static int unpack_superblocks(Vp3DecodeContext *s, GetBitContext *gb) { int superblock_starts[3] = { 0, s->u_superblock_start, s->v_superblock_start }; int bit = 0; int current_superblock = 0; int current_run = 0; int num_partial_superblocks = 0; int i, j; int current_fragment; int plane; if (s->keyframe) { memset(s->superblock_coding, SB_FULLY_CODED, s->superblock_count); } else { /* unpack the list of partially-coded superblocks */ bit = get_bits1(gb) ^ 1; current_run = 0; while (current_superblock < s->superblock_count && get_bits_left(gb) > 0) { if (s->theora && current_run == MAXIMUM_LONG_BIT_RUN) bit = get_bits1(gb); else bit ^= 1; current_run = get_vlc2(gb, s->superblock_run_length_vlc.table, 6, 2) + 1; if (current_run == 34) current_run += get_bits(gb, 12); if (current_superblock + current_run > s->superblock_count) { av_log(s->avctx, AV_LOG_ERROR, "Invalid partially coded superblock run length\n"); return -1; } memset(s->superblock_coding + current_superblock, bit, current_run); current_superblock += current_run; if (bit) num_partial_superblocks += current_run; } /* unpack the list of fully coded superblocks if any of the blocks were * not marked as partially coded in the previous step */ if (num_partial_superblocks < s->superblock_count) { int superblocks_decoded = 0; current_superblock = 0; bit = get_bits1(gb) ^ 1; current_run = 0; while (superblocks_decoded < s->superblock_count - num_partial_superblocks && get_bits_left(gb) > 0) { if (s->theora && current_run == MAXIMUM_LONG_BIT_RUN) bit = get_bits1(gb); else bit ^= 1; current_run = get_vlc2(gb, s->superblock_run_length_vlc.table, 6, 2) + 1; if (current_run == 34) current_run += get_bits(gb, 12); for (j = 0; j < current_run; current_superblock++) { if (current_superblock >= s->superblock_count) { av_log(s->avctx, AV_LOG_ERROR, "Invalid fully coded superblock run length\n"); return -1; } /* skip any superblocks already marked as partially coded */ if (s->superblock_coding[current_superblock] == SB_NOT_CODED) { s->superblock_coding[current_superblock] = 2 * bit; j++; } } superblocks_decoded += current_run; } } /* if there were partial blocks, initialize bitstream for * unpacking fragment codings */ if (num_partial_superblocks) { current_run = 0; bit = get_bits1(gb); /* toggle the bit because as soon as the first run length is * fetched the bit will be toggled again */ bit ^= 1; } } /* figure out which fragments are coded; iterate through each * superblock (all planes) */ s->total_num_coded_frags = 0; memset(s->macroblock_coding, MODE_COPY, s->macroblock_count); for (plane = 0; plane < 3; plane++) { int sb_start = superblock_starts[plane]; int sb_end = sb_start + (plane ? s->c_superblock_count : s->y_superblock_count); int num_coded_frags = 0; for (i = sb_start; i < sb_end && get_bits_left(gb) > 0; i++) { /* iterate through all 16 fragments in a superblock */ for (j = 0; j < 16; j++) { /* if the fragment is in bounds, check its coding status */ current_fragment = s->superblock_fragments[i * 16 + j]; if (current_fragment != -1) { int coded = s->superblock_coding[i]; if (s->superblock_coding[i] == SB_PARTIALLY_CODED) { /* fragment may or may not be coded; this is the case * that cares about the fragment coding runs */ if (current_run-- == 0) { bit ^= 1; current_run = get_vlc2(gb, s->fragment_run_length_vlc.table, 5, 2); } coded = bit; } if (coded) { /* default mode; actual mode will be decoded in * the next phase */ s->all_fragments[current_fragment].coding_method = MODE_INTER_NO_MV; s->coded_fragment_list[plane][num_coded_frags++] = current_fragment; } else { /* not coded; copy this fragment from the prior frame */ s->all_fragments[current_fragment].coding_method = MODE_COPY; } } } } s->total_num_coded_frags += num_coded_frags; for (i = 0; i < 64; i++) s->num_coded_frags[plane][i] = num_coded_frags; if (plane < 2) s->coded_fragment_list[plane + 1] = s->coded_fragment_list[plane] + num_coded_frags; } return 0; }