Exemple #1
0
static int h263_decode_block(MpegEncContext * s, int16_t * block,
                             int n, int coded)
{
    int level, i, j, run;
    RLTable *rl = &ff_h263_rl_inter;
    const uint8_t *scan_table;
    GetBitContext gb= s->gb;

    scan_table = s->intra_scantable.permutated;
    if (s->h263_aic && s->mb_intra) {
        rl = &ff_rl_intra_aic;
        i = 0;
        if (s->ac_pred) {
            if (s->h263_aic_dir)
                scan_table = s->intra_v_scantable.permutated; /* left */
            else
                scan_table = s->intra_h_scantable.permutated; /* top */
        }
    } else if (s->mb_intra) {
        /* DC coef */
        if (CONFIG_RV10_DECODER && s->codec_id == AV_CODEC_ID_RV10) {
          if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
            int component, diff;
            component = (n <= 3 ? 0 : n - 4 + 1);
            level = s->last_dc[component];
            if (s->rv10_first_dc_coded[component]) {
                diff = ff_rv_decode_dc(s, n);
                if (diff == 0xffff)
                    return -1;
                level += diff;
                level = level & 0xff; /* handle wrap round */
                s->last_dc[component] = level;
            } else {
                s->rv10_first_dc_coded[component] = 1;
            }
          } else {
                level = get_bits(&s->gb, 8);
                if (level == 255)
                    level = 128;
          }
        }else{
            level = get_bits(&s->gb, 8);
            if((level&0x7F) == 0){
                av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
                if (s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
                    return -1;
            }
            if (level == 255)
                level = 128;
        }
        block[0] = level;
        i = 1;
    } else {
        i = 0;
    }
    if (!coded) {
        if (s->mb_intra && s->h263_aic)
            goto not_coded;
        s->block_last_index[n] = i - 1;
        return 0;
    }
retry:
    {
    OPEN_READER(re, &s->gb);
    i--; // offset by -1 to allow direct indexing of scan_table
    for(;;) {
        UPDATE_CACHE(re, &s->gb);
        GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
        if (run == 66) {
            if (level){
                CLOSE_READER(re, &s->gb);
                av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
                return -1;
            }
            /* escape */
            if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
                int is11 = SHOW_UBITS(re, &s->gb, 1);
                SKIP_CACHE(re, &s->gb, 1);
                run = SHOW_UBITS(re, &s->gb, 7) + 1;
                if (is11) {
                    SKIP_COUNTER(re, &s->gb, 1 + 7);
                    UPDATE_CACHE(re, &s->gb);
                    level = SHOW_SBITS(re, &s->gb, 11);
                    SKIP_COUNTER(re, &s->gb, 11);
                } else {
                    SKIP_CACHE(re, &s->gb, 7);
                    level = SHOW_SBITS(re, &s->gb, 7);
                    SKIP_COUNTER(re, &s->gb, 1 + 7 + 7);
                }
            } else {
                run = SHOW_UBITS(re, &s->gb, 7) + 1;
                SKIP_CACHE(re, &s->gb, 7);
                level = (int8_t)SHOW_UBITS(re, &s->gb, 8);
                SKIP_COUNTER(re, &s->gb, 7 + 8);
                if(level == -128){
                    UPDATE_CACHE(re, &s->gb);
                    if (s->codec_id == AV_CODEC_ID_RV10) {
                        /* XXX: should patch encoder too */
                        level = SHOW_SBITS(re, &s->gb, 12);
                        SKIP_COUNTER(re, &s->gb, 12);
                    }else{
                        level = SHOW_UBITS(re, &s->gb, 5);
                        SKIP_CACHE(re, &s->gb, 5);
                        level |= SHOW_SBITS(re, &s->gb, 6)<<5;
                        SKIP_COUNTER(re, &s->gb, 5 + 6);
                    }
                }
            }
        } else {
            if (SHOW_UBITS(re, &s->gb, 1))
                level = -level;
            SKIP_COUNTER(re, &s->gb, 1);
        }
        i += run;
        if (i >= 64){
            CLOSE_READER(re, &s->gb);
            // redo update without last flag, revert -1 offset
            i = i - run + ((run-1)&63) + 1;
            if (i < 64) {
                // only last marker, no overrun
                block[scan_table[i]] = level;
                break;
            }
            if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
                //Looks like a hack but no, it's the way it is supposed to work ...
                rl = &ff_rl_intra_aic;
                i = 0;
                s->gb= gb;
                s->bdsp.clear_block(block);
                goto retry;
            }
            av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
            return -1;
        }
        j = scan_table[i];
        block[j] = level;
    }
    }
not_coded:
    if (s->mb_intra && s->h263_aic) {
        ff_h263_pred_acdc(s, block, n);
        i = 63;
    }
    s->block_last_index[n] = i;
    return 0;
}
Exemple #2
0
/**
 * Decode a macroblock.
 * @return <0 if an error occurred
 */
static int h261_decode_block(H261Context *h, int16_t *block, int n, int coded)
{
    MpegEncContext *const s = &h->s;
    int level, i, j, run;
    RLTable *rl = &ff_h261_rl_tcoeff;
    const uint8_t *scan_table;

    /* For the variable length encoding there are two code tables, one being
     * used for the first transmitted LEVEL in INTER, INTER + MC and
     * INTER + MC + FIL blocks, the second for all other LEVELs except the
     * first one in INTRA blocks which is fixed length coded with 8 bits.
     * NOTE: The two code tables only differ in one VLC so we handle that
     * manually. */
    scan_table = s->intra_scantable.permutated;
    if (s->mb_intra) {
        /* DC coef */
        level = get_bits(&s->gb, 8);
        // 0 (00000000b) and -128 (10000000b) are FORBIDDEN
        if ((level & 0x7F) == 0) {
            av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n",
                   level, s->mb_x, s->mb_y);
            return -1;
        }
        /* The code 1000 0000 is not used, the reconstruction level of 1024
         * being coded as 1111 1111. */
        if (level == 255)
            level = 128;
        block[0] = level;
        i        = 1;
    } else if (coded) {
        // Run  Level   Code
        // EOB          Not possible for first level when cbp is available (that's why the table is different)
        // 0    1       1s
        // *    *       0*
        int check = show_bits(&s->gb, 2);
        i = 0;
        if (check & 0x2) {
            skip_bits(&s->gb, 2);
            block[0] = (check & 0x1) ? -1 : 1;
            i        = 1;
        }
    } else {
        i = 0;
    }
    if (!coded) {
        s->block_last_index[n] = i - 1;
        return 0;
    }
    {
    OPEN_READER(re, &s->gb);
    i--; // offset by -1 to allow direct indexing of scan_table
    for (;;) {
        UPDATE_CACHE(re, &s->gb);
        GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TCOEFF_VLC_BITS, 2, 0);
        if (run == 66) {
            if (level) {
                CLOSE_READER(re, &s->gb);
                av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n",
                       s->mb_x, s->mb_y);
                return -1;
            }
            /* escape */
            /* The remaining combinations of (run, level) are encoded with a
             * 20-bit word consisting of 6 bits escape, 6 bits run and 8 bits
             * level. */
            run   = SHOW_UBITS(re, &s->gb, 6) + 1;
            SKIP_CACHE(re, &s->gb, 6);
            level = SHOW_SBITS(re, &s->gb, 8);
            SKIP_COUNTER(re, &s->gb, 6 + 8);
        } else if (level == 0) {
            break;
        } else {
            if (SHOW_UBITS(re, &s->gb, 1))
                level = -level;
            SKIP_COUNTER(re, &s->gb, 1);
        }
        i += run;
        if (i >= 64) {
            CLOSE_READER(re, &s->gb);
            av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d\n",
                   s->mb_x, s->mb_y);
            return -1;
        }
        j        = scan_table[i];
        block[j] = level;
    }
    CLOSE_READER(re, &s->gb);
    }
    s->block_last_index[n] = i;
    return 0;
}