ratecontrol.c.svn-base

H.264 source codes

    {
        rc->psz_stat_file_tmpname = x264_malloc( strlen(h->param.rc.psz_stat_out) + 6 );
        strcpy( rc->psz_stat_file_tmpname, h->param.rc.psz_stat_out );
        strcat( rc->psz_stat_file_tmpname, ".temp" );

        rc->p_stat_file_out = fopen( rc->psz_stat_file_tmpname, "wb" );
        if( rc->p_stat_file_out == NULL )
        {
            x264_log(h, X264_LOG_ERROR, "ratecontrol_init: can't open stats file\n");
            return -1;
        }
    }

    return 0;
}

void x264_ratecontrol_delete( x264_t *h )
{
    x264_ratecontrol_t *rc = h->rc;

    if( rc->p_stat_file_out )
    {
        fclose( rc->p_stat_file_out );
        if( h->i_frame >= rc->num_entries - h->param.i_bframe )
            if( rename( rc->psz_stat_file_tmpname, h->param.rc.psz_stat_out ) != 0 )
            {
                x264_log( h, X264_LOG_ERROR, "failed to rename \"%s\" to \"%s\"\n",
                          rc->psz_stat_file_tmpname, h->param.rc.psz_stat_out );
            }
        x264_free( rc->psz_stat_file_tmpname );
    }
    if( rc->entry )
        x264_free(rc->entry);
    x264_free( rc );
}

/* Before encoding a frame, choose a QP for it */
void x264_ratecontrol_start( x264_t *h, int i_slice_type, int i_force_qp )
{
    x264_ratecontrol_t *rc = h->rc;

    x264_cpu_restore( h->param.cpu );

    rc->qp_force = i_force_qp;
    rc->slice_type = i_slice_type;

    if( i_force_qp )
    {
        rc->qpa = rc->qp = i_force_qp - 1;
    }
    else if( rc->b_abr )
    {
        rc->qpa = rc->qp =
            x264_clip3( (int)(qscale2qp( rate_estimate_qscale( h, i_slice_type ) ) + .5), 0, 51 );
    }
    else if( rc->b_2pass )
    {
        int frame = h->fenc->i_frame;
        ratecontrol_entry_t *rce;
        assert( frame >= 0 && frame < rc->num_entries );
        rce = h->rc->rce = &h->rc->entry[frame];

        rce->new_qscale = rate_estimate_qscale( h, i_slice_type );
        rc->qpa = rc->qp = rce->new_qp =
            x264_clip3( (int)(qscale2qp(rce->new_qscale) + 0.5), 0, 51 );
    }
    else /* CQP */
    {
        int q;
        if( i_slice_type == SLICE_TYPE_B && h->fdec->b_kept_as_ref )
            q = ( rc->qp_constant[ SLICE_TYPE_B ] + rc->qp_constant[ SLICE_TYPE_P ] ) / 2;
        else
            q = rc->qp_constant[ i_slice_type ];
        rc->qpa = rc->qp = q;
    }
}

void x264_ratecontrol_mb( x264_t *h, int bits )
{
    /* currently no adaptive quant */
}

int x264_ratecontrol_qp( x264_t *h )
{
    return h->rc->qp;
}

/* In 2pass, force the same frame types as in the 1st pass */
int x264_ratecontrol_slice_type( x264_t *h, int frame_num )
{
    if( h->param.rc.b_stat_read )
    {
        if( frame_num >= h->rc->num_entries )
        {
            x264_log(h, X264_LOG_ERROR, "More input frames than in the 1st pass\n");
            return X264_TYPE_P;
        }
        switch( h->rc->entry[frame_num].pict_type )
        {
            case SLICE_TYPE_I:
                return h->rc->entry[frame_num].kept_as_ref ? X264_TYPE_IDR : X264_TYPE_I;

            case SLICE_TYPE_B:
                return h->rc->entry[frame_num].kept_as_ref ? X264_TYPE_BREF : X264_TYPE_B;

            case SLICE_TYPE_P:
            default:
                return X264_TYPE_P;
        }
    }
    else
    {
        return X264_TYPE_AUTO;
    }
}

/* After encoding one frame, save stats and update ratecontrol state */
void x264_ratecontrol_end( x264_t *h, int bits )
{
    x264_ratecontrol_t *rc = h->rc;
    int i;

    x264_cpu_restore( h->param.cpu );

    h->stat.frame.i_mb_count_skip = h->stat.frame.i_mb_count[P_SKIP] + h->stat.frame.i_mb_count[B_SKIP];
    h->stat.frame.i_mb_count_p = h->stat.frame.i_mb_count[P_L0] + h->stat.frame.i_mb_count[P_8x8];
    for( i = B_DIRECT; i < B_8x8; i++ )
        h->stat.frame.i_mb_count_p += h->stat.frame.i_mb_count[i];

    if( h->param.rc.b_stat_write )
    {
        char c_type = rc->slice_type==SLICE_TYPE_I ? (h->fenc->i_poc==0 ? 'I' : 'i')
                    : rc->slice_type==SLICE_TYPE_P ? 'P'
                    : h->fenc->b_kept_as_ref ? 'B' : 'b';
        fprintf( rc->p_stat_file_out,
                 "in:%d out:%d type:%c q:%.2f itex:%d ptex:%d mv:%d misc:%d imb:%d pmb:%d smb:%d;\n",
                 h->fenc->i_frame, h->i_frame-1,
                 c_type, rc->qpa,
                 h->stat.frame.i_itex_bits, h->stat.frame.i_ptex_bits,
                 h->stat.frame.i_hdr_bits, h->stat.frame.i_misc_bits,
                 h->stat.frame.i_mb_count[I_4x4] + h->stat.frame.i_mb_count[I_16x16],
                 h->stat.frame.i_mb_count_p,
                 h->stat.frame.i_mb_count_skip);
    }

    if( rc->b_abr )
    {
        if( rc->slice_type != SLICE_TYPE_B )
            rc->cplxr_sum += bits * qp2qscale(rc->qpa) / rc->last_rceq;
        else
        {
            /* Depends on the fact that B-frame's QP is an offset from the following P-frame's.
             * Not perfectly accurate with B-refs, but good enough. */
            rc->cplxr_sum += bits * qp2qscale(rc->qpa) / (rc->last_rceq * fabs(h->param.rc.f_pb_factor));
        }
        rc->cplxr_sum *= rc->cbr_decay;
        rc->wanted_bits_window += rc->bitrate / rc->fps;
        rc->wanted_bits_window *= rc->cbr_decay;

        rc->accum_p_qp   *= .95;
        rc->accum_p_norm *= .95;
        rc->accum_p_norm += 1;
        if( rc->slice_type == SLICE_TYPE_I )
            rc->accum_p_qp += rc->qpa * fabs(h->param.rc.f_ip_factor);
        else
            rc->accum_p_qp += rc->qpa;
    }

    if( rc->b_2pass )
    {
        rc->expected_bits_sum += qscale2bits( rc->rce, qp2qscale(rc->rce->new_qp) );
    }

    update_vbv( h, bits );

    if( rc->slice_type != SLICE_TYPE_B )
        rc->last_non_b_pict_type = rc->slice_type;
}

/****************************************************************************
 * 2 pass functions
 ***************************************************************************/

double x264_eval( char *s, double *const_value, const char **const_name,
                  double (**func1)(void *, double), const char **func1_name,
                  double (**func2)(void *, double, double), char **func2_name,
                  void *opaque );

/**
 * modify the bitrate curve from pass1 for one frame
 */
static double get_qscale(x264_t *h, ratecontrol_entry_t *rce, double rate_factor)
{
    x264_ratecontrol_t *rcc= h->rc;
    const int pict_type = rce->pict_type;
    double q;

    double const_values[]={
        rce->i_tex_bits * rce->qscale,
        rce->p_tex_bits * rce->qscale,
        (rce->i_tex_bits + rce->p_tex_bits) * rce->qscale,
        rce->mv_bits * rce->qscale,
        (double)rce->i_count / rcc->nmb,
        (double)rce->p_count / rcc->nmb,
        (double)rce->s_count / rcc->nmb,
        rce->pict_type == SLICE_TYPE_I,
        rce->pict_type == SLICE_TYPE_P,
        rce->pict_type == SLICE_TYPE_B,
        h->param.rc.f_qcompress,
        rcc->i_cplx_sum[SLICE_TYPE_I] / rcc->frame_count[SLICE_TYPE_I],
        rcc->i_cplx_sum[SLICE_TYPE_P] / rcc->frame_count[SLICE_TYPE_P],
        rcc->p_cplx_sum[SLICE_TYPE_P] / rcc->frame_count[SLICE_TYPE_P],
        rcc->p_cplx_sum[SLICE_TYPE_B] / rcc->frame_count[SLICE_TYPE_B],
        (rcc->i_cplx_sum[pict_type] + rcc->p_cplx_sum[pict_type]) / rcc->frame_count[pict_type],
        rce->blurred_complexity,
        0
    };
    static const char *const_names[]={
        "iTex",
        "pTex",
        "tex",
        "mv",
        "iCount",
        "pCount",
        "sCount",
        "isI",
        "isP",
        "isB",
        "qComp",
        "avgIITex",
        "avgPITex",
        "avgPPTex",
        "avgBPTex",
        "avgTex",
        "blurCplx",
        NULL
    };
    static double (*func1[])(void *, double)={
//      (void *)bits2qscale,
        (void *)qscale2bits,
        NULL
    };
    static const char *func1_names[]={
//      "bits2qp",
        "qp2bits",
        NULL
    };

    q = x264_eval((char*)h->param.rc.psz_rc_eq, const_values, const_names, func1, func1_names, NULL, NULL, rce);
    q /= rate_factor;

    // avoid NaN's in the rc_eq
    if(q != q || rce->i_tex_bits + rce->p_tex_bits + rce->mv_bits == 0)
        q = rcc->last_qscale;
    else
        rcc->last_qscale = q;

    return q;
}

static double get_diff_limited_q(x264_t *h, ratecontrol_entry_t *rce, double q)
{
    x264_ratecontrol_t *rcc = h->rc;
    const int pict_type = rce->pict_type;

    // force I/B quants as a function of P quants
    const double last_p_q    = rcc->last_qscale_for[SLICE_TYPE_P];
    const double last_non_b_q= rcc->last_qscale_for[rcc->last_non_b_pict_type];
    if( pict_type == SLICE_TYPE_I )
    {
        double iq = q;
        double pq = qp2qscale( rcc->accum_p_qp / rcc->accum_p_norm );
        double ip_factor = fabs( h->param.rc.f_ip_factor );
        /* don't apply ip_factor if the following frame is also I */
        if( rcc->accum_p_norm <= 0 )
            q = iq;
        else if( h->param.rc.f_ip_factor < 0 )
            q = iq / ip_factor;
        else if( rcc->accum_p_norm >= 1 )
            q = pq / ip_factor;
        else
            q = rcc->accum_p_norm * pq / ip_factor + (1 - rcc->accum_p_norm) * iq;
    }
    else if( pict_type == SLICE_TYPE_B )
    {
        if( h->param.rc.f_pb_factor > 0 )
            q = last_non_b_q;
        if( !rce->kept_as_ref )
            q *= fabs( h->param.rc.f_pb_factor );
    }
    else if( pict_type == SLICE_TYPE_P
             && rcc->last_non_b_pict_type == SLICE_TYPE_P
             && rce->i_tex_bits + rce->p_tex_bits == 0 )
    {
        q = last_p_q;
    }

    /* last qscale / qdiff stuff */
    if(rcc->last_non_b_pict_type==pict_type
       && (pict_type!=SLICE_TYPE_I || rcc->last_accum_p_norm < 1))
    {
        double last_q = rcc->last_qscale_for[pict_type];
        double max_qscale = last_q * rcc->lstep;
        double min_qscale = last_q / rcc->lstep;

        if     (q > max_qscale) q = max_qscale;
        else if(q < min_qscale) q = min_qscale;
    }

    rcc->last_qscale_for[pict_type] = q;
    if(pict_type!=SLICE_TYPE_B)
        rcc->last_non_b_pict_type = pict_type;
    if(pict_type==SLICE_TYPE_I)
    {
        rcc->last_accum_p_norm = rcc->accum_p_norm;
        rcc->accum_p_norm = 0;
        rcc->accum_p_qp = 0;
    }
    if(pict_type==SLICE_TYPE_P)
    {
        float mask = 1 - pow( (float)rce->i_count / rcc->nmb, 2 );
        rcc->accum_p_qp   = mask * (qscale2qp(q) + rcc->accum_p_qp);
        rcc->accum_p_norm = mask * (1 + rcc->accum_p_norm);
    }
    return q;
}

static double predict_size( predictor_t *p, double q, double var )
{
     return p->coeff*var / (q*p->count);
}

static void update_predictor( predictor_t *p, double q, double var, double bits )
{
    p->count *= p->decay;
    p->coeff *= p->decay;
    p->count ++;
    p->coeff += bits*q / var;
}

static void update_vbv( x264_t *h, int bits )
{
    x264_ratecontrol_t *rcc = h->rc;
    if( !rcc->buffer_size )
        return;

    rcc->buffer_fill += rcc->buffer_rate - bits;
    if( rcc->buffer_fill < 0 && !rcc->b_2pass )
        x264_log( h, X264_LOG_WARNING, "VBV underflow (%.0f bits)\n", rcc->buffer_fill );
    rcc->buffer_fill = x264_clip3( rcc->buffer_fill, 0, rcc->buffer_size );

    if(rcc->last_satd > 100)
        update_predictor( &rcc->pred[rcc->slice_type], qp2qscale(rcc->qpa), rcc->last_satd, bits );
}