double vp8_calc_psnr(YV12_BUFFER_CONFIG *source, YV12_BUFFER_CONFIG *dest, double *YPsnr, double *UPsnr, double *VPsnr, double *sq_error)
{
    int i, j;
    int Diff;
    double frame_psnr;
    double Total;
    double grand_total;
    unsigned char *src = source->y_buffer;
    unsigned char *dst = dest->y_buffer;

    Total = 0.0;
    grand_total = 0.0;

    // Loop throught the Y plane raw and reconstruction data summing (square differences)
    for (i = 0; i < source->y_height; i++)
    {

        for (j = 0; j < source->y_width; j++)
        {
            Diff        = (int)(src[j]) - (int)(dst[j]);
            Total      += Diff * Diff;
        }

        src += source->y_stride;
        dst += dest->y_stride;
    }

    // Work out Y PSNR
    *YPsnr = vp8_mse2psnr(source->y_height * source->y_width, 255.0, Total);
    grand_total += Total;
    Total = 0;


    // Loop through the U plane
    src = source->u_buffer;
    dst = dest->u_buffer;

    for (i = 0; i < source->uv_height; i++)
    {

        for (j = 0; j < source->uv_width; j++)
        {
            Diff        = (int)(src[j]) - (int)(dst[j]);
            Total      += Diff * Diff;
        }

        src += source->uv_stride;
        dst += dest->uv_stride;
    }

    // Work out U PSNR
    *UPsnr = vp8_mse2psnr(source->uv_height * source->uv_width, 255.0, Total);
    grand_total += Total;
    Total = 0;


    // V PSNR
    src = source->v_buffer;
    dst = dest->v_buffer;

    for (i = 0; i < source->uv_height; i++)
    {

        for (j = 0; j < source->uv_width; j++)
        {
            Diff        = (int)(src[j]) - (int)(dst[j]);
            Total      += Diff * Diff;
        }

        src += source->uv_stride;
        dst += dest->uv_stride;
    }

    // Work out UV PSNR
    *VPsnr = vp8_mse2psnr(source->uv_height * source->uv_width, 255.0, Total);
    grand_total += Total;
    Total = 0;

    // Work out total PSNR
    frame_psnr = vp8_mse2psnr(source->y_height * source->y_width * 3 / 2 , 255.0, grand_total);

    *sq_error = 1.0 * grand_total;

    return frame_psnr;
}
int main(int argc, char **argv)
{
    FILE                *infile, *outfile[NUM_ENCODERS];
    vpx_codec_ctx_t      codec[NUM_ENCODERS];
    vpx_codec_enc_cfg_t  cfg[NUM_ENCODERS];
    vpx_codec_pts_t      frame_cnt = 0;
    vpx_image_t          raw[NUM_ENCODERS];
    vpx_codec_err_t      res[NUM_ENCODERS];

    int                  i;
    long                 width;
    long                 height;
    int                  frame_avail;
    int                  got_data;
    int                  flags = 0;

    /*Currently, only realtime mode is supported in multi-resolution encoding.*/
    int                  arg_deadline = VPX_DL_REALTIME;

    /* Set show_psnr to 1/0 to show/not show PSNR. Choose show_psnr=0 if you
       don't need to know PSNR, which will skip PSNR calculation and save
       encoding time. */
    int                  show_psnr = 0;
    uint64_t             psnr_sse_total[NUM_ENCODERS] = {0};
    uint64_t             psnr_samples_total[NUM_ENCODERS] = {0};
    double               psnr_totals[NUM_ENCODERS][4] = {{0,0}};
    int                  psnr_count[NUM_ENCODERS] = {0};

    /* Set the required target bitrates for each resolution level. */
    unsigned int         target_bitrate[NUM_ENCODERS]={1400, 500, 100};
    /* Enter the frame rate of the input video */
    int                  framerate = 30;
    /* Set down-sampling factor for each resolution level.
       dsf[0] controls down sampling from level 0 to level 1;
       dsf[1] controls down sampling from level 1 to level 2;
       dsf[2] is not used. */
    vpx_rational_t dsf[NUM_ENCODERS] = {{2, 1}, {2, 1}, {1, 1}};

    if(argc!= (5+NUM_ENCODERS))
        die("Usage: %s <width> <height> <infile> <outfile(s)> <output psnr?>\n",
            argv[0]);

    printf("Using %s\n",vpx_codec_iface_name(interface));

    width = strtol(argv[1], NULL, 0);
    height = strtol(argv[2], NULL, 0);

    if(width < 16 || width%2 || height <16 || height%2)
        die("Invalid resolution: %ldx%ld", width, height);

    /* Open input video file for encoding */
    if(!(infile = fopen(argv[3], "rb")))
        die("Failed to open %s for reading", argv[3]);

    /* Open output file for each encoder to output bitstreams */
    for (i=0; i< NUM_ENCODERS; i++)
    {
        if(!(outfile[i] = fopen(argv[i+4], "wb")))
            die("Failed to open %s for writing", argv[i+4]);
    }

    show_psnr = strtol(argv[NUM_ENCODERS + 4], NULL, 0);

    /* Populate default encoder configuration */
    for (i=0; i< NUM_ENCODERS; i++)
    {
        res[i] = vpx_codec_enc_config_default(interface, &cfg[i], 0);
        if(res[i]) {
            printf("Failed to get config: %s\n", vpx_codec_err_to_string(res[i]));
            return EXIT_FAILURE;
        }
    }

    /*
     * Update the default configuration according to needs of the application.
     */
    /* Highest-resolution encoder settings */
    cfg[0].g_w = width;
    cfg[0].g_h = height;
    cfg[0].g_threads = 1;                           /* number of threads used */
    cfg[0].rc_dropframe_thresh = 0;
    cfg[0].rc_end_usage = VPX_CBR;
    cfg[0].rc_resize_allowed = 0;
    cfg[0].rc_min_quantizer = 4;
    cfg[0].rc_max_quantizer = 56;
    cfg[0].rc_undershoot_pct = 98;
    cfg[0].rc_overshoot_pct = 100;
    cfg[0].rc_buf_initial_sz = 500;
    cfg[0].rc_buf_optimal_sz = 600;
    cfg[0].rc_buf_sz = 1000;
    //cfg[0].rc_dropframe_thresh = 10;
    cfg[0].g_error_resilient = 1;              /* Enable error resilient mode */
    cfg[0].g_lag_in_frames   = 0;

    /* Disable automatic keyframe placement */
    //cfg[0].kf_mode           = VPX_KF_DISABLED;
    cfg[0].kf_min_dist = cfg[0].kf_max_dist = 1000;

    cfg[0].rc_target_bitrate = target_bitrate[0];       /* Set target bitrate */
    cfg[0].g_timebase.num = 1;                          /* Set fps */
    cfg[0].g_timebase.den = framerate;

    /* Other-resolution encoder settings */
    for (i=1; i< NUM_ENCODERS; i++)
    {
        memcpy(&cfg[i], &cfg[0], sizeof(vpx_codec_enc_cfg_t));

        cfg[i].g_threads = 1;                       /* number of threads used */
        cfg[i].rc_target_bitrate = target_bitrate[i];

        /* Note: Width & height of other-resolution encoders are calculated
         * from the highest-resolution encoder's size and the corresponding
         * down_sampling_factor.
         */
        {
            unsigned int iw = cfg[i-1].g_w*dsf[i-1].den + dsf[i-1].num - 1;
            unsigned int ih = cfg[i-1].g_h*dsf[i-1].den + dsf[i-1].num - 1;
            cfg[i].g_w = iw/dsf[i-1].num;
            cfg[i].g_h = ih/dsf[i-1].num;
        }

        /* Make width & height to be multiplier of 2. */
        // Should support odd size ???
        if((cfg[i].g_w)%2)cfg[i].g_w++;
        if((cfg[i].g_h)%2)cfg[i].g_h++;
    }

    /* Allocate image for each encoder */
    for (i=0; i< NUM_ENCODERS; i++)
        if(!vpx_img_alloc(&raw[i], VPX_IMG_FMT_I420, cfg[i].g_w, cfg[i].g_h, 32))
            die("Failed to allocate image", cfg[i].g_w, cfg[i].g_h);

    if (raw[0].stride[VPX_PLANE_Y] == raw[0].d_w)
        read_frame_p = read_frame;
    else
        read_frame_p = read_frame_by_row;

    for (i=0; i< NUM_ENCODERS; i++)
        write_ivf_file_header(outfile[i], &cfg[i], 0);

    /* Initialize multi-encoder */
    if(vpx_codec_enc_init_multi(&codec[0], interface, &cfg[0], NUM_ENCODERS,
                                (show_psnr ? VPX_CODEC_USE_PSNR : 0), &dsf[0]))
        die_codec(&codec[0], "Failed to initialize encoder");

    /* The extra encoding configuration parameters can be set as follows. */
    /* Set encoding speed */
    for ( i=0; i<NUM_ENCODERS; i++)
    {
        int speed = -6;
        if(vpx_codec_control(&codec[i], VP8E_SET_CPUUSED, speed))
            die_codec(&codec[i], "Failed to set cpu_used");
    }
    /* Set static thresh for highest-resolution encoder. Set it to 1000 for
     * better performance. */
    {
        unsigned int static_thresh = 1000;
        if(vpx_codec_control(&codec[0], VP8E_SET_STATIC_THRESHOLD, static_thresh))
            die_codec(&codec[0], "Failed to set static threshold");
    }
    /* Set static thresh = 0 for other encoders for better quality */
    for ( i=1; i<NUM_ENCODERS; i++)
    {
        unsigned int static_thresh = 0;
        if(vpx_codec_control(&codec[i], VP8E_SET_STATIC_THRESHOLD, static_thresh))
            die_codec(&codec[i], "Failed to set static threshold");
    }

    frame_avail = 1;
    got_data = 0;

    while(frame_avail || got_data)
    {
        vpx_codec_iter_t iter[NUM_ENCODERS]={NULL};
        const vpx_codec_cx_pkt_t *pkt[NUM_ENCODERS];

        flags = 0;
        frame_avail = read_frame_p(infile, &raw[0]);

        if(frame_avail)
        {
            for ( i=1; i<NUM_ENCODERS; i++)
            {
                /*Scale the image down a number of times by downsampling factor*/
                /* FilterMode 1 or 2 give better psnr than FilterMode 0. */
                I420Scale(raw[i-1].planes[VPX_PLANE_Y], raw[i-1].stride[VPX_PLANE_Y],
                          raw[i-1].planes[VPX_PLANE_U], raw[i-1].stride[VPX_PLANE_U],
                          raw[i-1].planes[VPX_PLANE_V], raw[i-1].stride[VPX_PLANE_V],
                          raw[i-1].d_w, raw[i-1].d_h,
                          raw[i].planes[VPX_PLANE_Y], raw[i].stride[VPX_PLANE_Y],
                          raw[i].planes[VPX_PLANE_U], raw[i].stride[VPX_PLANE_U],
                          raw[i].planes[VPX_PLANE_V], raw[i].stride[VPX_PLANE_V],
                          raw[i].d_w, raw[i].d_h, 1);
            }
        }

        /* Encode each frame at multi-levels */
        if(vpx_codec_encode(&codec[0], frame_avail? &raw[0] : NULL,
            frame_cnt, 1, flags, arg_deadline))
            die_codec(&codec[0], "Failed to encode frame");

        for (i=NUM_ENCODERS-1; i>=0 ; i--)
        {
            got_data = 0;

            while( (pkt[i] = vpx_codec_get_cx_data(&codec[i], &iter[i])) )
            {
                got_data = 1;
                switch(pkt[i]->kind) {
                    case VPX_CODEC_CX_FRAME_PKT:
                        write_ivf_frame_header(outfile[i], pkt[i]);
                        if(fwrite(pkt[i]->data.frame.buf, 1, pkt[i]->data.frame.sz,
                                  outfile[i]));
                    break;
                    case VPX_CODEC_PSNR_PKT:
                        if (show_psnr)
                        {
                            int j;

                            psnr_sse_total[i] += pkt[i]->data.psnr.sse[0];
                            psnr_samples_total[i] += pkt[i]->data.psnr.samples[0];
                            for (j = 0; j < 4; j++)
                            {
                                //fprintf(stderr, "%.3lf ", pkt[i]->data.psnr.psnr[j]);
                                psnr_totals[i][j] += pkt[i]->data.psnr.psnr[j];
                            }
                            psnr_count[i]++;
                        }

                        break;
                    default:
                        break;
                }
                printf(pkt[i]->kind == VPX_CODEC_CX_FRAME_PKT
                       && (pkt[i]->data.frame.flags & VPX_FRAME_IS_KEY)? "K":".");
                fflush(stdout);
            }
        }
        frame_cnt++;
    }
    printf("\n");

    fclose(infile);

    for (i=0; i< NUM_ENCODERS; i++)
    {
        printf("Processed %ld frames.\n",(long int)frame_cnt-1);

        /* Calculate PSNR and print it out */
        if ( (show_psnr) && (psnr_count[i]>0) )
        {
            int j;
            double ovpsnr = vp8_mse2psnr(psnr_samples_total[i], 255.0,
                                         psnr_sse_total[i]);

            fprintf(stderr, "\n ENC%d PSNR (Overall/Avg/Y/U/V)", i);

            fprintf(stderr, " %.3lf", ovpsnr);
            for (j = 0; j < 4; j++)
            {
                fprintf(stderr, " %.3lf", psnr_totals[i][j]/psnr_count[i]);
            }
        }

        if(vpx_codec_destroy(&codec[i]))
            die_codec(&codec[i], "Failed to destroy codec");

        /* Try to rewrite the file header with the actual frame count */
        if(!fseek(outfile[i], 0, SEEK_SET))
            write_ivf_file_header(outfile[i], &cfg[i], frame_cnt-1);
        fclose(outfile[i]);

        vpx_img_free(&raw[i]);
    }

    return EXIT_SUCCESS;
}