// Copyright 2010 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. // ----------------------------------------------------------------------------- // // Frame-reconstruction function. Memory allocation. // // Author: Skal (pascal.massimino@gmail.com) #include #include "./vp8i.h" #include "../utils/utils.h" #define ALIGN_MASK (32 - 1) static void ReconstructRow(const VP8Decoder* const dec, const VP8ThreadContext* ctx); // TODO(skal): remove //------------------------------------------------------------------------------ // Filtering // 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 }; static void DoFilter(const VP8Decoder* const dec, int mb_x, int mb_y) { const VP8ThreadContext* const ctx = &dec->thread_ctx_; const int cache_id = ctx->id_; const int y_bps = dec->cache_y_stride_; const VP8FInfo* const f_info = ctx->f_info_ + mb_x; uint8_t* const y_dst = dec->cache_y_ + cache_id * 16 * y_bps + mb_x * 16; const int ilevel = f_info->f_ilevel_; const int limit = f_info->f_limit_; if (limit == 0) { return; } assert(limit >= 3); if (dec->filter_type_ == 1) { // simple if (mb_x > 0) { VP8SimpleHFilter16(y_dst, y_bps, limit + 4); } if (f_info->f_inner_) { VP8SimpleHFilter16i(y_dst, y_bps, limit); } if (mb_y > 0) { VP8SimpleVFilter16(y_dst, y_bps, limit + 4); } if (f_info->f_inner_) { VP8SimpleVFilter16i(y_dst, y_bps, limit); } } else { // complex const int uv_bps = dec->cache_uv_stride_; uint8_t* const u_dst = dec->cache_u_ + cache_id * 8 * uv_bps + mb_x * 8; uint8_t* const v_dst = dec->cache_v_ + cache_id * 8 * uv_bps + mb_x * 8; const int hev_thresh = f_info->hev_thresh_; 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 (f_info->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 (f_info->f_inner_) { VP8VFilter16i(y_dst, y_bps, limit, ilevel, hev_thresh); VP8VFilter8i(u_dst, v_dst, uv_bps, limit, ilevel, hev_thresh); } } } // Filter the decoded macroblock row (if needed) static void FilterRow(const VP8Decoder* const dec) { int mb_x; const int mb_y = dec->thread_ctx_.mb_y_; assert(dec->thread_ctx_.filter_row_); for (mb_x = dec->tl_mb_x_; mb_x < dec->br_mb_x_; ++mb_x) { DoFilter(dec, mb_x, mb_y); } } //------------------------------------------------------------------------------ // Precompute the filtering strength for each segment and each i4x4/i16x16 mode. static void PrecomputeFilterStrengths(VP8Decoder* const dec) { if (dec->filter_type_ > 0) { int s; const VP8FilterHeader* const hdr = &dec->filter_hdr_; for (s = 0; s < NUM_MB_SEGMENTS; ++s) { int i4x4; // First, compute the initial level int base_level; if (dec->segment_hdr_.use_segment_) { base_level = dec->segment_hdr_.filter_strength_[s]; if (!dec->segment_hdr_.absolute_delta_) { base_level += hdr->level_; } } else { base_level = hdr->level_; } for (i4x4 = 0; i4x4 <= 1; ++i4x4) { VP8FInfo* const info = &dec->fstrengths_[s][i4x4]; int level = base_level; if (hdr->use_lf_delta_) { // TODO(skal): only CURRENT is handled for now. level += hdr->ref_lf_delta_[0]; if (i4x4) { level += hdr->mode_lf_delta_[0]; } } level = (level < 0) ? 0 : (level > 63) ? 63 : level; if (level > 0) { int ilevel = level; if (hdr->sharpness_ > 0) { if (hdr->sharpness_ > 4) { ilevel >>= 2; } else { ilevel >>= 1; } if (ilevel > 9 - hdr->sharpness_) { ilevel = 9 - hdr->sharpness_; } } if (ilevel < 1) ilevel = 1; info->f_ilevel_ = ilevel; info->f_limit_ = 2 * level + ilevel; info->hev_thresh_ = (level >= 40) ? 2 : (level >= 15) ? 1 : 0; } else { info->f_limit_ = 0; // no filtering } info->f_inner_ = i4x4; } } } } //------------------------------------------------------------------------------ // Dithering #define DITHER_AMP_TAB_SIZE 12 static const int kQuantToDitherAmp[DITHER_AMP_TAB_SIZE] = { // roughly, it's dqm->uv_mat_[1] 8, 7, 6, 4, 4, 2, 2, 2, 1, 1, 1, 1 }; void VP8InitDithering(const WebPDecoderOptions* const options, VP8Decoder* const dec) { assert(dec != NULL); if (options != NULL) { const int d = options->dithering_strength; const int max_amp = (1 << VP8_RANDOM_DITHER_FIX) - 1; const int f = (d < 0) ? 0 : (d > 100) ? max_amp : (d * max_amp / 100); if (f > 0) { int s; int all_amp = 0; for (s = 0; s < NUM_MB_SEGMENTS; ++s) { VP8QuantMatrix* const dqm = &dec->dqm_[s]; if (dqm->uv_quant_ < DITHER_AMP_TAB_SIZE) { // TODO(skal): should we specially dither more for uv_quant_ < 0? const int idx = (dqm->uv_quant_ < 0) ? 0 : dqm->uv_quant_; dqm->dither_ = (f * kQuantToDitherAmp[idx]) >> 3; } all_amp |= dqm->dither_; } if (all_amp != 0) { VP8InitRandom(&dec->dithering_rg_, 1.0f); dec->dither_ = 1; } } } } // minimal amp that will provide a non-zero dithering effect #define MIN_DITHER_AMP 4 #define DITHER_DESCALE 4 #define DITHER_DESCALE_ROUNDER (1 << (DITHER_DESCALE - 1)) #define DITHER_AMP_BITS 8 #define DITHER_AMP_CENTER (1 << DITHER_AMP_BITS) static void Dither8x8(VP8Random* const rg, uint8_t* dst, int bps, int amp) { int i, j; for (j = 0; j < 8; ++j) { for (i = 0; i < 8; ++i) { // TODO: could be made faster with SSE2 const int bits = VP8RandomBits2(rg, DITHER_AMP_BITS + 1, amp) - DITHER_AMP_CENTER; // Convert to range: [-2,2] for dither=50, [-4,4] for dither=100 const int delta = (bits + DITHER_DESCALE_ROUNDER) >> DITHER_DESCALE; const int v = (int)dst[i] + delta; dst[i] = (v < 0) ? 0 : (v > 255) ? 255u : (uint8_t)v; } dst += bps; } } static void DitherRow(VP8Decoder* const dec) { int mb_x; assert(dec->dither_); for (mb_x = dec->tl_mb_x_; mb_x < dec->br_mb_x_; ++mb_x) { const VP8ThreadContext* const ctx = &dec->thread_ctx_; const VP8MBData* const data = ctx->mb_data_ + mb_x; const int cache_id = ctx->id_; const int uv_bps = dec->cache_uv_stride_; if (data->dither_ >= MIN_DITHER_AMP) { uint8_t* const u_dst = dec->cache_u_ + cache_id * 8 * uv_bps + mb_x * 8; uint8_t* const v_dst = dec->cache_v_ + cache_id * 8 * uv_bps + mb_x * 8; Dither8x8(&dec->dithering_rg_, u_dst, uv_bps, data->dither_); Dither8x8(&dec->dithering_rg_, v_dst, uv_bps, data->dither_); } } } //------------------------------------------------------------------------------ // This function is called after a row of macroblocks is finished decoding. // It also takes into account the following restrictions: // * In case of in-loop filtering, we must hold off sending some of the bottom // pixels as they are yet unfiltered. They will be when the next macroblock // row is decoded. Meanwhile, we must preserve them by rotating them in the // cache area. This doesn't hold for the very bottom row of the uncropped // picture of course. // * we must clip the remaining pixels against the cropping area. The VP8Io // struct must have the following fields set correctly before calling put(): #define MACROBLOCK_VPOS(mb_y) ((mb_y) * 16) // vertical position of a MB // Finalize and transmit a complete row. Return false in case of user-abort. static int FinishRow(VP8Decoder* const dec, VP8Io* const io) { int ok = 1; const VP8ThreadContext* const ctx = &dec->thread_ctx_; const int cache_id = ctx->id_; 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 y_offset = cache_id * 16 * dec->cache_y_stride_; const int uv_offset = cache_id * 8 * dec->cache_uv_stride_; uint8_t* const ydst = dec->cache_y_ - ysize + y_offset; uint8_t* const udst = dec->cache_u_ - uvsize + uv_offset; uint8_t* const vdst = dec->cache_v_ - uvsize + uv_offset; const int mb_y = ctx->mb_y_; const int is_first_row = (mb_y == 0); const int is_last_row = (mb_y >= dec->br_mb_y_ - 1); if (dec->mt_method_ == 2) { ReconstructRow(dec, ctx); } if (ctx->filter_row_) { FilterRow(dec); } if (dec->dither_) { DitherRow(dec); } if (io->put != NULL) { int y_start = MACROBLOCK_VPOS(mb_y); int y_end = MACROBLOCK_VPOS(mb_y + 1); if (!is_first_row) { y_start -= extra_y_rows; io->y = ydst; io->u = udst; io->v = vdst; } else { io->y = dec->cache_y_ + y_offset; io->u = dec->cache_u_ + uv_offset; io->v = dec->cache_v_ + uv_offset; } if (!is_last_row) { y_end -= extra_y_rows; } if (y_end > io->crop_bottom) { y_end = io->crop_bottom; // make sure we don't overflow on last row. } io->a = NULL; if (dec->alpha_data_ != NULL && y_start < y_end) { // TODO(skal): testing presence of alpha with dec->alpha_data_ is not a // good idea. 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."); } } if (y_start < io->crop_top) { const int delta_y = io->crop_top - y_start; y_start = io->crop_top; assert(!(delta_y & 1)); io->y += dec->cache_y_stride_ * delta_y; io->u += dec->cache_uv_stride_ * (delta_y >> 1); io->v += dec->cache_uv_stride_ * (delta_y >> 1); if (io->a != NULL) { io->a += io->width * delta_y; } } if (y_start < y_end) { io->y += io->crop_left; io->u += io->crop_left >> 1; io->v += io->crop_left >> 1; if (io->a != NULL) { io->a += io->crop_left; } io->mb_y = y_start - io->crop_top; io->mb_w = io->crop_right - io->crop_left; io->mb_h = y_end - y_start; ok = io->put(io); } } // rotate top samples if needed if (cache_id + 1 == dec->num_caches_) { if (!is_last_row) { memcpy(dec->cache_y_ - ysize, ydst + 16 * dec->cache_y_stride_, ysize); memcpy(dec->cache_u_ - uvsize, udst + 8 * dec->cache_uv_stride_, uvsize); memcpy(dec->cache_v_ - uvsize, vdst + 8 * dec->cache_uv_stride_, uvsize); } } return ok; } #undef MACROBLOCK_VPOS //------------------------------------------------------------------------------ int VP8ProcessRow(VP8Decoder* const dec, VP8Io* const io) { int ok = 1; VP8ThreadContext* const ctx = &dec->thread_ctx_; const int filter_row = (dec->filter_type_ > 0) && (dec->mb_y_ >= dec->tl_mb_y_) && (dec->mb_y_ <= dec->br_mb_y_); if (dec->mt_method_ == 0) { // ctx->id_ and ctx->f_info_ are already set ctx->mb_y_ = dec->mb_y_; ctx->filter_row_ = filter_row; ReconstructRow(dec, ctx); ok = FinishRow(dec, io); } else { WebPWorker* const worker = &dec->worker_; // Finish previous job *before* updating context ok &= WebPWorkerSync(worker); assert(worker->status_ == OK); if (ok) { // spawn a new deblocking/output job ctx->io_ = *io; ctx->id_ = dec->cache_id_; ctx->mb_y_ = dec->mb_y_; ctx->filter_row_ = filter_row; if (dec->mt_method_ == 2) { // swap macroblock data VP8MBData* const tmp = ctx->mb_data_; ctx->mb_data_ = dec->mb_data_; dec->mb_data_ = tmp; } else { // perform reconstruction directly in main thread ReconstructRow(dec, ctx); } if (filter_row) { // swap filter info VP8FInfo* const tmp = ctx->f_info_; ctx->f_info_ = dec->f_info_; dec->f_info_ = tmp; } WebPWorkerLaunch(worker); // (reconstruct)+filter in parallel if (++dec->cache_id_ == dec->num_caches_) { dec->cache_id_ = 0; } } } return ok; } //------------------------------------------------------------------------------ // Finish setting up the decoding parameter once user's setup() is called. VP8StatusCode VP8EnterCritical(VP8Decoder* const dec, VP8Io* const io) { // Call setup() first. This may trigger additional decoding features on 'io'. // Note: Afterward, we must call teardown() no matter what. if (io->setup != NULL && !io->setup(io)) { VP8SetError(dec, VP8_STATUS_USER_ABORT, "Frame setup failed"); return dec->status_; } // Disable filtering per user request if (io->bypass_filtering) { dec->filter_type_ = 0; } // TODO(skal): filter type / strength / sharpness forcing // Define the area where we can skip in-loop filtering, in case of cropping. // // 'Simple' filter reads two luma samples outside of the macroblock // and filters one. It doesn't filter the chroma samples. Hence, we can // avoid doing the in-loop filtering before crop_top/crop_left position. // For the 'Complex' filter, 3 samples are read and up to 3 are filtered. // Means: there's a dependency chain that goes all the way up to the // top-left corner of the picture (MB #0). We must filter all the previous // macroblocks. // TODO(skal): add an 'approximate_decoding' option, that won't produce // a 1:1 bit-exactness for complex filtering? { const int extra_pixels = kFilterExtraRows[dec->filter_type_]; if (dec->filter_type_ == 2) { // For complex filter, we need to preserve the dependency chain. dec->tl_mb_x_ = 0; dec->tl_mb_y_ = 0; } else { // For simple filter, we can filter only the cropped region. // We include 'extra_pixels' on the other side of the boundary, since // vertical or horizontal filtering of the previous macroblock can // modify some abutting pixels. dec->tl_mb_x_ = (io->crop_left - extra_pixels) >> 4; dec->tl_mb_y_ = (io->crop_top - extra_pixels) >> 4; if (dec->tl_mb_x_ < 0) dec->tl_mb_x_ = 0; if (dec->tl_mb_y_ < 0) dec->tl_mb_y_ = 0; } // We need some 'extra' pixels on the right/bottom. dec->br_mb_y_ = (io->crop_bottom + 15 + extra_pixels) >> 4; dec->br_mb_x_ = (io->crop_right + 15 + extra_pixels) >> 4; if (dec->br_mb_x_ > dec->mb_w_) { dec->br_mb_x_ = dec->mb_w_; } if (dec->br_mb_y_ > dec->mb_h_) { dec->br_mb_y_ = dec->mb_h_; } } PrecomputeFilterStrengths(dec); return VP8_STATUS_OK; } int VP8ExitCritical(VP8Decoder* const dec, VP8Io* const io) { int ok = 1; if (dec->mt_method_ > 0) { ok = WebPWorkerSync(&dec->worker_); } if (io->teardown != NULL) { io->teardown(io); } return ok; } //------------------------------------------------------------------------------ // For multi-threaded decoding we need to use 3 rows of 16 pixels as delay line. // // Reason is: the deblocking filter cannot deblock the bottom horizontal edges // immediately, and needs to wait for first few rows of the next macroblock to // be decoded. Hence, deblocking is lagging behind by 4 or 8 pixels (depending // on strength). // With two threads, the vertical positions of the rows being decoded are: // Decode: [ 0..15][16..31][32..47][48..63][64..79][... // Deblock: [ 0..11][12..27][28..43][44..59][... // If we use two threads and two caches of 16 pixels, the sequence would be: // Decode: [ 0..15][16..31][ 0..15!!][16..31][ 0..15][... // Deblock: [ 0..11][12..27!!][-4..11][12..27][... // The problem occurs during row [12..15!!] that both the decoding and // deblocking threads are writing simultaneously. // With 3 cache lines, one get a safe write pattern: // Decode: [ 0..15][16..31][32..47][ 0..15][16..31][32..47][0.. // Deblock: [ 0..11][12..27][28..43][-4..11][12..27][28... // Note that multi-threaded output _without_ deblocking can make use of two // cache lines of 16 pixels only, since there's no lagging behind. The decoding // and output process have non-concurrent writing: // Decode: [ 0..15][16..31][ 0..15][16..31][... // io->put: [ 0..15][16..31][ 0..15][... #define MT_CACHE_LINES 3 #define ST_CACHE_LINES 1 // 1 cache row only for single-threaded case // Initialize multi/single-thread worker static int InitThreadContext(VP8Decoder* const dec) { dec->cache_id_ = 0; if (dec->mt_method_ > 0) { WebPWorker* const worker = &dec->worker_; if (!WebPWorkerReset(worker)) { return VP8SetError(dec, VP8_STATUS_OUT_OF_MEMORY, "thread initialization failed."); } worker->data1 = dec; worker->data2 = (void*)&dec->thread_ctx_.io_; worker->hook = (WebPWorkerHook)FinishRow; dec->num_caches_ = (dec->filter_type_ > 0) ? MT_CACHE_LINES : MT_CACHE_LINES - 1; } else { dec->num_caches_ = ST_CACHE_LINES; } return 1; } int VP8GetThreadMethod(const WebPDecoderOptions* const options, const WebPHeaderStructure* const headers, int width, int height) { if (options == NULL || options->use_threads == 0) { return 0; } (void)headers; (void)width; (void)height; assert(!headers->is_lossless); #if defined(WEBP_USE_THREAD) if (width < MIN_WIDTH_FOR_THREADS) return 0; // TODO(skal): tune the heuristic further #if 0 if (height < 2 * width) return 2; #endif return 2; #else // !WEBP_USE_THREAD return 0; #endif } #undef MT_CACHE_LINES #undef ST_CACHE_LINES //------------------------------------------------------------------------------ // Memory setup static int AllocateMemory(VP8Decoder* const dec) { const int num_caches = dec->num_caches_; const int mb_w = dec->mb_w_; // Note: we use 'size_t' when there's no overflow risk, uint64_t otherwise. const size_t intra_pred_mode_size = 4 * mb_w * sizeof(uint8_t); const size_t top_size = sizeof(VP8TopSamples) * mb_w; const size_t mb_info_size = (mb_w + 1) * sizeof(VP8MB); const size_t f_info_size = (dec->filter_type_ > 0) ? mb_w * (dec->mt_method_ > 0 ? 2 : 1) * sizeof(VP8FInfo) : 0; const size_t yuv_size = YUV_SIZE * sizeof(*dec->yuv_b_); const size_t mb_data_size = (dec->mt_method_ == 2 ? 2 : 1) * mb_w * sizeof(*dec->mb_data_); const size_t cache_height = (16 * num_caches + kFilterExtraRows[dec->filter_type_]) * 3 / 2; const size_t cache_size = top_size * cache_height; // alpha_size is the only one that scales as width x height. const uint64_t alpha_size = (dec->alpha_data_ != NULL) ? (uint64_t)dec->pic_hdr_.width_ * dec->pic_hdr_.height_ : 0ULL; const uint64_t needed = (uint64_t)intra_pred_mode_size + top_size + mb_info_size + f_info_size + yuv_size + mb_data_size + cache_size + alpha_size + ALIGN_MASK; uint8_t* mem; if (needed != (size_t)needed) return 0; // check for overflow if (needed > dec->mem_size_) { free(dec->mem_); dec->mem_size_ = 0; dec->mem_ = WebPSafeMalloc(needed, sizeof(uint8_t)); if (dec->mem_ == NULL) { return VP8SetError(dec, VP8_STATUS_OUT_OF_MEMORY, "no memory during frame initialization."); } // down-cast is ok, thanks to WebPSafeAlloc() above. dec->mem_size_ = (size_t)needed; } mem = (uint8_t*)dec->mem_; dec->intra_t_ = (uint8_t*)mem; mem += intra_pred_mode_size; dec->yuv_t_ = (VP8TopSamples*)mem; mem += top_size; dec->mb_info_ = ((VP8MB*)mem) + 1; mem += mb_info_size; dec->f_info_ = f_info_size ? (VP8FInfo*)mem : NULL; mem += f_info_size; dec->thread_ctx_.id_ = 0; dec->thread_ctx_.f_info_ = dec->f_info_; if (dec->mt_method_ > 0) { // secondary cache line. The deblocking process need to make use of the // filtering strength from previous macroblock row, while the new ones // are being decoded in parallel. We'll just swap the pointers. dec->thread_ctx_.f_info_ += mb_w; } 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->mb_data_ = (VP8MBData*)mem; dec->thread_ctx_.mb_data_ = (VP8MBData*)mem; if (dec->mt_method_ == 2) { dec->thread_ctx_.mb_data_ += mb_w; } mem += mb_data_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 * num_caches * dec->cache_y_stride_ + extra_uv; dec->cache_v_ = dec->cache_u_ + 8 * num_caches * dec->cache_uv_stride_ + extra_uv; dec->cache_id_ = 0; } mem += cache_size; // alpha plane dec->alpha_plane_ = alpha_size ? (uint8_t*)mem : NULL; mem += alpha_size; assert(mem <= (uint8_t*)dec->mem_ + dec->mem_size_); // note: left/top-info is initialized once for all. memset(dec->mb_info_ - 1, 0, mb_info_size); VP8InitScanline(dec); // initialize left too. // initialize top memset(dec->intra_t_, B_DC_PRED, intra_pred_mode_size); return 1; } static void InitIo(VP8Decoder* const dec, VP8Io* io) { // prepare 'io' 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->a = NULL; } int VP8InitFrame(VP8Decoder* const dec, VP8Io* io) { if (!InitThreadContext(dec)) return 0; // call first. Sets dec->num_caches_. if (!AllocateMemory(dec)) return 0; InitIo(dec, io); VP8DspInit(); // Init critical function pointers and look-up tables. 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 int CheckMode(int mb_x, int mb_y, int mode) { if (mode == B_DC_PRED) { if (mb_x == 0) { return (mb_y == 0) ? B_DC_PRED_NOTOPLEFT : B_DC_PRED_NOLEFT; } else { return (mb_y == 0) ? B_DC_PRED_NOTOP : B_DC_PRED; } } return mode; } static void Copy32b(uint8_t* dst, uint8_t* src) { memcpy(dst, src, 4); } static WEBP_INLINE 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); } } } static void ReconstructRow(const VP8Decoder* const dec, const VP8ThreadContext* ctx) { int j; int mb_x; const int mb_y = ctx->mb_y_; const int cache_id = ctx->id_; 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; for (mb_x = 0; mb_x < dec->mb_w_; ++mb_x) { const VP8MBData* const block = ctx->mb_data_ + mb_x; // 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 (mb_x > 0) { 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 { 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 (mb_y > 0) { y_dst[-1 - BPS] = u_dst[-1 - BPS] = v_dst[-1 - BPS] = 129; } } { // bring top samples into the cache VP8TopSamples* const top_yuv = dec->yuv_t_ + mb_x; const int16_t* const coeffs = block->coeffs_; uint32_t bits = block->non_zero_y_; int n; if (mb_y > 0) { memcpy(y_dst - BPS, top_yuv[0].y, 16); memcpy(u_dst - BPS, top_yuv[0].u, 8); memcpy(v_dst - BPS, top_yuv[0].v, 8); } else if (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 (block->is_i4x4_) { // 4x4 uint32_t* const top_right = (uint32_t*)(y_dst - BPS + 16); if (mb_y > 0) { if (mb_x >= dec->mb_w_ - 1) { // on rightmost border memset(top_right, top_yuv[0].y[15], sizeof(*top_right)); } else { memcpy(top_right, top_yuv[1].y, 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 residuals for all 4x4 blocks in turn. for (n = 0; n < 16; ++n, bits <<= 2) { uint8_t* const dst = y_dst + kScan[n]; VP8PredLuma4[block->imodes_[n]](dst); DoTransform(bits, coeffs + n * 16, dst); } } else { // 16x16 const int pred_func = CheckMode(mb_x, mb_y, block->imodes_[0]); VP8PredLuma16[pred_func](y_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(mb_x, mb_y, block->uvmode_); VP8PredChroma8[pred_func](u_dst); VP8PredChroma8[pred_func](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 if (mb_y < dec->mb_h_ - 1) { memcpy(top_yuv[0].y, y_dst + 15 * BPS, 16); memcpy(top_yuv[0].u, u_dst + 7 * BPS, 8); memcpy(top_yuv[0].v, v_dst + 7 * BPS, 8); } } // Transfer reconstructed samples from yuv_b_ cache to final destination. { const int y_offset = cache_id * 16 * dec->cache_y_stride_; const int uv_offset = cache_id * 8 * dec->cache_uv_stride_; uint8_t* const y_out = dec->cache_y_ + mb_x * 16 + y_offset; uint8_t* const u_out = dec->cache_u_ + mb_x * 8 + uv_offset; uint8_t* const v_out = dec->cache_v_ + mb_x * 8 + uv_offset; for (j = 0; j < 16; ++j) { memcpy(y_out + j * dec->cache_y_stride_, y_dst + j * BPS, 16); } for (j = 0; j < 8; ++j) { memcpy(u_out + j * dec->cache_uv_stride_, u_dst + j * BPS, 8); memcpy(v_out + j * dec->cache_uv_stride_, v_dst + j * BPS, 8); } } } } //------------------------------------------------------------------------------