xref: /aosp_15_r20/external/libvpx/vp8/decoder/decodeframe.c (revision fb1b10ab9aebc7c7068eedab379b749d7e3900be)

/*
 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE 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.
 */

#include "vpx_config.h"
#include "vp8_rtcd.h"
#include "./vpx_scale_rtcd.h"
#include "onyxd_int.h"
#include "vp8/common/header.h"
#include "vp8/common/reconintra4x4.h"
#include "vp8/common/reconinter.h"
#include "detokenize.h"
#include "vp8/common/common.h"
#include "vp8/common/invtrans.h"
#include "vp8/common/alloccommon.h"
#include "vp8/common/entropymode.h"
#include "vp8/common/quant_common.h"
#include "vpx_scale/vpx_scale.h"
#include "vp8/common/reconintra.h"
#include "vp8/common/setupintrarecon.h"

#include "decodemv.h"
#include "vp8/common/extend.h"
#if CONFIG_ERROR_CONCEALMENT
#include "error_concealment.h"
#endif
#include "vpx_mem/vpx_mem.h"
#include "vp8/common/threading.h"
#include "decoderthreading.h"
#include "dboolhuff.h"
#include "vpx_dsp/vpx_dsp_common.h"

#include <assert.h>
#include <stdio.h>

void vp8cx_init_de_quantizer(VP8D_COMP *pbi) {
  int Q;
  VP8_COMMON *const pc = &pbi->common;

  for (Q = 0; Q < QINDEX_RANGE; ++Q) {
    pc->Y1dequant[Q][0] = (short)vp8_dc_quant(Q, pc->y1dc_delta_q);
    pc->Y2dequant[Q][0] = (short)vp8_dc2quant(Q, pc->y2dc_delta_q);
    pc->UVdequant[Q][0] = (short)vp8_dc_uv_quant(Q, pc->uvdc_delta_q);

    pc->Y1dequant[Q][1] = (short)vp8_ac_yquant(Q);
    pc->Y2dequant[Q][1] = (short)vp8_ac2quant(Q, pc->y2ac_delta_q);
    pc->UVdequant[Q][1] = (short)vp8_ac_uv_quant(Q, pc->uvac_delta_q);
  }
}

void vp8_mb_init_dequantizer(VP8D_COMP *pbi, MACROBLOCKD *xd) {
  int i;
  int QIndex;
  MB_MODE_INFO *mbmi = &xd->mode_info_context->mbmi;
  VP8_COMMON *const pc = &pbi->common;

  /* Decide whether to use the default or alternate baseline Q value. */
  if (xd->segmentation_enabled) {
    /* Abs Value */
    if (xd->mb_segment_abs_delta == SEGMENT_ABSDATA) {
      QIndex = xd->segment_feature_data[MB_LVL_ALT_Q][mbmi->segment_id];

      /* Delta Value */
    } else {
      QIndex = pc->base_qindex +
               xd->segment_feature_data[MB_LVL_ALT_Q][mbmi->segment_id];
    }

    QIndex = (QIndex >= 0) ? ((QIndex <= MAXQ) ? QIndex : MAXQ)
                           : 0; /* Clamp to valid range */
  } else {
    QIndex = pc->base_qindex;
  }

  /* Set up the macroblock dequant constants */
  xd->dequant_y1_dc[0] = 1;
  xd->dequant_y1[0] = pc->Y1dequant[QIndex][0];
  xd->dequant_y2[0] = pc->Y2dequant[QIndex][0];
  xd->dequant_uv[0] = pc->UVdequant[QIndex][0];

  for (i = 1; i < 16; ++i) {
    xd->dequant_y1_dc[i] = xd->dequant_y1[i] = pc->Y1dequant[QIndex][1];
    xd->dequant_y2[i] = pc->Y2dequant[QIndex][1];
    xd->dequant_uv[i] = pc->UVdequant[QIndex][1];
  }
}

static void decode_macroblock(VP8D_COMP *pbi, MACROBLOCKD *xd,
                              unsigned int mb_idx) {
  MB_PREDICTION_MODE mode;
  int i;
#if CONFIG_ERROR_CONCEALMENT
  int corruption_detected = 0;
#else
  (void)mb_idx;
#endif

  if (xd->mode_info_context->mbmi.mb_skip_coeff) {
    vp8_reset_mb_tokens_context(xd);
  } else if (!vp8dx_bool_error(xd->current_bc)) {
    int eobtotal;
    eobtotal = vp8_decode_mb_tokens(pbi, xd);

    /* Special case:  Force the loopfilter to skip when eobtotal is zero */
    xd->mode_info_context->mbmi.mb_skip_coeff = (eobtotal == 0);
  }

  mode = xd->mode_info_context->mbmi.mode;

  if (xd->segmentation_enabled) vp8_mb_init_dequantizer(pbi, xd);

#if CONFIG_ERROR_CONCEALMENT

  if (pbi->ec_active) {
    int throw_residual;
    /* When we have independent partitions we can apply residual even
     * though other partitions within the frame are corrupt.
     */
    throw_residual =
        (!pbi->independent_partitions && pbi->frame_corrupt_residual);
    throw_residual = (throw_residual || vp8dx_bool_error(xd->current_bc));

    if ((mb_idx >= pbi->mvs_corrupt_from_mb || throw_residual)) {
      /* MB with corrupt residuals or corrupt mode/motion vectors.
       * Better to use the predictor as reconstruction.
       */
      pbi->frame_corrupt_residual = 1;
      memset(xd->qcoeff, 0, sizeof(xd->qcoeff));

      corruption_detected = 1;

      /* force idct to be skipped for B_PRED and use the
       * prediction only for reconstruction
       * */
      memset(xd->eobs, 0, 25);
    }
  }
#endif

  /* do prediction */
  if (xd->mode_info_context->mbmi.ref_frame == INTRA_FRAME) {
    vp8_build_intra_predictors_mbuv_s(
        xd, xd->recon_above[1], xd->recon_above[2], xd->recon_left[1],
        xd->recon_left[2], xd->recon_left_stride[1], xd->dst.u_buffer,
        xd->dst.v_buffer, xd->dst.uv_stride);

    if (mode != B_PRED) {
      vp8_build_intra_predictors_mby_s(
          xd, xd->recon_above[0], xd->recon_left[0], xd->recon_left_stride[0],
          xd->dst.y_buffer, xd->dst.y_stride);
    } else {
      short *DQC = xd->dequant_y1;
      int dst_stride = xd->dst.y_stride;

      /* clear out residual eob info */
      if (xd->mode_info_context->mbmi.mb_skip_coeff) memset(xd->eobs, 0, 25);

      intra_prediction_down_copy(xd, xd->recon_above[0] + 16);

      for (i = 0; i < 16; ++i) {
        BLOCKD *b = &xd->block[i];
        unsigned char *dst = xd->dst.y_buffer + b->offset;
        B_PREDICTION_MODE b_mode = xd->mode_info_context->bmi[i].as_mode;
        unsigned char *Above = dst - dst_stride;
        unsigned char *yleft = dst - 1;
        int left_stride = dst_stride;
        unsigned char top_left = Above[-1];

        vp8_intra4x4_predict(Above, yleft, left_stride, b_mode, dst, dst_stride,
                             top_left);

        if (xd->eobs[i]) {
          if (xd->eobs[i] > 1) {
            vp8_dequant_idct_add(b->qcoeff, DQC, dst, dst_stride);
          } else {
            vp8_dc_only_idct_add(b->qcoeff[0] * DQC[0], dst, dst_stride, dst,
                                 dst_stride);
            memset(b->qcoeff, 0, 2 * sizeof(b->qcoeff[0]));
          }
        }
      }
    }
  } else {
    vp8_build_inter_predictors_mb(xd);
  }

#if CONFIG_ERROR_CONCEALMENT
  if (corruption_detected) {
    return;
  }
#endif

  if (!xd->mode_info_context->mbmi.mb_skip_coeff) {
    /* dequantization and idct */
    if (mode != B_PRED) {
      short *DQC = xd->dequant_y1;

      if (mode != SPLITMV) {
        BLOCKD *b = &xd->block[24];

        /* do 2nd order transform on the dc block */
        if (xd->eobs[24] > 1) {
          vp8_dequantize_b(b, xd->dequant_y2);

          vp8_short_inv_walsh4x4(&b->dqcoeff[0], xd->qcoeff);
          memset(b->qcoeff, 0, 16 * sizeof(b->qcoeff[0]));
        } else {
          b->dqcoeff[0] = (short)(b->qcoeff[0] * xd->dequant_y2[0]);
          vp8_short_inv_walsh4x4_1(&b->dqcoeff[0], xd->qcoeff);
          memset(b->qcoeff, 0, 2 * sizeof(b->qcoeff[0]));
        }

        /* override the dc dequant constant in order to preserve the
         * dc components
         */
        DQC = xd->dequant_y1_dc;
      }

      vp8_dequant_idct_add_y_block(xd->qcoeff, DQC, xd->dst.y_buffer,
                                   xd->dst.y_stride, xd->eobs);
    }

    vp8_dequant_idct_add_uv_block(xd->qcoeff + 16 * 16, xd->dequant_uv,
                                  xd->dst.u_buffer, xd->dst.v_buffer,
                                  xd->dst.uv_stride, xd->eobs + 16);
  }
}

static int get_delta_q(vp8_reader *bc, int prev, int *q_update) {
  int ret_val = 0;

  if (vp8_read_bit(bc)) {
    ret_val = vp8_read_literal(bc, 4);

    if (vp8_read_bit(bc)) ret_val = -ret_val;
  }

  /* Trigger a quantizer update if the delta-q value has changed */
  if (ret_val != prev) *q_update = 1;

  return ret_val;
}

#ifdef PACKET_TESTING
#include <stdio.h>
FILE *vpxlog = 0;
#endif

static void yv12_extend_frame_top_c(YV12_BUFFER_CONFIG *ybf) {
  int i;
  unsigned char *src_ptr1;
  unsigned char *dest_ptr1;

  unsigned int Border;
  int plane_stride;

  /***********/
  /* Y Plane */
  /***********/
  Border = ybf->border;
  plane_stride = ybf->y_stride;
  src_ptr1 = ybf->y_buffer - Border;
  dest_ptr1 = src_ptr1 - (Border * plane_stride);

  for (i = 0; i < (int)Border; ++i) {
    memcpy(dest_ptr1, src_ptr1, plane_stride);
    dest_ptr1 += plane_stride;
  }

  /***********/
  /* U Plane */
  /***********/
  plane_stride = ybf->uv_stride;
  Border /= 2;
  src_ptr1 = ybf->u_buffer - Border;
  dest_ptr1 = src_ptr1 - (Border * plane_stride);

  for (i = 0; i < (int)(Border); ++i) {
    memcpy(dest_ptr1, src_ptr1, plane_stride);
    dest_ptr1 += plane_stride;
  }

  /***********/
  /* V Plane */
  /***********/

  src_ptr1 = ybf->v_buffer - Border;
  dest_ptr1 = src_ptr1 - (Border * plane_stride);

  for (i = 0; i < (int)(Border); ++i) {
    memcpy(dest_ptr1, src_ptr1, plane_stride);
    dest_ptr1 += plane_stride;
  }
}

static void yv12_extend_frame_bottom_c(YV12_BUFFER_CONFIG *ybf) {
  int i;
  unsigned char *src_ptr1, *src_ptr2;
  unsigned char *dest_ptr2;

  unsigned int Border;
  int plane_stride;
  int plane_height;

  /***********/
  /* Y Plane */
  /***********/
  Border = ybf->border;
  plane_stride = ybf->y_stride;
  plane_height = ybf->y_height;

  src_ptr1 = ybf->y_buffer - Border;
  src_ptr2 = src_ptr1 + (plane_height * plane_stride) - plane_stride;
  dest_ptr2 = src_ptr2 + plane_stride;

  for (i = 0; i < (int)Border; ++i) {
    memcpy(dest_ptr2, src_ptr2, plane_stride);
    dest_ptr2 += plane_stride;
  }

  /***********/
  /* U Plane */
  /***********/
  plane_stride = ybf->uv_stride;
  plane_height = ybf->uv_height;
  Border /= 2;

  src_ptr1 = ybf->u_buffer - Border;
  src_ptr2 = src_ptr1 + (plane_height * plane_stride) - plane_stride;
  dest_ptr2 = src_ptr2 + plane_stride;

  for (i = 0; i < (int)(Border); ++i) {
    memcpy(dest_ptr2, src_ptr2, plane_stride);
    dest_ptr2 += plane_stride;
  }

  /***********/
  /* V Plane */
  /***********/

  src_ptr1 = ybf->v_buffer - Border;
  src_ptr2 = src_ptr1 + (plane_height * plane_stride) - plane_stride;
  dest_ptr2 = src_ptr2 + plane_stride;

  for (i = 0; i < (int)(Border); ++i) {
    memcpy(dest_ptr2, src_ptr2, plane_stride);
    dest_ptr2 += plane_stride;
  }
}

static void yv12_extend_frame_left_right_c(YV12_BUFFER_CONFIG *ybf,
                                           unsigned char *y_src,
                                           unsigned char *u_src,
                                           unsigned char *v_src) {
  int i;
  unsigned char *src_ptr1, *src_ptr2;
  unsigned char *dest_ptr1, *dest_ptr2;

  unsigned int Border;
  int plane_stride;
  int plane_height;
  int plane_width;

  /***********/
  /* Y Plane */
  /***********/
  Border = ybf->border;
  plane_stride = ybf->y_stride;
  plane_height = 16;
  plane_width = ybf->y_width;

  /* copy the left and right most columns out */
  src_ptr1 = y_src;
  src_ptr2 = src_ptr1 + plane_width - 1;
  dest_ptr1 = src_ptr1 - Border;
  dest_ptr2 = src_ptr2 + 1;

  for (i = 0; i < plane_height; ++i) {
    memset(dest_ptr1, src_ptr1[0], Border);
    memset(dest_ptr2, src_ptr2[0], Border);
    src_ptr1 += plane_stride;
    src_ptr2 += plane_stride;
    dest_ptr1 += plane_stride;
    dest_ptr2 += plane_stride;
  }

  /***********/
  /* U Plane */
  /***********/
  plane_stride = ybf->uv_stride;
  plane_height = 8;
  plane_width = ybf->uv_width;
  Border /= 2;

  /* copy the left and right most columns out */
  src_ptr1 = u_src;
  src_ptr2 = src_ptr1 + plane_width - 1;
  dest_ptr1 = src_ptr1 - Border;
  dest_ptr2 = src_ptr2 + 1;

  for (i = 0; i < plane_height; ++i) {
    memset(dest_ptr1, src_ptr1[0], Border);
    memset(dest_ptr2, src_ptr2[0], Border);
    src_ptr1 += plane_stride;
    src_ptr2 += plane_stride;
    dest_ptr1 += plane_stride;
    dest_ptr2 += plane_stride;
  }

  /***********/
  /* V Plane */
  /***********/

  /* copy the left and right most columns out */
  src_ptr1 = v_src;
  src_ptr2 = src_ptr1 + plane_width - 1;
  dest_ptr1 = src_ptr1 - Border;
  dest_ptr2 = src_ptr2 + 1;

  for (i = 0; i < plane_height; ++i) {
    memset(dest_ptr1, src_ptr1[0], Border);
    memset(dest_ptr2, src_ptr2[0], Border);
    src_ptr1 += plane_stride;
    src_ptr2 += plane_stride;
    dest_ptr1 += plane_stride;
    dest_ptr2 += plane_stride;
  }
}

static void decode_mb_rows(VP8D_COMP *pbi) {
  VP8_COMMON *const pc = &pbi->common;
  MACROBLOCKD *const xd = &pbi->mb;

  MODE_INFO *lf_mic = xd->mode_info_context;

  int ibc = 0;
  int num_part = 1 << pc->multi_token_partition;

  int recon_yoffset, recon_uvoffset;
  int mb_row, mb_col;
  int mb_idx = 0;

  YV12_BUFFER_CONFIG *yv12_fb_new = pbi->dec_fb_ref[INTRA_FRAME];

  int recon_y_stride = yv12_fb_new->y_stride;
  int recon_uv_stride = yv12_fb_new->uv_stride;

  unsigned char *ref_buffer[MAX_REF_FRAMES][3];
  unsigned char *dst_buffer[3];
  unsigned char *lf_dst[3];
  unsigned char *eb_dst[3];
  int i;
  int ref_fb_corrupted[MAX_REF_FRAMES];

  ref_fb_corrupted[INTRA_FRAME] = 0;

  for (i = 1; i < MAX_REF_FRAMES; ++i) {
    YV12_BUFFER_CONFIG *this_fb = pbi->dec_fb_ref[i];

    ref_buffer[i][0] = this_fb->y_buffer;
    ref_buffer[i][1] = this_fb->u_buffer;
    ref_buffer[i][2] = this_fb->v_buffer;

    ref_fb_corrupted[i] = this_fb->corrupted;
  }

  /* Set up the buffer pointers */
  eb_dst[0] = lf_dst[0] = dst_buffer[0] = yv12_fb_new->y_buffer;
  eb_dst[1] = lf_dst[1] = dst_buffer[1] = yv12_fb_new->u_buffer;
  eb_dst[2] = lf_dst[2] = dst_buffer[2] = yv12_fb_new->v_buffer;

  xd->up_available = 0;

  /* Initialize the loop filter for this frame. */
  if (pc->filter_level) vp8_loop_filter_frame_init(pc, xd, pc->filter_level);

  vp8_setup_intra_recon_top_line(yv12_fb_new);

  /* Decode the individual macro block */
  for (mb_row = 0; mb_row < pc->mb_rows; ++mb_row) {
    if (num_part > 1) {
      xd->current_bc = &pbi->mbc[ibc];
      ibc++;

      if (ibc == num_part) ibc = 0;
    }

    recon_yoffset = mb_row * recon_y_stride * 16;
    recon_uvoffset = mb_row * recon_uv_stride * 8;

    /* reset contexts */
    xd->above_context = pc->above_context;
    memset(xd->left_context, 0, sizeof(ENTROPY_CONTEXT_PLANES));

    xd->left_available = 0;

    xd->mb_to_top_edge = -((mb_row * 16) << 3);
    xd->mb_to_bottom_edge = ((pc->mb_rows - 1 - mb_row) * 16) << 3;

    xd->recon_above[0] = dst_buffer[0] + recon_yoffset;
    xd->recon_above[1] = dst_buffer[1] + recon_uvoffset;
    xd->recon_above[2] = dst_buffer[2] + recon_uvoffset;

    xd->recon_left[0] = xd->recon_above[0] - 1;
    xd->recon_left[1] = xd->recon_above[1] - 1;
    xd->recon_left[2] = xd->recon_above[2] - 1;

    xd->recon_above[0] -= xd->dst.y_stride;
    xd->recon_above[1] -= xd->dst.uv_stride;
    xd->recon_above[2] -= xd->dst.uv_stride;

    /* TODO: move to outside row loop */
    xd->recon_left_stride[0] = xd->dst.y_stride;
    xd->recon_left_stride[1] = xd->dst.uv_stride;

    setup_intra_recon_left(xd->recon_left[0], xd->recon_left[1],
                           xd->recon_left[2], xd->dst.y_stride,
                           xd->dst.uv_stride);

    for (mb_col = 0; mb_col < pc->mb_cols; ++mb_col) {
      /* Distance of Mb to the various image edges.
       * These are specified to 8th pel as they are always compared to values
       * that are in 1/8th pel units
       */
      xd->mb_to_left_edge = -((mb_col * 16) << 3);
      xd->mb_to_right_edge = ((pc->mb_cols - 1 - mb_col) * 16) << 3;

#if CONFIG_ERROR_CONCEALMENT
      {
        int corrupt_residual =
            (!pbi->independent_partitions && pbi->frame_corrupt_residual) ||
            vp8dx_bool_error(xd->current_bc);
        if (pbi->ec_active &&
            xd->mode_info_context->mbmi.ref_frame == INTRA_FRAME &&
            corrupt_residual) {
          /* We have an intra block with corrupt coefficients, better to
           * conceal with an inter block. Interpolate MVs from neighboring
           * MBs.
           *
           * Note that for the first mb with corrupt residual in a frame,
           * we might not discover that before decoding the residual. That
           * happens after this check, and therefore no inter concealment
           * will be done.
           */
          vp8_interpolate_motion(xd, mb_row, mb_col, pc->mb_rows, pc->mb_cols);
        }
      }
#endif

      xd->dst.y_buffer = dst_buffer[0] + recon_yoffset;
      xd->dst.u_buffer = dst_buffer[1] + recon_uvoffset;
      xd->dst.v_buffer = dst_buffer[2] + recon_uvoffset;

      if (xd->mode_info_context->mbmi.ref_frame >= LAST_FRAME) {
        const MV_REFERENCE_FRAME ref = xd->mode_info_context->mbmi.ref_frame;
        xd->pre.y_buffer = ref_buffer[ref][0] + recon_yoffset;
        xd->pre.u_buffer = ref_buffer[ref][1] + recon_uvoffset;
        xd->pre.v_buffer = ref_buffer[ref][2] + recon_uvoffset;
      } else {
        // ref_frame is INTRA_FRAME, pre buffer should not be used.
        xd->pre.y_buffer = 0;
        xd->pre.u_buffer = 0;
        xd->pre.v_buffer = 0;
      }

      /* propagate errors from reference frames */
      xd->corrupted |= ref_fb_corrupted[xd->mode_info_context->mbmi.ref_frame];

      decode_macroblock(pbi, xd, mb_idx);

      mb_idx++;
      xd->left_available = 1;

      /* check if the boolean decoder has suffered an error */
      xd->corrupted |= vp8dx_bool_error(xd->current_bc);

      xd->recon_above[0] += 16;
      xd->recon_above[1] += 8;
      xd->recon_above[2] += 8;
      xd->recon_left[0] += 16;
      xd->recon_left[1] += 8;
      xd->recon_left[2] += 8;

      recon_yoffset += 16;
      recon_uvoffset += 8;

      ++xd->mode_info_context; /* next mb */

      xd->above_context++;
    }

    /* adjust to the next row of mbs */
    vp8_extend_mb_row(yv12_fb_new, xd->dst.y_buffer + 16, xd->dst.u_buffer + 8,
                      xd->dst.v_buffer + 8);

    ++xd->mode_info_context; /* skip prediction column */
    xd->up_available = 1;

    if (pc->filter_level) {
      if (mb_row > 0) {
        if (pc->filter_type == NORMAL_LOOPFILTER) {
          vp8_loop_filter_row_normal(pc, lf_mic, mb_row - 1, recon_y_stride,
                                     recon_uv_stride, lf_dst[0], lf_dst[1],
                                     lf_dst[2]);
        } else {
          vp8_loop_filter_row_simple(pc, lf_mic, mb_row - 1, recon_y_stride,
                                     lf_dst[0]);
        }
        if (mb_row > 1) {
          yv12_extend_frame_left_right_c(yv12_fb_new, eb_dst[0], eb_dst[1],
                                         eb_dst[2]);

          eb_dst[0] += recon_y_stride * 16;
          eb_dst[1] += recon_uv_stride * 8;
          eb_dst[2] += recon_uv_stride * 8;
        }

        lf_dst[0] += recon_y_stride * 16;
        lf_dst[1] += recon_uv_stride * 8;
        lf_dst[2] += recon_uv_stride * 8;
        lf_mic += pc->mb_cols;
        lf_mic++; /* Skip border mb */
      }
    } else {
      if (mb_row > 0) {
        /**/
        yv12_extend_frame_left_right_c(yv12_fb_new, eb_dst[0], eb_dst[1],
                                       eb_dst[2]);
        eb_dst[0] += recon_y_stride * 16;
        eb_dst[1] += recon_uv_stride * 8;
        eb_dst[2] += recon_uv_stride * 8;
      }
    }
  }

  if (pc->filter_level) {
    if (pc->filter_type == NORMAL_LOOPFILTER) {
      vp8_loop_filter_row_normal(pc, lf_mic, mb_row - 1, recon_y_stride,
                                 recon_uv_stride, lf_dst[0], lf_dst[1],
                                 lf_dst[2]);
    } else {
      vp8_loop_filter_row_simple(pc, lf_mic, mb_row - 1, recon_y_stride,
                                 lf_dst[0]);
    }

    yv12_extend_frame_left_right_c(yv12_fb_new, eb_dst[0], eb_dst[1],
                                   eb_dst[2]);
    eb_dst[0] += recon_y_stride * 16;
    eb_dst[1] += recon_uv_stride * 8;
    eb_dst[2] += recon_uv_stride * 8;
  }
  yv12_extend_frame_left_right_c(yv12_fb_new, eb_dst[0], eb_dst[1], eb_dst[2]);
  yv12_extend_frame_top_c(yv12_fb_new);
  yv12_extend_frame_bottom_c(yv12_fb_new);
}

static unsigned int read_partition_size(VP8D_COMP *pbi,
                                        const unsigned char *cx_size) {
  unsigned char temp[3];
  if (pbi->decrypt_cb) {
    pbi->decrypt_cb(pbi->decrypt_state, cx_size, temp, 3);
    cx_size = temp;
  }
  return cx_size[0] + (cx_size[1] << 8) + (cx_size[2] << 16);
}

static int read_is_valid(const unsigned char *start, size_t len,
                         const unsigned char *end) {
  return len != 0 && end > start && len <= (size_t)(end - start);
}

static unsigned int read_available_partition_size(
    VP8D_COMP *pbi, const unsigned char *token_part_sizes,
    const unsigned char *fragment_start,
    const unsigned char *first_fragment_end, const unsigned char *fragment_end,
    int i, int num_part) {
  VP8_COMMON *pc = &pbi->common;
  const unsigned char *partition_size_ptr = token_part_sizes + i * 3;
  unsigned int partition_size = 0;
  ptrdiff_t bytes_left = fragment_end - fragment_start;
  if (bytes_left < 0) {
    vpx_internal_error(
        &pc->error, VPX_CODEC_CORRUPT_FRAME,
        "Truncated packet or corrupt partition. No bytes left %d.",
        (int)bytes_left);
  }
  /* Calculate the length of this partition. The last partition
   * size is implicit. If the partition size can't be read, then
   * either use the remaining data in the buffer (for EC mode)
   * or throw an error.
   */
  if (i < num_part - 1) {
    if (read_is_valid(partition_size_ptr, 3, first_fragment_end)) {
      partition_size = read_partition_size(pbi, partition_size_ptr);
    } else if (pbi->ec_active) {
      partition_size = (unsigned int)bytes_left;
    } else {
      vpx_internal_error(&pc->error, VPX_CODEC_CORRUPT_FRAME,
                         "Truncated partition size data");
    }
  } else {
    partition_size = (unsigned int)bytes_left;
  }

  /* Validate the calculated partition length. If the buffer
   * described by the partition can't be fully read, then restrict
   * it to the portion that can be (for EC mode) or throw an error.
   */
  if (!read_is_valid(fragment_start, partition_size, fragment_end)) {
    if (pbi->ec_active) {
      partition_size = (unsigned int)bytes_left;
    } else {
      vpx_internal_error(&pc->error, VPX_CODEC_CORRUPT_FRAME,
                         "Truncated packet or corrupt partition "
                         "%d length",
                         i + 1);
    }
  }
  return partition_size;
}

static void setup_token_decoder(VP8D_COMP *pbi,
                                const unsigned char *token_part_sizes) {
  vp8_reader *bool_decoder = &pbi->mbc[0];
  unsigned int partition_idx;
  unsigned int fragment_idx;
  unsigned int num_token_partitions;
  const unsigned char *first_fragment_end =
      pbi->fragments.ptrs[0] + pbi->fragments.sizes[0];

  TOKEN_PARTITION multi_token_partition =
      (TOKEN_PARTITION)vp8_read_literal(&pbi->mbc[8], 2);
  if (!vp8dx_bool_error(&pbi->mbc[8])) {
    pbi->common.multi_token_partition = multi_token_partition;
  }
  num_token_partitions = 1 << pbi->common.multi_token_partition;

  /* Check for partitions within the fragments and unpack the fragments
   * so that each fragment pointer points to its corresponding partition. */
  for (fragment_idx = 0; fragment_idx < pbi->fragments.count; ++fragment_idx) {
    unsigned int fragment_size = pbi->fragments.sizes[fragment_idx];
    const unsigned char *fragment_end =
        pbi->fragments.ptrs[fragment_idx] + fragment_size;
    /* Special case for handling the first partition since we have already
     * read its size. */
    if (fragment_idx == 0) {
      /* Size of first partition + token partition sizes element */
      ptrdiff_t ext_first_part_size = token_part_sizes -
                                      pbi->fragments.ptrs[0] +
                                      3 * (num_token_partitions - 1);
      if (fragment_size < (unsigned int)ext_first_part_size)
        vpx_internal_error(&pbi->common.error, VPX_CODEC_CORRUPT_FRAME,
                           "Corrupted fragment size %d", fragment_size);
      fragment_size -= (unsigned int)ext_first_part_size;
      if (fragment_size > 0) {
        pbi->fragments.sizes[0] = (unsigned int)ext_first_part_size;
        /* The fragment contains an additional partition. Move to
         * next. */
        fragment_idx++;
        pbi->fragments.ptrs[fragment_idx] =
            pbi->fragments.ptrs[0] + pbi->fragments.sizes[0];
      }
    }
    /* Split the chunk into partitions read from the bitstream */
    while (fragment_size > 0) {
      ptrdiff_t partition_size = read_available_partition_size(
          pbi, token_part_sizes, pbi->fragments.ptrs[fragment_idx],
          first_fragment_end, fragment_end, fragment_idx - 1,
          num_token_partitions);
      pbi->fragments.sizes[fragment_idx] = (unsigned int)partition_size;
      if (fragment_size < (unsigned int)partition_size)
        vpx_internal_error(&pbi->common.error, VPX_CODEC_CORRUPT_FRAME,
                           "Corrupted fragment size %d", fragment_size);
      fragment_size -= (unsigned int)partition_size;
      assert(fragment_idx <= num_token_partitions);
      if (fragment_size > 0) {
        /* The fragment contains an additional partition.
         * Move to next. */
        fragment_idx++;
        pbi->fragments.ptrs[fragment_idx] =
            pbi->fragments.ptrs[fragment_idx - 1] + partition_size;
      }
    }
  }

  pbi->fragments.count = num_token_partitions + 1;

  for (partition_idx = 1; partition_idx < pbi->fragments.count;
       ++partition_idx) {
    if (vp8dx_start_decode(bool_decoder, pbi->fragments.ptrs[partition_idx],
                           pbi->fragments.sizes[partition_idx], pbi->decrypt_cb,
                           pbi->decrypt_state)) {
      vpx_internal_error(&pbi->common.error, VPX_CODEC_MEM_ERROR,
                         "Failed to allocate bool decoder %d", partition_idx);
    }

    bool_decoder++;
  }

#if CONFIG_MULTITHREAD
  /* Clamp number of decoder threads */
  if (pbi->decoding_thread_count > num_token_partitions - 1) {
    pbi->decoding_thread_count = num_token_partitions - 1;
  }
  if ((int)pbi->decoding_thread_count > pbi->common.mb_rows - 1) {
    assert(pbi->common.mb_rows > 0);
    pbi->decoding_thread_count = pbi->common.mb_rows - 1;
  }
#endif
}

static void init_frame(VP8D_COMP *pbi) {
  VP8_COMMON *const pc = &pbi->common;
  MACROBLOCKD *const xd = &pbi->mb;

  if (pc->frame_type == KEY_FRAME) {
    /* Various keyframe initializations */
    memcpy(pc->fc.mvc, vp8_default_mv_context, sizeof(vp8_default_mv_context));

    vp8_init_mbmode_probs(pc);

    vp8_default_coef_probs(pc);

    /* reset the segment feature data to 0 with delta coding (Default state). */
    memset(xd->segment_feature_data, 0, sizeof(xd->segment_feature_data));
    xd->mb_segment_abs_delta = SEGMENT_DELTADATA;

    /* reset the mode ref deltasa for loop filter */
    memset(xd->ref_lf_deltas, 0, sizeof(xd->ref_lf_deltas));
    memset(xd->mode_lf_deltas, 0, sizeof(xd->mode_lf_deltas));

    /* All buffers are implicitly updated on key frames. */
    pc->refresh_golden_frame = 1;
    pc->refresh_alt_ref_frame = 1;
    pc->copy_buffer_to_gf = 0;
    pc->copy_buffer_to_arf = 0;

    /* Note that Golden and Altref modes cannot be used on a key frame so
     * ref_frame_sign_bias[] is undefined and meaningless
     */
    pc->ref_frame_sign_bias[GOLDEN_FRAME] = 0;
    pc->ref_frame_sign_bias[ALTREF_FRAME] = 0;
  } else {
    /* To enable choice of different interploation filters */
    if (!pc->use_bilinear_mc_filter) {
      xd->subpixel_predict = vp8_sixtap_predict4x4;
      xd->subpixel_predict8x4 = vp8_sixtap_predict8x4;
      xd->subpixel_predict8x8 = vp8_sixtap_predict8x8;
      xd->subpixel_predict16x16 = vp8_sixtap_predict16x16;
    } else {
      xd->subpixel_predict = vp8_bilinear_predict4x4;
      xd->subpixel_predict8x4 = vp8_bilinear_predict8x4;
      xd->subpixel_predict8x8 = vp8_bilinear_predict8x8;
      xd->subpixel_predict16x16 = vp8_bilinear_predict16x16;
    }

    if (pbi->decoded_key_frame && pbi->ec_enabled && !pbi->ec_active) {
      pbi->ec_active = 1;
    }
  }

  xd->left_context = &pc->left_context;
  xd->mode_info_context = pc->mi;
  xd->frame_type = pc->frame_type;
  xd->mode_info_context->mbmi.mode = DC_PRED;
  xd->mode_info_stride = pc->mode_info_stride;
  xd->corrupted = 0; /* init without corruption */

  xd->fullpixel_mask = ~0;
  if (pc->full_pixel) xd->fullpixel_mask = ~7;
}

int vp8_decode_frame(VP8D_COMP *pbi) {
  vp8_reader *const bc = &pbi->mbc[8];
  VP8_COMMON *const pc = &pbi->common;
  MACROBLOCKD *const xd = &pbi->mb;
  const unsigned char *data = pbi->fragments.ptrs[0];
  const unsigned int data_sz = pbi->fragments.sizes[0];
  const unsigned char *data_end = data + data_sz;
  ptrdiff_t first_partition_length_in_bytes;

  int i, j, k, l;
  const int *const mb_feature_data_bits = vp8_mb_feature_data_bits;
  int corrupt_tokens = 0;
  int prev_independent_partitions = pbi->independent_partitions;

  YV12_BUFFER_CONFIG *yv12_fb_new = pbi->dec_fb_ref[INTRA_FRAME];

  /* start with no corruption of current frame */
  xd->corrupted = 0;
  yv12_fb_new->corrupted = 0;

  if (data_end - data < 3) {
    if (!pbi->ec_active) {
      vpx_internal_error(&pc->error, VPX_CODEC_CORRUPT_FRAME,
                         "Truncated packet");
    }

    /* Declare the missing frame as an inter frame since it will
       be handled as an inter frame when we have estimated its
       motion vectors. */
    pc->frame_type = INTER_FRAME;
    pc->version = 0;
    pc->show_frame = 1;
    first_partition_length_in_bytes = 0;
  } else {
    unsigned char clear_buffer[10];
    const unsigned char *clear = data;
    if (pbi->decrypt_cb) {
      int n = (int)VPXMIN(sizeof(clear_buffer), data_sz);
      pbi->decrypt_cb(pbi->decrypt_state, data, clear_buffer, n);
      clear = clear_buffer;
    }

    pc->frame_type = (FRAME_TYPE)(clear[0] & 1);
    pc->version = (clear[0] >> 1) & 7;
    pc->show_frame = (clear[0] >> 4) & 1;
    first_partition_length_in_bytes =
        (clear[0] | (clear[1] << 8) | (clear[2] << 16)) >> 5;

    if (!pbi->ec_active && (data + first_partition_length_in_bytes > data_end ||
                            data + first_partition_length_in_bytes < data)) {
      vpx_internal_error(&pc->error, VPX_CODEC_CORRUPT_FRAME,
                         "Truncated packet or corrupt partition 0 length");
    }

    data += 3;
    clear += 3;

    vp8_setup_version(pc);

    if (pc->frame_type == KEY_FRAME) {
      /* vet via sync code */
      /* When error concealment is enabled we should only check the sync
       * code if we have enough bits available
       */
      if (data + 3 < data_end) {
        if (clear[0] != 0x9d || clear[1] != 0x01 || clear[2] != 0x2a) {
          vpx_internal_error(&pc->error, VPX_CODEC_UNSUP_BITSTREAM,
                             "Invalid frame sync code");
        }
      }

      /* If error concealment is enabled we should only parse the new size
       * if we have enough data. Otherwise we will end up with the wrong
       * size.
       */
      if (data + 6 < data_end) {
        pc->Width = (clear[3] | (clear[4] << 8)) & 0x3fff;
        pc->horiz_scale = clear[4] >> 6;
        pc->Height = (clear[5] | (clear[6] << 8)) & 0x3fff;
        pc->vert_scale = clear[6] >> 6;
        data += 7;
      } else if (!pbi->ec_active) {
        vpx_internal_error(&pc->error, VPX_CODEC_CORRUPT_FRAME,
                           "Truncated key frame header");
      } else {
        /* Error concealment is active, clear the frame. */
        data = data_end;
      }
    } else {
      memcpy(&xd->pre, yv12_fb_new, sizeof(YV12_BUFFER_CONFIG));
      memcpy(&xd->dst, yv12_fb_new, sizeof(YV12_BUFFER_CONFIG));
    }
  }
  if ((!pbi->decoded_key_frame && pc->frame_type != KEY_FRAME)) {
    return -1;
  }

  init_frame(pbi);

  if (vp8dx_start_decode(bc, data, (unsigned int)(data_end - data),
                         pbi->decrypt_cb, pbi->decrypt_state)) {
    vpx_internal_error(&pc->error, VPX_CODEC_MEM_ERROR,
                       "Failed to allocate bool decoder 0");
  }
  if (pc->frame_type == KEY_FRAME) {
    (void)vp8_read_bit(bc);  // colorspace
    pc->clamp_type = (CLAMP_TYPE)vp8_read_bit(bc);
  }

  /* Is segmentation enabled */
  xd->segmentation_enabled = (unsigned char)vp8_read_bit(bc);

  if (xd->segmentation_enabled) {
    /* Signal whether or not the segmentation map is being explicitly updated
     * this frame. */
    xd->update_mb_segmentation_map = (unsigned char)vp8_read_bit(bc);
    xd->update_mb_segmentation_data = (unsigned char)vp8_read_bit(bc);

    if (xd->update_mb_segmentation_data) {
      xd->mb_segment_abs_delta = (unsigned char)vp8_read_bit(bc);

      memset(xd->segment_feature_data, 0, sizeof(xd->segment_feature_data));

      /* For each segmentation feature (Quant and loop filter level) */
      for (i = 0; i < MB_LVL_MAX; ++i) {
        for (j = 0; j < MAX_MB_SEGMENTS; ++j) {
          /* Frame level data */
          if (vp8_read_bit(bc)) {
            xd->segment_feature_data[i][j] =
                (signed char)vp8_read_literal(bc, mb_feature_data_bits[i]);

            if (vp8_read_bit(bc)) {
              xd->segment_feature_data[i][j] = -xd->segment_feature_data[i][j];
            }
          } else {
            xd->segment_feature_data[i][j] = 0;
          }
        }
      }
    }

    if (xd->update_mb_segmentation_map) {
      /* Which macro block level features are enabled */
      memset(xd->mb_segment_tree_probs, 255, sizeof(xd->mb_segment_tree_probs));

      /* Read the probs used to decode the segment id for each macro block. */
      for (i = 0; i < MB_FEATURE_TREE_PROBS; ++i) {
        /* If not explicitly set value is defaulted to 255 by memset above */
        if (vp8_read_bit(bc)) {
          xd->mb_segment_tree_probs[i] = (vp8_prob)vp8_read_literal(bc, 8);
        }
      }
    }
  } else {
    /* No segmentation updates on this frame */
    xd->update_mb_segmentation_map = 0;
    xd->update_mb_segmentation_data = 0;
  }

  /* Read the loop filter level and type */
  pc->filter_type = (LOOPFILTERTYPE)vp8_read_bit(bc);
  pc->filter_level = vp8_read_literal(bc, 6);
  pc->sharpness_level = vp8_read_literal(bc, 3);

  /* Read in loop filter deltas applied at the MB level based on mode or ref
   * frame. */
  xd->mode_ref_lf_delta_update = 0;
  xd->mode_ref_lf_delta_enabled = (unsigned char)vp8_read_bit(bc);

  if (xd->mode_ref_lf_delta_enabled) {
    /* Do the deltas need to be updated */
    xd->mode_ref_lf_delta_update = (unsigned char)vp8_read_bit(bc);

    if (xd->mode_ref_lf_delta_update) {
      /* Send update */
      for (i = 0; i < MAX_REF_LF_DELTAS; ++i) {
        if (vp8_read_bit(bc)) {
          /*sign = vp8_read_bit( bc );*/
          xd->ref_lf_deltas[i] = (signed char)vp8_read_literal(bc, 6);

          if (vp8_read_bit(bc)) { /* Apply sign */
            xd->ref_lf_deltas[i] = xd->ref_lf_deltas[i] * -1;
          }
        }
      }

      /* Send update */
      for (i = 0; i < MAX_MODE_LF_DELTAS; ++i) {
        if (vp8_read_bit(bc)) {
          /*sign = vp8_read_bit( bc );*/
          xd->mode_lf_deltas[i] = (signed char)vp8_read_literal(bc, 6);

          if (vp8_read_bit(bc)) { /* Apply sign */
            xd->mode_lf_deltas[i] = xd->mode_lf_deltas[i] * -1;
          }
        }
      }
    }
  }

  setup_token_decoder(pbi, data + first_partition_length_in_bytes);

  xd->current_bc = &pbi->mbc[0];

  /* Read the default quantizers. */
  {
    int Q, q_update;

    Q = vp8_read_literal(bc, 7); /* AC 1st order Q = default */
    pc->base_qindex = Q;
    q_update = 0;
    pc->y1dc_delta_q = get_delta_q(bc, pc->y1dc_delta_q, &q_update);
    pc->y2dc_delta_q = get_delta_q(bc, pc->y2dc_delta_q, &q_update);
    pc->y2ac_delta_q = get_delta_q(bc, pc->y2ac_delta_q, &q_update);
    pc->uvdc_delta_q = get_delta_q(bc, pc->uvdc_delta_q, &q_update);
    pc->uvac_delta_q = get_delta_q(bc, pc->uvac_delta_q, &q_update);

    if (q_update) vp8cx_init_de_quantizer(pbi);

    /* MB level dequantizer setup */
    vp8_mb_init_dequantizer(pbi, &pbi->mb);
  }

  /* Determine if the golden frame or ARF buffer should be updated and how.
   * For all non key frames the GF and ARF refresh flags and sign bias
   * flags must be set explicitly.
   */
  if (pc->frame_type != KEY_FRAME) {
    /* Should the GF or ARF be updated from the current frame */
    pc->refresh_golden_frame = vp8_read_bit(bc);
#if CONFIG_ERROR_CONCEALMENT
    /* Assume we shouldn't refresh golden if the bit is missing */
    xd->corrupted |= vp8dx_bool_error(bc);
    if (pbi->ec_active && xd->corrupted) pc->refresh_golden_frame = 0;
#endif

    pc->refresh_alt_ref_frame = vp8_read_bit(bc);
#if CONFIG_ERROR_CONCEALMENT
    /* Assume we shouldn't refresh altref if the bit is missing */
    xd->corrupted |= vp8dx_bool_error(bc);
    if (pbi->ec_active && xd->corrupted) pc->refresh_alt_ref_frame = 0;
#endif

    /* Buffer to buffer copy flags. */
    pc->copy_buffer_to_gf = 0;

    if (!pc->refresh_golden_frame) {
      pc->copy_buffer_to_gf = vp8_read_literal(bc, 2);
    }

#if CONFIG_ERROR_CONCEALMENT
    /* Assume we shouldn't copy to the golden if the bit is missing */
    xd->corrupted |= vp8dx_bool_error(bc);
    if (pbi->ec_active && xd->corrupted) pc->copy_buffer_to_gf = 0;
#endif

    pc->copy_buffer_to_arf = 0;

    if (!pc->refresh_alt_ref_frame) {
      pc->copy_buffer_to_arf = vp8_read_literal(bc, 2);
    }

#if CONFIG_ERROR_CONCEALMENT
    /* Assume we shouldn't copy to the alt-ref if the bit is missing */
    xd->corrupted |= vp8dx_bool_error(bc);
    if (pbi->ec_active && xd->corrupted) pc->copy_buffer_to_arf = 0;
#endif

    pc->ref_frame_sign_bias[GOLDEN_FRAME] = vp8_read_bit(bc);
    pc->ref_frame_sign_bias[ALTREF_FRAME] = vp8_read_bit(bc);
  }

  pc->refresh_entropy_probs = vp8_read_bit(bc);
#if CONFIG_ERROR_CONCEALMENT
  /* Assume we shouldn't refresh the probabilities if the bit is
   * missing */
  xd->corrupted |= vp8dx_bool_error(bc);
  if (pbi->ec_active && xd->corrupted) pc->refresh_entropy_probs = 0;
#endif
  if (pc->refresh_entropy_probs == 0) {
    memcpy(&pc->lfc, &pc->fc, sizeof(pc->fc));
  }

  pc->refresh_last_frame = pc->frame_type == KEY_FRAME || vp8_read_bit(bc);

#if CONFIG_ERROR_CONCEALMENT
  /* Assume we should refresh the last frame if the bit is missing */
  xd->corrupted |= vp8dx_bool_error(bc);
  if (pbi->ec_active && xd->corrupted) pc->refresh_last_frame = 1;
#endif

  {
    pbi->independent_partitions = 1;

    /* read coef probability tree */
    for (i = 0; i < BLOCK_TYPES; ++i) {
      for (j = 0; j < COEF_BANDS; ++j) {
        for (k = 0; k < PREV_COEF_CONTEXTS; ++k) {
          for (l = 0; l < ENTROPY_NODES; ++l) {
            vp8_prob *const p = pc->fc.coef_probs[i][j][k] + l;

            if (vp8_read(bc, vp8_coef_update_probs[i][j][k][l])) {
              *p = (vp8_prob)vp8_read_literal(bc, 8);
            }
            if (k > 0 && *p != pc->fc.coef_probs[i][j][k - 1][l]) {
              pbi->independent_partitions = 0;
            }
          }
        }
      }
    }
  }

  /* clear out the coeff buffer */
  memset(xd->qcoeff, 0, sizeof(xd->qcoeff));

  vp8_decode_mode_mvs(pbi);

#if CONFIG_ERROR_CONCEALMENT
  if (pbi->ec_active &&
      pbi->mvs_corrupt_from_mb < (unsigned int)pc->mb_cols * pc->mb_rows) {
    /* Motion vectors are missing in this frame. We will try to estimate
     * them and then continue decoding the frame as usual */
    vp8_estimate_missing_mvs(pbi);
  }
#endif

  memset(pc->above_context, 0, sizeof(ENTROPY_CONTEXT_PLANES) * pc->mb_cols);
  pbi->frame_corrupt_residual = 0;

#if CONFIG_MULTITHREAD
  if (vpx_atomic_load_acquire(&pbi->b_multithreaded_rd) &&
      pc->multi_token_partition != ONE_PARTITION) {
    unsigned int thread;
    if (vp8mt_decode_mb_rows(pbi, xd)) {
      vp8_decoder_remove_threads(pbi);
      pbi->restart_threads = 1;
      vpx_internal_error(&pbi->common.error, VPX_CODEC_CORRUPT_FRAME, NULL);
    }
    vp8_yv12_extend_frame_borders(yv12_fb_new);
    for (thread = 0; thread < pbi->decoding_thread_count; ++thread) {
      corrupt_tokens |= pbi->mb_row_di[thread].mbd.corrupted;
    }
  } else
#endif
  {
    decode_mb_rows(pbi);
    corrupt_tokens |= xd->corrupted;
  }

  /* Collect information about decoder corruption. */
  /* 1. Check first boolean decoder for errors. */
  yv12_fb_new->corrupted = vp8dx_bool_error(bc);
  /* 2. Check the macroblock information */
  yv12_fb_new->corrupted |= corrupt_tokens;

  if (!pbi->decoded_key_frame) {
    if (pc->frame_type == KEY_FRAME && !yv12_fb_new->corrupted) {
      pbi->decoded_key_frame = 1;
    } else {
      vpx_internal_error(&pbi->common.error, VPX_CODEC_CORRUPT_FRAME,
                         "A stream must start with a complete key frame");
    }
  }

  /* vpx_log("Decoder: Frame Decoded, Size Roughly:%d bytes
   * \n",bc->pos+pbi->bc2.pos); */

  if (pc->refresh_entropy_probs == 0) {
    memcpy(&pc->fc, &pc->lfc, sizeof(pc->fc));
    pbi->independent_partitions = prev_independent_partitions;
  }

#ifdef PACKET_TESTING
  {
    FILE *f = fopen("decompressor.VP8", "ab");
    unsigned int size = pbi->bc2.pos + pbi->bc.pos + 8;
    fwrite((void *)&size, 4, 1, f);
    fwrite((void *)pbi->Source, size, 1, f);
    fclose(f);
  }
#endif

  return 0;
}