encodeframe.c

    for (i = 0; i < 25; i++)
    {
        x->block[i].coeff = x->coeff + i * 16;
    }
}

void vp8_build_block_offsets(MACROBLOCK *x)
{
    int block = 0;
    int br, bc;

    vp8_build_block_doffsets(&x->e_mbd);

    // y blocks
    for (br = 0; br < 4; br++)
    {
        for (bc = 0; bc < 4; bc++)
        {
            BLOCK *this_block = &x->block[block];
            this_block->base_src = &x->src.y_buffer;
            this_block->src_stride = x->src.y_stride;
            this_block->src = 4 * br * this_block->src_stride + 4 * bc;
            ++block;
        }
    }

    // u blocks
    for (br = 0; br < 2; br++)
    {
        for (bc = 0; bc < 2; bc++)
        {
            BLOCK *this_block = &x->block[block];
            this_block->base_src = &x->src.u_buffer;
            this_block->src_stride = x->src.uv_stride;
            this_block->src = 4 * br * this_block->src_stride + 4 * bc;
            ++block;
        }
    }

    // v blocks
    for (br = 0; br < 2; br++)
    {
        for (bc = 0; bc < 2; bc++)
        {
            BLOCK *this_block = &x->block[block];
            this_block->base_src = &x->src.v_buffer;
            this_block->src_stride = x->src.uv_stride;
            this_block->src = 4 * br * this_block->src_stride + 4 * bc;
            ++block;
        }
    }
}

static void sum_intra_stats(VP8_COMP *cpi, MACROBLOCK *x)
{
    const MACROBLOCKD *xd = & x->e_mbd;
    const MB_PREDICTION_MODE m = xd->mode_info_context->mbmi.mode;
    const MB_PREDICTION_MODE uvm = xd->mode_info_context->mbmi.uv_mode;

#ifdef MODE_STATS
    const int is_key = cpi->common.frame_type == KEY_FRAME;

    ++ (is_key ? uv_modes : inter_uv_modes)[uvm];

    if (m == B_PRED)
    {
        unsigned int *const bct = is_key ? b_modes : inter_b_modes;

        int b = 0;

        do
        {
            ++ bct[xd->block[b].bmi.mode];
        }
        while (++b < 16);
    }

#endif

    ++cpi->ymode_count[m];
    ++cpi->uv_mode_count[uvm];

}

// Experimental stub function to create a per MB zbin adjustment based on
// some previously calculated measure of MB activity.
static void adjust_act_zbin( VP8_COMP *cpi, MACROBLOCK *x )
{
#if USE_ACT_INDEX
    x->act_zbin_adj = *(x->mb_activity_ptr);
#else
    INT64 a;
    INT64 b;
    INT64 act = *(x->mb_activity_ptr);

    // Apply the masking to the RD multiplier.
    a = act + 4*cpi->activity_avg;
    b = 4*act + cpi->activity_avg;

    if ( act > cpi->activity_avg )
        x->act_zbin_adj = (int)(((INT64)b + (a>>1))/a) - 1;
    else
        x->act_zbin_adj = 1 - (int)(((INT64)a + (b>>1))/b);
#endif
}

int vp8cx_encode_intra_macro_block(VP8_COMP *cpi, MACROBLOCK *x, TOKENEXTRA **t)
{
    int rate;

    if (cpi->sf.RD && cpi->compressor_speed != 2)
        vp8_rd_pick_intra_mode(cpi, x, &rate);
    else
        vp8_pick_intra_mode(cpi, x, &rate);

    if(cpi->oxcf.tuning == VP8_TUNE_SSIM)
    {
        adjust_act_zbin( cpi, x );
        vp8_update_zbin_extra(cpi, x);
    }

    if (x->e_mbd.mode_info_context->mbmi.mode == B_PRED)
        vp8_encode_intra4x4mby(IF_RTCD(&cpi->rtcd), x);
    else
        vp8_encode_intra16x16mby(IF_RTCD(&cpi->rtcd), x);

    vp8_encode_intra16x16mbuv(IF_RTCD(&cpi->rtcd), x);
    sum_intra_stats(cpi, x);
    vp8_tokenize_mb(cpi, &x->e_mbd, t);

    return rate;
}
#ifdef SPEEDSTATS
extern int cnt_pm;
#endif

extern void vp8_fix_contexts(MACROBLOCKD *x);

int vp8cx_encode_inter_macroblock
(
    VP8_COMP *cpi, MACROBLOCK *x, TOKENEXTRA **t,
    int recon_yoffset, int recon_uvoffset
)
{
    MACROBLOCKD *const xd = &x->e_mbd;
    int intra_error = 0;
    int rate;
    int distortion;

    x->skip = 0;

    if (xd->segmentation_enabled)
        x->encode_breakout = cpi->segment_encode_breakout[xd->mode_info_context->mbmi.segment_id];
    else
        x->encode_breakout = cpi->oxcf.encode_breakout;

    if (cpi->sf.RD)
    {
        int zbin_mode_boost_enabled = cpi->zbin_mode_boost_enabled;

        /* Are we using the fast quantizer for the mode selection? */
        if(cpi->sf.use_fastquant_for_pick)
        {
            cpi->mb.quantize_b      = QUANTIZE_INVOKE(&cpi->rtcd.quantize,
                                                      fastquantb);
            cpi->mb.quantize_b_pair = QUANTIZE_INVOKE(&cpi->rtcd.quantize,
                                                      fastquantb_pair);

            /* the fast quantizer does not use zbin_extra, so
             * do not recalculate */
            cpi->zbin_mode_boost_enabled = 0;
        }
        vp8_rd_pick_inter_mode(cpi, x, recon_yoffset, recon_uvoffset, &rate,
                               &distortion, &intra_error);

        /* switch back to the regular quantizer for the encode */
        if (cpi->sf.improved_quant)
        {
            cpi->mb.quantize_b      = QUANTIZE_INVOKE(&cpi->rtcd.quantize,
                                                      quantb);
            cpi->mb.quantize_b_pair = QUANTIZE_INVOKE(&cpi->rtcd.quantize,
                                                      quantb_pair);
        }

        /* restore cpi->zbin_mode_boost_enabled */
        cpi->zbin_mode_boost_enabled = zbin_mode_boost_enabled;

    }
    else
        vp8_pick_inter_mode(cpi, x, recon_yoffset, recon_uvoffset, &rate,
                            &distortion, &intra_error);

    cpi->prediction_error += distortion;
    cpi->intra_error += intra_error;

    if(cpi->oxcf.tuning == VP8_TUNE_SSIM)
    {
        // Adjust the zbin based on this MB rate.
        adjust_act_zbin( cpi, x );
    }

#if 0
    // Experimental RD code
    cpi->frame_distortion += distortion;
    cpi->last_mb_distortion = distortion;
#endif

    // MB level adjutment to quantizer setup
    if (xd->segmentation_enabled)
    {
        // If cyclic update enabled
        if (cpi->cyclic_refresh_mode_enabled)
        {
            // Clear segment_id back to 0 if not coded (last frame 0,0)
            if ((xd->mode_info_context->mbmi.segment_id == 1) &&
                ((xd->mode_info_context->mbmi.ref_frame != LAST_FRAME) || (xd->mode_info_context->mbmi.mode != ZEROMV)))
            {
                xd->mode_info_context->mbmi.segment_id = 0;

                /* segment_id changed, so update */
                vp8cx_mb_init_quantizer(cpi, x);
            }
        }
    }

    {
        // Experimental code. Special case for gf and arf zeromv modes.
        // Increase zbin size to supress noise
        cpi->zbin_mode_boost = 0;
        if (cpi->zbin_mode_boost_enabled)
        {
            if ( xd->mode_info_context->mbmi.ref_frame != INTRA_FRAME )
            {
                if (xd->mode_info_context->mbmi.mode == ZEROMV)
                {
                    if (xd->mode_info_context->mbmi.ref_frame != LAST_FRAME)
                        cpi->zbin_mode_boost = GF_ZEROMV_ZBIN_BOOST;
                    else
                        cpi->zbin_mode_boost = LF_ZEROMV_ZBIN_BOOST;
                }
                else if (xd->mode_info_context->mbmi.mode == SPLITMV)
                    cpi->zbin_mode_boost = 0;
                else
                    cpi->zbin_mode_boost = MV_ZBIN_BOOST;
            }
        }
        vp8_update_zbin_extra(cpi, x);
    }

    cpi->count_mb_ref_frame_usage[xd->mode_info_context->mbmi.ref_frame] ++;

    if (xd->mode_info_context->mbmi.ref_frame == INTRA_FRAME)
    {
        vp8_encode_intra16x16mbuv(IF_RTCD(&cpi->rtcd), x);

        if (xd->mode_info_context->mbmi.mode == B_PRED)
        {
            vp8_encode_intra4x4mby(IF_RTCD(&cpi->rtcd), x);
        }
        else
        {
            vp8_encode_intra16x16mby(IF_RTCD(&cpi->rtcd), x);
        }

        sum_intra_stats(cpi, x);
    }
    else
    {
        int ref_fb_idx;

        vp8_build_uvmvs(xd, cpi->common.full_pixel);

        if (xd->mode_info_context->mbmi.ref_frame == LAST_FRAME)
            ref_fb_idx = cpi->common.lst_fb_idx;
        else if (xd->mode_info_context->mbmi.ref_frame == GOLDEN_FRAME)
            ref_fb_idx = cpi->common.gld_fb_idx;
        else
            ref_fb_idx = cpi->common.alt_fb_idx;

        xd->pre.y_buffer = cpi->common.yv12_fb[ref_fb_idx].y_buffer + recon_yoffset;
        xd->pre.u_buffer = cpi->common.yv12_fb[ref_fb_idx].u_buffer + recon_uvoffset;
        xd->pre.v_buffer = cpi->common.yv12_fb[ref_fb_idx].v_buffer + recon_uvoffset;

        if (!x->skip)
        {
            vp8_encode_inter16x16(IF_RTCD(&cpi->rtcd), x);

            // Clear mb_skip_coeff if mb_no_coeff_skip is not set
            if (!cpi->common.mb_no_coeff_skip)
                xd->mode_info_context->mbmi.mb_skip_coeff = 0;

        }
        else
            vp8_build_inter16x16_predictors_mb(xd, xd->dst.y_buffer,
                                           xd->dst.u_buffer, xd->dst.v_buffer,
                                           xd->dst.y_stride, xd->dst.uv_stride);

    }

    if (!x->skip)
        vp8_tokenize_mb(cpi, xd, t);
    else
    {
        if (cpi->common.mb_no_coeff_skip)
        {
            xd->mode_info_context->mbmi.mb_skip_coeff = 1;
            cpi->skip_true_count ++;
            vp8_fix_contexts(xd);
        }
        else
        {
            vp8_stuff_mb(cpi, xd, t);
            xd->mode_info_context->mbmi.mb_skip_coeff = 0;
            cpi->skip_false_count ++;
        }
    }

    return rate;
}