diff --git a/floatimg.h b/floatimg.h
index 1f61a10..13a9fdb 100644
--- a/floatimg.h
+++ b/floatimg.h
@@ -88,5 +88,8 @@ int   fimg_save_as_png(FloatImg *src, char *outname, int flags);
 int   fimg_draw_something(FloatImg *fimg);
 
 int parse_WxH(char *str, int *pw, int *ph);
+int parse_double(char *str, double *dptr);
+
+
 
 
diff --git a/funcs/t.c b/funcs/t.c
index 0f90ab9..4f8a937 100644
--- a/funcs/t.c
+++ b/funcs/t.c
@@ -8,20 +8,28 @@
 
 #include "../floatimg.h"
 
-int fimg_pnm_infos(char *);
-
 /* --------------------------------------------------------------------- */
 int main(int argc, char *argv[])
 {
 int		foo;
-char		*infile = "foo.pnm";
+double		dval;
+char		*str;
 
-pnm_init(&argc, argv);
+str = "12.34";	dval = 0.0;
+foo = parse_double(str, &dval);
+printf("%-10s -> %3d   %g\n", str, foo, dval);
 
-if (2 == argc)	infile = argv[1];
+str = "12e4";	dval = 0.0;
+foo = parse_double(str, &dval);
+printf("%-10s -> %3d   %g\n", str, foo, dval);
 
-foo = fimg_pnm_infos(infile);
-fprintf(stderr, "got %d\n", foo);
+str = "5s";	dval = 0.0;
+foo = parse_double(str, &dval);
+printf("%-10s -> %3d   %g\n", str, foo, dval);
+
+str = "PORN";	dval = 0.0;
+foo = parse_double(str, &dval);
+printf("%-10s -> %3d   %g\n", str, foo, dval);
 
 return 0;
 }
diff --git a/funcs/utils.c b/funcs/utils.c
index f88bdf7..495fac6 100644
--- a/funcs/utils.c
+++ b/funcs/utils.c
@@ -29,3 +29,16 @@ if (2 != foo) {
 return 2;
 }
 /* --------------------------------------------------------------------- */
+int parse_double(char *str, double *dptr)
+{
+double		value;
+int		foo;
+
+foo = sscanf(str, "%lf", &value);
+if (1 == foo) {
+	*dptr = value;
+	return 1;
+	}
+return -1;
+}
+/* --------------------------------------------------------------------- */
diff --git a/v4l2/grabvidseq.c b/v4l2/grabvidseq.c
index b311544..6735316 100644
--- a/v4l2/grabvidseq.c
+++ b/v4l2/grabvidseq.c
@@ -122,7 +122,14 @@ while ((opt = getopt(argc, argv, "d:ghn:o:O:p:s:uv")) != -1) {
 		case 'n':	nbre_capt = atoi(optarg);	break;
 		case 'O':	dest_dir = optarg;		break;
 		case 'o':	outfile = optarg;		break;
-		case 'p':	period = 1e6*atof(optarg);	break;
+		case 'p':	foo = parse_double(optarg, &period);
+				if (foo<0) {
+					fprintf(stderr,
+						"error parsing -p arg '%s'\n",
+						optarg);
+					exit(1);
+					}
+				break;
 		case 's':	parse_WxH(optarg, &width, &height);
 				break;
 		case 'u':	upscaling = 1;			break;