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libwebp/src/dec/frame.c
Pascal Massimino 42548da9e3 shave one unneeded filter-cache line 
There was 1 unneeded sample line allocated for the filter cache in of simple filtering.
+ Add an explaining comment.

Change-Id: I775a596c8b8643e773e0eade8aa341dc23fb290f
2011-06-09 12:08:08 -07:00

439 lines
14 KiB
C
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// Copyright 2010 Google Inc.
//
// This code is licensed under the same terms as WebM:
// Software License Agreement: http://www.webmproject.org/license/software/
// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
// -----------------------------------------------------------------------------
//
// Frame-reconstruction function. Memory allocation.
//
// Author: Skal (pascal.massimino@gmail.com)
#include <stdlib.h>
#include "./vp8i.h"
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
#define ALIGN_MASK (32 - 1)
//-----------------------------------------------------------------------------
// Memory setup
// kFilterExtraRows[] = How many extra lines are needed on the MB boundary
// for caching, given a filtering level.
// Simple filter: up to 2 luma samples are read and 1 is written.
// Complex filter: up to 4 luma samples are read and 3 are written. Same for
// U/V, so it's 8 samples total (because of the 2x upsampling).
static const uint8_t kFilterExtraRows[3] = { 0, 2, 8 };
int VP8InitFrame(VP8Decoder* const dec, VP8Io* io) {
const int mb_w = dec->mb_w_;
const int intra_pred_mode_size = 4 * mb_w * sizeof(uint8_t);
const int top_size = (16 + 8 + 8) * mb_w;
const int info_size = (mb_w + 1) * sizeof(VP8MB);
const int yuv_size = YUV_SIZE * sizeof(*dec->yuv_b_);
const int coeffs_size = 384 * sizeof(*dec->coeffs_);
const int cache_height = (16 + kFilterExtraRows[dec->filter_type_]) * 3 / 2;
const int cache_size = top_size * cache_height;
const int alpha_size =
dec->alpha_data_ ? (dec->pic_hdr_.width_ * dec->pic_hdr_.height_) : 0;
const int needed = intra_pred_mode_size
+ top_size + info_size
+ yuv_size + coeffs_size
+ cache_size + alpha_size + ALIGN_MASK;
uint8_t* mem;
if (needed > dec->mem_size_) {
free(dec->mem_);
dec->mem_size_ = 0;
dec->mem_ = (uint8_t*)malloc(needed);
if (dec->mem_ == NULL) {
return VP8SetError(dec, VP8_STATUS_OUT_OF_MEMORY,
"no memory during frame initialization.");
}
dec->mem_size_ = needed;
}
mem = (uint8_t*)dec->mem_;
dec->intra_t_ = (uint8_t*)mem;
mem += intra_pred_mode_size;
dec->y_t_ = (uint8_t*)mem;
mem += 16 * mb_w;
dec->u_t_ = (uint8_t*)mem;
mem += 8 * mb_w;
dec->v_t_ = (uint8_t*)mem;
mem += 8 * mb_w;
dec->mb_info_ = ((VP8MB*)mem) + 1;
mem += info_size;
mem = (uint8_t*)((uintptr_t)(mem + ALIGN_MASK) & ~ALIGN_MASK);
assert((yuv_size & ALIGN_MASK) == 0);
dec->yuv_b_ = (uint8_t*)mem;
mem += yuv_size;
dec->coeffs_ = (int16_t*)mem;
mem += coeffs_size;
dec->cache_y_stride_ = 16 * mb_w;
dec->cache_uv_stride_ = 8 * mb_w;
{
const int extra_rows = kFilterExtraRows[dec->filter_type_];
const int extra_y = extra_rows * dec->cache_y_stride_;
const int extra_uv = (extra_rows / 2) * dec->cache_uv_stride_;
dec->cache_y_ = ((uint8_t*)mem) + extra_y;
dec->cache_u_ = dec->cache_y_ + 16 * dec->cache_y_stride_ + extra_uv;
dec->cache_v_ = dec->cache_u_ + 8 * dec->cache_uv_stride_ + extra_uv;
}
mem += cache_size;
// alpha plane
dec->alpha_plane_ = alpha_size ? (uint8_t*)mem : NULL;
mem += alpha_size;
// note: left-info is initialized once for all.
memset(dec->mb_info_ - 1, 0, (mb_w + 1) * sizeof(*dec->mb_info_));
// initialize top
memset(dec->intra_t_, B_DC_PRED, intra_pred_mode_size);
// prepare 'io'
io->width = dec->pic_hdr_.width_;
io->height = dec->pic_hdr_.height_;
io->mb_y = 0;
io->y = dec->cache_y_;
io->u = dec->cache_u_;
io->v = dec->cache_v_;
io->y_stride = dec->cache_y_stride_;
io->uv_stride = dec->cache_uv_stride_;
io->fancy_upscaling = 0; // default
io->a = NULL;
// Init critical function pointers and look-up tables.
VP8DspInitTables();
VP8DspInit();
return 1;
}
//-----------------------------------------------------------------------------
// Filtering
static inline int hev_thresh_from_level(int level, int keyframe) {
if (keyframe) {
return (level >= 40) ? 2 : (level >= 15) ? 1 : 0;
} else {
return (level >= 40) ? 3 : (level >= 20) ? 2 : (level >= 15) ? 1 : 0;
}
}
static void DoFilter(VP8Decoder* const dec, int mb_x, int mb_y) {
VP8MB* const mb = dec->mb_info_ + mb_x;
uint8_t* const y_dst = dec->cache_y_ + mb_x * 16;
const int y_bps = dec->cache_y_stride_;
const int level = mb->f_level_;
const int ilevel = mb->f_ilevel_;
const int limit = 2 * level + ilevel;
if (level == 0) {
return;
}
if (dec->filter_type_ == 1) { // simple
if (mb_x > 0) {
VP8SimpleHFilter16(y_dst, y_bps, limit + 4);
}
if (mb->f_inner_) {
VP8SimpleHFilter16i(y_dst, y_bps, limit);
}
if (mb_y > 0) {
VP8SimpleVFilter16(y_dst, y_bps, limit + 4);
}
if (mb->f_inner_) {
VP8SimpleVFilter16i(y_dst, y_bps, limit);
}
} else { // complex
uint8_t* const u_dst = dec->cache_u_ + mb_x * 8;
uint8_t* const v_dst = dec->cache_v_ + mb_x * 8;
const int uv_bps = dec->cache_uv_stride_;
const int hev_thresh =
hev_thresh_from_level(level, dec->frm_hdr_.key_frame_);
if (mb_x > 0) {
VP8HFilter16(y_dst, y_bps, limit + 4, ilevel, hev_thresh);
VP8HFilter8(u_dst, v_dst, uv_bps, limit + 4, ilevel, hev_thresh);
}
if (mb->f_inner_) {
VP8HFilter16i(y_dst, y_bps, limit, ilevel, hev_thresh);
VP8HFilter8i(u_dst, v_dst, uv_bps, limit, ilevel, hev_thresh);
}
if (mb_y > 0) {
VP8VFilter16(y_dst, y_bps, limit + 4, ilevel, hev_thresh);
VP8VFilter8(u_dst, v_dst, uv_bps, limit + 4, ilevel, hev_thresh);
}
if (mb->f_inner_) {
VP8VFilter16i(y_dst, y_bps, limit, ilevel, hev_thresh);
VP8VFilter8i(u_dst, v_dst, uv_bps, limit, ilevel, hev_thresh);
}
}
}
void VP8StoreBlock(VP8Decoder* const dec) {
if (dec->filter_type_ > 0) {
VP8MB* const info = dec->mb_info_ + dec->mb_x_;
int level = dec->filter_levels_[dec->segment_];
if (dec->filter_hdr_.use_lf_delta_) {
// TODO(skal): only CURRENT is handled for now.
level += dec->filter_hdr_.ref_lf_delta_[0];
if (dec->is_i4x4_) {
level += dec->filter_hdr_.mode_lf_delta_[0];
}
}
level = (level < 0) ? 0 : (level > 63) ? 63 : level;
info->f_level_ = level;
if (dec->filter_hdr_.sharpness_ > 0) {
if (dec->filter_hdr_.sharpness_ > 4) {
level >>= 2;
} else {
level >>= 1;
}
if (level > 9 - dec->filter_hdr_.sharpness_) {
level = 9 - dec->filter_hdr_.sharpness_;
}
}
info->f_ilevel_ = (level < 1) ? 1 : level;
info->f_inner_ = (!info->skip_ || dec->is_i4x4_);
}
{
// Transfer samples to row cache
int y;
uint8_t* const ydst = dec->cache_y_ + dec->mb_x_ * 16;
uint8_t* const udst = dec->cache_u_ + dec->mb_x_ * 8;
uint8_t* const vdst = dec->cache_v_ + dec->mb_x_ * 8;
for (y = 0; y < 16; ++y) {
memcpy(ydst + y * dec->cache_y_stride_,
dec->yuv_b_ + Y_OFF + y * BPS, 16);
}
for (y = 0; y < 8; ++y) {
memcpy(udst + y * dec->cache_uv_stride_,
dec->yuv_b_ + U_OFF + y * BPS, 8);
memcpy(vdst + y * dec->cache_uv_stride_,
dec->yuv_b_ + V_OFF + y * BPS, 8);
}
}
}
int VP8FinishRow(VP8Decoder* const dec, VP8Io* io) {
const int extra_y_rows = kFilterExtraRows[dec->filter_type_];
const int ysize = extra_y_rows * dec->cache_y_stride_;
const int uvsize = (extra_y_rows / 2) * dec->cache_uv_stride_;
const int first_row = (dec->mb_y_ == 0);
const int last_row = (dec->mb_y_ >= dec->mb_h_ - 1);
uint8_t* const ydst = dec->cache_y_ - ysize;
uint8_t* const udst = dec->cache_u_ - uvsize;
uint8_t* const vdst = dec->cache_v_ - uvsize;
if (dec->filter_type_ > 0) {
int mb_x;
for (mb_x = 0; mb_x < dec->mb_w_; ++mb_x) {
DoFilter(dec, mb_x, dec->mb_y_);
}
}
if (io->put) {
int y_start = dec->mb_y_ * 16;
int y_end = y_start + 16;
if (!first_row) {
y_start -= extra_y_rows;
io->y = ydst;
io->u = udst;
io->v = vdst;
} else {
io->y = dec->cache_y_;
io->u = dec->cache_u_;
io->v = dec->cache_v_;
}
if (!last_row) {
y_end -= extra_y_rows;
}
if (y_end > io->height) {
y_end = io->height;
}
io->mb_y = y_start;
io->mb_h = y_end - y_start;
io->a = NULL;
#ifdef WEBP_EXPERIMENTAL_FEATURES
if (dec->alpha_data_) {
io->a = VP8DecompressAlphaRows(dec, y_start, y_end - y_start);
if (io->a == NULL) {
return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
"Could not decode alpha data.");
}
}
#endif
if (!io->put(io)) {
return 0;
}
}
// rotate top samples
if (!last_row) {
memcpy(ydst, ydst + 16 * dec->cache_y_stride_, ysize);
memcpy(udst, udst + 8 * dec->cache_uv_stride_, uvsize);
memcpy(vdst, vdst + 8 * dec->cache_uv_stride_, uvsize);
}
return 1;
}
//-----------------------------------------------------------------------------
// Main reconstruction function.
static const int kScan[16] = {
0 + 0 * BPS, 4 + 0 * BPS, 8 + 0 * BPS, 12 + 0 * BPS,
0 + 4 * BPS, 4 + 4 * BPS, 8 + 4 * BPS, 12 + 4 * BPS,
0 + 8 * BPS, 4 + 8 * BPS, 8 + 8 * BPS, 12 + 8 * BPS,
0 + 12 * BPS, 4 + 12 * BPS, 8 + 12 * BPS, 12 + 12 * BPS
};
static inline int CheckMode(VP8Decoder* const dec, int mode) {
if (mode == B_DC_PRED) {
if (dec->mb_x_ == 0) {
return (dec->mb_y_ == 0) ? B_DC_PRED_NOTOPLEFT : B_DC_PRED_NOLEFT;
} else {
return (dec->mb_y_ == 0) ? B_DC_PRED_NOTOP : B_DC_PRED;
}
}
return mode;
}
static inline void Copy32b(uint8_t* dst, uint8_t* src) {
*(uint32_t*)dst = *(uint32_t*)src;
}
void VP8ReconstructBlock(VP8Decoder* const dec) {
uint8_t* const y_dst = dec->yuv_b_ + Y_OFF;
uint8_t* const u_dst = dec->yuv_b_ + U_OFF;
uint8_t* const v_dst = dec->yuv_b_ + V_OFF;
// Rotate in the left samples from previously decoded block. We move four
// pixels at a time for alignment reason, and because of in-loop filter.
if (dec->mb_x_ > 0) {
int j;
for (j = -1; j < 16; ++j) {
Copy32b(&y_dst[j * BPS - 4], &y_dst[j * BPS + 12]);
}
for (j = -1; j < 8; ++j) {
Copy32b(&u_dst[j * BPS - 4], &u_dst[j * BPS + 4]);
Copy32b(&v_dst[j * BPS - 4], &v_dst[j * BPS + 4]);
}
} else {
int j;
for (j = 0; j < 16; ++j) {
y_dst[j * BPS - 1] = 129;
}
for (j = 0; j < 8; ++j) {
u_dst[j * BPS - 1] = 129;
v_dst[j * BPS - 1] = 129;
}
// Init top-left sample on left column too
if (dec->mb_y_ > 0) {
y_dst[-1 - BPS] = u_dst[-1 - BPS] = v_dst[-1 - BPS] = 129;
}
}
{
// bring top samples into the cache
uint8_t* const top_y = dec->y_t_ + dec->mb_x_ * 16;
uint8_t* const top_u = dec->u_t_ + dec->mb_x_ * 8;
uint8_t* const top_v = dec->v_t_ + dec->mb_x_ * 8;
const int16_t* coeffs = dec->coeffs_;
int n;
if (dec->mb_y_ > 0) {
memcpy(y_dst - BPS, top_y, 16);
memcpy(u_dst - BPS, top_u, 8);
memcpy(v_dst - BPS, top_v, 8);
} else if (dec->mb_x_ == 0) {
// we only need to do this init once at block (0,0).
// Afterward, it remains valid for the whole topmost row.
memset(y_dst - BPS - 1, 127, 16 + 4 + 1);
memset(u_dst - BPS - 1, 127, 8 + 1);
memset(v_dst - BPS - 1, 127, 8 + 1);
}
// predict and add residuals
if (dec->is_i4x4_) { // 4x4
uint32_t* const top_right = (uint32_t*)(y_dst - BPS + 16);
if (dec->mb_y_ > 0) {
if (dec->mb_x_ >= dec->mb_w_ - 1) { // on rightmost border
top_right[0] = top_y[15] * 0x01010101u;
} else {
memcpy(top_right, top_y + 16, sizeof(*top_right));
}
}
// replicate the top-right pixels below
top_right[BPS] = top_right[2 * BPS] = top_right[3 * BPS] = top_right[0];
// predict and add residues for all 4x4 blocks in turn.
for (n = 0; n < 16; n++) {
uint8_t* const dst = y_dst + kScan[n];
VP8PredLuma4[dec->imodes_[n]](dst);
if (dec->non_zero_ac_ & (1 << n)) {
VP8Transform(coeffs + n * 16, dst);
} else if (dec->non_zero_ & (1 << n)) { // only DC is present
VP8TransformDC(coeffs + n * 16, dst);
}
}
} else { // 16x16
const int pred_func = CheckMode(dec, dec->imodes_[0]);
VP8PredLuma16[pred_func](y_dst);
if (dec->non_zero_) {
for (n = 0; n < 16; n++) {
uint8_t* const dst = y_dst + kScan[n];
if (dec->non_zero_ac_ & (1 << n)) {
VP8Transform(coeffs + n * 16, dst);
} else if (dec->non_zero_ & (1 << n)) { // only DC is present
VP8TransformDC(coeffs + n * 16, dst);
}
}
}
}
{
// Chroma
const int pred_func = CheckMode(dec, dec->uvmode_);
VP8PredChroma8[pred_func](u_dst);
VP8PredChroma8[pred_func](v_dst);
if (dec->non_zero_ & 0x0f0000) { // chroma-U
const int16_t* const u_coeffs = dec->coeffs_ + 16 * 16;
if (dec->non_zero_ac_ & 0x0f0000) {
VP8TransformUV(u_coeffs, u_dst);
} else {
VP8TransformDCUV(u_coeffs, u_dst);
}
}
if (dec->non_zero_ & 0xf00000) { // chroma-V
const int16_t* const v_coeffs = dec->coeffs_ + 20 * 16;
if (dec->non_zero_ac_ & 0xf00000) {
VP8TransformUV(v_coeffs, v_dst);
} else {
VP8TransformDCUV(v_coeffs, v_dst);
}
}
// stash away top samples for next block
if (dec->mb_y_ < dec->mb_h_ - 1) {
memcpy(top_y, y_dst + 15 * BPS, 16);
memcpy(top_u, u_dst + 7 * BPS, 8);
memcpy(top_v, v_dst + 7 * BPS, 8);
}
}
}
}
//-----------------------------------------------------------------------------
#if defined(__cplusplus) || defined(c_plusplus)
} // extern "C"
#endif
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