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// Copyright 2011 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Header syntax writing
//
// Author: Skal (pascal.massimino@gmail.com)
#include <assert.h>
#include "src/utils/utils.h"
#include "src/webp/format_constants.h" // RIFF constants
#include "src/webp/mux_types.h" // ALPHA_FLAG
#include "src/enc/vp8i_enc.h"
//------------------------------------------------------------------------------
// Helper functions
static int IsVP8XNeeded(const VP8Encoder* const enc) {
return !!enc->has_alpha_; // Currently the only case when VP8X is needed.
// This could change in the future.
}
static int PutPaddingByte(const WebPPicture* const pic) {
const uint8_t pad_byte[1] = { 0 };
return !!pic->writer(pad_byte, 1, pic);
}
//------------------------------------------------------------------------------
// Writers for header's various pieces (in order of appearance)
static WebPEncodingError PutRIFFHeader(const VP8Encoder* const enc,
size_t riff_size) {
const WebPPicture* const pic = enc->pic_;
uint8_t riff[RIFF_HEADER_SIZE] = {
'R', 'I', 'F', 'F', 0, 0, 0, 0, 'W', 'E', 'B', 'P'
};
assert(riff_size == (uint32_t)riff_size);
PutLE32(riff + TAG_SIZE, (uint32_t)riff_size);
if (!pic->writer(riff, sizeof(riff), pic)) {
return VP8_ENC_ERROR_BAD_WRITE;
}
return VP8_ENC_OK;
}
static WebPEncodingError PutVP8XHeader(const VP8Encoder* const enc) {
const WebPPicture* const pic = enc->pic_;
uint8_t vp8x[CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE] = {
'V', 'P', '8', 'X'
};
uint32_t flags = 0;
assert(IsVP8XNeeded(enc));
assert(pic->width >= 1 && pic->height >= 1);
assert(pic->width <= MAX_CANVAS_SIZE && pic->height <= MAX_CANVAS_SIZE);
if (enc->has_alpha_) {
flags |= ALPHA_FLAG;
}
PutLE32(vp8x + TAG_SIZE, VP8X_CHUNK_SIZE);
PutLE32(vp8x + CHUNK_HEADER_SIZE, flags);
PutLE24(vp8x + CHUNK_HEADER_SIZE + 4, pic->width - 1);
PutLE24(vp8x + CHUNK_HEADER_SIZE + 7, pic->height - 1);
if (!pic->writer(vp8x, sizeof(vp8x), pic)) {
return VP8_ENC_ERROR_BAD_WRITE;
}
return VP8_ENC_OK;
}
static WebPEncodingError PutAlphaChunk(const VP8Encoder* const enc) {
const WebPPicture* const pic = enc->pic_;
uint8_t alpha_chunk_hdr[CHUNK_HEADER_SIZE] = {
'A', 'L', 'P', 'H'
};
assert(enc->has_alpha_);
// Alpha chunk header.
PutLE32(alpha_chunk_hdr + TAG_SIZE, enc->alpha_data_size_);
if (!pic->writer(alpha_chunk_hdr, sizeof(alpha_chunk_hdr), pic)) {
return VP8_ENC_ERROR_BAD_WRITE;
}
// Alpha chunk data.
if (!pic->writer(enc->alpha_data_, enc->alpha_data_size_, pic)) {
return VP8_ENC_ERROR_BAD_WRITE;
}
// Padding.
if ((enc->alpha_data_size_ & 1) && !PutPaddingByte(pic)) {
return VP8_ENC_ERROR_BAD_WRITE;
}
return VP8_ENC_OK;
}
static WebPEncodingError PutVP8Header(const WebPPicture* const pic,
size_t vp8_size) {
uint8_t vp8_chunk_hdr[CHUNK_HEADER_SIZE] = {
'V', 'P', '8', ' '
};
assert(vp8_size == (uint32_t)vp8_size);
PutLE32(vp8_chunk_hdr + TAG_SIZE, (uint32_t)vp8_size);
if (!pic->writer(vp8_chunk_hdr, sizeof(vp8_chunk_hdr), pic)) {
return VP8_ENC_ERROR_BAD_WRITE;
}
return VP8_ENC_OK;
}
static WebPEncodingError PutVP8FrameHeader(const WebPPicture* const pic,
int profile, size_t size0) {
uint8_t vp8_frm_hdr[VP8_FRAME_HEADER_SIZE];
uint32_t bits;
if (size0 >= VP8_MAX_PARTITION0_SIZE) { // partition #0 is too big to fit
return VP8_ENC_ERROR_PARTITION0_OVERFLOW;
}
// Paragraph 9.1.
bits = 0 // keyframe (1b)
| (profile << 1) // profile (3b)
| (1 << 4) // visible (1b)
| ((uint32_t)size0 << 5); // partition length (19b)
vp8_frm_hdr[0] = (bits >> 0) & 0xff;
vp8_frm_hdr[1] = (bits >> 8) & 0xff;
vp8_frm_hdr[2] = (bits >> 16) & 0xff;
// signature
vp8_frm_hdr[3] = (VP8_SIGNATURE >> 16) & 0xff;
vp8_frm_hdr[4] = (VP8_SIGNATURE >> 8) & 0xff;
vp8_frm_hdr[5] = (VP8_SIGNATURE >> 0) & 0xff;
// dimensions
vp8_frm_hdr[6] = pic->width & 0xff;
vp8_frm_hdr[7] = pic->width >> 8;
vp8_frm_hdr[8] = pic->height & 0xff;
vp8_frm_hdr[9] = pic->height >> 8;
if (!pic->writer(vp8_frm_hdr, sizeof(vp8_frm_hdr), pic)) {
return VP8_ENC_ERROR_BAD_WRITE;
}
return VP8_ENC_OK;
}
// WebP Headers.
static int PutWebPHeaders(const VP8Encoder* const enc, size_t size0,
size_t vp8_size, size_t riff_size) {
WebPPicture* const pic = enc->pic_;
WebPEncodingError err = VP8_ENC_OK;
// RIFF header.
err = PutRIFFHeader(enc, riff_size);
if (err != VP8_ENC_OK) goto Error;
// VP8X.
if (IsVP8XNeeded(enc)) {
err = PutVP8XHeader(enc);
if (err != VP8_ENC_OK) goto Error;
}
// Alpha.
if (enc->has_alpha_) {
err = PutAlphaChunk(enc);
if (err != VP8_ENC_OK) goto Error;
}
// VP8 header.
err = PutVP8Header(pic, vp8_size);
if (err != VP8_ENC_OK) goto Error;
// VP8 frame header.
err = PutVP8FrameHeader(pic, enc->profile_, size0);
if (err != VP8_ENC_OK) goto Error;
// All OK.
return 1;
// Error.
Error:
return WebPEncodingSetError(pic, err);
}
// Segmentation header
static void PutSegmentHeader(VP8BitWriter* const bw,
const VP8Encoder* const enc) {
const VP8EncSegmentHeader* const hdr = &enc->segment_hdr_;
const VP8EncProba* const proba = &enc->proba_;
if (VP8PutBitUniform(bw, (hdr->num_segments_ > 1))) {
// We always 'update' the quant and filter strength values
const int update_data = 1;
int s;
VP8PutBitUniform(bw, hdr->update_map_);
if (VP8PutBitUniform(bw, update_data)) {
// we always use absolute values, not relative ones
VP8PutBitUniform(bw, 1); // (segment_feature_mode = 1. Paragraph 9.3.)
for (s = 0; s < NUM_MB_SEGMENTS; ++s) {
VP8PutSignedBits(bw, enc->dqm_[s].quant_, 7);
}
for (s = 0; s < NUM_MB_SEGMENTS; ++s) {
VP8PutSignedBits(bw, enc->dqm_[s].fstrength_, 6);
}
}
if (hdr->update_map_) {
for (s = 0; s < 3; ++s) {
if (VP8PutBitUniform(bw, (proba->segments_[s] != 255u))) {
VP8PutBits(bw, proba->segments_[s], 8);
}
}
}
}
}
// Filtering parameters header
static void PutFilterHeader(VP8BitWriter* const bw,
const VP8EncFilterHeader* const hdr) {
const int use_lf_delta = (hdr->i4x4_lf_delta_ != 0);
VP8PutBitUniform(bw, hdr->simple_);
VP8PutBits(bw, hdr->level_, 6);
VP8PutBits(bw, hdr->sharpness_, 3);
if (VP8PutBitUniform(bw, use_lf_delta)) {
// '0' is the default value for i4x4_lf_delta_ at frame #0.
const int need_update = (hdr->i4x4_lf_delta_ != 0);
if (VP8PutBitUniform(bw, need_update)) {
// we don't use ref_lf_delta => emit four 0 bits
VP8PutBits(bw, 0, 4);
// we use mode_lf_delta for i4x4
VP8PutSignedBits(bw, hdr->i4x4_lf_delta_, 6);
VP8PutBits(bw, 0, 3); // all others unused
}
}
}
// Nominal quantization parameters
static void PutQuant(VP8BitWriter* const bw,
const VP8Encoder* const enc) {
VP8PutBits(bw, enc->base_quant_, 7);
VP8PutSignedBits(bw, enc->dq_y1_dc_, 4);
VP8PutSignedBits(bw, enc->dq_y2_dc_, 4);
VP8PutSignedBits(bw, enc->dq_y2_ac_, 4);
VP8PutSignedBits(bw, enc->dq_uv_dc_, 4);
VP8PutSignedBits(bw, enc->dq_uv_ac_, 4);
}
// Partition sizes
static int EmitPartitionsSize(const VP8Encoder* const enc,
WebPPicture* const pic) {
uint8_t buf[3 * (MAX_NUM_PARTITIONS - 1)];
int p;
for (p = 0; p < enc->num_parts_ - 1; ++p) {
const size_t part_size = VP8BitWriterSize(enc->parts_ + p);
if (part_size >= VP8_MAX_PARTITION_SIZE) {
return WebPEncodingSetError(pic, VP8_ENC_ERROR_PARTITION_OVERFLOW);
}
buf[3 * p + 0] = (part_size >> 0) & 0xff;
buf[3 * p + 1] = (part_size >> 8) & 0xff;
buf[3 * p + 2] = (part_size >> 16) & 0xff;
}
return p ? pic->writer(buf, 3 * p, pic) : 1;
}
//------------------------------------------------------------------------------
static int GeneratePartition0(VP8Encoder* const enc) {
VP8BitWriter* const bw = &enc->bw_;
const int mb_size = enc->mb_w_ * enc->mb_h_;
uint64_t pos1, pos2, pos3;
pos1 = VP8BitWriterPos(bw);
if (!VP8BitWriterInit(bw, mb_size * 7 / 8)) { // ~7 bits per macroblock
return WebPEncodingSetError(enc->pic_, VP8_ENC_ERROR_OUT_OF_MEMORY);
}
VP8PutBitUniform(bw, 0); // colorspace
VP8PutBitUniform(bw, 0); // clamp type
PutSegmentHeader(bw, enc);
PutFilterHeader(bw, &enc->filter_hdr_);
VP8PutBits(bw, enc->num_parts_ == 8 ? 3 :
enc->num_parts_ == 4 ? 2 :
enc->num_parts_ == 2 ? 1 : 0, 2);
PutQuant(bw, enc);
VP8PutBitUniform(bw, 0); // no proba update
VP8WriteProbas(bw, &enc->proba_);
pos2 = VP8BitWriterPos(bw);
VP8CodeIntraModes(enc);
VP8BitWriterFinish(bw);
pos3 = VP8BitWriterPos(bw);
#if !defined(WEBP_DISABLE_STATS)
if (enc->pic_->stats) {
enc->pic_->stats->header_bytes[0] = (int)((pos2 - pos1 + 7) >> 3);
enc->pic_->stats->header_bytes[1] = (int)((pos3 - pos2 + 7) >> 3);
enc->pic_->stats->alpha_data_size = (int)enc->alpha_data_size_;
}
#else
(void)pos1;
(void)pos2;
(void)pos3;
#endif
if (bw->error_) {
return WebPEncodingSetError(enc->pic_, VP8_ENC_ERROR_OUT_OF_MEMORY);
}
return 1;
}
void VP8EncFreeBitWriters(VP8Encoder* const enc) {
int p;
VP8BitWriterWipeOut(&enc->bw_);
for (p = 0; p < enc->num_parts_; ++p) {
VP8BitWriterWipeOut(enc->parts_ + p);
}
}
int VP8EncWrite(VP8Encoder* const enc) {
WebPPicture* const pic = enc->pic_;
VP8BitWriter* const bw = &enc->bw_;
const int task_percent = 19;
const int percent_per_part = task_percent / enc->num_parts_;
const int final_percent = enc->percent_ + task_percent;
int ok = 0;
size_t vp8_size, pad, riff_size;
int p;
// Partition #0 with header and partition sizes
ok = GeneratePartition0(enc);
if (!ok) return 0;
// Compute VP8 size
vp8_size = VP8_FRAME_HEADER_SIZE +
VP8BitWriterSize(bw) +
3 * (enc->num_parts_ - 1);
for (p = 0; p < enc->num_parts_; ++p) {
vp8_size += VP8BitWriterSize(enc->parts_ + p);
}
pad = vp8_size & 1;
vp8_size += pad;
// Compute RIFF size
// At the minimum it is: "WEBPVP8 nnnn" + VP8 data size.
riff_size = TAG_SIZE + CHUNK_HEADER_SIZE + vp8_size;
if (IsVP8XNeeded(enc)) { // Add size for: VP8X header + data.
riff_size += CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE;
}
if (enc->has_alpha_) { // Add size for: ALPH header + data.
const uint32_t padded_alpha_size = enc->alpha_data_size_ +
(enc->alpha_data_size_ & 1);
riff_size += CHUNK_HEADER_SIZE + padded_alpha_size;
}
// RIFF size should fit in 32-bits.
if (riff_size > 0xfffffffeU) {
return WebPEncodingSetError(pic, VP8_ENC_ERROR_FILE_TOO_BIG);
}
// Emit headers and partition #0
{
const uint8_t* const part0 = VP8BitWriterBuf(bw);
const size_t size0 = VP8BitWriterSize(bw);
ok = ok && PutWebPHeaders(enc, size0, vp8_size, riff_size)
&& pic->writer(part0, size0, pic)
&& EmitPartitionsSize(enc, pic);
VP8BitWriterWipeOut(bw); // will free the internal buffer.
}
// Token partitions
for (p = 0; p < enc->num_parts_; ++p) {
const uint8_t* const buf = VP8BitWriterBuf(enc->parts_ + p);
const size_t size = VP8BitWriterSize(enc->parts_ + p);
if (size) ok = ok && pic->writer(buf, size, pic);
VP8BitWriterWipeOut(enc->parts_ + p); // will free the internal buffer.
ok = ok && WebPReportProgress(pic, enc->percent_ + percent_per_part,
&enc->percent_);
}
// Padding byte
if (ok && pad) {
ok = PutPaddingByte(pic);
}
enc->coded_size_ = (int)(CHUNK_HEADER_SIZE + riff_size);
ok = ok && WebPReportProgress(pic, final_percent, &enc->percent_);
return ok;
}
//------------------------------------------------------------------------------