013-05-08 17:19:04 -07:00
parent 4cb234d5b5
commit 8eae188a62
6 changed files with 159 additions and 94 deletions
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4
src/utils/filters.c
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@ -154,8 +154,7 @@ static void GradientUnfilter(int width, int height, int stride, uint8_t* data) {
#undef SANITY_CHECK
// -----------------------------------------------------------------------------
// Quick estimate of a potentially interesting filter mode to try, in addition
// to the default NONE.
// Quick estimate of a potentially interesting filter mode to try.
#define SMAX 16
#define SDIFF(a, b) (abs((a) - (b)) >> 4) // Scoring diff, in [0..SMAX)
@ -165,6 +164,7 @@ WEBP_FILTER_TYPE EstimateBestFilter(const uint8_t* data,
int i, j;
int bins[WEBP_FILTER_LAST][SMAX];
memset(bins, 0, sizeof(bins));
// We only sample every other pixels. That's enough.
for (j = 2; j < height - 1; j += 2) {
const uint8_t* const p = data + j * stride;