]> git.donarmstrong.com Git - samtools.git/blobdiff - bam2bcf.c
Update 'samtools depad' help text regarding FASTA reference file
[samtools.git] / bam2bcf.c
index d61060ed309b6dd4e5a18a9fafb0a5076c14b46f..7947a31f5d2a627fe7f2651f60cbb597048b715c 100644 (file)
--- a/bam2bcf.c
+++ b/bam2bcf.c
 #include <math.h>
 #include <stdint.h>
+#include <assert.h>
 #include "bam.h"
 #include "kstring.h"
 #include "bam2bcf.h"
-#include "bcf.h"
+#include "errmod.h"
+#include "bcftools/bcf.h"
 
 extern void ks_introsort_uint32_t(size_t n, uint32_t a[]);
 
 #define CALL_ETA 0.03f
 #define CALL_MAX 256
-#define CALL_DEFTHETA 0.85f
+#define CALL_DEFTHETA 0.83f
+#define DEF_MAPQ 20
 
-struct __bcf_callaux_t {
-       int max_info, capQ;
-       double *fk;
-       uint32_t *info;
-};
+#define CAP_DIST 25
 
-bcf_callaux_t *bcf_call_init(double theta)
+bcf_callaux_t *bcf_call_init(double theta, int min_baseQ)
 {
        bcf_callaux_t *bca;
-       int n;
        if (theta <= 0.) theta = CALL_DEFTHETA;
        bca = calloc(1, sizeof(bcf_callaux_t));
        bca->capQ = 60;
-       bca->fk = calloc(CALL_MAX, sizeof(double));
-       bca->fk[0] = 1.;
-       for (n = 1; n < CALL_MAX; ++n)
-               bca->fk[n] = theta >= 1.? 1. : pow(theta, n) * (1.0 - CALL_ETA) + CALL_ETA;
-       bca->fk[CALL_MAX-1] = 0.;
-       return bca;
+       bca->openQ = 40; bca->extQ = 20; bca->tandemQ = 100;
+       bca->min_baseQ = min_baseQ;
+       bca->e = errmod_init(1. - theta);
+       bca->min_frac = 0.002;
+       bca->min_support = 1;
+    bca->per_sample_flt = 0;
+    bca->npos = 100;
+    bca->ref_pos = calloc(bca->npos, sizeof(int));
+    bca->alt_pos = calloc(bca->npos, sizeof(int));
+       return bca;
 }
 
-void bcf_call_destroy(bcf_callaux_t *bca)
+
+static int get_position(const bam_pileup1_t *p, int *len)
 {
-       if (bca) {
-               free(bca->info); free(bca->fk); free(bca);
-       }
+    int icig, n_tot_bases = 0, iread = 0, edist = p->qpos + 1;
+    for (icig=0; icig<p->b->core.n_cigar; icig++) 
+    {
+        // Conversion from uint32_t to MIDNSHP
+        //  0123456
+        //  MIDNSHP
+        int cig  = bam1_cigar(p->b)[icig] & BAM_CIGAR_MASK;
+        int ncig = bam1_cigar(p->b)[icig] >> BAM_CIGAR_SHIFT;
+        if ( cig==0 )
+        {
+            n_tot_bases += ncig;
+            iread += ncig;
+        }
+        else if ( cig==1 )
+        {
+            n_tot_bases += ncig;
+            iread += ncig;
+        }
+        else if ( cig==4 )
+        {
+            iread += ncig;
+            if ( iread<=p->qpos ) edist -= ncig;
+        }
+    }
+    *len = n_tot_bases;
+    return edist;
 }
 
-typedef struct {
-       float esum[4], fsum[4];
-       uint32_t c[4];
-       int w[8];
-} auxaux_t;
-
-/*
-  The following code is nearly identical to bam_maqcns_glfgen() under
-  the simplified SOAPsnp model. It does the following:
-
-  1) Collect strand, base, quality and mapping quality information for
-     each base and combine them in an integer:
-
-          x = min{baseQ,mapQ}<<24 | 1<<21 | strand<<18 | base<<16 | baseQ<<8 | mapQ
+void bcf_call_destroy(bcf_callaux_t *bca)
+{
+       if (bca == 0) return;
+       errmod_destroy(bca->e);
+    if (bca->npos) { free(bca->ref_pos); free(bca->alt_pos); bca->npos = 0; }
+       free(bca->bases); free(bca->inscns); free(bca);
+}
+/* ref_base is the 4-bit representation of the reference base. It is
+ * negative if we are looking at an indel. */
+int bcf_call_glfgen(int _n, const bam_pileup1_t *pl, int ref_base, bcf_callaux_t *bca, bcf_callret1_t *r)
+{
+       int i, n, ref4, is_indel, ori_depth = 0;
+       memset(r, 0, sizeof(bcf_callret1_t));
+       if (ref_base >= 0) {
+               ref4 = bam_nt16_nt4_table[ref_base];
+               is_indel = 0;
+       } else ref4 = 4, is_indel = 1;
+       if (_n == 0) return -1;
+       // enlarge the bases array if necessary
+       if (bca->max_bases < _n) {
+               bca->max_bases = _n;
+               kroundup32(bca->max_bases);
+               bca->bases = (uint16_t*)realloc(bca->bases, 2 * bca->max_bases);
+       }
+       // fill the bases array
+       for (i = n = r->n_supp = 0; i < _n; ++i) {
+               const bam_pileup1_t *p = pl + i;
+               int q, b, mapQ, baseQ, is_diff, min_dist, seqQ;
+               // set base
+               if (p->is_del || p->is_refskip || (p->b->core.flag&BAM_FUNMAP)) continue;
+               ++ori_depth;
+               baseQ = q = is_indel? p->aux&0xff : (int)bam1_qual(p->b)[p->qpos]; // base/indel quality
+               seqQ = is_indel? (p->aux>>8&0xff) : 99;
+               if (q < bca->min_baseQ) continue;
+               if (q > seqQ) q = seqQ;
+               mapQ = p->b->core.qual < 255? p->b->core.qual : DEF_MAPQ; // special case for mapQ==255
+               mapQ = mapQ < bca->capQ? mapQ : bca->capQ;
+               if (q > mapQ) q = mapQ;
+               if (q > 63) q = 63;
+               if (q < 4) q = 4;
+               if (!is_indel) {
+                       b = bam1_seqi(bam1_seq(p->b), p->qpos); // base
+                       b = bam_nt16_nt4_table[b? b : ref_base]; // b is the 2-bit base
+                       is_diff = (ref4 < 4 && b == ref4)? 0 : 1;
+               } else {
+                       b = p->aux>>16&0x3f;
+                       is_diff = (b != 0);
+               }
+               if (is_diff) ++r->n_supp;
+               bca->bases[n++] = q<<5 | (int)bam1_strand(p->b)<<4 | b;
+               // collect annotations
+               if (b < 4) r->qsum[b] += q;
+               ++r->anno[0<<2|is_diff<<1|bam1_strand(p->b)];
+               min_dist = p->b->core.l_qseq - 1 - p->qpos;
+               if (min_dist > p->qpos) min_dist = p->qpos;
+               if (min_dist > CAP_DIST) min_dist = CAP_DIST;
+               r->anno[1<<2|is_diff<<1|0] += baseQ;
+               r->anno[1<<2|is_diff<<1|1] += baseQ * baseQ;
+               r->anno[2<<2|is_diff<<1|0] += mapQ;
+               r->anno[2<<2|is_diff<<1|1] += mapQ * mapQ;
+               r->anno[3<<2|is_diff<<1|0] += min_dist;
+               r->anno[3<<2|is_diff<<1|1] += min_dist * min_dist;
 
-  2) Sort the list of integers for the next step.
+        // collect read positions for ReadPosBias
+        int len, pos = get_position(p, &len);
+        int epos = (double)pos/(len+1) * bca->npos;
+        if ( bam1_seqi(bam1_seq(p->b),p->qpos) == ref_base )
+            bca->ref_pos[epos]++;
+        else
+            bca->alt_pos[epos]++;
+       }
+       r->depth = n; r->ori_depth = ori_depth;
+       // glfgen
+       errmod_cal(bca->e, n, 5, bca->bases, r->p);
+       return r->depth;
+}
 
-  3) For each base, calculate e_b, the sum of weighted qualities. For
-     each type of base on each strand, the best quality has the highest
-     weight. Only the top 255 bases on each strand are used (different
-     from maqcns).
+double mann_whitney_1947(int n, int m, int U)
+{
+    if (U<0) return 0;
+    if (n==0||m==0) return U==0 ? 1 : 0;
+    return (double)n/(n+m)*mann_whitney_1947(n-1,m,U-m) + (double)m/(n+m)*mann_whitney_1947(n,m-1,U);
+}
 
-  4) Rescale the total read depth to 255.
+void calc_ReadPosBias(bcf_callaux_t *bca, bcf_call_t *call)
+{
+    int i, nref = 0, nalt = 0;
+    unsigned long int U = 0;
+    for (i=0; i<bca->npos; i++) 
+    {
+        nref += bca->ref_pos[i];
+        nalt += bca->alt_pos[i];
+        U += nref*bca->alt_pos[i];
+        bca->ref_pos[i] = 0;
+        bca->alt_pos[i] = 0;
+    }
+#if 0
+//todo
+    double var = 0, avg = (double)(nref+nalt)/bca->npos;
+    for (i=0; i<bca->npos; i++) 
+    {
+        double ediff = bca->ref_pos[i] + bca->alt_pos[i] - avg;
+        var += ediff*ediff;
+        bca->ref_pos[i] = 0;
+        bca->alt_pos[i] = 0;
+    }
+    call->read_pos.avg = avg;
+    call->read_pos.var = sqrt(var/bca->npos);
+    call->read_pos.dp  = nref+nalt;
+#endif
+    if ( !nref || !nalt )
+    {
+        call->read_pos_bias = -1;
+        return;
+    }
 
-  5) Calculate Q(D|g) = -10\log_{10}P(D|g) (d_a is the allele count):
+    if ( nref>=8 || nalt>=8 )
+    {
+        // normal approximation
+        double mean = ((double)nref*nalt+1.0)/2.0;
+        double var2 = (double)nref*nalt*(nref+nalt+1.0)/12.0;
+        double z    = (U-mean)/sqrt(var2);
+        call->read_pos_bias = z;
+        //fprintf(stderr,"nref=%d  nalt=%d  U=%ld  mean=%e  var=%e  zval=%e\n", nref,nalt,U,mean,sqrt(var2),call->read_pos_bias);
+    }
+    else
+    {
+        double p = mann_whitney_1947(nalt,nref,U);
+        // biased form claimed by GATK to behave better empirically
+        // double var2 = (1.0+1.0/(nref+nalt+1.0))*(double)nref*nalt*(nref+nalt+1.0)/12.0;
+        double var2 = (double)nref*nalt*(nref+nalt+1.0)/12.0;
+        double z;
+        if ( p >= 1./sqrt(var2*2*M_PI) ) z = 0;   // equal to mean
+        else
+        {
+            if ( U >= nref*nalt/2. ) z = sqrt(-2*log(sqrt(var2*2*M_PI)*p));
+            else z = -sqrt(-2*log(sqrt(var2*2*M_PI)*p));
+        }
+        call->read_pos_bias = z;
+        //fprintf(stderr,"nref=%d  nalt=%d  U=%ld  p=%e var2=%e  zval=%e\n", nref,nalt,U, p,var2,call->read_pos_bias);
+    }
+}
 
-       Q(D|<aa>)=\sum_{b\not=a}e_b
-          Q(D|<aA>)=3*(d_a+d_A)+\sum_{b\not=a,b\not=A}e_b
- */
-int bcf_call_glfgen(int _n, const bam_pileup1_t *pl, int ref_base /*4-bit*/, bcf_callaux_t *bca, bcf_callret1_t *r)
+float mean_diff_to_prob(float mdiff, int dp, int readlen)
 {
-       int i, j, k, c, n;
-       float *p = r->p;
-       auxaux_t aux;
+    if ( dp==2 )
+    {
+        if ( mdiff==0 )
+            return (2.0*readlen + 4.0*(readlen-1.0))/((float)readlen*readlen);
+        else
+            return 8.0*(readlen - 4.0*mdiff)/((float)readlen*readlen);
+    }
 
-       memset(r, 0, sizeof(bcf_callret1_t));
-       if (_n == 0) return -1;
+    // This is crude empirical approximation and is not very accurate for
+    // shorter read lengths (<100bp). There certainly is a room for
+    // improvement.
+    const float mv[24][2] = { {0,0}, {0,0}, {0,0},
+        { 9.108, 4.934}, { 9.999, 3.991}, {10.273, 3.485}, {10.579, 3.160},
+        {10.828, 2.889}, {11.014, 2.703}, {11.028, 2.546}, {11.244, 2.391},
+        {11.231, 2.320}, {11.323, 2.138}, {11.403, 2.123}, {11.394, 1.994},
+        {11.451, 1.928}, {11.445, 1.862}, {11.516, 1.815}, {11.560, 1.761},
+        {11.544, 1.728}, {11.605, 1.674}, {11.592, 1.652}, {11.674, 1.613},
+        {11.641, 1.570} };
 
-       // enlarge the aux array if necessary
-       if (bca->max_info < _n) {
-               bca->max_info = _n;
-               kroundup32(bca->max_info);
-               bca->info = (uint32_t*)realloc(bca->info, 4 * bca->max_info);
-       }
-       // fill the aux array
-       for (i = n = 0; i < _n; ++i) {
-               const bam_pileup1_t *p = pl + i;
-               uint32_t q, x = 0, qq;
-               if (p->is_del || (p->b->core.flag&BAM_FUNMAP)) continue; // skip unmapped reads and deleted bases
-               q = (uint32_t)bam1_qual(p->b)[p->qpos]; // base quality
-               x |= (uint32_t)bam1_strand(p->b) << 18 | q << 8 | p->b->core.qual;
-               if (p->b->core.qual < q) q = p->b->core.qual; // cap the overall quality at mapping quality
-               x |= q << 24;
-               qq = bam1_seqi(bam1_seq(p->b), p->qpos); // base
-               q = bam_nt16_nt4_table[qq? qq : ref_base]; // q is the 2-bit base
-               if (q < 4) x |= 1 << 21 | q << 16;
-               
-               bca->info[n++] = x;
-       }
-       ks_introsort_uint32_t(n, bca->info);
-       r->depth = n;
-       // generate esum and fsum
-       memset(&aux, 0, sizeof(auxaux_t));
-       for (j = n - 1, r->sum_Q2 = 0; j >= 0; --j) { // calculate esum and fsum
-               uint32_t info = bca->info[j];
-               int tmp;
-               if (info>>24 < 4 && (info>>8&0x3f) != 0) info = 4<<24 | (info&0xffffff);
-               k = info>>16&7;
-               if (info>>24 > 0) {
-                       aux.esum[k&3] += bca->fk[aux.w[k]] * (info>>24);
-                       aux.fsum[k&3] += bca->fk[aux.w[k]];
-                       if (aux.w[k] + 1 < CALL_MAX) ++aux.w[k];
-                       ++aux.c[k&3];
-               }
-               tmp = (int)(info&0xff) < bca->capQ? (int)(info&0xff) : bca->capQ;
-               r->sum_Q2 += tmp * tmp;
-       }
-       memcpy(r->esum, aux.esum, 4 * sizeof(float));
-       // rescale ->c[]
-       for (j = c = 0; j != 4; ++j) c += aux.c[j];
-       if (c > 255) {
-               for (j = 0; j != 4; ++j) aux.c[j] = (int)(254.0 * aux.c[j] / c + 0.499);
-               for (j = c = 0; j != 4; ++j) c += aux.c[j];
-       }
-       // generate likelihood
-       for (j = 0; j != 4; ++j) {
-               float tmp;
-               // homozygous
-               for (k = 0, tmp = 0.0; k != 4; ++k)
-                       if (j != k) tmp += aux.esum[k];
-               p[j<<2|j] = tmp; // anything that is not j
-               // heterozygous
-               for (k = j + 1; k < 4; ++k) {
-                       for (i = 0, tmp = 0.0; i != 4; ++i)
-                               if (i != j && i != k) tmp += aux.esum[i];
-                       p[j<<2|k] = p[k<<2|j] = 3.01 * (aux.c[j] + aux.c[k]) + tmp;
-               }
-       }
-       return 0;
+    float m, v;
+    if ( dp>=24 )
+    {
+        m = readlen/8.;
+        if (dp>100) dp = 100;
+        v = 1.476/(0.182*pow(dp,0.514));
+        v = v*(readlen/100.);
+    }
+    else
+    {
+        m = mv[dp][0];
+        v = mv[dp][1];
+        m = m*readlen/100.;
+        v = v*readlen/100.;
+        v *= 1.2;   // allow more variability
+    }
+    return 1.0/(v*sqrt(2*M_PI)) * exp(-0.5*((mdiff-m)/v)*((mdiff-m)/v));
 }
 
-/*
-  1) Find the top 2 bases (from esum[4]).
+void calc_vdb(bcf_callaux_t *bca, bcf_call_t *call)
+{
+    int i, dp = 0;
+    float mean_pos = 0, mean_diff = 0;
+    for (i=0; i<bca->npos; i++)
+    {
+        if ( !bca->alt_pos[i] ) continue;
+        dp += bca->alt_pos[i];
+        int j = i<bca->npos/2 ? i : bca->npos - i;
+        mean_pos += bca->alt_pos[i]*j;
+    }
+    if ( dp<2 )
+    {
+        call->vdb = -1;
+        return;
+    }
+    mean_pos /= dp;
+    for (i=0; i<bca->npos; i++)
+    {
+        if ( !bca->alt_pos[i] ) continue;
+        int j = i<bca->npos/2 ? i : bca->npos - i;
+        mean_diff += bca->alt_pos[i] * fabs(j - mean_pos);
+    }
+    mean_diff /= dp;
+    call->vdb = mean_diff_to_prob(mean_diff, dp, bca->npos);
+}
 
-  2) If the reference base is among the top 2, consider the locus is
-     potentially biallelic and set call->a[2] as -1; otherwise, the
-     locus is potentially triallelic. If the reference is ambiguous,
-     take the weakest call as the pseudo-reference.
+/**
+ *  bcf_call_combine() - sets the PL array and VDB, RPB annotations, finds the top two alleles
+ *  @n:         number of samples
+ *  @calls:     each sample's calls
+ *  @bca:       auxiliary data structure for holding temporary values
+ *  @ref_base:  the reference base
+ *  @call:      filled with the annotations
  */
-int bcf_call_combine(int n, const bcf_callret1_t *calls, int ref_base /*4-bit*/, bcf_call_t *call)
+int bcf_call_combine(int n, const bcf_callret1_t *calls, bcf_callaux_t *bca, int ref_base /*4-bit*/, bcf_call_t *call)
 {
-       int ref4, i, j;
-       int64_t sum[4], tmp;
-       call->ori_ref = ref4 = bam_nt16_nt4_table[ref_base];
-       if (ref4 > 4) ref4 = 4;
-       { // calculate esum
-               double esum[4];
-               memset(esum, 0, sizeof(double) * 4);
-               for (i = 0; i < n; ++i) {
-                       for (j = 0; j < 4; ++j)
-                               esum[j] += calls[i].esum[j];
-               }
+       int ref4, i, j, qsum[4];
+       int64_t tmp;
+       if (ref_base >= 0) {
+               call->ori_ref = ref4 = bam_nt16_nt4_table[ref_base];
+               if (ref4 > 4) ref4 = 4;
+       } else call->ori_ref = -1, ref4 = 0;
+       // calculate qsum
+       memset(qsum, 0, 4 * sizeof(int));
+       for (i = 0; i < n; ++i)
                for (j = 0; j < 4; ++j)
-                       sum[j] = (int)(esum[j] * 100. + .499) << 2 | j;
-       }
+                       qsum[j] += calls[i].qsum[j];
+    int qsum_tot=0;
+    for (j=0; j<4; j++) { qsum_tot += qsum[j]; call->qsum[j] = 0; }
+       for (j = 0; j < 4; ++j) qsum[j] = qsum[j] << 2 | j;
        // find the top 2 alleles
        for (i = 1; i < 4; ++i) // insertion sort
-               for (j = i; j > 0 && sum[j] < sum[j-1]; --j)
-                       tmp = sum[j], sum[j] = sum[j-1], sum[j-1] = tmp;
+               for (j = i; j > 0 && qsum[j] < qsum[j-1]; --j)
+                       tmp = qsum[j], qsum[j] = qsum[j-1], qsum[j-1] = tmp;
        // set the reference allele and alternative allele(s)
-       for (i = 0; i < 4; ++i) call->a[i] = -1;
+       for (i = 0; i < 5; ++i) call->a[i] = -1;
        call->unseen = -1;
-       if (ref4 < 4) {
-               call->a[0] = ref4;
-               for (i = 3, j = 1; i >= 0; --i) {
-                       if ((sum[i]&3) != ref4) {
-                               if (sum[i]>>2 != 0) call->a[j++] = sum[i]&3;
-                               else break;
-                       }
+       call->a[0] = ref4;
+       for (i = 3, j = 1; i >= 0; --i) {
+               if ((qsum[i]&3) != ref4) {
+                       if (qsum[i]>>2 != 0) 
+            {
+                if ( j<4 ) call->qsum[j] = (float)(qsum[i]>>2)/qsum_tot; // ref N can make j>=4
+                call->a[j++]  = qsum[i]&3;
+            }
+                       else break;
                }
-               if (j < 4 && i >= 0) call->unseen = j, call->a[j++] = sum[i]&3;
+        else 
+            call->qsum[0] = (float)(qsum[i]>>2)/qsum_tot;
+       }
+       if (ref_base >= 0) { // for SNPs, find the "unseen" base
+               if (((ref4 < 4 && j < 4) || (ref4 == 4 && j < 5)) && i >= 0)
+                       call->unseen = j, call->a[j++] = qsum[i]&3;
                call->n_alleles = j;
        } else {
-               for (i = 3, j = 0; i >= 0; --i)
-                       if (sum[i]>>2 != 0) call->a[j++] = sum[i]&3;
-                       else break;
-               if (j < 4 && i >= 0) call->unseen = j, call->a[j++] = sum[i]&3;
                call->n_alleles = j;
+               if (call->n_alleles == 1) return -1; // no reliable supporting read. stop doing anything
        }
        // set the PL array
        if (call->n < n) {
                call->n = n;
-               call->PL = realloc(call->PL, 10 * n);
+               call->PL = realloc(call->PL, 15 * n);
        }
        {
-               int x, g[6], z;
+               int x, g[15], z;
                double sum_min = 0.;
                x = call->n_alleles * (call->n_alleles + 1) / 2;
                // get the possible genotypes
                for (i = z = 0; i < call->n_alleles; ++i)
-                       for (j = i; j < call->n_alleles; ++j)
-                               g[z++] = call->a[i]<<2 | call->a[j];
+                       for (j = 0; j <= i; ++j)
+                               g[z++] = call->a[j] * 5 + call->a[i];
                for (i = 0; i < n; ++i) {
                        uint8_t *PL = call->PL + x * i;
                        const bcf_callret1_t *r = calls + i;
@@ -215,37 +354,114 @@ int bcf_call_combine(int n, const bcf_callret1_t *calls, int ref_base /*4-bit*/,
                                PL[j] = y;
                        }
                }
+//             if (ref_base < 0) fprintf(stderr, "%d,%d,%f,%d\n", call->n_alleles, x, sum_min, call->unseen);
                call->shift = (int)(sum_min + .499);
        }
-       for (i = call->depth = 0, tmp = 0; i < n; ++i) {
+       // combine annotations
+       memset(call->anno, 0, 16 * sizeof(int));
+       for (i = call->depth = call->ori_depth = 0, tmp = 0; i < n; ++i) {
                call->depth += calls[i].depth;
-               tmp += calls[i].sum_Q2;
+               call->ori_depth += calls[i].ori_depth;
+               for (j = 0; j < 16; ++j) call->anno[j] += calls[i].anno[j];
        }
-       call->rmsQ = (int)(sqrt((double)tmp / call->depth) + .499);
+
+    calc_vdb(bca, call);
+    calc_ReadPosBias(bca, call);
+
        return 0;
 }
 
-int bcf_call2bcf(int tid, int pos, bcf_call_t *bc, bcf1_t *b)
+int bcf_call2bcf(int tid, int pos, bcf_call_t *bc, bcf1_t *b, bcf_callret1_t *bcr, int fmt_flag,
+                                const bcf_callaux_t *bca, const char *ref)
 {
+       extern double kt_fisher_exact(int n11, int n12, int n21, int n22, double *_left, double *_right, double *two);
        kstring_t s;
-       int i, beg;
+       int i, j;
+       b->n_smpl = bc->n;
        b->tid = tid; b->pos = pos; b->qual = 0;
        s.s = b->str; s.m = b->m_str; s.l = 0;
        kputc('\0', &s);
-       kputc("ACGTN"[bc->ori_ref], &s); kputc('\0', &s);
-       beg = bc->ori_ref > 3? 0 : 1;
-       for (i = beg; i < 4; ++i) {
-               if (bc->a[i] < 0) break;
-               if (i > beg) kputc(',', &s);
-//             kputc(bc->unseen == i && i != 3? 'X' : "ACGT"[bc->a[i]], &s);
-               kputc(bc->unseen == i? 'X' : "ACGT"[bc->a[i]], &s);
+       if (bc->ori_ref < 0) { // an indel
+               // write REF
+               kputc(ref[pos], &s);
+               for (j = 0; j < bca->indelreg; ++j) kputc(ref[pos+1+j], &s);
+               kputc('\0', &s);
+               // write ALT
+               kputc(ref[pos], &s);
+               for (i = 1; i < 4; ++i) {
+                       if (bc->a[i] < 0) break;
+                       if (i > 1) {
+                               kputc(',', &s); kputc(ref[pos], &s);
+                       }
+                       if (bca->indel_types[bc->a[i]] < 0) { // deletion
+                               for (j = -bca->indel_types[bc->a[i]]; j < bca->indelreg; ++j)
+                                       kputc(ref[pos+1+j], &s);
+                       } else { // insertion; cannot be a reference unless a bug
+                               char *inscns = &bca->inscns[bc->a[i] * bca->maxins];
+                               for (j = 0; j < bca->indel_types[bc->a[i]]; ++j)
+                                       kputc("ACGTN"[(int)inscns[j]], &s);
+                               for (j = 0; j < bca->indelreg; ++j) kputc(ref[pos+1+j], &s);
+                       }
+               }
+               kputc('\0', &s);
+       } else { // a SNP
+               kputc("ACGTN"[bc->ori_ref], &s); kputc('\0', &s);
+               for (i = 1; i < 5; ++i) {
+                       if (bc->a[i] < 0) break;
+                       if (i > 1) kputc(',', &s);
+                       kputc(bc->unseen == i? 'X' : "ACGT"[bc->a[i]], &s);
+               }
+               kputc('\0', &s);
        }
        kputc('\0', &s);
+       // INFO
+       if (bc->ori_ref < 0) ksprintf(&s,"INDEL;IDV=%d;IMF=%f;", bca->max_support, bca->max_frac);
+       kputs("DP=", &s); kputw(bc->ori_depth, &s); kputs(";I16=", &s);
+       for (i = 0; i < 16; ++i) {
+               if (i) kputc(',', &s);
+               kputw(bc->anno[i], &s);
+       }
+    //ksprintf(&s,";RPS=%d,%f,%f", bc->read_pos.dp,bc->read_pos.avg,bc->read_pos.var);
+    ksprintf(&s,";QS=%f,%f,%f,%f", bc->qsum[0],bc->qsum[1],bc->qsum[2],bc->qsum[3]);
+    if (bc->vdb != -1)
+        ksprintf(&s, ";VDB=%e", bc->vdb);
+    if (bc->read_pos_bias != -1 )
+        ksprintf(&s, ";RPB=%e", bc->read_pos_bias);
+       kputc('\0', &s);
+       // FMT
+       kputs("PL", &s);
+       if (bcr && fmt_flag) {
+               if (fmt_flag & B2B_FMT_DP) kputs(":DP", &s);
+               if (fmt_flag & B2B_FMT_DV) kputs(":DV", &s);
+               if (fmt_flag & B2B_FMT_SP) kputs(":SP", &s);
+       }
        kputc('\0', &s);
-       kputs("MQ=", &s); kputw(bc->rmsQ, &s); kputs(";DP=", &s); kputw(bc->depth, &s); kputc('\0', &s);
-       kputs("PL", &s); kputc('\0', &s);
        b->m_str = s.m; b->str = s.s; b->l_str = s.l;
-       bcf_sync(bc->n, b);
+       bcf_sync(b);
        memcpy(b->gi[0].data, bc->PL, b->gi[0].len * bc->n);
+       if (bcr && fmt_flag) {
+               uint16_t *dp = (fmt_flag & B2B_FMT_DP)? b->gi[1].data : 0;
+               uint16_t *dv = (fmt_flag & B2B_FMT_DV)? b->gi[1 + ((fmt_flag & B2B_FMT_DP) != 0)].data : 0;
+               int32_t  *sp = (fmt_flag & B2B_FMT_SP)? b->gi[1 + ((fmt_flag & B2B_FMT_DP) != 0) + ((fmt_flag & B2B_FMT_DV) != 0)].data : 0;
+               for (i = 0; i < bc->n; ++i) {
+                       bcf_callret1_t *p = bcr + i;
+                       if (dp) dp[i] = p->depth  < 0xffff? p->depth  : 0xffff;
+                       if (dv) dv[i] = p->n_supp < 0xffff? p->n_supp : 0xffff;
+                       if (sp) {
+                               if (p->anno[0] + p->anno[1] < 2 || p->anno[2] + p->anno[3] < 2
+                                       || p->anno[0] + p->anno[2] < 2 || p->anno[1] + p->anno[3] < 2)
+                               {
+                                       sp[i] = 0;
+                               } else {
+                                       double left, right, two;
+                                       int x;
+                                       kt_fisher_exact(p->anno[0], p->anno[1], p->anno[2], p->anno[3], &left, &right, &two);
+                                       x = (int)(-4.343 * log(two) + .499);
+                                       if (x > 255) x = 255;
+                                       sp[i] = x;
+                               }
+                       }
+               }
+       }
        return 0;
 }