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Special-case sparse transform

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If the number of non-zero coeffs is <= 3, use a
simplified transform for luma.

Change-Id: I78a1252704228d21720d4bc1221252c84338d9c8
This commit is contained in:
skal 2013-10-08 22:05:38 +02:00
parent 00125196f3
commit f9bbc2a034
6 changed files with 159 additions and 72 deletions
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70
src/dec/frame.c
View File

@ -544,6 +544,34 @@ static void Copy32b(uint8_t* dst, uint8_t* src) {
memcpy(dst, src, 4);
}
static void DoTransform(uint32_t bits, const int16_t* const src,
uint8_t* const dst) {
switch (bits >> 30) {
case 3:
VP8Transform(src, dst, 0);
break;
case 2:
VP8TransformAC3(src, dst);
break;
case 1:
VP8TransformDC(src, dst);
break;
default:
break;
}
}
static void DoUVTransform(uint32_t bits, const int16_t* const src,
uint8_t* const dst) {
if (bits & 0xff) { // any non-zero coeff at all?
if (bits & 0xaa) { // any non-zero AC coefficient?
VP8TransformUV(src, dst); // note we don't use the AC3 variant for U/V
} else {
VP8TransformDCUV(src, dst);
}
}
}
void VP8ReconstructBlock(const VP8Decoder* const dec) {
int j;
uint8_t* const y_dst = dec->yuv_b_ + Y_OFF;
@ -578,6 +606,7 @@ void VP8ReconstructBlock(const VP8Decoder* const dec) {
// bring top samples into the cache
VP8TopSamples* const top_yuv = dec->yuv_t_ + dec->mb_x_;
const int16_t* const coeffs = block->coeffs_;
uint32_t bits = block->non_zero_y_;
int n;
if (dec->mb_y_ > 0) {
@ -595,7 +624,6 @@ void VP8ReconstructBlock(const VP8Decoder* const dec) {
// predict and add residuals
if (block->is_i4x4_) { // 4x4
uint32_t* const top_right = (uint32_t*)(y_dst - BPS + 16);
uint32_t bits = (block->non_zero_ & 0xffff) | (block->non_zero_ac_ << 16);
if (dec->mb_y_ > 0) {
if (dec->mb_x_ >= dec->mb_w_ - 1) { // on rightmost border
@ -608,53 +636,29 @@ void VP8ReconstructBlock(const VP8Decoder* const dec) {
top_right[BPS] = top_right[2 * BPS] = top_right[3 * BPS] = top_right[0];
// predict and add residuals for all 4x4 blocks in turn.
for (n = 0; n < 16; ++n, bits <<= 1) {
for (n = 0; n < 16; ++n, bits <<= 2) {
uint8_t* const dst = y_dst + kScan[n];
VP8PredLuma4[block->imodes_[n]](dst);
if (bits & (1UL << 31)) {
VP8Transform(coeffs + n * 16, dst, 0);
} else if (bits & (1UL << 15)) { // only DC is present
VP8TransformDC(coeffs + n * 16, dst);
}
DoTransform(bits, coeffs + n * 16, dst);
}
} else { // 16x16
const int pred_func = CheckMode(dec->mb_x_, dec->mb_y_,
block->imodes_[0]);
uint32_t bits = (block->non_zero_ & 0xffff) | (block->non_zero_ac_ << 16);
VP8PredLuma16[pred_func](y_dst);
if (bits & 0xffff) {
for (n = 0; n < 16; ++n, bits <<= 1) {
uint8_t* const dst = y_dst + kScan[n];
if (bits & (1UL << 31)) {
VP8Transform(coeffs + n * 16, dst, 0);
} else if (bits & (1UL << 15)) { // only DC is present
VP8TransformDC(coeffs + n * 16, dst);
}
if (bits != 0) {
for (n = 0; n < 16; ++n, bits <<= 2) {
DoTransform(bits, coeffs + n * 16, y_dst + kScan[n]);
}
}
}
{
// Chroma
const uint32_t bits_uv = block->non_zero_uv_;
const int pred_func = CheckMode(dec->mb_x_, dec->mb_y_, block->uvmode_);
VP8PredChroma8[pred_func](u_dst);
VP8PredChroma8[pred_func](v_dst);
if (block->non_zero_ & 0x0f0000) { // chroma-U
const int16_t* const u_coeffs = coeffs + 16 * 16;
if (block->non_zero_ac_ & 0x0f0000) {
VP8TransformUV(u_coeffs, u_dst);
} else {
VP8TransformDCUV(u_coeffs, u_dst);
}
}
if (block->non_zero_ & 0xf00000) { // chroma-V
const int16_t* const v_coeffs = coeffs + 20 * 16;
if (block->non_zero_ac_ & 0xf00000) {
VP8TransformUV(v_coeffs, v_dst);
} else {
VP8TransformDCUV(v_coeffs, v_dst);
}
}
DoUVTransform(bits_uv >> 0, coeffs + 16 * 16, u_dst);
DoUVTransform(bits_uv >> 8, coeffs + 20 * 16, v_dst);
}
// stash away top samples for next block

36
src/dec/vp8.c
View File

@ -509,8 +509,8 @@ static int ParseResiduals(VP8Decoder* const dec,
int16_t* dst = block->coeffs_;
VP8MB* const left_mb = dec->mb_info_ - 1;
uint8_t tnz, lnz;
uint32_t non_zero_ac = 0;
uint32_t non_zero_dc = 0;
uint32_t non_zero_y = 0;
uint32_t non_zero_uv = 0;
int x, y, ch;
uint32_t out_t_nz, out_l_nz;
int first;
@ -539,26 +539,27 @@ static int ParseResiduals(VP8Decoder* const dec,
lnz = left_mb->nz_ & 0x0f;
for (y = 0; y < 4; ++y) {
int l = lnz & 1;
uint32_t nz_dc = 0, nz_ac = 0;
uint32_t nz_coeffs = 0;
for (x = 0; x < 4; ++x) {
const int ctx = l + (tnz & 1);
const int nz = GetCoeffs(token_br, ac_proba, ctx, q->y1_mat_, first, dst);
l = (nz > first);
tnz = (tnz >> 1) | (l << 7);
nz_dc = (nz_dc << 1) | (dst[0] != 0);
nz_ac = (nz_ac << 1) | (nz > 1);
nz_coeffs <<= 2;
if (nz > 3) nz_coeffs |= 3;
else if (nz > 1) nz_coeffs |= 2;
else if (dst[0] != 0) nz_coeffs |= 1;
dst += 16;
}
tnz >>= 4;
lnz = (lnz >> 1) | (l << 7);
non_zero_dc = (non_zero_dc << 4) | nz_dc;
non_zero_ac = (non_zero_ac << 4) | nz_ac;
non_zero_y = (non_zero_y << 8) | nz_coeffs;
}
out_t_nz = tnz;
out_l_nz = lnz >> 4;
for (ch = 0; ch < 4; ch += 2) {
uint32_t nz_dc = 0, nz_ac = 0;
uint32_t nz_coeffs = 0;
tnz = mb->nz_ >> (4 + ch);
lnz = left_mb->nz_ >> (4 + ch);
for (y = 0; y < 2; ++y) {
@ -568,25 +569,26 @@ static int ParseResiduals(VP8Decoder* const dec,
const int nz = GetCoeffs(token_br, bands[2], ctx, q->uv_mat_, 0, dst);
l = (nz > 0);
tnz = (tnz >> 1) | (l << 3);
nz_dc = (nz_dc << 1) | (dst[0] != 0);
nz_ac = (nz_ac << 1) | (nz > 1);
nz_coeffs <<= 2;
if (nz > 3) nz_coeffs |= 3;
else if (nz > 1) nz_coeffs |= 2;
else if (dst[0] != 0) nz_coeffs |= 1;
dst += 16;
}
tnz >>= 2;
lnz = (lnz >> 1) | (l << 5);
}
// Note: we don't really need the per-4x4 details for U/V blocks.
non_zero_dc |= (nz_dc & 0x0f) << (16 + 2 * ch);
non_zero_ac |= (nz_ac & 0x0f) << (16 + 2 * ch);
non_zero_uv |= nz_coeffs << (4 * ch);
out_t_nz |= (tnz << 4) << ch;
out_l_nz |= (lnz & 0xf0) << ch;
}
mb->nz_ = out_t_nz;
left_mb->nz_ = out_l_nz;
block->non_zero_ac_ = non_zero_ac;
block->non_zero_ = non_zero_ac | non_zero_dc;
return !block->non_zero_; // will be used for further optimization
block->non_zero_y_ = non_zero_y;
block->non_zero_uv_ = non_zero_uv;
return !(non_zero_y | non_zero_uv); // will be used for further optimization
}
//------------------------------------------------------------------------------
@ -621,8 +623,8 @@ int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br) {
if (!block->is_i4x4_) {
left->nz_dc_ = mb->nz_dc_ = 0;
}
block->non_zero_ = 0;
block->non_zero_ac_ = 0;
block->non_zero_y_ = 0;
block->non_zero_uv_ = 0;
}
if (dec->filter_type_ > 0) { // store filter info

15
src/dec/vp8i.h
View File

@ -184,12 +184,15 @@ typedef struct {
uint8_t is_i4x4_; // true if intra4x4
uint8_t imodes_[16]; // one 16x16 mode (#0) or sixteen 4x4 modes
uint8_t uvmode_; // chroma prediction mode
// bit-wise info about the content of each sub-4x4 blocks: there are 16 bits
// for luma (bits #15->#0), then 4 bits for chroma-u (#19->#16) and 4 bits for
// chroma-v (#23->#20), each corresponding to one 4x4 block in decoding order.
// If the bit is set, the 4x4 block contains some non-zero coefficients.
uint32_t non_zero_;
uint32_t non_zero_ac_;
// bit-wise info about the content of each sub-4x4 blocks (in decoding order).
// Each of the 4x4 blocks for y/u/v is associated with a 2b code according to:
// code=0 -> no coefficient
// code=1 -> only DC
// code=2 -> first three coefficients are non-zero
// code=3 -> more than three coefficients are non-zero
// This allows to call specialized transform functions.
uint32_t non_zero_y_;
uint32_t non_zero_uv_;
} VP8MBData;
// Persistent information needed by the parallel processing

24
src/dsp/dec.c
View File

@ -61,6 +61,14 @@ static WEBP_INLINE uint8_t clip_8b(int v) {
#define STORE(x, y, v) \
dst[x + y * BPS] = clip_8b(dst[x + y * BPS] + ((v) >> 3))
#define STORE2(y, dc, d, c) do { \
const int DC = (dc); \
STORE(0, y, DC + (d)); \
STORE(1, y, DC + (c)); \
STORE(2, y, DC - (c)); \
STORE(3, y, DC - (d)); \
} while (0)
static const int kC1 = 20091 + (1 << 16);
static const int kC2 = 35468;
#define MUL(a, b) (((a) * (b)) >> 16)
@ -103,7 +111,21 @@ static void TransformOne(const int16_t* in, uint8_t* dst) {
dst += BPS;
}
}
// Simplified transform when only in[0], in[1] and in[4] are non-zero
static void TransformAC3(const int16_t* in, uint8_t* dst) {
const int a = in[0] + 4;
const int c4 = MUL(in[4], kC2);
const int d4 = MUL(in[4], kC1);
const int c1 = MUL(in[1], kC2);
const int d1 = MUL(in[1], kC1);
STORE2(0, a + d4, d1, c1);
STORE2(1, a + c4, d1, c1);
STORE2(2, a - c4, d1, c1);
STORE2(3, a - d4, d1, c1);
}
#undef MUL
#undef STORE2
static void TransformTwo(const int16_t* in, uint8_t* dst, int do_two) {
TransformOne(in, dst);
@ -679,6 +701,7 @@ static void HFilter8i(uint8_t* u, uint8_t* v, int stride,
//------------------------------------------------------------------------------
VP8DecIdct2 VP8Transform;
VP8DecIdct VP8TransformAC3;
VP8DecIdct VP8TransformUV;
VP8DecIdct VP8TransformDC;
VP8DecIdct VP8TransformDCUV;
@ -706,6 +729,7 @@ void VP8DspInit(void) {
VP8TransformUV = TransformUV;
VP8TransformDC = TransformDC;
VP8TransformDCUV = TransformDCUV;
VP8TransformAC3 = TransformAC3;
VP8VFilter16 = VFilter16;
VP8HFilter16 = HFilter16;

85
src/dsp/dec_sse2.c
View File

@ -20,6 +20,10 @@ extern "C" {
#if defined(WEBP_USE_SSE2)
// The 3-coeff sparse transform in SSE2 is not really faster than the plain-C
// one it seems => disable it by default. Uncomment the following to enable:
// #define USE_TRANSFORM_AC3
#include <emmintrin.h>
#include "../dec/vp8i.h"
@ -201,16 +205,16 @@ static void TransformSSE2(const int16_t* in, uint8_t* dst, int do_two) {
__m128i dst0, dst1, dst2, dst3;
if (do_two) {
// Load eight bytes/pixels per line.
dst0 = _mm_loadl_epi64((__m128i*)&dst[0 * BPS]);
dst1 = _mm_loadl_epi64((__m128i*)&dst[1 * BPS]);
dst2 = _mm_loadl_epi64((__m128i*)&dst[2 * BPS]);
dst3 = _mm_loadl_epi64((__m128i*)&dst[3 * BPS]);
dst0 = _mm_loadl_epi64((__m128i*)(dst + 0 * BPS));
dst1 = _mm_loadl_epi64((__m128i*)(dst + 1 * BPS));
dst2 = _mm_loadl_epi64((__m128i*)(dst + 2 * BPS));
dst3 = _mm_loadl_epi64((__m128i*)(dst + 3 * BPS));
} else {
// Load four bytes/pixels per line.
dst0 = _mm_cvtsi32_si128(*(int*)&dst[0 * BPS]);
dst1 = _mm_cvtsi32_si128(*(int*)&dst[1 * BPS]);
dst2 = _mm_cvtsi32_si128(*(int*)&dst[2 * BPS]);
dst3 = _mm_cvtsi32_si128(*(int*)&dst[3 * BPS]);
dst0 = _mm_cvtsi32_si128(*(int*)(dst + 0 * BPS));
dst1 = _mm_cvtsi32_si128(*(int*)(dst + 1 * BPS));
dst2 = _mm_cvtsi32_si128(*(int*)(dst + 2 * BPS));
dst3 = _mm_cvtsi32_si128(*(int*)(dst + 3 * BPS));
}
// Convert to 16b.
dst0 = _mm_unpacklo_epi8(dst0, zero);
@ -230,20 +234,66 @@ static void TransformSSE2(const int16_t* in, uint8_t* dst, int do_two) {
// Store the results.
if (do_two) {
// Store eight bytes/pixels per line.
_mm_storel_epi64((__m128i*)&dst[0 * BPS], dst0);
_mm_storel_epi64((__m128i*)&dst[1 * BPS], dst1);
_mm_storel_epi64((__m128i*)&dst[2 * BPS], dst2);
_mm_storel_epi64((__m128i*)&dst[3 * BPS], dst3);
_mm_storel_epi64((__m128i*)(dst + 0 * BPS), dst0);
_mm_storel_epi64((__m128i*)(dst + 1 * BPS), dst1);
_mm_storel_epi64((__m128i*)(dst + 2 * BPS), dst2);
_mm_storel_epi64((__m128i*)(dst + 3 * BPS), dst3);
} else {
// Store four bytes/pixels per line.
*((int32_t *)&dst[0 * BPS]) = _mm_cvtsi128_si32(dst0);
*((int32_t *)&dst[1 * BPS]) = _mm_cvtsi128_si32(dst1);
*((int32_t *)&dst[2 * BPS]) = _mm_cvtsi128_si32(dst2);
*((int32_t *)&dst[3 * BPS]) = _mm_cvtsi128_si32(dst3);
*(int*)(dst + 0 * BPS) = _mm_cvtsi128_si32(dst0);
*(int*)(dst + 1 * BPS) = _mm_cvtsi128_si32(dst1);
*(int*)(dst + 2 * BPS) = _mm_cvtsi128_si32(dst2);
*(int*)(dst + 3 * BPS) = _mm_cvtsi128_si32(dst3);
}
}
}
#if defined(USE_TRANSFORM_AC3)
#define MUL(a, b) (((a) * (b)) >> 16)
static void TransformAC3SSE2(const int16_t* in, uint8_t* dst) {
static const int kC1 = 20091 + (1 << 16);
static const int kC2 = 35468;
const __m128i A = _mm_set1_epi16(in[0] + 4);
const __m128i c4 = _mm_set1_epi16(MUL(in[4], kC2));
const __m128i d4 = _mm_set1_epi16(MUL(in[4], kC1));
const int c1 = MUL(in[1], kC2);
const int d1 = MUL(in[1], kC1);
const __m128i CD = _mm_set_epi16(0, 0, 0, 0, -d1, -c1, c1, d1);
const __m128i B = _mm_adds_epi16(A, CD);
const __m128i m0 = _mm_adds_epi16(B, d4);
const __m128i m1 = _mm_adds_epi16(B, c4);
const __m128i m2 = _mm_subs_epi16(B, c4);
const __m128i m3 = _mm_subs_epi16(B, d4);
const __m128i zero = _mm_setzero_si128();
// Load the source pixels.
__m128i dst0 = _mm_cvtsi32_si128(*(int*)(dst + 0 * BPS));
__m128i dst1 = _mm_cvtsi32_si128(*(int*)(dst + 1 * BPS));
__m128i dst2 = _mm_cvtsi32_si128(*(int*)(dst + 2 * BPS));
__m128i dst3 = _mm_cvtsi32_si128(*(int*)(dst + 3 * BPS));
// Convert to 16b.
dst0 = _mm_unpacklo_epi8(dst0, zero);
dst1 = _mm_unpacklo_epi8(dst1, zero);
dst2 = _mm_unpacklo_epi8(dst2, zero);
dst3 = _mm_unpacklo_epi8(dst3, zero);
// Add the inverse transform.
dst0 = _mm_adds_epi16(dst0, _mm_srai_epi16(m0, 3));
dst1 = _mm_adds_epi16(dst1, _mm_srai_epi16(m1, 3));
dst2 = _mm_adds_epi16(dst2, _mm_srai_epi16(m2, 3));
dst3 = _mm_adds_epi16(dst3, _mm_srai_epi16(m3, 3));
// Unsigned saturate to 8b.
dst0 = _mm_packus_epi16(dst0, dst0);
dst1 = _mm_packus_epi16(dst1, dst1);
dst2 = _mm_packus_epi16(dst2, dst2);
dst3 = _mm_packus_epi16(dst3, dst3);
// Store the results.
*(int*)(dst + 0 * BPS) = _mm_cvtsi128_si32(dst0);
*(int*)(dst + 1 * BPS) = _mm_cvtsi128_si32(dst1);
*(int*)(dst + 2 * BPS) = _mm_cvtsi128_si32(dst2);
*(int*)(dst + 3 * BPS) = _mm_cvtsi128_si32(dst3);
}
#undef MUL
#endif // USE_TRANSFORM_AC3
//------------------------------------------------------------------------------
// Loop Filter (Paragraph 15)
@ -888,6 +938,9 @@ extern void VP8DspInitSSE2(void);
void VP8DspInitSSE2(void) {
#if defined(WEBP_USE_SSE2)
VP8Transform = TransformSSE2;
#if defined(USE_TRANSFORM_AC3)
VP8TransformAC3 = TransformAC3SSE2;
#endif
VP8VFilter16 = VFilter16SSE2;
VP8HFilter16 = HFilter16SSE2;

1
src/dsp/dsp.h
View File

@ -103,6 +103,7 @@ typedef void (*VP8DecIdct)(const int16_t* coeffs, uint8_t* dst);
// when doing two transforms, coeffs is actually int16_t[2][16].
typedef void (*VP8DecIdct2)(const int16_t* coeffs, uint8_t* dst, int do_two);
extern VP8DecIdct2 VP8Transform;
extern VP8DecIdct VP8TransformAC3;
extern VP8DecIdct VP8TransformUV;
extern VP8DecIdct VP8TransformDC;
extern VP8DecIdct VP8TransformDCUV;