diff --git a/lib/fimg-core.c b/lib/fimg-core.c
index 669764a..421c730 100644
--- a/lib/fimg-core.c
+++ b/lib/fimg-core.c
@@ -161,7 +161,7 @@ if ( ! fimg_type_is_valid(fimg->type) ) {
 	return -2;
 	}
 
-size = fimg->width * fimg->height * fimg->type * sizeof(float);		
+size = fimg->width * fimg->height * fimg->type * sizeof(float);
 memset(fimg->R, 0, size);
 
 return 0;
diff --git a/v4l2/Makefile b/v4l2/Makefile
index 6ce9dfc..60395bf 100644
--- a/v4l2/Makefile
+++ b/v4l2/Makefile
@@ -1,6 +1,6 @@
 
 
-COPT = -Wall -fpic -g -DDEBUG_LEVEL=1
+COPT = -Wall -fpic -g -pg -DDEBUG_LEVEL=1
 DEPS = ../floatimg.h  ../libfloatimg.a Makefile
 
 all:	grabvidseq t
@@ -18,7 +18,7 @@ v4l2_pr_structs.o:	v4l2_pr_structs.c v4l2_pr_structs.h Makefile
 	gcc ${COPT} -c $<
 
 grabvidseq: grabvidseq.c Makefile rgb2fimg.o
-	gcc -Wall -g $<  rgb2fimg.o ../libfloatimg.a -lv4l2 -o $@
+	gcc ${COPT}  $<  rgb2fimg.o ../libfloatimg.a -lm -lv4l2 -o $@
 
 video-infos: video-infos.c Makefile funcs.o v4l2_pr_structs.o
 	gcc -Wall -g $<  funcs.o v4l2_pr_structs.o -o $@
diff --git a/v4l2/grabvidseq.c b/v4l2/grabvidseq.c
index 5cb3092..1c4516f 100644
--- a/v4l2/grabvidseq.c
+++ b/v4l2/grabvidseq.c
@@ -32,8 +32,9 @@
 /* --------------------------------------------------------------------- */
 /*	compilation control */
 
+#define SAVE_AS_CUMUL	1
 #define SAVE_AS_PNM	0
-#define SAVE_AS_FIMG	1
+#define SAVE_AS_FIMG	0
 
 /* --------------------------------------------------------------------- */
 
@@ -74,6 +75,7 @@ puts("options :");
 puts("\t-d /dev/?\tselect video device");
 puts("\t-n NNN\t\thow many frames ?");
 puts("\t-O ./\t\tset Output dir");
+puts("\t-o bla\t\tset oputput filename");
 puts("\t-p NNN\t\tperiod in seconds");
 puts("\t-v\t\tincrease verbosity");
 exit(0);
@@ -101,13 +103,19 @@ int		nbre_capt = 1;		/* nombre de captures */
 int		opt;
 double		t_debut, t_final;
 char		*dest_dir = ".";	/* no trailing slash */
+char		*outfile = "out.pnm";
 
-while ((opt = getopt(argc, argv, "d:hn:O:p:v")) != -1) {
+#if SAVE_AS_CUMUL
+FloatImg	grab, cumul;
+#endif
+
+while ((opt = getopt(argc, argv, "d:hn:o:O:p:v")) != -1) {
 	switch(opt) {
 		case 'd':	dev_name = optarg;		break;
 		case 'h':	help(0);			break;
 		case 'n':	nbre_capt = atoi(optarg);	break;
 		case 'O':	dest_dir = optarg;		break;
+		case 'o':	outfile = optarg;		break;
 		case 'p':	period = atoi(optarg);		break;
 		case 'v':	verbosity++;			break;
 		}
@@ -176,6 +184,16 @@ for (i = 0; i < n_buffers; ++i) {
 	xioctl(fd, VIDIOC_QBUF, &buf);
 	}
 
+#if SAVE_AS_CUMUL
+foo = fimg_create(&grab,
+		fmt.fmt.pix.width, fmt.fmt.pix.height,
+		FIMG_TYPE_RGB);
+foo = fimg_create(&cumul,
+		fmt.fmt.pix.width, fmt.fmt.pix.height,
+		FIMG_TYPE_RGB);
+fimg_clear(&cumul);
+#endif
+
 type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
 xioctl(fd, VIDIOC_STREAMON, &type);
 
@@ -205,7 +223,6 @@ for (i = 0; i < nbre_capt; i++) {
 	xioctl(fd, VIDIOC_DQBUF, &buf);
 
 #if SAVE_AS_PNM
-
 	/* at this time,we'v got a picture in-memory,
 	   so we can blast in on storage */
 	sprintf(out_name, "%s/%05d.ppm", dest_dir, i);
@@ -219,7 +236,12 @@ for (i = 0; i < nbre_capt; i++) {
 			    fmt.fmt.pix.width, fmt.fmt.pix.height);
 	fwrite(buffers[buf.index].start, buf.bytesused, 1, fout);
 	fclose(fout);
+#endif
 
+#if SAVE_AS_CUMUL
+	x_rgb2fimg(buffers[buf.index].start,
+		fmt.fmt.pix.width, fmt.fmt.pix.height, &grab);
+	fimg_add(&grab, &cumul, &cumul);
 #endif
 
 #if SAVE_AS_FIMG
@@ -239,6 +261,15 @@ for (i = 0; i < nbre_capt; i++) {
 
 t_final = fimg_timer_get(0);
 fprintf(stderr, "pid %d : elapsed time %g s\n", getpid(), t_final);
+fprintf(stderr, "\t%.2f fps\n", (double)nbre_capt / t_final);
+
+#if SAVE_AS_CUMUL
+	// save cumul to file
+foo = fimg_save_as_pnm(&cumul, outfile, 0);
+	// free buffers
+fimg_destroy(&grab);
+fimg_destroy(&cumul);
+#endif
 
 type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
 xioctl(fd, VIDIOC_STREAMOFF, &type);
diff --git a/v4l2/rgb2fimg.c b/v4l2/rgb2fimg.c
index 57154d4..686a4fc 100644
--- a/v4l2/rgb2fimg.c
+++ b/v4l2/rgb2fimg.c
@@ -12,7 +12,7 @@ int			iter, size;
 float			*rp, *gp, *bp;
 
 size = w * h;
-rp = d->R, gp = d->G, bp = d->G;
+rp = d->R, gp = d->G, bp = d->B;
 
 for (iter=0; iter<size; iter++) {
 	*rp++ = (float)*src++;