cavs.c

linux下的MPEG1

static inline void check_for_slice(AVSContext *h);

/**
 * save predictors for later macroblocks and increase
 * macroblock address
 * @returns 0 if end of frame is reached, 1 otherwise
 */
static inline int next_mb(AVSContext *h) {
    int i;

    h->flags |= A_AVAIL;
    h->cy += 16;
    h->cu += 8;
    h->cv += 8;
    /* copy mvs as predictors to the left */
    for(i=0;i<=20;i+=4)
        h->mv[i] = h->mv[i+2];
    /* copy bottom mvs from cache to top line */
    h->top_mv[0][h->mbx*2+0] = h->mv[MV_FWD_X2];
    h->top_mv[0][h->mbx*2+1] = h->mv[MV_FWD_X3];
    h->top_mv[1][h->mbx*2+0] = h->mv[MV_BWD_X2];
    h->top_mv[1][h->mbx*2+1] = h->mv[MV_BWD_X3];
    /* next MB address */
    h->mbx++;
    if(h->mbx == h->mb_width) { //new mb line
        h->flags = B_AVAIL|C_AVAIL;
        /* clear left pred_modes */
        h->pred_mode_Y[3] = h->pred_mode_Y[6] = NOT_AVAIL;
        /* clear left mv predictors */
        for(i=0;i<=20;i+=4)
            h->mv[i] = un_mv;
        h->mbx = 0;
        h->mby++;
        /* re-calculate sample pointers */
        h->cy = h->picture.data[0] + h->mby*16*h->l_stride;
        h->cu = h->picture.data[1] + h->mby*8*h->c_stride;
        h->cv = h->picture.data[2] + h->mby*8*h->c_stride;
        if(h->mby == h->mb_height) { //frame end
            return 0;
        } else {
            //check_for_slice(h);
        }
    }
    return 1;
}

static int decode_mb_i(AVSContext *h, int cbp_code) {
    GetBitContext *gb = &h->s.gb;
    int block, pred_mode_uv;
    uint8_t top[18];
    uint8_t *left = NULL;
    uint8_t *d;

    init_mb(h);

    /* get intra prediction modes from stream */
    for(block=0;block<4;block++) {
        int nA,nB,predpred;
        int pos = scan3x3[block];

        nA = h->pred_mode_Y[pos-1];
        nB = h->pred_mode_Y[pos-3];
        predpred = FFMIN(nA,nB);
        if(predpred == NOT_AVAIL) // if either is not available
            predpred = INTRA_L_LP;
        if(!get_bits1(gb)){
            int rem_mode= get_bits(gb, 2);
            predpred = rem_mode + (rem_mode >= predpred);
        }
        h->pred_mode_Y[pos] = predpred;
    }
    pred_mode_uv = get_ue_golomb(gb);
    if(pred_mode_uv > 6) {
        av_log(h->s.avctx, AV_LOG_ERROR, "illegal intra chroma pred mode\n");
        return -1;
    }

    /* save pred modes before they get modified */
    h->pred_mode_Y[3] =  h->pred_mode_Y[5];
    h->pred_mode_Y[6] =  h->pred_mode_Y[8];
    h->top_pred_Y[h->mbx*2+0] = h->pred_mode_Y[7];
    h->top_pred_Y[h->mbx*2+1] = h->pred_mode_Y[8];

    /* modify pred modes according to availability of neighbour samples */
    if(!(h->flags & A_AVAIL)) {
        modify_pred(left_modifier_l, &h->pred_mode_Y[4] );
        modify_pred(left_modifier_l, &h->pred_mode_Y[7] );
        modify_pred(left_modifier_c, &pred_mode_uv );
    }
    if(!(h->flags & B_AVAIL)) {
        modify_pred(top_modifier_l, &h->pred_mode_Y[4] );
        modify_pred(top_modifier_l, &h->pred_mode_Y[5] );
        modify_pred(top_modifier_c, &pred_mode_uv );
    }

    /* get coded block pattern */
    if(h->pic_type == FF_I_TYPE)
        cbp_code = get_ue_golomb(gb);
    if(cbp_code > 63){
        av_log(h->s.avctx, AV_LOG_ERROR, "illegal intra cbp\n");
        return -1;
    }
    h->cbp = cbp_tab[cbp_code][0];
    if(h->cbp && !h->qp_fixed)
        h->qp = (h->qp + get_se_golomb(gb)) & 63; //qp_delta

    /* luma intra prediction interleaved with residual decode/transform/add */
    for(block=0;block<4;block++) {
        d = h->cy + h->luma_scan[block];
        load_intra_pred_luma(h, top, &left, block);
        h->intra_pred_l[h->pred_mode_Y[scan3x3[block]]]
            (d, top, left, h->l_stride);
        if(h->cbp & (1<<block))
            decode_residual_block(h,gb,intra_2dvlc,1,h->qp,d,h->l_stride);
    }

    /* chroma intra prediction */
    /* extend borders by one pixel */
    h->left_border_u[9] = h->left_border_u[8];
    h->left_border_v[9] = h->left_border_v[8];
    h->top_border_u[h->mbx*10+9] = h->top_border_u[h->mbx*10+8];
    h->top_border_v[h->mbx*10+9] = h->top_border_v[h->mbx*10+8];
    if(h->mbx && h->mby) {
        h->top_border_u[h->mbx*10] = h->left_border_u[0] = h->topleft_border_u;
        h->top_border_v[h->mbx*10] = h->left_border_v[0] = h->topleft_border_v;
    } else {
        h->left_border_u[0] = h->left_border_u[1];
        h->left_border_v[0] = h->left_border_v[1];
        h->top_border_u[h->mbx*10] = h->top_border_u[h->mbx*10+1];
        h->top_border_v[h->mbx*10] = h->top_border_v[h->mbx*10+1];
    }
    h->intra_pred_c[pred_mode_uv](h->cu, &h->top_border_u[h->mbx*10],
                                  h->left_border_u, h->c_stride);
    h->intra_pred_c[pred_mode_uv](h->cv, &h->top_border_v[h->mbx*10],
                                  h->left_border_v, h->c_stride);

    decode_residual_chroma(h);
    filter_mb(h,I_8X8);

    /* mark motion vectors as intra */
    h->mv[MV_FWD_X0] = intra_mv;
    set_mvs(&h->mv[MV_FWD_X0], BLK_16X16);
    h->mv[MV_BWD_X0] = intra_mv;
    set_mvs(&h->mv[MV_BWD_X0], BLK_16X16);
    if(h->pic_type != FF_B_TYPE)
        *h->col_type = I_8X8;

    return 0;
}

static void decode_mb_p(AVSContext *h, enum mb_t mb_type) {
    GetBitContext *gb = &h->s.gb;
    int ref[4];

    init_mb(h);
    switch(mb_type) {
    case P_SKIP:
        mv_pred(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_PSKIP, BLK_16X16, 0);
        break;
    case P_16X16:
        ref[0] = h->ref_flag ? 0 : get_bits1(gb);
        mv_pred(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN,   BLK_16X16,ref[0]);
        break;
    case P_16X8:
        ref[0] = h->ref_flag ? 0 : get_bits1(gb);
        ref[2] = h->ref_flag ? 0 : get_bits1(gb);
        mv_pred(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_TOP,      BLK_16X8, ref[0]);
        mv_pred(h, MV_FWD_X2, MV_FWD_A1, MV_PRED_LEFT,     BLK_16X8, ref[2]);
        break;
    case P_8X16:
        ref[0] = h->ref_flag ? 0 : get_bits1(gb);
        ref[1] = h->ref_flag ? 0 : get_bits1(gb);
        mv_pred(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_LEFT,     BLK_8X16, ref[0]);
        mv_pred(h, MV_FWD_X1, MV_FWD_C2, MV_PRED_TOPRIGHT, BLK_8X16, ref[1]);
        break;
    case P_8X8:
        ref[0] = h->ref_flag ? 0 : get_bits1(gb);
        ref[1] = h->ref_flag ? 0 : get_bits1(gb);
        ref[2] = h->ref_flag ? 0 : get_bits1(gb);
        ref[3] = h->ref_flag ? 0 : get_bits1(gb);
        mv_pred(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_MEDIAN,   BLK_8X8, ref[0]);
        mv_pred(h, MV_FWD_X1, MV_FWD_C2, MV_PRED_MEDIAN,   BLK_8X8, ref[1]);
        mv_pred(h, MV_FWD_X2, MV_FWD_X1, MV_PRED_MEDIAN,   BLK_8X8, ref[2]);
        mv_pred(h, MV_FWD_X3, MV_FWD_X0, MV_PRED_MEDIAN,   BLK_8X8, ref[3]);
    }
    inter_pred(h, mb_type);
    store_mvs(h);
    if(mb_type != P_SKIP)
        decode_residual_inter(h);
    filter_mb(h,mb_type);
    *h->col_type = mb_type;
}

static void decode_mb_b(AVSContext *h, enum mb_t mb_type) {
    int block;
    enum sub_mb_t sub_type[4];
    int flags;

    init_mb(h);

    /* reset all MVs */
    h->mv[MV_FWD_X0] = dir_mv;
    set_mvs(&h->mv[MV_FWD_X0], BLK_16X16);
    h->mv[MV_BWD_X0] = dir_mv;
    set_mvs(&h->mv[MV_BWD_X0], BLK_16X16);
    switch(mb_type) {
    case B_SKIP:
    case B_DIRECT:
        if(!(*h->col_type)) {
            /* intra MB at co-location, do in-plane prediction */
            mv_pred(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_BSKIP, BLK_16X16, 1);
            mv_pred(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_BSKIP, BLK_16X16, 0);
        } else
            /* direct prediction from co-located P MB, block-wise */
            for(block=0;block<4;block++)
                mv_pred_direct(h,&h->mv[mv_scan[block]],
                            &h->col_mv[(h->mby*h->mb_width+h->mbx)*4 + block]);
        break;
    case B_FWD_16X16:
        mv_pred(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN, BLK_16X16, 1);
        break;
    case B_SYM_16X16:
        mv_pred(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN, BLK_16X16, 1);
        mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_16X16);
        break;
    case B_BWD_16X16:
        mv_pred(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_MEDIAN, BLK_16X16, 0);
        break;
    case B_8X8:
        for(block=0;block<4;block++)
            sub_type[block] = get_bits(&h->s.gb,2);
        for(block=0;block<4;block++) {
            switch(sub_type[block]) {
            case B_SUB_DIRECT:
                if(!(*h->col_type)) {
                    /* intra MB at co-location, do in-plane prediction */
                    mv_pred(h, mv_scan[block], mv_scan[block]-3,
                            MV_PRED_BSKIP, BLK_8X8, 1);
                    mv_pred(h, mv_scan[block]+MV_BWD_OFFS,
                            mv_scan[block]-3+MV_BWD_OFFS,
                            MV_PRED_BSKIP, BLK_8X8, 0);
                } else
                    mv_pred_direct(h,&h->mv[mv_scan[block]],
                                   &h->col_mv[(h->mby*h->mb_width + h->mbx)*4 + block]);
                break;
            case B_SUB_FWD:
                mv_pred(h, mv_scan[block], mv_scan[block]-3,
                        MV_PRED_MEDIAN, BLK_8X8, 1);
                break;
            case B_SUB_SYM:
                mv_pred(h, mv_scan[block], mv_scan[block]-3,
                        MV_PRED_MEDIAN, BLK_8X8, 1);
                mv_pred_sym(h, &h->mv[mv_scan[block]], BLK_8X8);
                break;
            }
        }
        for(block=0;block<4;block++) {
            if(sub_type[block] == B_SUB_BWD)
                mv_pred(h, mv_scan[block]+MV_BWD_OFFS,
                        mv_scan[block]+MV_BWD_OFFS-3,
                        MV_PRED_MEDIAN, BLK_8X8, 0);
        }
        break;
    default:
        assert((mb_type > B_SYM_16X16) && (mb_type < B_8X8));
        flags = partition_flags[mb_type];
        if(mb_type & 1) { /* 16x8 macroblock types */
            if(flags & FWD0)
                mv_pred(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_TOP,  BLK_16X8, 1);
            if(flags & SYM0)
                mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_16X8);
            if(flags & FWD1)
                mv_pred(h, MV_FWD_X2, MV_FWD_A1, MV_PRED_LEFT, BLK_16X8, 1);
            if(flags & SYM1)
                mv_pred_sym(h, &h->mv[MV_FWD_X2], BLK_16X8);
            if(flags & BWD0)
                mv_pred(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_TOP,  BLK_16X8, 0);
            if(flags & BWD1)
                mv_pred(h, MV_BWD_X2, MV_BWD_A1, MV_PRED_LEFT, BLK_16X8, 0);
        } else {          /* 8x16 macroblock types */
            if(flags & FWD0)
                mv_pred(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_LEFT, BLK_8X16, 1);
            if(flags & SYM0)
                mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_8X16);
            if(flags & FWD1)
                mv_pred(h, MV_FWD_X1, MV_FWD_C2, MV_PRED_TOPRIGHT,BLK_8X16, 1);
            if(flags & SYM1)
                mv_pred_sym(h, &h->mv[MV_FWD_X1], BLK_8X16);
            if(flags & BWD0)
                mv_pred(h, MV_BWD_X0, MV_BWD_B3, MV_PRED_LEFT, BLK_8X16, 0);
            if(flags & BWD1)
                mv_pred(h, MV_BWD_X1, MV_BWD_C2, MV_PRED_TOPRIGHT,BLK_8X16, 0);
        }
    }
    inter_pred(h, mb_type);
    if(mb_type != B_SKIP)
        decode_residual_inter(h);
    filter_mb(h,mb_type);
}

/*****************************************************************************
 *
 * slice level
 *
 ****************************************************************************/

static inline int decode_slice_header(AVSContext *h, GetBitContext *gb) {
    if(h->stc > 0xAF)
        av_log(h->s.avctx, AV_LOG_ERROR, "unexpected start code 0x%02x\n", h->stc);
    h->mby = h->stc;
    if((h->mby == 0) && (!h->qp_fixed)){
        h->qp_fixed = get_bits1(gb);
        h->qp = get_bits(gb,6);
    }
    /* inter frame or second slice can have weighting params */
    if((h->pic_type != FF_I_TYPE) || (!h->pic_structure && h->mby >= h->mb_width/2))
        if(get_bits1(gb)) { //slice_weighting_flag
            av_log(h->s.avctx, AV_LOG_ERROR,
                   "weighted prediction not yet supported\n");
        }
    return 0;
}

static inline void check_for_slice(AVSContext *h) {
    GetBitContext *gb = &h->s.gb;
    int align;
    align = (-get_bits_count(gb)) & 7;
    if((show_bits_long(gb,24+align) & 0xFFFFFF) == 0x000001) {
        get_bits_long(gb,24+align);
        h->stc = get_bits(gb,8);
        decode_slice_header(h,gb);
    }
}

/*****************************************************************************
 *
 * frame level
 *
 ****************************************************************************/

static void init_pic(AVSContext *h) {
    int i;

    /* clear some predictors */
    for(i=0;i<=20;i+=4)
        h->mv[i] = un_mv;
    h->mv[MV_BWD_X0] = dir_mv;
    set_mvs(&h->mv[MV_BWD_X0], BLK_16X16);
    h->mv[MV_FWD_X0] = dir_mv;
    set_mvs(&h->mv[MV_FWD_X0], BLK_16X16);
    h->pred_mode_Y[3] = h->pred_mode_Y[6] = NOT_AVAIL;
    h->cy = h->picture.data[0];
    h->cu = h->picture.data[1];
    h->cv = h->picture.data[2];
    h->l_stride = h->picture.linesize[0];
    h->c_stride = h->picture.linesize[1];
    h->luma_scan[2] = 8*h->l_stride;
    h->luma_scan[3] = 8*h->l_stride+8;
    h->mbx = h->mby = 0;
    h->flags = 0;
}

static int decode_pic(AVSContext *h) {
    MpegEncContext *s = &h->s;
    int skip_count;
    enum mb_t mb_type;

    if (!s->context_initialized) {
        s->avctx->idct_algo = FF_IDCT_CAVS;
        if (MPV_common_init(s) < 0)
            return -1;
        ff_init_scantable(s->dsp.idct_permutation,&h->scantable,ff_zigzag_direct);
    }
    get_bits(&s->gb,16);//bbv_dwlay
    if(h->stc == PIC_PB_START_CODE) {
        h->pic_type = get_bits(&s->gb,2) + FF_I_TYPE;
        if(h->pic_type > FF_B_TYPE) {
            av_log(s->avctx, AV_LOG_ERROR, "illegal picture type\n");
            return -1;
        }
        /* make sure we have the reference frames we need */
        if(!h->DPB[0].data[0] ||
          (!h->DPB[1].data[0] && h->pic_type == FF_B_TYPE))
            return -1;
    } else {