libwebp/src/enc/iterator_enc.c
Pascal Massimino 96bf07c560 use DC error diffusion for U/V at low-quality
This fixes some color smearing due to heavy quantization.
This is only enabled for q <= 30 (cf ERROR_DIFFUSION_QUALITY)

Change-Id: I07e83a4d38461357a32c9e214f7eadc6db73baa9
2017-12-11 06:37:40 -08:00

460 lines
14 KiB
C

// Copyright 2011 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// VP8Iterator: block iterator
//
// Author: Skal (pascal.massimino@gmail.com)
#include <string.h>
#include "src/enc/vp8i_enc.h"
//------------------------------------------------------------------------------
// VP8Iterator
//------------------------------------------------------------------------------
static void InitLeft(VP8EncIterator* const it) {
it->y_left_[-1] = it->u_left_[-1] = it->v_left_[-1] =
(it->y_ > 0) ? 129 : 127;
memset(it->y_left_, 129, 16);
memset(it->u_left_, 129, 8);
memset(it->v_left_, 129, 8);
it->left_nz_[8] = 0;
if (it->top_derr_ != NULL) {
memset(&it->left_derr_, 0, sizeof(it->left_derr_));
}
}
static void InitTop(VP8EncIterator* const it) {
const VP8Encoder* const enc = it->enc_;
const size_t top_size = enc->mb_w_ * 16;
memset(enc->y_top_, 127, 2 * top_size);
memset(enc->nz_, 0, enc->mb_w_ * sizeof(*enc->nz_));
if (enc->top_derr_ != NULL) {
memset(enc->top_derr_, 0, enc->mb_w_ * sizeof(*enc->top_derr_));
}
}
void VP8IteratorSetRow(VP8EncIterator* const it, int y) {
VP8Encoder* const enc = it->enc_;
it->x_ = 0;
it->y_ = y;
it->bw_ = &enc->parts_[y & (enc->num_parts_ - 1)];
it->preds_ = enc->preds_ + y * 4 * enc->preds_w_;
it->nz_ = enc->nz_;
it->mb_ = enc->mb_info_ + y * enc->mb_w_;
it->y_top_ = enc->y_top_;
it->uv_top_ = enc->uv_top_;
InitLeft(it);
}
void VP8IteratorReset(VP8EncIterator* const it) {
VP8Encoder* const enc = it->enc_;
VP8IteratorSetRow(it, 0);
VP8IteratorSetCountDown(it, enc->mb_w_ * enc->mb_h_); // default
InitTop(it);
memset(it->bit_count_, 0, sizeof(it->bit_count_));
it->do_trellis_ = 0;
}
void VP8IteratorSetCountDown(VP8EncIterator* const it, int count_down) {
it->count_down_ = it->count_down0_ = count_down;
}
int VP8IteratorIsDone(const VP8EncIterator* const it) {
return (it->count_down_ <= 0);
}
void VP8IteratorInit(VP8Encoder* const enc, VP8EncIterator* const it) {
it->enc_ = enc;
it->yuv_in_ = (uint8_t*)WEBP_ALIGN(it->yuv_mem_);
it->yuv_out_ = it->yuv_in_ + YUV_SIZE_ENC;
it->yuv_out2_ = it->yuv_out_ + YUV_SIZE_ENC;
it->yuv_p_ = it->yuv_out2_ + YUV_SIZE_ENC;
it->lf_stats_ = enc->lf_stats_;
it->percent0_ = enc->percent_;
it->y_left_ = (uint8_t*)WEBP_ALIGN(it->yuv_left_mem_ + 1);
it->u_left_ = it->y_left_ + 16 + 16;
it->v_left_ = it->u_left_ + 16;
it->top_derr_ = enc->top_derr_;
VP8IteratorReset(it);
}
int VP8IteratorProgress(const VP8EncIterator* const it, int delta) {
VP8Encoder* const enc = it->enc_;
if (delta && enc->pic_->progress_hook != NULL) {
const int done = it->count_down0_ - it->count_down_;
const int percent = (it->count_down0_ <= 0)
? it->percent0_
: it->percent0_ + delta * done / it->count_down0_;
return WebPReportProgress(enc->pic_, percent, &enc->percent_);
}
return 1;
}
//------------------------------------------------------------------------------
// Import the source samples into the cache. Takes care of replicating
// boundary pixels if necessary.
static WEBP_INLINE int MinSize(int a, int b) { return (a < b) ? a : b; }
static void ImportBlock(const uint8_t* src, int src_stride,
uint8_t* dst, int w, int h, int size) {
int i;
for (i = 0; i < h; ++i) {
memcpy(dst, src, w);
if (w < size) {
memset(dst + w, dst[w - 1], size - w);
}
dst += BPS;
src += src_stride;
}
for (i = h; i < size; ++i) {
memcpy(dst, dst - BPS, size);
dst += BPS;
}
}
static void ImportLine(const uint8_t* src, int src_stride,
uint8_t* dst, int len, int total_len) {
int i;
for (i = 0; i < len; ++i, src += src_stride) dst[i] = *src;
for (; i < total_len; ++i) dst[i] = dst[len - 1];
}
void VP8IteratorImport(VP8EncIterator* const it, uint8_t* tmp_32) {
const VP8Encoder* const enc = it->enc_;
const int x = it->x_, y = it->y_;
const WebPPicture* const pic = enc->pic_;
const uint8_t* const ysrc = pic->y + (y * pic->y_stride + x) * 16;
const uint8_t* const usrc = pic->u + (y * pic->uv_stride + x) * 8;
const uint8_t* const vsrc = pic->v + (y * pic->uv_stride + x) * 8;
const int w = MinSize(pic->width - x * 16, 16);
const int h = MinSize(pic->height - y * 16, 16);
const int uv_w = (w + 1) >> 1;
const int uv_h = (h + 1) >> 1;
ImportBlock(ysrc, pic->y_stride, it->yuv_in_ + Y_OFF_ENC, w, h, 16);
ImportBlock(usrc, pic->uv_stride, it->yuv_in_ + U_OFF_ENC, uv_w, uv_h, 8);
ImportBlock(vsrc, pic->uv_stride, it->yuv_in_ + V_OFF_ENC, uv_w, uv_h, 8);
if (tmp_32 == NULL) return;
// Import source (uncompressed) samples into boundary.
if (x == 0) {
InitLeft(it);
} else {
if (y == 0) {
it->y_left_[-1] = it->u_left_[-1] = it->v_left_[-1] = 127;
} else {
it->y_left_[-1] = ysrc[- 1 - pic->y_stride];
it->u_left_[-1] = usrc[- 1 - pic->uv_stride];
it->v_left_[-1] = vsrc[- 1 - pic->uv_stride];
}
ImportLine(ysrc - 1, pic->y_stride, it->y_left_, h, 16);
ImportLine(usrc - 1, pic->uv_stride, it->u_left_, uv_h, 8);
ImportLine(vsrc - 1, pic->uv_stride, it->v_left_, uv_h, 8);
}
it->y_top_ = tmp_32 + 0;
it->uv_top_ = tmp_32 + 16;
if (y == 0) {
memset(tmp_32, 127, 32 * sizeof(*tmp_32));
} else {
ImportLine(ysrc - pic->y_stride, 1, tmp_32, w, 16);
ImportLine(usrc - pic->uv_stride, 1, tmp_32 + 16, uv_w, 8);
ImportLine(vsrc - pic->uv_stride, 1, tmp_32 + 16 + 8, uv_w, 8);
}
}
//------------------------------------------------------------------------------
// Copy back the compressed samples into user space if requested.
static void ExportBlock(const uint8_t* src, uint8_t* dst, int dst_stride,
int w, int h) {
while (h-- > 0) {
memcpy(dst, src, w);
dst += dst_stride;
src += BPS;
}
}
void VP8IteratorExport(const VP8EncIterator* const it) {
const VP8Encoder* const enc = it->enc_;
if (enc->config_->show_compressed) {
const int x = it->x_, y = it->y_;
const uint8_t* const ysrc = it->yuv_out_ + Y_OFF_ENC;
const uint8_t* const usrc = it->yuv_out_ + U_OFF_ENC;
const uint8_t* const vsrc = it->yuv_out_ + V_OFF_ENC;
const WebPPicture* const pic = enc->pic_;
uint8_t* const ydst = pic->y + (y * pic->y_stride + x) * 16;
uint8_t* const udst = pic->u + (y * pic->uv_stride + x) * 8;
uint8_t* const vdst = pic->v + (y * pic->uv_stride + x) * 8;
int w = (pic->width - x * 16);
int h = (pic->height - y * 16);
if (w > 16) w = 16;
if (h > 16) h = 16;
// Luma plane
ExportBlock(ysrc, ydst, pic->y_stride, w, h);
{ // U/V planes
const int uv_w = (w + 1) >> 1;
const int uv_h = (h + 1) >> 1;
ExportBlock(usrc, udst, pic->uv_stride, uv_w, uv_h);
ExportBlock(vsrc, vdst, pic->uv_stride, uv_w, uv_h);
}
}
}
//------------------------------------------------------------------------------
// Non-zero contexts setup/teardown
// Nz bits:
// 0 1 2 3 Y
// 4 5 6 7
// 8 9 10 11
// 12 13 14 15
// 16 17 U
// 18 19
// 20 21 V
// 22 23
// 24 DC-intra16
// Convert packed context to byte array
#define BIT(nz, n) (!!((nz) & (1 << (n))))
void VP8IteratorNzToBytes(VP8EncIterator* const it) {
const int tnz = it->nz_[0], lnz = it->nz_[-1];
int* const top_nz = it->top_nz_;
int* const left_nz = it->left_nz_;
// Top-Y
top_nz[0] = BIT(tnz, 12);
top_nz[1] = BIT(tnz, 13);
top_nz[2] = BIT(tnz, 14);
top_nz[3] = BIT(tnz, 15);
// Top-U
top_nz[4] = BIT(tnz, 18);
top_nz[5] = BIT(tnz, 19);
// Top-V
top_nz[6] = BIT(tnz, 22);
top_nz[7] = BIT(tnz, 23);
// DC
top_nz[8] = BIT(tnz, 24);
// left-Y
left_nz[0] = BIT(lnz, 3);
left_nz[1] = BIT(lnz, 7);
left_nz[2] = BIT(lnz, 11);
left_nz[3] = BIT(lnz, 15);
// left-U
left_nz[4] = BIT(lnz, 17);
left_nz[5] = BIT(lnz, 19);
// left-V
left_nz[6] = BIT(lnz, 21);
left_nz[7] = BIT(lnz, 23);
// left-DC is special, iterated separately
}
void VP8IteratorBytesToNz(VP8EncIterator* const it) {
uint32_t nz = 0;
const int* const top_nz = it->top_nz_;
const int* const left_nz = it->left_nz_;
// top
nz |= (top_nz[0] << 12) | (top_nz[1] << 13);
nz |= (top_nz[2] << 14) | (top_nz[3] << 15);
nz |= (top_nz[4] << 18) | (top_nz[5] << 19);
nz |= (top_nz[6] << 22) | (top_nz[7] << 23);
nz |= (top_nz[8] << 24); // we propagate the _top_ bit, esp. for intra4
// left
nz |= (left_nz[0] << 3) | (left_nz[1] << 7);
nz |= (left_nz[2] << 11);
nz |= (left_nz[4] << 17) | (left_nz[6] << 21);
*it->nz_ = nz;
}
#undef BIT
//------------------------------------------------------------------------------
// Advance to the next position, doing the bookkeeping.
void VP8IteratorSaveBoundary(VP8EncIterator* const it) {
VP8Encoder* const enc = it->enc_;
const int x = it->x_, y = it->y_;
const uint8_t* const ysrc = it->yuv_out_ + Y_OFF_ENC;
const uint8_t* const uvsrc = it->yuv_out_ + U_OFF_ENC;
if (x < enc->mb_w_ - 1) { // left
int i;
for (i = 0; i < 16; ++i) {
it->y_left_[i] = ysrc[15 + i * BPS];
}
for (i = 0; i < 8; ++i) {
it->u_left_[i] = uvsrc[7 + i * BPS];
it->v_left_[i] = uvsrc[15 + i * BPS];
}
// top-left (before 'top'!)
it->y_left_[-1] = it->y_top_[15];
it->u_left_[-1] = it->uv_top_[0 + 7];
it->v_left_[-1] = it->uv_top_[8 + 7];
}
if (y < enc->mb_h_ - 1) { // top
memcpy(it->y_top_, ysrc + 15 * BPS, 16);
memcpy(it->uv_top_, uvsrc + 7 * BPS, 8 + 8);
}
}
int VP8IteratorNext(VP8EncIterator* const it) {
if (++it->x_ == it->enc_->mb_w_) {
VP8IteratorSetRow(it, ++it->y_);
} else {
it->preds_ += 4;
it->mb_ += 1;
it->nz_ += 1;
it->y_top_ += 16;
it->uv_top_ += 16;
}
return (0 < --it->count_down_);
}
//------------------------------------------------------------------------------
// Helper function to set mode properties
void VP8SetIntra16Mode(const VP8EncIterator* const it, int mode) {
uint8_t* preds = it->preds_;
int y;
for (y = 0; y < 4; ++y) {
memset(preds, mode, 4);
preds += it->enc_->preds_w_;
}
it->mb_->type_ = 1;
}
void VP8SetIntra4Mode(const VP8EncIterator* const it, const uint8_t* modes) {
uint8_t* preds = it->preds_;
int y;
for (y = 4; y > 0; --y) {
memcpy(preds, modes, 4 * sizeof(*modes));
preds += it->enc_->preds_w_;
modes += 4;
}
it->mb_->type_ = 0;
}
void VP8SetIntraUVMode(const VP8EncIterator* const it, int mode) {
it->mb_->uv_mode_ = mode;
}
void VP8SetSkip(const VP8EncIterator* const it, int skip) {
it->mb_->skip_ = skip;
}
void VP8SetSegment(const VP8EncIterator* const it, int segment) {
it->mb_->segment_ = segment;
}
//------------------------------------------------------------------------------
// Intra4x4 sub-blocks iteration
//
// We store and update the boundary samples into an array of 37 pixels. They
// are updated as we iterate and reconstructs each intra4x4 blocks in turn.
// The position of the samples has the following snake pattern:
//
// 16|17 18 19 20|21 22 23 24|25 26 27 28|29 30 31 32|33 34 35 36 <- Top-right
// --+-----------+-----------+-----------+-----------+
// 15| 19| 23| 27| 31|
// 14| 18| 22| 26| 30|
// 13| 17| 21| 25| 29|
// 12|13 14 15 16|17 18 19 20|21 22 23 24|25 26 27 28|
// --+-----------+-----------+-----------+-----------+
// 11| 15| 19| 23| 27|
// 10| 14| 18| 22| 26|
// 9| 13| 17| 21| 25|
// 8| 9 10 11 12|13 14 15 16|17 18 19 20|21 22 23 24|
// --+-----------+-----------+-----------+-----------+
// 7| 11| 15| 19| 23|
// 6| 10| 14| 18| 22|
// 5| 9| 13| 17| 21|
// 4| 5 6 7 8| 9 10 11 12|13 14 15 16|17 18 19 20|
// --+-----------+-----------+-----------+-----------+
// 3| 7| 11| 15| 19|
// 2| 6| 10| 14| 18|
// 1| 5| 9| 13| 17|
// 0| 1 2 3 4| 5 6 7 8| 9 10 11 12|13 14 15 16|
// --+-----------+-----------+-----------+-----------+
// Array to record the position of the top sample to pass to the prediction
// functions in dsp.c.
static const uint8_t VP8TopLeftI4[16] = {
17, 21, 25, 29,
13, 17, 21, 25,
9, 13, 17, 21,
5, 9, 13, 17
};
void VP8IteratorStartI4(VP8EncIterator* const it) {
const VP8Encoder* const enc = it->enc_;
int i;
it->i4_ = 0; // first 4x4 sub-block
it->i4_top_ = it->i4_boundary_ + VP8TopLeftI4[0];
// Import the boundary samples
for (i = 0; i < 17; ++i) { // left
it->i4_boundary_[i] = it->y_left_[15 - i];
}
for (i = 0; i < 16; ++i) { // top
it->i4_boundary_[17 + i] = it->y_top_[i];
}
// top-right samples have a special case on the far right of the picture
if (it->x_ < enc->mb_w_ - 1) {
for (i = 16; i < 16 + 4; ++i) {
it->i4_boundary_[17 + i] = it->y_top_[i];
}
} else { // else, replicate the last valid pixel four times
for (i = 16; i < 16 + 4; ++i) {
it->i4_boundary_[17 + i] = it->i4_boundary_[17 + 15];
}
}
VP8IteratorNzToBytes(it); // import the non-zero context
}
int VP8IteratorRotateI4(VP8EncIterator* const it,
const uint8_t* const yuv_out) {
const uint8_t* const blk = yuv_out + VP8Scan[it->i4_];
uint8_t* const top = it->i4_top_;
int i;
// Update the cache with 7 fresh samples
for (i = 0; i <= 3; ++i) {
top[-4 + i] = blk[i + 3 * BPS]; // store future top samples
}
if ((it->i4_ & 3) != 3) { // if not on the right sub-blocks #3, #7, #11, #15
for (i = 0; i <= 2; ++i) { // store future left samples
top[i] = blk[3 + (2 - i) * BPS];
}
} else { // else replicate top-right samples, as says the specs.
for (i = 0; i <= 3; ++i) {
top[i] = top[i + 4];
}
}
// move pointers to next sub-block
++it->i4_;
if (it->i4_ == 16) { // we're done
return 0;
}
it->i4_top_ = it->i4_boundary_ + VP8TopLeftI4[it->i4_];
return 1;
}
//------------------------------------------------------------------------------