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enable sparse dc/ac transforms

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non-zero dc-bit was mixed with non-zero ac-bit, preventing
finer optimization during VP8ReconstructBlock.
Depending on sparsity, i see 2-5% gain on average.

Change-Id: I7f34f18d0701c77837de3540b732e5b7d85d7c5d
This commit is contained in:
Pascal Massimino 2011-03-14 12:27:12 -07:00
parent 07dbb8d5af
commit 4c0da7aad5
1 changed files with 14 additions and 11 deletions
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25
src/dec/vp8.c
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@ -386,7 +386,8 @@ static const uint8_t kZigzag[16] = {
typedef const uint8_t (*ProbaArray)[NUM_CTX][NUM_PROBAS]; // for const-casting typedef const uint8_t (*ProbaArray)[NUM_CTX][NUM_PROBAS]; // for const-casting
// Returns 1 if there's non-zero coeffs, 0 otherwise // Returns the position of the last non-zero coeff plus one
// (and 0 if there's no coeff at all)
static int GetCoeffs(VP8BitReader* const br, ProbaArray prob, static int GetCoeffs(VP8BitReader* const br, ProbaArray prob,
int ctx, const uint16_t dq[2], int n, int16_t* out) { int ctx, const uint16_t dq[2], int n, int16_t* out) {
const uint8_t* p = prob[kBands[n]][ctx]; const uint8_t* p = prob[kBands[n]][ctx];
@ -433,14 +434,13 @@ static int GetCoeffs(VP8BitReader* const br, ProbaArray prob,
j = kZigzag[n - 1]; j = kZigzag[n - 1];
out[j] = VP8GetSigned(br, v) * dq[j > 0]; out[j] = VP8GetSigned(br, v) * dq[j > 0];
if (n == 16 || !VP8GetBit(br, p[0])) { // EOB if (n == 16 || !VP8GetBit(br, p[0])) { // EOB
return 1; return n;
} }
} }
if (n == 16) { if (n == 16) {
return 1; return 16;
} }
} }
return 0;
} }
// Alias-safe way of converting 4bytes to 32bits. // Alias-safe way of converting 4bytes to 32bits.
@ -483,8 +483,8 @@ static void ParseResiduals(VP8Decoder* const dec,
int16_t dc[16] = { 0 }; int16_t dc[16] = { 0 };
const int ctx = mb->dc_nz_ + left_mb->dc_nz_; const int ctx = mb->dc_nz_ + left_mb->dc_nz_;
mb->dc_nz_ = left_mb->dc_nz_ = mb->dc_nz_ = left_mb->dc_nz_ =
GetCoeffs(token_br, (ProbaArray)dec->proba_.coeffs_[1], (GetCoeffs(token_br, (ProbaArray)dec->proba_.coeffs_[1],
ctx, q->y2_mat_, 0, dc); ctx, q->y2_mat_, 0, dc) > 0);
first = 1; first = 1;
ac_prob = (ProbaArray)dec->proba_.coeffs_[0]; ac_prob = (ProbaArray)dec->proba_.coeffs_[0];
VP8TransformWHT(dc, dst); VP8TransformWHT(dc, dst);
@ -499,10 +499,11 @@ static void ParseResiduals(VP8Decoder* const dec,
int l = lnz.i8[y]; int l = lnz.i8[y];
for (x = 0; x < 4; ++x) { for (x = 0; x < 4; ++x) {
const int ctx = l + tnz.i8[x]; const int ctx = l + tnz.i8[x];
l = GetCoeffs(token_br, ac_prob, ctx, const int nz = GetCoeffs(token_br, ac_prob, ctx,
q->y1_mat_, first, dst); q->y1_mat_, first, dst);
tnz.i8[x] = l = (nz > 0);
nz_dc.i8[x] = (dst[0] != 0); nz_dc.i8[x] = (dst[0] != 0);
nz_ac.i8[x] = tnz.i8[x] = l; nz_ac.i8[x] = (nz > 1);
dst += 16; dst += 16;
} }
lnz.i8[y] = l; lnz.i8[y] = l;
@ -519,10 +520,12 @@ static void ParseResiduals(VP8Decoder* const dec,
int l = lnz.i8[ch + y]; int l = lnz.i8[ch + y];
for (x = 0; x < 2; ++x) { for (x = 0; x < 2; ++x) {
const int ctx = l + tnz.i8[ch + x]; const int ctx = l + tnz.i8[ch + x];
l = GetCoeffs(token_br, (ProbaArray)dec->proba_.coeffs_[2], const int nz =
GetCoeffs(token_br, (ProbaArray)dec->proba_.coeffs_[2],
ctx, q->uv_mat_, 0, dst); ctx, q->uv_mat_, 0, dst);
tnz.i8[ch + x] = l = (nz > 0);
nz_dc.i8[y * 2 + x] = (dst[0] != 0); nz_dc.i8[y * 2 + x] = (dst[0] != 0);
nz_ac.i8[y * 2 + x] = tnz.i8[ch + x] = l; nz_ac.i8[y * 2 + x] = (nz > 1);
dst += 16; dst += 16;
} }
lnz.i8[ch + y] = l; lnz.i8[ch + y] = l;