# Install bcftools, its manpage, bcf-fix.pl, vcfutils.pl, and new examples.
[samtools.git] / bam_plcmd.c
index 5bf1ed095096b7cd91fc99d2256467b89e394d33..dca85181f99bf1c7343650846039153a019e7ea9 100644 (file)
@@ -18,6 +18,11 @@ KHASH_MAP_INIT_INT64(64, indel_list_t)
 #define BAM_PLF_GLF        0x08
 #define BAM_PLF_VAR_ONLY   0x10
 #define BAM_PLF_2ND        0x20
+#define BAM_PLF_RANBASE    0x40
+#define BAM_PLF_1STBASE    0x80
+#define BAM_PLF_ALLBASE    0x100
+#define BAM_PLF_READPOS    0x200
+#define BAM_PLF_NOBAQ      0x400
 
 typedef struct {
        bam_header_t *h;
@@ -28,6 +33,8 @@ typedef struct {
        uint32_t format;
        int tid, len, last_pos;
        int mask;
+       int capQ_thres, min_baseQ;
+    int max_depth;  // for indel calling, ignore reads with the depth too high. 0 for unlimited
        char *ref;
        glfFile fp_glf; // for glf output only
 } pu_data_t;
@@ -84,6 +91,21 @@ static khash_t(64) *load_pos(const char *fn, bam_header_t *h)
        return hash;
 }
 
+static inline int printw(int c, FILE *fp)
+{
+       char buf[16];
+       int l, x;
+       if (c == 0) return fputc('0', fp);
+       for (l = 0, x = c < 0? -c : c; x > 0; x /= 10) buf[l++] = x%10 + '0';
+       if (c < 0) buf[l++] = '-';
+       buf[l] = 0;
+       for (x = 0; x < l/2; ++x) {
+               int y = buf[x]; buf[x] = buf[l-1-x]; buf[l-1-x] = y;
+       }
+       fputs(buf, fp);
+       return 0;
+}
+
 // an analogy to pileup_func() below
 static int glt3_func(uint32_t tid, uint32_t pos, int n, const bam_pileup1_t *pu, void *data)
 {
@@ -121,9 +143,12 @@ static int glt3_func(uint32_t tid, uint32_t pos, int n, const bam_pileup1_t *pu,
        g3->offset = pos - d->last_pos;
        d->last_pos = pos;
        glf3_write1(d->fp_glf, g3);
-       if (proposed_indels)
-               r = bam_maqindel(n, pos, d->ido, pu, d->ref, proposed_indels[0], proposed_indels+1);
-       else r = bam_maqindel(n, pos, d->ido, pu, d->ref, 0, 0);
+    if (pos < d->len) {
+        int m = (!d->max_depth || d->max_depth>n) ? n : d->max_depth;
+               if (proposed_indels)
+                       r = bam_maqindel(m, pos, d->ido, pu, d->ref, proposed_indels[0], proposed_indels+1);
+               else r = bam_maqindel(m, pos, d->ido, pu, d->ref, 0, 0);
+       }
        if (r) { // then write indel line
                int het = 3 * n, min;
                min = het;
@@ -150,11 +175,46 @@ static int glt3_func(uint32_t tid, uint32_t pos, int n, const bam_pileup1_t *pu,
        return 0;
 }
 
+static inline void pileup_seq(const bam_pileup1_t *p, int pos, int ref_len, const char *ref)
+{
+       int j;
+       if (p->is_head) {
+               putchar('^');
+               putchar(p->b->core.qual > 93? 126 : p->b->core.qual + 33);
+       }
+       if (!p->is_del) {
+               int c = bam_nt16_rev_table[bam1_seqi(bam1_seq(p->b), p->qpos)];
+               if (ref) {
+                       int rb = pos < ref_len? ref[pos] : 'N';
+                       if (c == '=' || bam_nt16_table[c] == bam_nt16_table[rb]) c = bam1_strand(p->b)? ',' : '.';
+                       else c = bam1_strand(p->b)? tolower(c) : toupper(c);
+               } else {
+                       if (c == '=') c = bam1_strand(p->b)? ',' : '.';
+                       else c = bam1_strand(p->b)? tolower(c) : toupper(c);
+               }
+               putchar(c);
+       } else putchar(p->is_refskip? (bam1_strand(p->b)? '<' : '>') : '*');
+       if (p->indel > 0) {
+               putchar('+'); printw(p->indel, stdout);
+               for (j = 1; j <= p->indel; ++j) {
+                       int c = bam_nt16_rev_table[bam1_seqi(bam1_seq(p->b), p->qpos + j)];
+                       putchar(bam1_strand(p->b)? tolower(c) : toupper(c));
+               }
+       } else if (p->indel < 0) {
+               printw(p->indel, stdout);
+               for (j = 1; j <= -p->indel; ++j) {
+                       int c = (ref && (int)pos+j < ref_len)? ref[pos+j] : 'N';
+                       putchar(bam1_strand(p->b)? tolower(c) : toupper(c));
+               }
+       }
+       if (p->is_tail) putchar('$');
+}
+
 static int pileup_func(uint32_t tid, uint32_t pos, int n, const bam_pileup1_t *pu, void *data)
 {
        pu_data_t *d = (pu_data_t*)data;
        bam_maqindel_ret_t *r = 0;
-       int i, j, rb, rms_mapq = -1, *proposed_indels = 0;
+       int i, rb, rms_mapq = -1, *proposed_indels = 0;
        uint64_t rms_aux;
        uint32_t cns = 0;
 
@@ -169,7 +229,7 @@ static int pileup_func(uint32_t tid, uint32_t pos, int n, const bam_pileup1_t *p
        // update d->ref if necessary
        if (d->fai && (int)tid != d->tid) {
                free(d->ref);
-               d->ref = fai_fetch(d->fai, d->h->target_name[tid], &d->len);
+               d->ref = faidx_fetch_seq(d->fai, d->h->target_name[tid], 0, 0x7fffffff, &d->len);
                d->tid = tid;
        }
        rb = (d->ref && (int)pos < d->len)? d->ref[pos] : 'N';
@@ -180,16 +240,39 @@ static int pileup_func(uint32_t tid, uint32_t pos, int n, const bam_pileup1_t *p
                if (i == n) return 0;
        }
        // call the consensus and indel
-       if (d->format & BAM_PLF_CNS) // call consensus
-               cns = bam_maqcns_call(n, pu, d->c);
-       if ((d->format & (BAM_PLF_CNS|BAM_PLF_INDEL_ONLY)) && d->ref) { // call indels
-               if (proposed_indels) // the first element gives the size of the array
-                       r = bam_maqindel(n, pos, d->ido, pu, d->ref, proposed_indels[0], proposed_indels+1);
-               else r = bam_maqindel(n, pos, d->ido, pu, d->ref, 0, 0);
+       if (d->format & BAM_PLF_CNS) { // call consensus
+               if (d->format & (BAM_PLF_RANBASE|BAM_PLF_1STBASE)) { // use a random base or the 1st base as the consensus call
+                       const bam_pileup1_t *p = (d->format & BAM_PLF_1STBASE)? pu : pu + (int)(drand48() * n);
+                       int q = bam1_qual(p->b)[p->qpos];
+                       int mapQ = p->b->core.qual < d->c->cap_mapQ? p->b->core.qual : d->c->cap_mapQ;
+                       uint32_t b = bam1_seqi(bam1_seq(p->b), p->qpos);
+                       cns = b<<28 | 0xf<<24 | mapQ<<16 | q<<8;
+               } else if (d->format & BAM_PLF_ALLBASE) { // collapse all bases
+                       uint64_t rmsQ = 0;
+                       uint32_t b = 0;
+                       for (i = 0; i < n; ++i) {
+                               const bam_pileup1_t *p = pu + i;
+                               int q = p->b->core.qual < d->c->cap_mapQ? p->b->core.qual : d->c->cap_mapQ;
+                               b |= bam1_seqi(bam1_seq(p->b), p->qpos);
+                               rmsQ += q * q;
+                       }
+                       rmsQ = (uint64_t)(sqrt((double)rmsQ / n) + .499);
+                       cns = b<<28 | 0xf<<24 | rmsQ<<16 | 60<<8;
+               } else {
+                       glf1_t *g = bam_maqcns_glfgen(n, pu, bam_nt16_table[rb], d->c);
+                       cns = g->depth == 0? (0xfu<<28 | 0xf<<24) : glf2cns(g, (int)(d->c->q_r + .499));
+                       free(g);
+               }
+       }
+    if ((d->format & (BAM_PLF_CNS|BAM_PLF_INDEL_ONLY)) && d->ref && pos < d->len) { // call indels
+        int m = (!d->max_depth || d->max_depth>n) ? n : d->max_depth;
+        if (proposed_indels) // the first element gives the size of the array
+            r = bam_maqindel(m, pos, d->ido, pu, d->ref, proposed_indels[0], proposed_indels+1);
+        else r = bam_maqindel(m, pos, d->ido, pu, d->ref, 0, 0);
        }
        // when only variant sites are asked for, test if the site is a variant
        if ((d->format & BAM_PLF_CNS) && (d->format & BAM_PLF_VAR_ONLY)) {
-               if (!(bam_nt16_table[rb] != 15 && cns>>28 != bam_nt16_table[rb])) { // not a SNP
+               if (!(bam_nt16_table[rb] != 15 && cns>>28 != 15 && cns>>28 != bam_nt16_table[rb])) { // not a SNP
                        if (!(r && (r->gt == 2 || strcmp(r->s[r->gt], "*")))) { // not an indel
                                if (r) bam_maqindel_ret_destroy(r);
                                return 0;
@@ -197,50 +280,29 @@ static int pileup_func(uint32_t tid, uint32_t pos, int n, const bam_pileup1_t *p
                }
        }
        // print the first 3 columns
-       printf("%s\t%d\t%c\t", d->h->target_name[tid], pos + 1, rb);
+       fputs(d->h->target_name[tid], stdout); putchar('\t');
+       printw(pos+1, stdout); putchar('\t'); putchar(rb); putchar('\t');
        // print consensus information if required
        if (d->format & BAM_PLF_CNS) {
-               int ref_q, rb4 = bam_nt16_table[rb];
-               ref_q = 0;
-               if (rb4 != 15 && cns>>28 != 15 && cns>>28 != rb4) { // a SNP
-                       ref_q = ((cns>>24&0xf) == rb4)? cns>>8&0xff : (cns>>8&0xff) + (cns&0xff);
-                       if (ref_q > 255) ref_q = 255;
-               }
-               rms_mapq = cns>>16&0xff;
-               printf("%c\t%d\t%d\t%d\t", bam_nt16_rev_table[cns>>28], cns>>8&0xff, ref_q, rms_mapq);
+               putchar(bam_nt16_rev_table[cns>>28]); putchar('\t');
+               printw(cns>>8&0xff, stdout); putchar('\t');
+               printw(cns&0xff, stdout); putchar('\t');
+               printw(cns>>16&0xff, stdout); putchar('\t');
        }
        // print pileup sequences
-       printf("%d\t", n);
-       rms_aux = 0; // we need to recalculate rms_mapq when -c is not flagged on the command line
-       for (i = 0; i < n; ++i) {
-               const bam_pileup1_t *p = pu + i;
-               int tmp = p->b->core.qual < d->c->cap_mapQ? p->b->core.qual : d->c->cap_mapQ;
-               rms_aux += tmp * tmp;
-               if (p->is_head) printf("^%c", p->b->core.qual > 93? 126 : p->b->core.qual + 33);
-               if (!p->is_del) {
-                       int c = bam_nt16_rev_table[bam1_seqi(bam1_seq(p->b), p->qpos)];
-                       if (c == '=' || toupper(c) == toupper(rb)) c = bam1_strand(p->b)? ',' : '.';
-                       else c = bam1_strand(p->b)? tolower(c) : toupper(c);
-                       putchar(c);
-                       if (p->indel > 0) {
-                               printf("+%d", p->indel);
-                               for (j = 1; j <= p->indel; ++j) {
-                                       c = bam_nt16_rev_table[bam1_seqi(bam1_seq(p->b), p->qpos + j)];
-                                       putchar(bam1_strand(p->b)? tolower(c) : toupper(c));
-                               }
-                       } else if (p->indel < 0) {
-                               printf("%d", p->indel);
-                               for (j = 1; j <= -p->indel; ++j) {
-                                       c = (d->ref && (int)pos+j < d->len)? d->ref[pos+j] : 'N';
-                                       putchar(bam1_strand(p->b)? tolower(c) : toupper(c));
-                               }
-                       }
-               } else putchar('*');
-               if (p->is_tail) putchar('$');
-       }
+       printw(n, stdout); putchar('\t');
+       for (i = 0; i < n; ++i)
+               pileup_seq(pu + i, pos, d->len, d->ref);
        // finalize rms_mapq
-       rms_aux = (uint64_t)(sqrt((double)rms_aux / n) + .499);
-       if (rms_mapq < 0) rms_mapq = rms_aux;
+       if (d->format & BAM_PLF_CNS) {
+               for (i = rms_aux = 0; i < n; ++i) {
+                       const bam_pileup1_t *p = pu + i;
+                       int tmp = p->b->core.qual < d->c->cap_mapQ? p->b->core.qual : d->c->cap_mapQ;
+                       rms_aux += tmp * tmp;
+               }
+               rms_aux = (uint64_t)(sqrt((double)rms_aux / n) + .499);
+               if (rms_mapq < 0) rms_mapq = rms_aux;
+       }
        putchar('\t');
        // print quality
        for (i = 0; i < n; ++i) {
@@ -273,6 +335,15 @@ static int pileup_func(uint32_t tid, uint32_t pos, int n, const bam_pileup1_t *p
                        putchar(c);
                }
        }
+       // print read position
+       if (d->format & BAM_PLF_READPOS) {
+               putchar('\t');
+               for (i = 0; i < n; ++i) {
+                       int x = pu[i].qpos;
+                       int l = pu[i].b->core.l_qseq;
+                       printw(x < l/2? x+1 : -((l-1)-x+1), stdout); putchar(',');
+               }
+       }
        putchar('\n');
        // print the indel line if r has been calculated. This only happens if:
        // a) -c or -i are flagged, AND b) the reference sequence is available
@@ -296,56 +367,78 @@ int bam_pileup(int argc, char *argv[])
        int c, is_SAM = 0;
        char *fn_list = 0, *fn_fa = 0, *fn_pos = 0;
        pu_data_t *d = (pu_data_t*)calloc(1, sizeof(pu_data_t));
-       d->tid = -1; d->mask = BAM_DEF_MASK;
+    d->max_depth = 1024; d->tid = -1; d->mask = BAM_DEF_MASK; d->min_baseQ = 13;
        d->c = bam_maqcns_init();
+       d->c->errmod = BAM_ERRMOD_MAQ2; // change the default model
        d->ido = bam_maqindel_opt_init();
-       while ((c = getopt(argc, argv, "st:f:cT:N:r:l:im:gI:G:vM:S2")) >= 0) {
+       while ((c = getopt(argc, argv, "st:f:cT:N:r:l:d:im:gI:G:vM:S2aR:PAQ:C:B")) >= 0) {
                switch (c) {
+               case 'Q': d->c->min_baseQ = atoi(optarg); break;
+               case 'C': d->capQ_thres = atoi(optarg); break;
+               case 'B': d->format |= BAM_PLF_NOBAQ; break;
+               case 'a': d->c->errmod = BAM_ERRMOD_SOAP; break;
+               case 'A': d->c->errmod = BAM_ERRMOD_MAQ; break;
                case 's': d->format |= BAM_PLF_SIMPLE; break;
                case 't': fn_list = strdup(optarg); break;
                case 'l': fn_pos = strdup(optarg); break;
                case 'f': fn_fa = strdup(optarg); break;
                case 'T': d->c->theta = atof(optarg); break;
                case 'N': d->c->n_hap = atoi(optarg); break;
-               case 'r': d->c->het_rate = atof(optarg); break;
+               case 'r': d->c->het_rate = atof(optarg); d->ido->r_snp = d->c->het_rate; break;
                case 'M': d->c->cap_mapQ = atoi(optarg); break;
+               case 'd': d->max_depth = atoi(optarg); break;
                case 'c': d->format |= BAM_PLF_CNS; break;
                case 'i': d->format |= BAM_PLF_INDEL_ONLY; break;
                case 'v': d->format |= BAM_PLF_VAR_ONLY; break;
                case 'm': d->mask = strtol(optarg, 0, 0); break;
                case 'g': d->format |= BAM_PLF_GLF; break;
                case '2': d->format |= BAM_PLF_2ND; break;
+               case 'P': d->format |= BAM_PLF_READPOS; break;
                case 'I': d->ido->q_indel = atoi(optarg); break;
                case 'G': d->ido->r_indel = atof(optarg); break;
                case 'S': is_SAM = 1; break;
+               case 'R':
+                       if (strcmp(optarg, "random") == 0) d->format |= BAM_PLF_RANBASE;
+                       else if (strcmp(optarg, "first") == 0) d->format |= BAM_PLF_1STBASE;
+                       else if (strcmp(optarg, "all") == 0) d->format |= BAM_PLF_ALLBASE;
+                       else fprintf(stderr, "[bam_pileup] unrecognized -R\n");
+                       break;
                default: fprintf(stderr, "Unrecognizd option '-%c'.\n", c); return 1;
                }
        }
+       if (d->c->errmod != BAM_ERRMOD_MAQ2) d->c->theta += 0.02;
+       if (d->c->theta > 1.0) d->c->theta = 1.0;
        if (fn_list) is_SAM = 1;
        if (optind == argc) {
                fprintf(stderr, "\n");
                fprintf(stderr, "Usage:  samtools pileup [options] <in.bam>|<in.sam>\n\n");
                fprintf(stderr, "Option: -s        simple (yet incomplete) pileup format\n");
                fprintf(stderr, "        -S        the input is in SAM\n");
+               fprintf(stderr, "        -B        disable BAQ computation\n");
+               fprintf(stderr, "        -A        use the original MAQ model for SNP calling (DEPRECATED)\n");
                fprintf(stderr, "        -2        output the 2nd best call and quality\n");
                fprintf(stderr, "        -i        only show lines/consensus with indels\n");
-               fprintf(stderr, "        -m INT    filtering reads with bits in INT [%d]\n", d->mask);
+               fprintf(stderr, "        -Q INT    min base quality (possibly capped by BAQ) [%d]\n", d->c->min_baseQ);
+               fprintf(stderr, "        -C INT    coefficient for adjusting mapQ of poor mappings [%d]\n", d->capQ_thres);
+               fprintf(stderr, "        -m INT    filtering reads with bits in INT [0x%x]\n", d->mask);
                fprintf(stderr, "        -M INT    cap mapping quality at INT [%d]\n", d->c->cap_mapQ);
+        fprintf(stderr, "        -d INT    limit maximum depth for indels [%d]\n", d->max_depth);
                fprintf(stderr, "        -t FILE   list of reference sequences (force -S)\n");
                fprintf(stderr, "        -l FILE   list of sites at which pileup is output\n");
                fprintf(stderr, "        -f FILE   reference sequence in the FASTA format\n\n");
-               fprintf(stderr, "        -c        output the maq consensus sequence\n");
+               fprintf(stderr, "        -c        compute the consensus sequence\n");
                fprintf(stderr, "        -v        print variants only (for -c)\n");
-               fprintf(stderr, "        -g        output in the GLFv3 format (suppressing -c/-i/-s)\n");
-               fprintf(stderr, "        -T FLOAT  theta in maq consensus calling model (for -c/-g) [%f]\n", d->c->theta);
-               fprintf(stderr, "        -N INT    number of haplotypes in the sample (for -c/-g) [%d]\n", d->c->n_hap);
-               fprintf(stderr, "        -r FLOAT  prior of a difference between two haplotypes (for -c/-g) [%f]\n", d->c->het_rate);
-               fprintf(stderr, "        -G FLOAT  prior of an indel between two haplotypes (for -c/-g) [%f]\n", d->ido->r_indel);
-               fprintf(stderr, "        -I INT    phred prob. of an indel in sequencing/prep. (for -c/-g) [%d]\n", d->ido->q_indel);
+               fprintf(stderr, "        -g        output in the GLFv3 format (DEPRECATED)\n");
+               fprintf(stderr, "        -T FLOAT  theta in maq consensus calling model (for -c) [%.4g]\n", d->c->theta);
+               fprintf(stderr, "        -N INT    number of haplotypes in the sample (for -c) [%d]\n", d->c->n_hap);
+               fprintf(stderr, "        -r FLOAT  prior of a difference between two haplotypes (for -c) [%.4g]\n", d->c->het_rate);
+               fprintf(stderr, "        -G FLOAT  prior of an indel between two haplotypes (for -c) [%.4g]\n", d->ido->r_indel);
+               fprintf(stderr, "        -I INT    phred prob. of an indel in sequencing/prep. (for -c) [%d]\n", d->ido->q_indel);
                fprintf(stderr, "\n");
                free(fn_list); free(fn_fa); free(d);
                return 1;
        }
+       if (d->format & (BAM_PLF_RANBASE|BAM_PLF_1STBASE|BAM_PLF_ALLBASE)) d->format |= BAM_PLF_CNS;
        if (fn_fa) d->fai = fai_load(fn_fa);
        if (d->format & (BAM_PLF_CNS|BAM_PLF_GLF)) bam_maqcns_prepare(d->c); // consensus calling
        if (d->format & BAM_PLF_GLF) { // for glf output
@@ -368,7 +461,43 @@ int bam_pileup(int argc, char *argv[])
                }
                d->h = fp->header;
                if (fn_pos) d->hash = load_pos(fn_pos, d->h);
-               sampileup(fp, d->mask, pileup_func, d);
+               { // run pileup
+                       extern int bam_prob_realn(bam1_t *b, const char *ref);
+                       extern int bam_cap_mapQ(bam1_t *b, char *ref, int thres);
+                       bam1_t *b;
+                       int ret, tid, pos, n_plp;
+                       bam_plp_t iter;
+                       const bam_pileup1_t *plp;
+                       b = bam_init1();
+                       iter = bam_plp_init(0, 0);
+                       bam_plp_set_mask(iter, d->mask);
+                       while ((ret = samread(fp, b)) >= 0) {
+                               int skip = 0;
+                               if ((int)b->core.tid < 0) break;
+                               // update d->ref if necessary
+                               if (d->fai && (int)b->core.tid != d->tid) {
+                                       free(d->ref);
+                                       d->ref = faidx_fetch_seq(d->fai, d->h->target_name[b->core.tid], 0, 0x7fffffff, &d->len);
+                                       d->tid = b->core.tid;
+                               }
+                               if (d->ref && (d->format&BAM_PLF_CNS) && !(d->format&BAM_PLF_NOBAQ)) bam_prob_realn(b, d->ref);
+                               if (d->ref && (d->format&BAM_PLF_CNS) && d->capQ_thres > 10) {
+                                       int q = bam_cap_mapQ(b, d->ref, d->capQ_thres);
+                                       if (q < 0) skip = 1;
+                                       else if (b->core.qual > q) b->core.qual = q;
+                               } else if (b->core.flag&BAM_FUNMAP) skip = 1;
+                               else if ((d->format&BAM_PLF_CNS) && (b->core.flag&1) && !(b->core.flag&2)) skip = 1;
+                               if (skip) continue;
+                               bam_plp_push(iter, b);
+                               while ((plp = bam_plp_next(iter, &tid, &pos, &n_plp)) != 0)
+                                       pileup_func(tid, pos, n_plp, plp, d);
+                       }
+                       bam_plp_push(iter, 0);
+                       while ((plp = bam_plp_next(iter, &tid, &pos, &n_plp)) != 0)
+                               pileup_func(tid, pos, n_plp, plp, d);
+                       bam_plp_destroy(iter);
+                       bam_destroy1(b);
+               }
                samclose(fp); // d->h will be destroyed here
        }
 
@@ -386,3 +515,299 @@ int bam_pileup(int argc, char *argv[])
        free(d->ido); free(d->ref); free(d);
        return 0;
 }
+
+/***********
+ * mpileup *
+ ***********/
+
+#include <assert.h>
+#include "bam2bcf.h"
+#include "sample.h"
+
+#define MPLP_GLF   0x10
+#define MPLP_NO_COMP 0x20
+#define MPLP_NO_ORPHAN 0x40
+#define MPLP_REALN   0x80
+
+typedef struct {
+       int max_mq, min_mq, flag, min_baseQ, capQ_thres;
+       char *reg, *fn_pos;
+       faidx_t *fai;
+       kh_64_t *hash;
+} mplp_conf_t;
+
+typedef struct {
+       bamFile fp;
+       bam_iter_t iter;
+       int min_mq, flag, ref_id, capQ_thres;
+       char *ref;
+} mplp_aux_t;
+
+typedef struct {
+       int n;
+       int *n_plp, *m_plp;
+       bam_pileup1_t **plp;
+} mplp_pileup_t;
+
+static int mplp_func(void *data, bam1_t *b)
+{
+       extern int bam_realn(bam1_t *b, const char *ref);
+       extern int bam_prob_realn(bam1_t *b, const char *ref);
+       extern int bam_cap_mapQ(bam1_t *b, char *ref, int thres);
+       mplp_aux_t *ma = (mplp_aux_t*)data;
+       int ret, skip = 0;
+       do {
+               int has_ref = (ma->ref && ma->ref_id == b->core.tid)? 1 : 0;
+               ret = ma->iter? bam_iter_read(ma->fp, ma->iter, b) : bam_read1(ma->fp, b);
+               if (ret < 0) break;
+               skip = 0;
+               if (has_ref && (ma->flag&MPLP_REALN)) bam_prob_realn(b, ma->ref);
+               if (has_ref && ma->capQ_thres > 10) {
+                       int q = bam_cap_mapQ(b, ma->ref, ma->capQ_thres);
+                       if (q < 0) skip = 1;
+                       else if (b->core.qual > q) b->core.qual = q;
+               } else if (b->core.flag&BAM_FUNMAP) skip = 1;
+               else if (b->core.qual < ma->min_mq) skip = 1; 
+               else if ((ma->flag&MPLP_NO_ORPHAN) && (b->core.flag&1) && !(b->core.flag&2)) skip = 1;
+       } while (skip);
+       return ret;
+}
+
+static void group_smpl(mplp_pileup_t *m, bam_sample_t *sm, kstring_t *buf,
+                                          int n, char *const*fn, int *n_plp, const bam_pileup1_t **plp)
+{
+       int i, j;
+       memset(m->n_plp, 0, m->n * sizeof(int));
+       for (i = 0; i < n; ++i) {
+               for (j = 0; j < n_plp[i]; ++j) {
+                       const bam_pileup1_t *p = plp[i] + j;
+                       uint8_t *q;
+                       int id = -1;
+                       q = bam_aux_get(p->b, "RG");
+                       if (q) id = bam_smpl_rg2smid(sm, fn[i], (char*)q+1, buf);
+                       if (id < 0) id = bam_smpl_rg2smid(sm, fn[i], 0, buf);
+                       assert(id >= 0 && id < m->n);
+                       if (m->n_plp[id] == m->m_plp[id]) {
+                               m->m_plp[id] = m->m_plp[id]? m->m_plp[id]<<1 : 8;
+                               m->plp[id] = realloc(m->plp[id], sizeof(bam_pileup1_t) * m->m_plp[id]);
+                       }
+                       m->plp[id][m->n_plp[id]++] = *p;
+               }
+       }
+}
+
+static int mpileup(mplp_conf_t *conf, int n, char **fn)
+{
+       mplp_aux_t **data;
+       int i, tid, pos, *n_plp, beg0 = 0, end0 = 1u<<29, ref_len, ref_tid;
+       const bam_pileup1_t **plp;
+       bam_mplp_t iter;
+       bam_header_t *h = 0;
+       char *ref;
+       khash_t(64) *hash = 0;
+
+       bcf_callaux_t *bca = 0;
+       bcf_callret1_t *bcr = 0;
+       bcf_call_t bc;
+       bcf_t *bp = 0;
+       bcf_hdr_t *bh = 0;
+
+       bam_sample_t *sm = 0;
+       kstring_t buf;
+       mplp_pileup_t gplp;
+
+       memset(&gplp, 0, sizeof(mplp_pileup_t));
+       memset(&buf, 0, sizeof(kstring_t));
+       memset(&bc, 0, sizeof(bcf_call_t));
+       data = calloc(n, sizeof(void*));
+       plp = calloc(n, sizeof(void*));
+       n_plp = calloc(n, sizeof(int*));
+       sm = bam_smpl_init();
+
+       // read the header and initialize data
+       for (i = 0; i < n; ++i) {
+               bam_header_t *h_tmp;
+               data[i] = calloc(1, sizeof(mplp_aux_t));
+               data[i]->min_mq = conf->min_mq;
+               data[i]->flag = conf->flag;
+               data[i]->capQ_thres = conf->capQ_thres;
+               data[i]->fp = strcmp(fn[i], "-") == 0? bam_dopen(fileno(stdin), "r") : bam_open(fn[i], "r");
+               h_tmp = bam_header_read(data[i]->fp);
+               bam_smpl_add(sm, fn[i], h_tmp->text);
+               if (conf->reg) {
+                       int beg, end;
+                       bam_index_t *idx;
+                       idx = bam_index_load(fn[i]);
+                       if (idx == 0) {
+                               fprintf(stderr, "[%s] fail to load index for %d-th input.\n", __func__, i+1);
+                               exit(1);
+                       }
+                       if (bam_parse_region(h_tmp, conf->reg, &tid, &beg, &end) < 0) {
+                               fprintf(stderr, "[%s] malformatted region or wrong seqname for %d-th input.\n", __func__, i+1);
+                               exit(1);
+                       }
+                       if (i == 0) beg0 = beg, end0 = end;
+                       data[i]->iter = bam_iter_query(idx, tid, beg, end);
+                       bam_index_destroy(idx);
+               }
+               if (i == 0) h = h_tmp;
+               else {
+                       // FIXME: to check consistency
+                       bam_header_destroy(h_tmp);
+               }
+       }
+       gplp.n = sm->n;
+       gplp.n_plp = calloc(sm->n, sizeof(int));
+       gplp.m_plp = calloc(sm->n, sizeof(int));
+       gplp.plp = calloc(sm->n, sizeof(void*));
+
+       fprintf(stderr, "[%s] %d samples in %d input files\n", __func__, sm->n, n);
+       if (conf->fn_pos) hash = load_pos(conf->fn_pos, h);
+       // write the VCF header
+       if (conf->flag & MPLP_GLF) {
+               kstring_t s;
+               bh = calloc(1, sizeof(bcf_hdr_t));
+               s.l = s.m = 0; s.s = 0;
+               bp = bcf_open("-", (conf->flag&MPLP_NO_COMP)? "wu" : "w");
+               for (i = 0; i < h->n_targets; ++i) {
+                       kputs(h->target_name[i], &s);
+                       kputc('\0', &s);
+               }
+               bh->l_nm = s.l;
+               bh->name = malloc(s.l);
+               memcpy(bh->name, s.s, s.l);
+               s.l = 0;
+               for (i = 0; i < sm->n; ++i) {
+                       kputs(sm->smpl[i], &s); kputc('\0', &s);
+               }
+               bh->l_smpl = s.l;
+               bh->sname = malloc(s.l);
+               memcpy(bh->sname, s.s, s.l);
+               bh->l_txt = 0;
+               free(s.s);
+               bcf_hdr_sync(bh);
+               bcf_hdr_write(bp, bh);
+               bca = bcf_call_init(-1., conf->min_baseQ);
+               bcr = calloc(sm->n, sizeof(bcf_callret1_t));
+       }
+       ref_tid = -1; ref = 0;
+       iter = bam_mplp_init(n, mplp_func, (void**)data);
+       while (bam_mplp_auto(iter, &tid, &pos, n_plp, plp) > 0) {
+               if (conf->reg && (pos < beg0 || pos >= end0)) continue; // out of the region requested
+               if (hash) {
+                       khint_t k;
+                       k = kh_get(64, hash, (uint64_t)tid<<32 | pos);
+                       if (k == kh_end(hash)) continue;
+               }
+               if (tid != ref_tid) {
+                       free(ref); ref = 0;
+                       if (conf->fai) ref = fai_fetch(conf->fai, h->target_name[tid], &ref_len);
+                       for (i = 0; i < n; ++i) data[i]->ref = ref, data[i]->ref_id = tid;
+                       ref_tid = tid;
+               }
+               if (conf->flag & MPLP_GLF) {
+                       int _ref0, ref16;
+                       bcf1_t *b = calloc(1, sizeof(bcf1_t));
+                       group_smpl(&gplp, sm, &buf, n, fn, n_plp, plp);
+                       _ref0 = (ref && pos < ref_len)? ref[pos] : 'N';
+                       ref16 = bam_nt16_table[_ref0];
+                       for (i = 0; i < gplp.n; ++i)
+                               bcf_call_glfgen(gplp.n_plp[i], gplp.plp[i], ref16, bca, bcr + i);
+                       bcf_call_combine(gplp.n, bcr, ref16, &bc);
+                       bcf_call2bcf(tid, pos, &bc, b);
+                       bcf_write(bp, bh, b);
+                       bcf_destroy(b);
+               } else {
+                       printf("%s\t%d\t%c", h->target_name[tid], pos + 1, (ref && pos < ref_len)? ref[pos] : 'N');
+                       for (i = 0; i < n; ++i) {
+                               int j;
+                               printf("\t%d\t", n_plp[i]);
+                               if (n_plp[i] == 0) printf("*\t*");
+                               else {
+                                       for (j = 0; j < n_plp[i]; ++j)
+                                               pileup_seq(plp[i] + j, pos, ref_len, ref);
+                                       putchar('\t');
+                                       for (j = 0; j < n_plp[i]; ++j) {
+                                               const bam_pileup1_t *p = plp[i] + j;
+                                               int c = bam1_qual(p->b)[p->qpos] + 33;
+                                               if (c > 126) c = 126;
+                                               putchar(c);
+                                       }
+                               }
+                       }
+                       putchar('\n');
+               }
+       }
+
+       bcf_close(bp);
+       bam_smpl_destroy(sm); free(buf.s);
+       for (i = 0; i < gplp.n; ++i) free(gplp.plp[i]);
+       free(gplp.plp); free(gplp.n_plp); free(gplp.m_plp);
+       if (hash) { // free the hash table
+               khint_t k;
+               for (k = kh_begin(hash); k < kh_end(hash); ++k)
+                       if (kh_exist(hash, k)) free(kh_val(hash, k));
+               kh_destroy(64, hash);
+       }
+       bcf_hdr_destroy(bh); bcf_call_destroy(bca); free(bc.PL); free(bcr);
+       bam_mplp_destroy(iter);
+       bam_header_destroy(h);
+       for (i = 0; i < n; ++i) {
+               bam_close(data[i]->fp);
+               if (data[i]->iter) bam_iter_destroy(data[i]->iter);
+               free(data[i]);
+       }
+       free(data); free(plp); free(ref); free(n_plp);
+       return 0;
+}
+
+int bam_mpileup(int argc, char *argv[])
+{
+       int c;
+       mplp_conf_t mplp;
+       memset(&mplp, 0, sizeof(mplp_conf_t));
+       mplp.max_mq = 60;
+       mplp.min_baseQ = 13;
+       mplp.capQ_thres = 0;
+       mplp.flag = MPLP_NO_ORPHAN | MPLP_REALN;
+       while ((c = getopt(argc, argv, "gf:r:l:M:q:Q:uaORC:B")) >= 0) {
+               switch (c) {
+               case 'f':
+                       mplp.fai = fai_load(optarg);
+                       if (mplp.fai == 0) return 1;
+                       break;
+               case 'r': mplp.reg = strdup(optarg); break;
+               case 'l': mplp.fn_pos = strdup(optarg); break;
+               case 'g': mplp.flag |= MPLP_GLF; break;
+               case 'u': mplp.flag |= MPLP_NO_COMP | MPLP_GLF; break;
+               case 'a': mplp.flag |= MPLP_NO_ORPHAN | MPLP_REALN; break;
+               case 'B': mplp.flag &= ~MPLP_REALN & ~MPLP_NO_ORPHAN; break;
+               case 'O': mplp.flag |= MPLP_NO_ORPHAN; break;
+               case 'R': mplp.flag |= MPLP_REALN; break;
+               case 'C': mplp.capQ_thres = atoi(optarg); break;
+               case 'M': mplp.max_mq = atoi(optarg); break;
+               case 'q': mplp.min_mq = atoi(optarg); break;
+               case 'Q': mplp.min_baseQ = atoi(optarg); break;
+               }
+       }
+       if (argc == 1) {
+               fprintf(stderr, "\n");
+               fprintf(stderr, "Usage:   samtools mpileup [options] in1.bam [in2.bam [...]]\n\n");
+               fprintf(stderr, "Options: -f FILE     reference sequence file [null]\n");
+               fprintf(stderr, "         -r STR      region in which pileup is generated [null]\n");
+               fprintf(stderr, "         -l FILE     list of positions (format: chr pos) [null]\n");
+               fprintf(stderr, "         -M INT      cap mapping quality at INT [%d]\n", mplp.max_mq);
+               fprintf(stderr, "         -Q INT      min base quality [%d]\n", mplp.min_baseQ);
+               fprintf(stderr, "         -q INT      filter out alignment with MQ smaller than INT [%d]\n", mplp.min_mq);
+               fprintf(stderr, "         -g          generate BCF output\n");
+               fprintf(stderr, "         -u          do not compress BCF output\n");
+               fprintf(stderr, "         -B          disable BAQ computation\n");
+               fprintf(stderr, "\n");
+               fprintf(stderr, "Notes: Assuming diploid individuals.\n\n");
+               return 1;
+       }
+       mpileup(&mplp, argc - optind, argv + optind);
+       free(mplp.reg);
+       if (mplp.fai) fai_destroy(mplp.fai);
+       return 0;
+}