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authorwolfbeast <mcwerewolf@gmail.com>2017-07-24 13:19:25 +0200
committerwolfbeast <mcwerewolf@gmail.com>2018-02-03 09:57:42 +0100
commit2c1f833a092ef7af17f072749940bcb47da19aa6 (patch)
treee1904491a9c9a745d77df2225b679d921156affc /media/libwebp/dec/frame_dec.c
parentc0cfd6f89cd6b25cc8aaea1a1eb7bc004c88c206 (diff)
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Add libwebp 0.6.0 to the tree
Diffstat (limited to 'media/libwebp/dec/frame_dec.c')
-rw-r--r--media/libwebp/dec/frame_dec.c812
1 files changed, 812 insertions, 0 deletions
diff --git a/media/libwebp/dec/frame_dec.c b/media/libwebp/dec/frame_dec.c
new file mode 100644
index 000000000..f91e27f7c
--- /dev/null
+++ b/media/libwebp/dec/frame_dec.c
@@ -0,0 +1,812 @@
+// 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 <stdlib.h>
+#include "./vp8i_dec.h"
+#include "../utils/utils.h"
+
+//------------------------------------------------------------------------------
+// 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* const dst, const uint8_t* const 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;
+
+ // Initialize left-most block.
+ 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;
+ } else {
+ // 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);
+ }
+
+ // Reconstruct one row.
+ 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]);
+ }
+ }
+ {
+ // 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);
+ }
+
+ // 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);
+ }
+ }
+ }
+}
+
+//------------------------------------------------------------------------------
+// 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_) {
+ 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
+
+// minimal amp that will provide a non-zero dithering effect
+#define MIN_DITHER_AMP 4
+
+#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;
+ }
+ }
+ // potentially allow alpha dithering
+ dec->alpha_dithering_ = options->alpha_dithering_strength;
+ if (dec->alpha_dithering_ > 100) {
+ dec->alpha_dithering_ = 100;
+ } else if (dec->alpha_dithering_ < 0) {
+ dec->alpha_dithering_ = 0;
+ }
+ }
+}
+
+// Convert to range: [-2,2] for dither=50, [-4,4] for dither=100
+static void Dither8x8(VP8Random* const rg, uint8_t* dst, int bps, int amp) {
+ uint8_t dither[64];
+ int i;
+ for (i = 0; i < 8 * 8; ++i) {
+ dither[i] = VP8RandomBits2(rg, VP8_DITHER_AMP_BITS + 1, amp);
+ }
+ VP8DitherCombine8x8(dither, 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, io, 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 &= WebPGetWorkerInterface()->Sync(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;
+ }
+ // (reconstruct)+filter in parallel
+ WebPGetWorkerInterface()->Launch(worker);
+ 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 = WebPGetWorkerInterface()->Sync(&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 (!WebPGetWorkerInterface()->Reset(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 == NULL || !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 + WEBP_ALIGN_CST;
+ uint8_t* mem;
+
+ if (needed != (size_t)needed) return 0; // check for overflow
+ if (needed > dec->mem_size_) {
+ WebPSafeFree(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 WebPSafeMalloc() 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*)WEBP_ALIGN(mem);
+ assert((yuv_size & WEBP_ALIGN_CST) == 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* const 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;
+}
+
+//------------------------------------------------------------------------------