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SSE2 version of GradientUnfilter

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somewhat 1-2% faster decoder for lossy+alpha

Change-Id: Ib317e26e9fcb8d37af02668ffbfccc4664e659fe
This commit is contained in:
Pascal Massimino 2015-01-31 23:16:10 +01:00
parent 72831f6b28
commit 77724f70e9
1 changed files with 45 additions and 15 deletions
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60
src/dsp/filters_sse2.c
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@ -36,6 +36,7 @@ static void PredictLineTop(const uint8_t* src, const uint8_t* pred,
uint8_t* dst, int length, int inverse) {
int i;
const int max_pos = length & ~31;
assert(length >= 0);
if (inverse) {
for (i = 0; i < max_pos; i += 32) {
const __m128i A0 = _mm_loadu_si128((const __m128i*)&src[i + 0]);
@ -67,10 +68,10 @@ static void PredictLineTop(const uint8_t* src, const uint8_t* pred,
static void PredictLineLeft(const uint8_t* src, uint8_t* dst, int length,
int inverse) {
int i;
if (length <= 0) return;
if (inverse) {
const int max_pos = length & ~7;
__m128i last =
_mm_set_epi8(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, dst[-1]);
__m128i last = _mm_set_epi32(0, 0, 0, dst[-1]);
for (i = 0; i < max_pos; i += 8) {
const __m128i A0 = _mm_loadl_epi64((const __m128i*)(src + i));
const __m128i A1 = _mm_add_epi8(A0, last);
@ -218,45 +219,74 @@ static void GradientPredictDirect(const uint8_t* const row,
}
}
static void GradientPredictInverse(const uint8_t* const in,
const uint8_t* const top,
uint8_t* const row, int length) {
if (length > 0) {
int i;
const int max_pos = length & ~7;
const __m128i zero = _mm_setzero_si128();
__m128i A = _mm_set_epi32(0, 0, 0, row[-1]); // left sample
for (i = 0; i < max_pos; i += 8) {
const __m128i tmp0 = _mm_loadl_epi64((const __m128i*)&top[i]);
const __m128i tmp1 = _mm_loadl_epi64((const __m128i*)&top[i - 1]);
const __m128i B = _mm_unpacklo_epi8(tmp0, zero);
const __m128i C = _mm_unpacklo_epi8(tmp1, zero);
const __m128i tmp2 = _mm_loadl_epi64((const __m128i*)&in[i]);
const __m128i D = _mm_unpacklo_epi8(tmp2, zero); // base input
const __m128i E = _mm_sub_epi16(B, C); // unclipped gradient basis B - C
__m128i out = zero; // accumulator for output
__m128i mask_hi = _mm_set_epi32(0, 0, 0, 0xff);
int k = 8;
while (1) {
const __m128i tmp3 = _mm_add_epi16(A, E); // delta = A + B - C
const __m128i tmp4 = _mm_min_epi16(tmp3, mask_hi);
const __m128i tmp5 = _mm_max_epi16(tmp4, zero); // clipped delta
const __m128i tmp6 = _mm_add_epi16(tmp5, D); // add to in[] values
A = _mm_and_si128(tmp6, mask_hi); // 1-complement clip
out = _mm_or_si128(out, A); // accumulate output
if (--k == 0) break;
A = _mm_slli_si128(A, 2); // rotate left sample
mask_hi = _mm_slli_si128(mask_hi, 2); // rotate mask
}
A = _mm_srli_si128(A, 14); // prepare left sample for next iteration
_mm_storel_epi64((__m128i*)&row[i], _mm_packus_epi16(out, zero));
}
for (; i < length; ++i) {
row[i] = in[i] + GradientPredictorC(row[i - 1], top[i], top[i - 1]);
}
}
}
static WEBP_INLINE void DoGradientFilter(const uint8_t* in,
int width, int height, int stride,
int row, int num_rows,
int inverse, uint8_t* out) {
const uint8_t* preds;
const size_t start_offset = row * stride;
const int last_row = row + num_rows;
SANITY_CHECK(in, out);
in += start_offset;
out += start_offset;
preds = inverse ? out : in;
// left prediction for top scan-line
if (row == 0) {
out[0] = in[0];
PredictLineLeft(in + 1, out + 1, width - 1, inverse);
row = 1;
preds += stride;
in += stride;
out += stride;
}
// Filter line-by-line.
while (row < last_row) {
int w;
// leftmost pixel: predict from above.
PredictLineC(in, preds - stride, out, 1, inverse);
if (inverse) {
for (w = 1; w < width; ++w) {
const int pred = GradientPredictorC(out[w - 1],
out[w - stride],
out[w - stride - 1]);
out[w] = in[w] + pred;
}
PredictLineC(in, out - stride, out, 1, inverse); // predict from above
GradientPredictInverse(in + 1, out + 1 - stride, out + 1, width - 1);
} else {
PredictLineC(in, in - stride, out, 1, inverse);
GradientPredictDirect(in + 1, in + 1 - stride, out + 1, width - 1);
}
++row;
preds += stride;
in += stride;
out += stride;
}