mirror of
https://github.com/webmproject/libwebp.git
synced 2024-11-20 12:28:26 +01:00
f61d14aabf
converts PNG & JPEG to WebP This is an experimental early version, with lot of room of later optimizations in both speed and quality. Compile with the usual `./configure && make` Command line example is examples/cwebp Usage: cwebp [options] -q quality input.png -o output.webp where 'quality' is between 0 (poor) to 100 (very good). Typical value is around 80. More encoding options with 'cwebp -longhelp' Change-Id: I577a94f6f622a0c44bdfa9daf1086ace89d45539
407 lines
12 KiB
C
407 lines
12 KiB
C
// Copyright 2011 Google Inc.
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//
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// This code is licensed under the same terms as WebM:
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// Software License Agreement: http://www.webmproject.org/license/software/
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// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
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// -----------------------------------------------------------------------------
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//
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// VP8Iterator: block iterator
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#include <stdlib.h>
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#include <string.h>
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#include "vp8enci.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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//-----------------------------------------------------------------------------
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// VP8Iterator
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//-----------------------------------------------------------------------------
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static void InitLeft(VP8EncIterator* const it) {
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const VP8Encoder* const enc = it->enc_;
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enc->y_left_[-1] = enc->u_left_[-1] = enc->v_left_[-1] =
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(it->y_) > 0 ? 129 : 127;
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memset(enc->y_left_, 129, 16);
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memset(enc->u_left_, 129, 8);
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memset(enc->v_left_, 129, 8);
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it->left_nz_[8] = 0;
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}
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static void InitTop(VP8EncIterator* const it) {
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const VP8Encoder* const enc = it->enc_;
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const int top_size = enc->mb_w_ * 16;
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memset(enc->y_top_, 127, 2 * top_size);
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memset(enc->nz_, 0, enc->mb_w_ * sizeof(*enc->nz_));
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}
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void VP8IteratorReset(VP8EncIterator* const it) {
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VP8Encoder* const enc = it->enc_;
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it->x_ = 0;
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it->y_ = 0;
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it->y_offset_ = 0;
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it->uv_offset_ = 0;
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it->mb_ = enc->mb_info_;
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it->preds_ = enc->preds_;
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it->nz_ = enc->nz_;
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it->bw_ = &enc->parts_[0];
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it->done_ = enc->mb_w_* enc->mb_h_;
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InitTop(it);
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InitLeft(it);
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memset(it->bit_count_, 0, sizeof(it->bit_count_));
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it->do_trellis_ = 0;
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}
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void VP8IteratorInit(VP8Encoder* const enc, VP8EncIterator* const it) {
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it->enc_ = enc;
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it->y_stride_ = enc->pic_->y_stride;
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it->uv_stride_ = enc->pic_->uv_stride;
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// TODO(later): for multithreading, these should be owned by 'it'.
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it->yuv_in_ = enc->yuv_in_;
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it->yuv_out_ = enc->yuv_out_;
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it->yuv_out2_ = enc->yuv_out2_;
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it->yuv_p_ = enc->yuv_p_;
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it->lf_stats_ = enc->lf_stats_;
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VP8IteratorReset(it);
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}
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//-----------------------------------------------------------------------------
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// Import the source samples into the cache. Takes care of replicating
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// boundary pixels if necessary.
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void VP8IteratorImport(const VP8EncIterator* const it) {
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const VP8Encoder* const enc = it->enc_;
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const int x = it->x_, y = it->y_;
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const WebPPicture* const pic = enc->pic_;
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const uint8_t* ysrc = pic->y + (y * pic->y_stride + x) * 16;
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const uint8_t* usrc = pic->u + (y * pic->uv_stride + x) * 8;
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const uint8_t* vsrc = pic->v + (y * pic->uv_stride + x) * 8;
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uint8_t* ydst = it->yuv_in_ + Y_OFF;
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uint8_t* udst = it->yuv_in_ + U_OFF;
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uint8_t* vdst = it->yuv_in_ + V_OFF;
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int w = (pic->width - x * 16);
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int h = (pic->height - y * 16);
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int i;
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if (w > 16) w = 16;
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if (h > 16) h = 16;
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// Luma plane
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for (i = 0; i < h; ++i) {
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memcpy(ydst, ysrc, w);
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if (w < 16) memset(ydst + w, ydst[w - 1], 16 - w);
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ydst += BPS;
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ysrc += pic->y_stride;
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}
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for (i = h; i < 16; ++i) {
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memcpy(ydst, ydst - BPS, 16);
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ydst += BPS;
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}
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// U/V plane
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w = (w + 1) / 2;
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h = (h + 1) / 2;
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for (i = 0; i < h; ++i) {
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memcpy(udst, usrc, w);
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memcpy(vdst, vsrc, w);
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if (w < 8) {
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memset(udst + w, udst[w - 1], 8 - w);
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memset(vdst + w, vdst[w - 1], 8 - w);
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}
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udst += BPS;
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vdst += BPS;
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usrc += pic->uv_stride;
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vsrc += pic->uv_stride;
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}
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for (i = h; i < 8; ++i) {
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memcpy(udst, udst - BPS, 8);
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memcpy(vdst, vdst - BPS, 8);
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udst += BPS;
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vdst += BPS;
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}
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}
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//-----------------------------------------------------------------------------
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// Copy back the compressed samples into user space if requested.
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void VP8IteratorExport(const VP8EncIterator* const it) {
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const VP8Encoder* const enc = it->enc_;
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if (enc->config_->show_compressed) {
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const int x = it->x_, y = it->y_;
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const uint8_t* const ysrc = it->yuv_out_ + Y_OFF;
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const uint8_t* const usrc = it->yuv_out_ + U_OFF;
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const uint8_t* const vsrc = it->yuv_out_ + V_OFF;
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const WebPPicture* const pic = enc->pic_;
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uint8_t* ydst = pic->y + (y * pic->y_stride + x) * 16;
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uint8_t* udst = pic->u + (y * pic->uv_stride + x) * 8;
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uint8_t* vdst = pic->v + (y * pic->uv_stride + x) * 8;
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int w = (pic->width - x * 16);
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int h = (pic->height - y * 16);
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int i;
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if (w > 16) w = 16;
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if (h > 16) h = 16;
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// Luma plane
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for (i = 0; i < h; ++i) {
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memcpy(ydst + i * pic->y_stride, ysrc + i * BPS, w);
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}
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// U/V plane
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w = (w + 1) / 2;
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h = (h + 1) / 2;
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for (i = 0; i < h; ++i) {
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memcpy(udst + i * pic->uv_stride, usrc + i * BPS, w);
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memcpy(vdst + i * pic->uv_stride, vsrc + i * BPS, w);
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}
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}
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}
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//-----------------------------------------------------------------------------
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// Non-zero contexts setup/teardown
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// Nz bits:
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// 0 1 2 3 Y
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// 4 5 6 7
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// 8 9 10 11
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// 12 13 14 15
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// 16 17 U
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// 18 19
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// 20 21 V
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// 22 23
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// 24 DC-intra16
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// Convert packed context to byte array
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#define BIT(nz, n) (!!((nz) & (1 << (n))))
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void VP8IteratorNzToBytes(VP8EncIterator* const it) {
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const int tnz = it->nz_[0], lnz = it->nz_[-1];
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// Top-Y
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it->top_nz_[0] = BIT(tnz, 12);
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it->top_nz_[1] = BIT(tnz, 13);
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it->top_nz_[2] = BIT(tnz, 14);
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it->top_nz_[3] = BIT(tnz, 15);
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// Top-U
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it->top_nz_[4] = BIT(tnz, 18);
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it->top_nz_[5] = BIT(tnz, 19);
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// Top-V
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it->top_nz_[6] = BIT(tnz, 22);
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it->top_nz_[7] = BIT(tnz, 23);
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// DC
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it->top_nz_[8] = BIT(tnz, 24);
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// left-Y
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it->left_nz_[0] = BIT(lnz, 3);
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it->left_nz_[1] = BIT(lnz, 7);
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it->left_nz_[2] = BIT(lnz, 11);
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it->left_nz_[3] = BIT(lnz, 15);
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// left-U
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it->left_nz_[4] = BIT(lnz, 17);
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it->left_nz_[5] = BIT(lnz, 19);
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// left-V
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it->left_nz_[6] = BIT(lnz, 21);
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it->left_nz_[7] = BIT(lnz, 23);
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// left-DC is special, iterated separately
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}
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void VP8IteratorBytesToNz(VP8EncIterator* const it) {
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uint32_t nz = 0;
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// top
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nz |= (it->top_nz_[0] << 12) | (it->top_nz_[1] << 13);
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nz |= (it->top_nz_[2] << 14) | (it->top_nz_[3] << 15);
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nz |= (it->top_nz_[4] << 18) | (it->top_nz_[5] << 19);
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nz |= (it->top_nz_[6] << 22) | (it->top_nz_[7] << 23);
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nz |= (it->top_nz_[8] << 24); // we propagate the _top_ bit, esp. for intra4
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// left
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nz |= (it->left_nz_[0] << 3) | (it->left_nz_[1] << 7) | (it->left_nz_[2] << 11);
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nz |= (it->left_nz_[4] << 17) | (it->left_nz_[6] << 21);
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*it->nz_ = nz;
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}
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#undef BIT
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//-----------------------------------------------------------------------------
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// Advance to the next position, doing the bookeeping.
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int VP8IteratorNext(VP8EncIterator* const it,
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const uint8_t* const block_to_save) {
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VP8Encoder* const enc = it->enc_;
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if (block_to_save) {
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const int x = it->x_, y = it->y_;
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const uint8_t* const ysrc = block_to_save + Y_OFF;
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const uint8_t* const usrc = block_to_save + U_OFF;
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if (x < enc->mb_w_ - 1) { // left
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int i;
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for (i = 0; i < 16; ++i) {
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enc->y_left_[i] = ysrc[15 + i * BPS];
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}
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for (i = 0; i < 8; ++i) {
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enc->u_left_[i] = usrc[7 + i * BPS];
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enc->v_left_[i] = usrc[15 + i * BPS];
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}
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// top-left (before 'top'!)
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enc->y_left_[-1] = enc->y_top_[x * 16 + 15];
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enc->u_left_[-1] = enc->uv_top_[x * 16 + 0 + 7];
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enc->v_left_[-1] = enc->uv_top_[x * 16 + 8 + 7];
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}
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if (y < enc->mb_h_ - 1) { // top
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memcpy(enc->y_top_ + x * 16, ysrc + 15 * BPS, 16);
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memcpy(enc->uv_top_ + x * 16, usrc + 7 * BPS, 8 + 8);
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}
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}
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it->mb_++;
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it->preds_ += 4;
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it->nz_++;
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it->x_++;
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if (it->x_ == enc->mb_w_) {
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it->x_ = 0;
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it->y_++;
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it->bw_ = &enc->parts_[it->y_ & (enc->num_parts_ - 1)];
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it->preds_ = enc->preds_ + it->y_ * 4 * enc->preds_w_;
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it->nz_ = enc->nz_;
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InitLeft(it);
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}
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return (0 < --it->done_);
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}
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//-----------------------------------------------------------------------------
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// Helper function to set mode properties
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void VP8SetIntra16Mode(const VP8EncIterator* it, int mode) {
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int y;
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uint8_t* preds = it->preds_;
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for (y = 0; y < 4; ++y) {
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memset(preds, mode, 4);
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preds += it->enc_->preds_w_;
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}
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it->mb_->type_ = 1;
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}
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void VP8SetIntra4Mode(const VP8EncIterator* const it, int modes[16]) {
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int x, y;
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uint8_t* preds = it->preds_;
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for (y = 0; y < 4; ++y) {
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for (x = 0; x < 4; ++x) {
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preds[x] = modes[x + y * 4];
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}
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preds += it->enc_->preds_w_;
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}
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it->mb_->type_ = 0;
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}
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void VP8SetIntraUVMode(const VP8EncIterator* const it, int mode) {
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it->mb_->uv_mode_ = mode;
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}
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void VP8SetSkip(const VP8EncIterator* const it, int skip) {
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it->mb_->skip_ = skip;
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}
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void VP8SetSegment(const VP8EncIterator* const it, int segment) {
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it->mb_->segment_ = segment;
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}
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//-----------------------------------------------------------------------------
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// Intra4x4 sub-blocks iteration
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//
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// We store and update the boundary samples into an array of 37 pixels. They
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// are updated as we iterate and reconstructs each intra4x4 blocks in turn.
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// The position of the samples has the following snake pattern:
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//
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// 16|17 18 19 20|21 22 23 24|25 26 27 28|29 30 31 32|33 34 35 36 <- Top-right
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// --+-----------+-----------+-----------+-----------+
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// 15| 19| 23| 27| 31|
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// 14| 18| 22| 26| 30|
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// 13| 17| 21| 25| 29|
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// 12|13 14 15 16|17 18 19 20|21 22 23 24|25 26 27 28|
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// --+-----------+-----------+-----------+-----------+
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// 11| 15| 19| 23| 27|
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// 10| 14| 18| 22| 26|
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// 9| 13| 17| 21| 25|
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// 8| 9 10 11 12|13 14 15 16|17 18 19 20|21 22 23 24|
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// --+-----------+-----------+-----------+-----------+
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// 7| 11| 15| 19| 23|
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// 6| 10| 14| 18| 22|
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// 5| 9| 13| 17| 21|
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// 4| 5 6 7 8| 9 10 11 12|13 14 15 16|17 18 19 20|
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// --+-----------+-----------+-----------+-----------+
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// 3| 7| 11| 15| 19|
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// 2| 6| 10| 14| 18|
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// 1| 5| 9| 13| 17|
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// 0| 1 2 3 4| 5 6 7 8| 9 10 11 12|13 14 15 16|
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// --+-----------+-----------+-----------+-----------+
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// Array to record the position of the top sample to pass to the prediction
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// functions in dsp.c.
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static const uint8_t VP8TopLeftI4[16] = {
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17, 21, 25, 29,
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13, 17, 21, 25,
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9, 13, 17, 21,
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5, 9, 13, 17
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};
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void VP8IteratorStartI4(VP8EncIterator* const it) {
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VP8Encoder* const enc = it->enc_;
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int i;
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it->i4_ = 0; // first 4x4 sub-block
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it->i4_top_ = it->i4_boundary_ + VP8TopLeftI4[0];
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// Import the boundary samples
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for (i = 0; i < 17; ++i) { // left
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it->i4_boundary_[i] = enc->y_left_[15 - i];
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}
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for (i = 0; i < 16; ++i) { // top
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it->i4_boundary_[17 + i] = enc->y_top_[it->x_ * 16 + i];
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}
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// top-right samples have a special case on the far right of the picture
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if (it->x_ < enc->mb_w_ - 1) {
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for (i = 16; i < 16 + 4; ++i) {
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it->i4_boundary_[17 + i] = enc->y_top_[it->x_ * 16 + i];
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}
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} else { // else, replicate the last valid pixel four times
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for (i = 16; i < 16 + 4; ++i) {
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it->i4_boundary_[17 + i] = it->i4_boundary_[17 + 15];
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}
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}
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VP8IteratorNzToBytes(it); // import the non-zero context
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}
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int VP8IteratorRotateI4(VP8EncIterator* const it,
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const uint8_t* const yuv_out) {
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const uint8_t* const blk = yuv_out + VP8Scan[it->i4_];
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uint8_t* const top = it->i4_top_;
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int i;
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// Update the cache with 7 fresh samples
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for (i = 0; i <= 3; ++i) {
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top[-4 + i] = blk[i + 3 * BPS]; // store future top samples
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}
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if ((it->i4_ & 3) != 3) { // if not on the right sub-blocks #3, #7, #11, #15
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for (i = 0; i <= 2; ++i) { // store future left samples
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top[i] = blk[3 + (2 - i) * BPS];
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}
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} else { // else replicate top-right samples, as says the specs.
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for (i = 0; i <= 3; ++i) {
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top[i] = top[i + 4];
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}
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}
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// move pointers to next sub-block
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it->i4_++;
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if (it->i4_ == 16) { // we're done
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return 0;
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}
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it->i4_top_ = it->i4_boundary_ + VP8TopLeftI4[it->i4_];
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return 1;
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}
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//-----------------------------------------------------------------------------
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#if defined(__cplusplus) || defined(c_plusplus)
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} // extern "C"
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#endif
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