dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2025-07-18 23:09:52 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

Special-case sparse transform

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

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