s->block_index[0]= s->block_wrap[0]*(s->mb_y*2 + 1) - 1; s->block_index[1]= s->block_wrap[0]*(s->mb_y*2 + 1); s->block_index[2]= s->block_wrap[0]*(s->mb_y*2 + 2) - 1; s->block_index[3]= s->block_wrap[0]*(s->mb_y*2 + 2); s->block_index[4]= s->block_wrap[4]*(s->mb_y + 1)                    + s->block_wrap[0]*(s->mb_height*2 + 2); s->block_index[5]= s->block_wrap[4]*(s->mb_y + 1 + s->mb_height + 2) + s->block_wrap[0]*(s->mb_height*2 + 2);
static int rv10_decode_frame(AVCodecContext *avctx,                              void *data, int *data_size,                             UINT8 *buf, int buf_size){    MpegEncContext *s = avctx->priv_data;    int i, mb_count, mb_pos, left;    DCTELEM block[6][64];    AVPicture *pict = data; #ifdef DEBUG    printf("*****frame %d size=%d\n", avctx->frame_number, buf_size);#endif    /* no supplementary picture */    if (buf_size == 0) {        *data_size = 0;        return 0;    }    init_get_bits(&s->gb, buf, buf_size);    mb_count = rv10_decode_picture_header(s);    if (mb_count < 0) {#ifdef DEBUG        printf("HEADER ERROR\n");#endif        return -1;    }        if (s->mb_x >= s->mb_width ||        s->mb_y >= s->mb_height) {#ifdef DEBUG        printf("POS ERROR %d %d\n", s->mb_x, s->mb_y);#endif        return -1;    }    mb_pos = s->mb_y * s->mb_width + s->mb_x;    left = s->mb_width * s->mb_height - mb_pos;    if (mb_count > left) {#ifdef DEBUG        printf("COUNT ERROR\n");#endif        return -1;    }    if (s->mb_x == 0 && s->mb_y == 0) {        MPV_frame_start(s);    }#ifdef DEBUG    printf("qscale=%d\n", s->qscale);#endif    /* default quantization values */    s->y_dc_scale = 8;    s->c_dc_scale = 8;    s->rv10_first_dc_coded[0] = 0;    s->rv10_first_dc_coded[1] = 0;    s->rv10_first_dc_coded[2] = 0;        /* decode each macroblock */    for(i=0;i<mb_count;i++) {#ifdef DEBUG        printf("**mb x=%d y=%d\n", s->mb_x, s->mb_y);#endif                memset(block, 0, sizeof(block));        s->mv_dir = MV_DIR_FORWARD;        s->mv_type = MV_TYPE_16X16;         if (h263_decode_mb(s, block) < 0) {#ifdef DEBUG            printf("ERROR\n");#endif            return -1;        }        MPV_decode_mb(s, block);        if (++s->mb_x == s->mb_width) {            s->mb_x = 0;            s->mb_y++;        }    }    if (s->mb_x == 0 &&        s->mb_y == s->mb_height) {        MPV_frame_end(s);                pict->data[0] = s->current_picture[0];        pict->data[1] = s->current_picture[1];        pict->data[2] = s->current_picture[2];        pict->linesize[0] = s->linesize;        pict->linesize[1] = s->linesize / 2;        pict->linesize[2] = s->linesize / 2;                avctx->quality = s->qscale;        *data_size = sizeof(AVPicture);    } else {        *data_size = 0;    }    return buf_size;}