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src/Source/LibWebP/src/enc/enc.syntax.c  view on Meta::CPAN

    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 (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_;
  }
  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;
  }
  // Sanity check.
  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;
}

//------------------------------------------------------------------------------