// Copyright 2011 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/
// -----------------------------------------------------------------------------
//
// Header syntax writing
//
// Author: Skal (pascal.massimino@gmail.com)
#include <assert.h>
#include <math.h>
#include "vp8enci.h"
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
#define KSIGNATURE 0x9d012a
#define KHEADER_SIZE 10
#define KRIFF_SIZE 20
#define KSIZE_OFFSET (KRIFF_SIZE - 8)
#define MAX_PARTITION0_SIZE (1 << 19) // max size of mode partition
#define MAX_PARTITION_SIZE (1 << 24) // max size for token partition
//-----------------------------------------------------------------------------
// Writers for header's various pieces (in order of appearance)
// Main keyframe header
static void PutLE32(uint8_t* const data, uint32_t val) {
data[0] = (val >> 0) & 0xff;
data[1] = (val >> 8) & 0xff;
data[2] = (val >> 16) & 0xff;
data[3] = (val >> 24) & 0xff;
}
static int PutHeader(int profile, size_t size0, size_t total_size,
WebPPicture* const pic) {
uint8_t buf[KHEADER_SIZE];
uint8_t RIFF[KRIFF_SIZE] = {
'R', 'I', 'F', 'F', 0, 0, 0, 0, 'W', 'E', 'B', 'P', 'V', 'P', '8', ' '
};
uint32_t bits;
if (size0 >= MAX_PARTITION0_SIZE) { // partition #0 is too big to fit
return WebPEncodingSetError(pic, VP8_ENC_ERROR_PARTITION0_OVERFLOW);
}
PutLE32(RIFF + 4, total_size + KSIZE_OFFSET);
PutLE32(RIFF + 16, total_size);
if (!pic->writer(RIFF, sizeof(RIFF), pic)) {
return WebPEncodingSetError(pic, VP8_ENC_ERROR_BAD_WRITE);
}
bits = 0 // keyframe (1b)
| (profile << 1) // profile (3b)
| (1 << 4) // visible (1b)
| (size0 << 5); // partition length (19b)
buf[0] = bits & 0xff;
buf[1] = (bits >> 8) & 0xff;
buf[2] = (bits >> 16) & 0xff;
// signature
buf[3] = (KSIGNATURE >> 16) & 0xff;
buf[4] = (KSIGNATURE >> 8) & 0xff;
buf[5] = (KSIGNATURE >> 0) & 0xff;
// dimensions
buf[6] = pic->width & 0xff;
buf[7] = pic->width >> 8;
buf[8] = pic->height & 0xff;
buf[9] = pic->height >> 8;
return pic->writer(buf, sizeof(buf), pic);
}
// Segmentation header
static void PutSegmentHeader(VP8BitWriter* const bw,
const VP8Encoder* const enc) {
const VP8SegmentHeader* const hdr = &enc->segment_hdr_;
const VP8Proba* 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) {
VP8PutSignedValue(bw, enc->dqm_[s].quant_, 7);
}
for (s = 0; s < NUM_MB_SEGMENTS; ++s) {
VP8PutSignedValue(bw, enc->dqm_[s].fstrength_, 6);
}
}
if (hdr->update_map_) {
for (s = 0; s < 3; ++s) {
if (VP8PutBitUniform(bw, (proba->segments_[s] != 255u))) {
VP8PutValue(bw, proba->segments_[s], 8);
}
}
}
}
}
// Filtering parameters header
static void PutFilterHeader(VP8BitWriter* const bw,
const VP8FilterHeader* const hdr) {
const int use_lf_delta = (hdr->i4x4_lf_delta_ != 0);
VP8PutBitUniform(bw, hdr->simple_);
VP8PutValue(bw, hdr->level_, 6);
VP8PutValue(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
VP8PutValue(bw, 0, 4);
// we use mode_lf_delta for i4x4
VP8PutSignedValue(bw, hdr->i4x4_lf_delta_, 6);
VP8PutValue(bw, 0, 3); // all others unused
}
}
}
// Nominal quantization parameters
static void PutQuant(VP8BitWriter* const bw,
const VP8Encoder* const enc) {
VP8PutValue(bw, enc->base_quant_, 7);
VP8PutSignedValue(bw, enc->dq_y1_dc_, 4);
VP8PutSignedValue(bw, enc->dq_y2_dc_, 4);
VP8PutSignedValue(bw, enc->dq_y2_ac_, 4);
VP8PutSignedValue(bw, enc->dq_uv_dc_, 4);
VP8PutSignedValue(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 >= 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;
}
//-----------------------------------------------------------------------------
#ifdef WEBP_EXPERIMENTAL_FEATURES
#define KTRAILER_SIZE 8
static void PutLE24(uint8_t* buf, size_t value) {
buf[0] = (value >> 0) & 0xff;
buf[1] = (value >> 8) & 0xff;
buf[2] = (value >> 16) & 0xff;
}
static int WriteExtensions(VP8Encoder* const enc) {
uint8_t buffer[KTRAILER_SIZE];
VP8BitWriter* const bw = &enc->bw_;
WebPPicture* const pic = enc->pic_;
// Layer (bytes 0..3)
PutLE24(buffer + 0, enc->layer_data_size_);
buffer[3] = enc->pic_->colorspace & WEBP_CSP_UV_MASK;
if (enc->layer_data_size_ > 0) {
assert(enc->use_layer_);
// append layer data to last partition
if (!VP8BitWriterAppend(&enc->parts_[enc->num_parts_ - 1],
enc->layer_data_, enc->layer_data_size_)) {
return WebPEncodingSetError(pic, VP8_ENC_ERROR_BITSTREAM_OUT_OF_MEMORY);
}
}
// Alpha (bytes 4..6)
PutLE24(buffer + 4, enc->alpha_data_size_);
if (enc->alpha_data_size_ > 0) {
assert(enc->has_alpha_);
if (!VP8BitWriterAppend(bw, enc->alpha_data_, enc->alpha_data_size_)) {
return WebPEncodingSetError(pic, VP8_ENC_ERROR_BITSTREAM_OUT_OF_MEMORY);
}
}
buffer[KTRAILER_SIZE - 1] = 0x01; // marker
if (!VP8BitWriterAppend(bw, buffer, KTRAILER_SIZE)) {
return WebPEncodingSetError(pic, VP8_ENC_ERROR_BITSTREAM_OUT_OF_MEMORY);
}
return 1;
}
#endif /* WEBP_EXPERIMENTAL_FEATURES */
//-----------------------------------------------------------------------------
static size_t GeneratePartition0(VP8Encoder* const enc) {
VP8BitWriter* const bw = &enc->bw_;
const int mb_size = enc->mb_w_ * enc->mb_h_;
uint64_t pos1, pos2, pos3;
#ifdef WEBP_EXPERIMENTAL_FEATURES
const int need_extensions = enc->has_alpha_ || enc->use_layer_;
#endif
pos1 = VP8BitWriterPos(bw);
VP8BitWriterInit(bw, mb_size * 7 / 8); // ~7 bits per macroblock
#ifdef WEBP_EXPERIMENTAL_FEATURES
VP8PutBitUniform(bw, need_extensions); // extensions
#else
VP8PutBitUniform(bw, 0); // colorspace
#endif
VP8PutBitUniform(bw, 0); // clamp type
PutSegmentHeader(bw, enc);
PutFilterHeader(bw, &enc->filter_hdr_);
VP8PutValue(bw, enc->config_->partitions, 2);
PutQuant(bw, enc);
VP8PutBitUniform(bw, 0); // no proba update
VP8WriteProbas(bw, &enc->proba_);
pos2 = VP8BitWriterPos(bw);
VP8CodeIntraModes(enc);
VP8BitWriterFinish(bw);
#ifdef WEBP_EXPERIMENTAL_FEATURES
if (need_extensions && !WriteExtensions(enc)) {
return 0;
}
#endif
pos3 = VP8BitWriterPos(bw);
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 = enc->alpha_data_size_;
enc->pic_->stats->layer_data_size = enc->layer_data_size_;
}
return !bw->error_;
}
int VP8EncWrite(VP8Encoder* const enc) {
WebPPicture* const pic = enc->pic_;
VP8BitWriter* const bw = &enc->bw_;
int ok = 0;
size_t coded_size, pad;
int p;
// Partition #0 with header and partition sizes
ok = GeneratePartition0(enc);
// Compute total size (for the RIFF header)
coded_size = KHEADER_SIZE + VP8BitWriterSize(bw) + 3 * (enc->num_parts_ - 1);
for (p = 0; p < enc->num_parts_; ++p) {
coded_size += VP8BitWriterSize(enc->parts_ + p);
}
pad = coded_size & 1;
coded_size += pad;
// Emit headers and partition #0
{
const uint8_t* const part0 = VP8BitWriterBuf(bw);
const size_t size0 = VP8BitWriterSize(bw);
ok = ok && PutHeader(enc->profile_, size0, coded_size, pic)
&& pic->writer(part0, size0, pic)
&& EmitPartitionsSize(enc, pic);
free((void*)part0);
}
// 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);
free((void*)buf);
}
// Padding byte
if (ok && pad) {
const uint8_t pad_byte[1] = { 0 };
ok = pic->writer(pad_byte, 1, pic);
}
enc->coded_size_ = coded_size + KRIFF_SIZE;
return ok;
}
//-----------------------------------------------------------------------------
#if defined(__cplusplus) || defined(c_plusplus)
} // extern "C"
#endif