part_width  = 16; part_height = 16; dir0 = (mb_type == 2) ? 1 : 0; dir1 = (mb_type == 1) ? 0 : 1; }  for (dir=dir0; dir <= dir1; dir++) { for (i=0; i < 16; i+=part_height) { for (j=0; j < 16; j+=part_width) { int avg=(dir == 1 && dir0 != dir1); int dxy; x = 16*s->mb_x + j; y = 16*s->mb_y + i; k = ((j>>2)&1) + ((i>>1)&2) + ((j>>1)&4) + (i&8);  pred_motion (h, k, (part_width >> 2), dir, 1, &mx, &my);   mx = clip (mx, -6*x, 6*(s->h_edge_pos - part_width  - x)); my = clip (my, -6*y, 6*(s->v_edge_pos - part_height - y));   dy = svq3_get_se_golomb (&s->gb); dx = svq3_get_se_golomb (&s->gb);  if (dx == INVALID_VLC || dy == INVALID_VLC) { return -1; }  if (mode == THIRDPEL_MODE) { int fx, fy; mx = ((mx + 1)>>1) + dx; my = ((my + 1)>>1) + dy; fx= ((unsigned)(mx + 0x3000))/3 - 0x1000; fy= ((unsigned)(my + 0x3000))/3 - 0x1000; dxy= (mx - 3*fx) + 4*(my - 3*fy);  svq3_mc_dir_part (s, x, y, part_width, part_height, fx, fy, dxy, 1, dir, avg); mx += mx; my += my; } else if (mode == HALFPEL_MODE) { mx = ((unsigned)(mx + 1 + 0x3000))/3 + dx - 0x1000; my = ((unsigned)(my + 1 + 0x3000))/3 + dy - 0x1000; dxy= (mx&1) + 2*(my&1);  svq3_mc_dir_part (s, x, y, part_width, part_height, mx>>1, my>>1, dxy, 0, dir, avg); mx *= 3; my *= 3; } else { assert(mode == FULLPEL_MODE); mx = ((unsigned)(mx + 3 + 0x6000))/6 + dx - 0x1000; my = ((unsigned)(my + 3 + 0x6000))/6 + dy - 0x1000;  svq3_mc_dir_part (s, x, y, part_width, part_height, mx, my, 0, 0, dir, avg); mx *= 6; my *= 6; }   fill_rectangle(h->mv_cache[dir][scan8[k]], part_width>>2, part_height>>2, 8, pack16to32(mx,my), 4); } } }   if (s->pict_type == P_TYPE || mb_type != 2) { for (i=0; i < 4; i++) { memcpy (s->current_picture.motion_val[0][b_xy + i*h->b_stride], h->mv_cache[0][scan8[0] + 8*i], 4*2*sizeof(int16_t)); } } else { for (i=0; i < 4; i++) { memset (s->current_picture.motion_val[0][b_xy + i*h->b_stride], 0, 4*2*sizeof(int16_t)); } } if (s->pict_type == B_TYPE) {
if (mb_type != 2) { svq3_mc_dir (h, 0, mode, 0, 0); } else { for (i=0; i < 4; i++) { memset (s->current_picture.motion_val[0][b_xy + i*h->b_stride], 0, 4*2*sizeof(int16_t)); } }
static int svq3_decode_mb (H264Context *h, unsigned int mb_type) {  int cbp, dir, mode, mx, my, dx, dy, x, y, part_width, part_height;  int i, j, k, l, m;  uint32_t vlc;  int8_t *top, *left;  MpegEncContext *const s = (MpegEncContext *) h;  const int mb_xy = s->mb_x + s->mb_y*s->mb_stride;  const int b_xy = 4*s->mb_x + 4*s->mb_y*h->b_stride;  h->top_samples_available	= (s->mb_y == 0) ? 0x33FF : 0xFFFF;  h->left_samples_available	= (s->mb_x == 0) ? 0x5F5F : 0xFFFF;  h->topright_samples_available	= 0xFFFF;  if (mb_type == 0) {		/* SKIP */    if (s->pict_type == P_TYPE) {      svq3_mc_dir_part (s, 16*s->mb_x, 16*s->mb_y, 16, 16, 0, 0, 0, 0, 0, 0);      cbp = 0;      mb_type = MB_TYPE_SKIP;    } else {      for (dir=0; dir < 2; dir++) {	for (i=0; i < 4; i++) {	  for (j=0; j < 4; j++) {	    int dxy;	    x = 16*s->mb_x + 4*j;	    y = 16*s->mb_y + 4*i;	    mx = 2*s->next_picture.motion_val[0][b_xy + j + i*h->b_stride][0];	    my = 2*s->next_picture.motion_val[0][b_xy + j + i*h->b_stride][1];	    if (dir == 0) {	      mx = (mx * h->frame_num_offset) / h->prev_frame_num_offset;	      my = (my * h->frame_num_offset) / h->prev_frame_num_offset;	    } else {	      mx = (mx * (h->frame_num_offset - h->prev_frame_num_offset)) / h->prev_frame_num_offset;	      my = (my * (h->frame_num_offset - h->prev_frame_num_offset)) / h->prev_frame_num_offset;	    }	    mx = ((unsigned)(mx + 3 + 0x6000))/6 - 0x1000;	    my = ((unsigned)(my + 3 + 0x6000))/6 - 0x1000;	    dxy= (mx&1) + 2*(my&1);	    /* update mv_cache */	    s->current_picture.motion_val[dir][b_xy + j + i*h->b_stride][0] = 3*mx;	    s->current_picture.motion_val[dir][b_xy + j + i*h->b_stride][1] = 3*my;	    svq3_mc_dir_part (s, x, y, 4, 4, mx>>1, my>>1, dxy, 0, dir, (dir == 1));	  }	}      }      if ((vlc = svq3_get_ue_golomb (&s->gb)) >= 48)	return -1;      cbp = golomb_to_inter_cbp[vlc];      mb_type = MB_TYPE_16x16;    }  } else if (mb_type < 8) {	/* INTER */    int dir0, dir1;    if (h->thirdpel_flag && h->halfpel_flag == !get_bits (&s->gb, 1)) {      mode = THIRDPEL_MODE;    } else if (h->halfpel_flag && h->thirdpel_flag == !get_bits (&s->gb, 1)) {      mode = HALFPEL_MODE;    } else {      mode = FULLPEL_MODE;    }    /* fill caches */    /* note ref_cache should contain here:        ????????        ???11111        N??11111        N??11111        N??11111        N    */        for (m=0; m < 2; m++) {      if (s->mb_x > 0 && h->intra4x4_pred_mode[mb_xy - 1][0] != -1) {	for (i=0; i < 4; i++) {	  *(uint32_t *) h->mv_cache[m][scan8[0] - 1 + i*8] = *(uint32_t *) s->current_picture.motion_val[m][b_xy - 1 + i*h->b_stride];	}      } else {	for (i=0; i < 4; i++) {	  *(uint32_t *) h->mv_cache[m][scan8[0] - 1 + i*8] = 0;	}      }      if (s->mb_y > 0) {	memcpy (h->mv_cache[m][scan8[0] - 1*8], s->current_picture.motion_val[m][b_xy - h->b_stride], 4*2*sizeof(int16_t));	memset (&h->ref_cache[m][scan8[0] - 1*8], (h->intra4x4_pred_mode[mb_xy - s->mb_stride][4] == -1) ? PART_NOT_AVAILABLE : 1, 4);	if (s->mb_x < (s->mb_width - 1)) {	  *(uint32_t *) h->mv_cache[m][scan8[0] + 4 - 1*8] = *(uint32_t *) s->current_picture.motion_val[m][b_xy - h->b_stride + 4];	  h->ref_cache[m][scan8[0] + 4 - 1*8] =		  (h->intra4x4_pred_mode[mb_xy - s->mb_stride + 1][0] == -1 ||		   h->intra4x4_pred_mode[mb_xy - s->mb_stride][4] == -1) ? PART_NOT_AVAILABLE : 1;	}else	  h->ref_cache[m][scan8[0] + 4 - 1*8] = PART_NOT_AVAILABLE;	if (s->mb_x > 0) {	  *(uint32_t *) h->mv_cache[0][scan8[0] - 1 - 1*8] = *(uint32_t *) s->current_picture.motion_val[m][b_xy - h->b_stride - 1];	  h->ref_cache[m][scan8[0] - 1 - 1*8] = (h->intra4x4_pred_mode[mb_xy - s->mb_stride - 1][3] == -1) ? PART_NOT_AVAILABLE : 1;	}else	  h->ref_cache[m][scan8[0] - 1 - 1*8] = PART_NOT_AVAILABLE;      }else	memset (&h->ref_cache[m][scan8[0] - 1*8 - 1], PART_NOT_AVAILABLE, 8);      if (s->pict_type != B_TYPE)	break;    }    /* decode motion vector(s) and form prediction(s) */    if (s->pict_type == P_TYPE) {      part_width  = ((mb_type & 5) == 5) ? 4 : 8 << (mb_type & 1);      part_height = 16 >> ((unsigned) mb_type / 3);      dir0 = 0;      dir1 = 0;    } else {	/* B_TYPE */      part_width  = 16;      part_height = 16;      dir0 = (mb_type == 2) ? 1 : 0;      dir1 = (mb_type == 1) ? 0 : 1;    }  for (dir=dir0; dir <= dir1; dir++) {    for (i=0; i < 16; i+=part_height) {      for (j=0; j < 16; j+=part_width) {	int avg=(dir == 1 && dir0 != dir1);	int dxy;	x = 16*s->mb_x + j;	y = 16*s->mb_y + i;	k = ((j>>2)&1) + ((i>>1)&2) + ((j>>1)&4) + (i&8);	pred_motion (h, k, (part_width >> 2), dir, 1, &mx, &my);	/* clip motion vector prediction to frame border */	mx = clip (mx, -6*x, 6*(s->h_edge_pos - part_width  - x));	my = clip (my, -6*y, 6*(s->v_edge_pos - part_height - y));	/* get motion vector differential */	dy = svq3_get_se_golomb (&s->gb);	dx = svq3_get_se_golomb (&s->gb);	if (dx == INVALID_VLC || dy == INVALID_VLC) {	  return -1;	}	/* compute motion vector */	if (mode == THIRDPEL_MODE) {          int fx, fy;          mx = ((mx + 1)>>1) + dx;          my = ((my + 1)>>1) + dy;          fx= ((unsigned)(mx + 0x3000))/3 - 0x1000;          fy= ((unsigned)(my + 0x3000))/3 - 0x1000;          dxy= (mx - 3*fx) + 4*(my - 3*fy);          svq3_mc_dir_part (s, x, y, part_width, part_height, fx, fy, dxy, 1, dir, avg);          mx += mx;          my += my;	} else if (mode == HALFPEL_MODE) {	  mx = ((unsigned)(mx + 1 + 0x3000))/3 + dx - 0x1000;	  my = ((unsigned)(my + 1 + 0x3000))/3 + dy - 0x1000;          dxy= (mx&1) + 2*(my&1);          svq3_mc_dir_part (s, x, y, part_width, part_height, mx>>1, my>>1, dxy, 0, dir, avg);          mx *= 3;          my *= 3;	} else {          assert(mode == FULLPEL_MODE);	  mx = ((unsigned)(mx + 3 + 0x6000))/6 + dx - 0x1000;	  my = ((unsigned)(my + 3 + 0x6000))/6 + dy - 0x1000;	  svq3_mc_dir_part (s, x, y, part_width, part_height, mx, my, 0, 0, dir, avg);          mx *= 6;          my *= 6;	}        /* update mv_cache */        fill_rectangle(h->mv_cache[dir][scan8[k]], part_width>>2, part_height>>2, 8, pack16to32(mx,my), 4);      }    }  }    /* write back or clear motion vectors */    if (s->pict_type == P_TYPE || mb_type != 2) {      for (i=0; i < 4; i++) {	memcpy (s->current_picture.motion_val[0][b_xy + i*h->b_stride], h->mv_cache[0][scan8[0] + 8*i], 4*2*sizeof(int16_t));      }    } else {      for (i=0; i < 4; i++) {	memset (s->current_picture.motion_val[0][b_xy + i*h->b_stride], 0, 4*2*sizeof(int16_t));      }    }    if (s->pict_type == B_TYPE) {      if (mb_type != 1) {	for (i=0; i < 4; i++) {	  memcpy (s->current_picture.motion_val[1][b_xy + i*h->b_stride], h->mv_cache[1][scan8[0] + 8*i], 4*2*sizeof(int16_t));        }      } else {	for (i=0; i < 4; i++) {	  memset (s->current_picture.motion_val[1][b_xy + i*h->b_stride], 0, 4*2*sizeof(int16_t));	}      }    }    if ((vlc = svq3_get_ue_golomb (&s->gb)) >= 48)      return -1;    cbp = golomb_to_inter_cbp[vlc];    mb_type = MB_TYPE_16x16;  } else if (mb_type == 8 || mb_type == 33) {	/* INTRA4x4 */    memset (h->intra4x4_pred_mode_cache, -1, 8*5*sizeof(int8_t));    if (mb_type == 8) {      if (s->mb_x > 0) {	for (i=0; i < 4; i++) {	  h->intra4x4_pred_mode_cache[scan8[0] - 1 + i*8] = h->intra4x4_pred_mode[mb_xy - 1][i];	}	if (h->intra4x4_pred_mode_cache[scan8[0] - 1] == -1) {	  h->left_samples_available = 0x5F5F;	}      }      if (s->mb_y > 0) {	h->intra4x4_pred_mode_cache[4+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][4];	h->intra4x4_pred_mode_cache[5+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][5];	h->intra4x4_pred_mode_cache[6+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][6];	h->intra4x4_pred_mode_cache[7+8*0] = h->intra4x4_pred_mode[mb_xy - s->mb_stride][3];	if (h->intra4x4_pred_mode_cache[4+8*0] == -1) {	  h->top_samples_available = 0x33FF;	}      }      /* decode prediction codes for luma blocks */      for (i=0; i < 16; i+=2) {	vlc = svq3_get_ue_golomb (&s->gb);	if (vlc >= 25)	  return -1;	left	= &h->intra4x4_pred_mode_cache[scan8[i] - 1];	top	= &h->intra4x4_pred_mode_cache[scan8[i] - 8];	left[1]	= svq3_pred_1[top[0] + 1][left[0] + 1][svq3_pred_0[vlc][0]];	left[2]	= svq3_pred_1[top[1] + 1][left[1] + 1][svq3_pred_0[vlc][1]];	if (left[1] == -1 || left[2] == -1)	  return -1;      }    } else {      /* DC_128_PRED block type */      for (i=0; i < 4; i++) {	memset (&h->intra4x4_pred_mode_cache[scan8[0] + 8*i], DC_PRED, 4);      }    }    write_back_intra_pred_mode (h);    if (mb_type == 8) {      check_intra4x4_pred_mode (h);      h->top_samples_available  = (s->mb_y == 0) ? 0x33FF : 0xFFFF;      h->left_samples_available = (s->mb_x == 0) ? 0x5F5F : 0xFFFF;    } else {      for (i=0; i < 4; i++) {        memset (&h->intra4x4_pred_mode_cache[scan8[0] + 8*i], DC_128_PRED, 4);      }      h->top_samples_available  = 0x33FF;      h->left_samples_available = 0x5F5F;    }    if ((vlc = svq3_get_ue_golomb (&s->gb)) >= 48)      return -1;    cbp = golomb_to_intra4x4_cbp[vlc];    mb_type = MB_TYPE_INTRA4x4;  } else {			/* INTRA16x16 */    dir = i_mb_type_info[mb_type - 8].pred_mode;    dir = (dir >> 1) ^ 3*(dir & 1) ^ 1;    if ((h->intra16x16_pred_mode = check_intra_pred_mode (h, dir)) == -1)      return -1;    cbp = i_mb_type_info[mb_type - 8].cbp;    mb_type = MB_TYPE_INTRA16x16;  }  if (!IS_INTER(mb_type) && s->pict_type != I_TYPE) {    for (i=0; i < 4; i++) {      memset (s->current_picture.motion_val[0][b_xy + i*h->b_stride], 0, 4*2*sizeof(int16_t));    }    if (s->pict_type == B_TYPE) {      for (i=0; i < 4; i++) {	memset (s->current_picture.motion_val[1][b_xy + i*h->b_stride], 0, 4*2*sizeof(int16_t));      }    }  }  if (!IS_INTRA4x4(mb_type)) {    memset (h->intra4x4_pred_mode[mb_xy], DC_PRED, 8);  }  if (!IS_SKIP(mb_type)) {    memset (h->non_zero_count_cache + 8, 0, 4*9*sizeof(uint8_t));    s->dsp.clear_blocks(h->mb);  }  if (IS_INTRA16x16(mb_type) || (s->pict_type != I_TYPE && s->adaptive_quant && cbp)) {    s->qscale += svq3_get_se_golomb (&s->gb);    if (s->qscale > 31)      return -1;  }  if (IS_INTRA16x16(mb_type)) {    if (svq3_decode_block (&s->gb, h->mb, 0, 0))      return -1;  }  if (!IS_SKIP(mb_type) && cbp) {    l = IS_INTRA16x16(mb_type) ? 1 : 0;    m = ((s->qscale < 24 && IS_INTRA4x4(mb_type)) ? 2 : 1);    for (i=0; i < 4; i++) {      if ((cbp & (1 << i))) {	for (j=0; j < 4; j++) {	  k = l ? ((j&1) + 2*(i&1) + 2*(j&2) + 4*(i&2)) : (4*i + j);	  h->non_zero_count_cache[ scan8[k] ] = 1;	  if (svq3_decode_block (&s->gb, &h->mb[16*k], l, m))	    return -1;	}      }    }    if ((cbp & 0x30)) {      for (i=0; i < 2; ++i) {	if (svq3_decode_block (&s->gb, &h->mb[16*(16 + 4*i)], 0, 3))	  return -1;      }      if ((cbp & 0x20)) {	for (i=0; i < 8; i++) {	  h->non_zero_count_cache[ scan8[16+i] ] = 1;	  if (svq3_decode_block (&s->gb, &h->mb[16*(16 + i)], 1, 1))	    return -1;	}      }    }  }  s->current_picture.mb_type[mb_xy] = mb_type;  if (IS_INTRA(mb_type)) {    h->chroma_pred_mode = check_intra_pred_mode (h, DC_PRED8x8);  }  return 0;}